transupp.c

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/*
 * transupp.c
 *
 * Copyright (C) 1997-2019, Thomas G. Lane, Guido Vollbeding.
 * This file is part of the Independent JPEG Group's software.
 * For conditions of distribution and use, see the accompanying README file.
 *
 * This file contains image transformation routines and other utility code
 * used by the jpegtran sample application.  These are NOT part of the core
 * JPEG library.  But we keep these routines separate from jpegtran.c to
 * ease the task of maintaining jpegtran-like programs that have other user
 * interfaces.
 */
 
/* Although this file really shouldn't have access to the library internals,
 * it's helpful to let it call jround_up() and jcopy_block_row().
 * Also, the (switchable) virtual memory adaptation code for
 * the drop feature has dependencies on library internals.
 */
#define JPEG_INTERNALS
 
#include "jinclude.h"
#include "jpeglib.h"
#include "transupp.h"       /* My own external interface */
#include <ctype.h>      /* to declare isdigit() */
 
 
#if TRANSFORMS_SUPPORTED
 
/*
 * Lossless image transformation routines.  These routines work on DCT
 * coefficient arrays and thus do not require any lossy decompression
 * or recompression of the image.
 * Thanks to Guido Vollbeding for the initial design and code of this feature,
 * and to Ben Jackson for introducing the cropping feature.
 *
 * Horizontal flipping is done in-place, using a single top-to-bottom
 * pass through the virtual source array.  It will thus be much the
 * fastest option for images larger than main memory.
 *
 * The other routines require a set of destination virtual arrays, so they
 * need twice as much memory as jpegtran normally does.  The destination
 * arrays are always written in normal scan order (top to bottom) because
 * the virtual array manager expects this.  The source arrays will be scanned
 * in the corresponding order, which means multiple passes through the source
 * arrays for most of the transforms.  That could result in much thrashing
 * if the image is larger than main memory.
 *
 * If cropping or trimming is involved, the destination arrays may be smaller
 * than the source arrays.  Note it is not possible to do horizontal flip
 * in-place when a nonzero Y crop offset is specified, since we'd have to move
 * data from one block row to another but the virtual array manager doesn't
 * guarantee we can touch more than one row at a time.  So in that case,
 * we have to use a separate destination array.
 *
 * Some notes about the operating environment of the individual transform
 * routines:
 * 1. Both the source and destination virtual arrays are allocated from the
 *    source JPEG object, and therefore should be manipulated by calling the
 *    source's memory manager.
 * 2. The destination's component count should be used.  It may be smaller
 *    than the source's when forcing to grayscale.
 * 3. Likewise the destination's sampling factors should be used.  When
 *    forcing to grayscale the destination's sampling factors will be all 1,
 *    and we may as well take that as the effective iMCU size.
 * 4. When "trim" is in effect, the destination's dimensions will be the
 *    trimmed values but the source's will be untrimmed.
 * 5. When "crop" is in effect, the destination's dimensions will be the
 *    cropped values but the source's will be uncropped.  Each transform
 *    routine is responsible for picking up source data starting at the
 *    correct X and Y offset for the crop region.  (The X and Y offsets
 *    passed to the transform routines are measured in iMCU blocks of the
 *    destination.)
 * 6. All the routines assume that the source and destination buffers are
 *    padded out to a full iMCU boundary.  This is true, although for the
 *    source buffer it is an undocumented property of jdcoefct.c.
 */
 
 
/* Drop code may be used with or without virtual memory adaptation code.
 * This code has some dependencies on internal library behavior, so you
 * may choose to disable it.  For example, it doesn't make a difference
 * if you only use jmemnobs anyway.
 */
#ifndef DROP_REQUEST_FROM_SRC
#define DROP_REQUEST_FROM_SRC 1     /* 0 disables adaptation */
#endif
 
 
#if DROP_REQUEST_FROM_SRC
/* Force jpeg_read_coefficients to request
 * the virtual coefficient arrays from
 * the source decompression object.
 */
METHODDEF(jvirt_barray_ptr)
drop_request_virt_barray (j_common_ptr cinfo, int pool_id, boolean pre_zero,
              JDIMENSION blocksperrow, JDIMENSION numrows,
              JDIMENSION maxaccess)
{
  j_common_ptr srcinfo = (j_common_ptr) cinfo->client_data;
 
  return (*srcinfo->mem->request_virt_barray)
      (srcinfo, pool_id, pre_zero,
       blocksperrow, numrows, maxaccess);
}
 
 
/* Force jpeg_read_coefficients to return
 * after requesting and before accessing
 * the virtual coefficient arrays.
 */
METHODDEF(int)
drop_consume_input (j_decompress_ptr cinfo)
{
  return JPEG_SUSPENDED;
}
 
 
METHODDEF(void)
drop_start_input_pass (j_decompress_ptr cinfo)
{
  cinfo->inputctl->consume_input = drop_consume_input;
}
 
 
LOCAL(void)
drop_request_from_src (j_decompress_ptr dropinfo, j_decompress_ptr srcinfo)
{
  void *save_client_data;
  JMETHOD(jvirt_barray_ptr, save_request_virt_barray,
      (j_common_ptr cinfo, int pool_id, boolean pre_zero,
       JDIMENSION blocksperrow, JDIMENSION numrows, JDIMENSION maxaccess));
  JMETHOD(void, save_start_input_pass, (j_decompress_ptr cinfo));
 
  /* Set custom method pointers, save original pointers */
  save_client_data = dropinfo->client_data;
  dropinfo->client_data = (void *) srcinfo;
  save_request_virt_barray = dropinfo->mem->request_virt_barray;
  dropinfo->mem->request_virt_barray = drop_request_virt_barray;
  save_start_input_pass = dropinfo->inputctl->start_input_pass;
  dropinfo->inputctl->start_input_pass = drop_start_input_pass;
 
  /* Execute only initialization part.
   * Requested coefficient arrays will be realized later by the srcinfo object.
   * Next call to the same function will then do the actual data reading.
   * NB: since we request the coefficient arrays from another object,
   * the inherent realization call is effectively a no-op.
   */
  (void) jpeg_read_coefficients(dropinfo);
 
  /* Reset method pointers */
  dropinfo->client_data = save_client_data;
  dropinfo->mem->request_virt_barray = save_request_virt_barray;
  dropinfo->inputctl->start_input_pass = save_start_input_pass;
  /* Do input initialization for first scan now,
   * which also resets the consume_input method.
   */
  (*save_start_input_pass)(dropinfo);
}
#endif /* DROP_REQUEST_FROM_SRC */
 
 
LOCAL(void)
dequant_comp (j_decompress_ptr cinfo, jpeg_component_info *compptr,
          jvirt_barray_ptr coef_array, JQUANT_TBL *qtblptr1)
{
  JDIMENSION blk_x, blk_y;
  int offset_y, k;
  JQUANT_TBL *qtblptr;
  JBLOCKARRAY buffer;
  JBLOCKROW block;
  JCOEFPTR ptr;
 
  qtblptr = compptr->quant_table;
  for (blk_y = 0; blk_y < compptr->height_in_blocks;
       blk_y += compptr->v_samp_factor) {
    buffer = (*cinfo->mem->access_virt_barray)
      ((j_common_ptr) cinfo, coef_array, blk_y,
       (JDIMENSION) compptr->v_samp_factor, TRUE);
    for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
      block = buffer[offset_y];
      for (blk_x = 0; blk_x < compptr->width_in_blocks; blk_x++) {
    ptr = block[blk_x];
    for (k = 0; k < DCTSIZE2; k++)
      if (qtblptr->quantval[k] != qtblptr1->quantval[k])
        ptr[k] *= qtblptr->quantval[k] / qtblptr1->quantval[k];
      }
    }
  }
}
 
 
LOCAL(void)
requant_comp (j_decompress_ptr cinfo, jpeg_component_info *compptr,
          jvirt_barray_ptr coef_array, JQUANT_TBL *qtblptr1)
{
  JDIMENSION blk_x, blk_y;
  int offset_y, k;
  JQUANT_TBL *qtblptr;
  JBLOCKARRAY buffer;
  JBLOCKROW block;
  JCOEFPTR ptr;
  JCOEF temp, qval;
 
  qtblptr = compptr->quant_table;
  for (blk_y = 0; blk_y < compptr->height_in_blocks;
       blk_y += compptr->v_samp_factor) {
    buffer = (*cinfo->mem->access_virt_barray)
      ((j_common_ptr) cinfo, coef_array, blk_y,
       (JDIMENSION) compptr->v_samp_factor, TRUE);
    for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
      block = buffer[offset_y];
      for (blk_x = 0; blk_x < compptr->width_in_blocks; blk_x++) {
    ptr = block[blk_x];
    for (k = 0; k < DCTSIZE2; k++) {
      temp = qtblptr->quantval[k];
      qval = qtblptr1->quantval[k];
      if (temp != qval) {
        temp *= ptr[k];
        /* The following quantization code is a copy from jcdctmgr.c */
#ifdef FAST_DIVIDE
#define DIVIDE_BY(a,b)  a /= b
#else
#define DIVIDE_BY(a,b)  if (a >= b) a /= b; else a = 0
#endif
        if (temp < 0) {
          temp = -temp;
          temp += qval>>1;  /* for rounding */
          DIVIDE_BY(temp, qval);
          temp = -temp;
        } else {
          temp += qval>>1;  /* for rounding */
          DIVIDE_BY(temp, qval);
        }
        ptr[k] = temp;
      }
    }
      }
    }
  }
}
 
 
/* Calculate largest common denominator with Euclid's algorithm.
 */
LOCAL(JCOEF)
largest_common_denominator(JCOEF a, JCOEF b)
{
  JCOEF c;
 
  do {
    c = a % b;
    a = b;
    b = c;
  } while (c);
 
  return a;
}
 
 
LOCAL(void)
adjust_quant(j_decompress_ptr srcinfo, jvirt_barray_ptr *src_coef_arrays,
         j_decompress_ptr dropinfo, jvirt_barray_ptr *drop_coef_arrays,
         boolean trim, j_compress_ptr dstinfo)
{
  jpeg_component_info *compptr1, *compptr2;
  JQUANT_TBL *qtblptr1, *qtblptr2, *qtblptr3;
  int ci, k;
 
  for (ci = 0; ci < dstinfo->num_components &&
           ci < dropinfo->num_components; ci++) {
    compptr1 = srcinfo->comp_info + ci;
    compptr2 = dropinfo->comp_info + ci;
    qtblptr1 = compptr1->quant_table;
    qtblptr2 = compptr2->quant_table;
    for (k = 0; k < DCTSIZE2; k++) {
      if (qtblptr1->quantval[k] != qtblptr2->quantval[k]) {
    if (trim)
      requant_comp(dropinfo, compptr2, drop_coef_arrays[ci], qtblptr1);
    else {
      qtblptr3 = dstinfo->quant_tbl_ptrs[compptr1->quant_tbl_no];
      for (k = 0; k < DCTSIZE2; k++)
        if (qtblptr1->quantval[k] != qtblptr2->quantval[k])
          qtblptr3->quantval[k] = largest_common_denominator
        (qtblptr1->quantval[k], qtblptr2->quantval[k]);
      dequant_comp(srcinfo, compptr1, src_coef_arrays[ci], qtblptr3);
      dequant_comp(dropinfo, compptr2, drop_coef_arrays[ci], qtblptr3);
    }
    break;
      }
    }
  }
}
 
 
LOCAL(void)
do_drop (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
     JDIMENSION x_crop_offset, JDIMENSION y_crop_offset,
     jvirt_barray_ptr *src_coef_arrays,
     j_decompress_ptr dropinfo, jvirt_barray_ptr *drop_coef_arrays,
     JDIMENSION drop_width, JDIMENSION drop_height)
/* Drop.  If the dropinfo component number is smaller than the destination's,
 * we fill in the remaining components with zero.  This provides the feature
 * of dropping grayscale into (arbitrarily sampled) color images.
 */
{
  JDIMENSION comp_width, comp_height;
  JDIMENSION blk_y, x_drop_blocks, y_drop_blocks;
  int ci, offset_y;
  JBLOCKARRAY src_buffer, dst_buffer;
  jpeg_component_info *compptr;
 
  for (ci = 0; ci < dstinfo->num_components; ci++) {
    compptr = dstinfo->comp_info + ci;
    comp_width = drop_width * compptr->h_samp_factor;
    comp_height = drop_height * compptr->v_samp_factor;
    x_drop_blocks = x_crop_offset * compptr->h_samp_factor;
    y_drop_blocks = y_crop_offset * compptr->v_samp_factor;
    for (blk_y = 0; blk_y < comp_height; blk_y += compptr->v_samp_factor) {
      dst_buffer = (*srcinfo->mem->access_virt_barray)
    ((j_common_ptr) srcinfo, src_coef_arrays[ci], blk_y + y_drop_blocks,
     (JDIMENSION) compptr->v_samp_factor, TRUE);
      if (ci < dropinfo->num_components) {
#if DROP_REQUEST_FROM_SRC
    src_buffer = (*srcinfo->mem->access_virt_barray)
      ((j_common_ptr) srcinfo, drop_coef_arrays[ci], blk_y,
#else
    src_buffer = (*dropinfo->mem->access_virt_barray)
      ((j_common_ptr) dropinfo, drop_coef_arrays[ci], blk_y,
#endif
       (JDIMENSION) compptr->v_samp_factor, FALSE);
    for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
      jcopy_block_row(src_buffer[offset_y],
              dst_buffer[offset_y] + x_drop_blocks,
              comp_width);
    }
      } else {
    for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
      FMEMZERO(dst_buffer[offset_y] + x_drop_blocks,
           comp_width * SIZEOF(JBLOCK));
    }   
      }
    }
  }
}
 
 
LOCAL(void)
do_crop (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
     JDIMENSION x_crop_offset, JDIMENSION y_crop_offset,
     jvirt_barray_ptr *src_coef_arrays,
     jvirt_barray_ptr *dst_coef_arrays)
/* Crop.  This is only used when no rotate/flip is requested with the crop. */
{
  JDIMENSION dst_blk_y, x_crop_blocks, y_crop_blocks;
  int ci, offset_y;
  JBLOCKARRAY src_buffer, dst_buffer;
  jpeg_component_info *compptr;
 
  /* We simply have to copy the right amount of data (the destination's
   * image size) starting at the given X and Y offsets in the source.
   */
  for (ci = 0; ci < dstinfo->num_components; ci++) {
    compptr = dstinfo->comp_info + ci;
    x_crop_blocks = x_crop_offset * compptr->h_samp_factor;
    y_crop_blocks = y_crop_offset * compptr->v_samp_factor;
    for (dst_blk_y = 0; dst_blk_y < compptr->height_in_blocks;
     dst_blk_y += compptr->v_samp_factor) {
      dst_buffer = (*srcinfo->mem->access_virt_barray)
    ((j_common_ptr) srcinfo, dst_coef_arrays[ci], dst_blk_y,
     (JDIMENSION) compptr->v_samp_factor, TRUE);
      src_buffer = (*srcinfo->mem->access_virt_barray)
    ((j_common_ptr) srcinfo, src_coef_arrays[ci],
     dst_blk_y + y_crop_blocks,
     (JDIMENSION) compptr->v_samp_factor, FALSE);
      for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
    jcopy_block_row(src_buffer[offset_y] + x_crop_blocks,
            dst_buffer[offset_y],
            compptr->width_in_blocks);
      }
    }
  }
}
 
 
LOCAL(void)
do_crop_ext_zero (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
          JDIMENSION x_crop_offset, JDIMENSION y_crop_offset,
          jvirt_barray_ptr *src_coef_arrays,
          jvirt_barray_ptr *dst_coef_arrays)
/* Crop.  This is only used when no rotate/flip is requested with the crop.
 * Extension: If the destination size is larger than the source, we fill in
 * the extra area with zero (neutral gray).  Note we also have to zero partial
 * iMCUs at the right and bottom edge of the source image area in this case.
 */
{
  JDIMENSION MCU_cols, MCU_rows, comp_width, comp_height;
  JDIMENSION dst_blk_y, x_crop_blocks, y_crop_blocks;
  int ci, offset_y;
  JBLOCKARRAY src_buffer, dst_buffer;
  jpeg_component_info *compptr;
 
  MCU_cols = srcinfo->output_width /
    (dstinfo->max_h_samp_factor * dstinfo->min_DCT_h_scaled_size);
  MCU_rows = srcinfo->output_height /
    (dstinfo->max_v_samp_factor * dstinfo->min_DCT_v_scaled_size);
 
  for (ci = 0; ci < dstinfo->num_components; ci++) {
    compptr = dstinfo->comp_info + ci;
    comp_width = MCU_cols * compptr->h_samp_factor;
    comp_height = MCU_rows * compptr->v_samp_factor;
    x_crop_blocks = x_crop_offset * compptr->h_samp_factor;
    y_crop_blocks = y_crop_offset * compptr->v_samp_factor;
    for (dst_blk_y = 0; dst_blk_y < compptr->height_in_blocks;
     dst_blk_y += compptr->v_samp_factor) {
      dst_buffer = (*srcinfo->mem->access_virt_barray)
    ((j_common_ptr) srcinfo, dst_coef_arrays[ci], dst_blk_y,
     (JDIMENSION) compptr->v_samp_factor, TRUE);
      if (dstinfo->jpeg_height > srcinfo->output_height) {
    if (dst_blk_y < y_crop_blocks ||
        dst_blk_y >= y_crop_blocks + comp_height) {
      for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
        FMEMZERO(dst_buffer[offset_y],
             compptr->width_in_blocks * SIZEOF(JBLOCK));
      }
      continue;
    }
    src_buffer = (*srcinfo->mem->access_virt_barray)
      ((j_common_ptr) srcinfo, src_coef_arrays[ci],
       dst_blk_y - y_crop_blocks,
       (JDIMENSION) compptr->v_samp_factor, FALSE);
      } else {
    src_buffer = (*srcinfo->mem->access_virt_barray)
      ((j_common_ptr) srcinfo, src_coef_arrays[ci],
       dst_blk_y + y_crop_blocks,
       (JDIMENSION) compptr->v_samp_factor, FALSE);
      }
      for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
    if (dstinfo->jpeg_width > srcinfo->output_width) {
      if (x_crop_blocks > 0) {
        FMEMZERO(dst_buffer[offset_y],
             x_crop_blocks * SIZEOF(JBLOCK));
      }
      jcopy_block_row(src_buffer[offset_y],
              dst_buffer[offset_y] + x_crop_blocks,
              comp_width);
      if (compptr->width_in_blocks > x_crop_blocks + comp_width) {
        FMEMZERO(dst_buffer[offset_y] +
               x_crop_blocks + comp_width,
             (compptr->width_in_blocks -
               x_crop_blocks - comp_width) * SIZEOF(JBLOCK));
      }
    } else {
      jcopy_block_row(src_buffer[offset_y] + x_crop_blocks,
              dst_buffer[offset_y],
              compptr->width_in_blocks);
    }
      }
    }
  }
}
 
 
LOCAL(void)
do_crop_ext_flat (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
          JDIMENSION x_crop_offset, JDIMENSION y_crop_offset,
          jvirt_barray_ptr *src_coef_arrays,
          jvirt_barray_ptr *dst_coef_arrays)
/* Crop.  This is only used when no rotate/flip is requested with the crop.
 * Extension: The destination width is larger than the source and we fill in
 * the extra area with the DC of the adjacent block.  Note we also have to
 * fill partial iMCUs at the right and bottom edge of the source image area
 * in this case.
 */
{
  JDIMENSION MCU_cols, MCU_rows, comp_width, comp_height;
  JDIMENSION dst_blk_x, dst_blk_y, x_crop_blocks, y_crop_blocks;
  int ci, offset_y;
  JCOEF dc;
  JBLOCKARRAY src_buffer, dst_buffer;
  jpeg_component_info *compptr;
 
  MCU_cols = srcinfo->output_width /
    (dstinfo->max_h_samp_factor * dstinfo->min_DCT_h_scaled_size);
  MCU_rows = srcinfo->output_height /
    (dstinfo->max_v_samp_factor * dstinfo->min_DCT_v_scaled_size);
 
  for (ci = 0; ci < dstinfo->num_components; ci++) {
    compptr = dstinfo->comp_info + ci;
    comp_width = MCU_cols * compptr->h_samp_factor;
    comp_height = MCU_rows * compptr->v_samp_factor;
    x_crop_blocks = x_crop_offset * compptr->h_samp_factor;
    y_crop_blocks = y_crop_offset * compptr->v_samp_factor;
    for (dst_blk_y = 0; dst_blk_y < compptr->height_in_blocks;
     dst_blk_y += compptr->v_samp_factor) {
      dst_buffer = (*srcinfo->mem->access_virt_barray)
    ((j_common_ptr) srcinfo, dst_coef_arrays[ci], dst_blk_y,
     (JDIMENSION) compptr->v_samp_factor, TRUE);
      if (dstinfo->jpeg_height > srcinfo->output_height) {
    if (dst_blk_y < y_crop_blocks ||
        dst_blk_y >= y_crop_blocks + comp_height) {
      for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
        FMEMZERO(dst_buffer[offset_y],
             compptr->width_in_blocks * SIZEOF(JBLOCK));
      }
      continue;
    }
    src_buffer = (*srcinfo->mem->access_virt_barray)
      ((j_common_ptr) srcinfo, src_coef_arrays[ci],
       dst_blk_y - y_crop_blocks,
       (JDIMENSION) compptr->v_samp_factor, FALSE);
      } else {
    src_buffer = (*srcinfo->mem->access_virt_barray)
      ((j_common_ptr) srcinfo, src_coef_arrays[ci],
       dst_blk_y + y_crop_blocks,
       (JDIMENSION) compptr->v_samp_factor, FALSE);
      }
      for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
    if (x_crop_blocks > 0) {
      FMEMZERO(dst_buffer[offset_y],
           x_crop_blocks * SIZEOF(JBLOCK));
      dc = src_buffer[offset_y][0][0];
      for (dst_blk_x = 0; dst_blk_x < x_crop_blocks; dst_blk_x++) {
        dst_buffer[offset_y][dst_blk_x][0] = dc;
      }
    }
    jcopy_block_row(src_buffer[offset_y],
            dst_buffer[offset_y] + x_crop_blocks,
            comp_width);
    if (compptr->width_in_blocks > x_crop_blocks + comp_width) {
      FMEMZERO(dst_buffer[offset_y] +
             x_crop_blocks + comp_width,
           (compptr->width_in_blocks -
             x_crop_blocks - comp_width) * SIZEOF(JBLOCK));
      dc = src_buffer[offset_y][comp_width - 1][0];
      for (dst_blk_x = x_crop_blocks + comp_width;
           dst_blk_x < compptr->width_in_blocks; dst_blk_x++) {
        dst_buffer[offset_y][dst_blk_x][0] = dc;
      }
    }
      }
    }
  }
}
 
 
LOCAL(void)
do_crop_ext_reflect (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
             JDIMENSION x_crop_offset, JDIMENSION y_crop_offset,
             jvirt_barray_ptr *src_coef_arrays,
             jvirt_barray_ptr *dst_coef_arrays)
/* Crop.  This is only used when no rotate/flip is requested with the crop.
 * Extension: The destination width is larger than the source and we fill in
 * the extra area with repeated reflections of the source region.  Note we
 * also have to fill partial iMCUs at the right and bottom edge of the source
 * image area in this case.
 */
{
  JDIMENSION MCU_cols, MCU_rows, comp_width, comp_height, src_blk_x;
  JDIMENSION dst_blk_x, dst_blk_y, x_crop_blocks, y_crop_blocks;
  int ci, k, offset_y;
  JBLOCKARRAY src_buffer, dst_buffer;
  JBLOCKROW src_row_ptr, dst_row_ptr;
  JCOEFPTR src_ptr, dst_ptr;
  jpeg_component_info *compptr;
 
  MCU_cols = srcinfo->output_width /
    (dstinfo->max_h_samp_factor * dstinfo->min_DCT_h_scaled_size);
  MCU_rows = srcinfo->output_height /
    (dstinfo->max_v_samp_factor * dstinfo->min_DCT_v_scaled_size);
 
  for (ci = 0; ci < dstinfo->num_components; ci++) {
    compptr = dstinfo->comp_info + ci;
    comp_width = MCU_cols * compptr->h_samp_factor;
    comp_height = MCU_rows * compptr->v_samp_factor;
    x_crop_blocks = x_crop_offset * compptr->h_samp_factor;
    y_crop_blocks = y_crop_offset * compptr->v_samp_factor;
    for (dst_blk_y = 0; dst_blk_y < compptr->height_in_blocks;
     dst_blk_y += compptr->v_samp_factor) {
      dst_buffer = (*srcinfo->mem->access_virt_barray)
    ((j_common_ptr) srcinfo, dst_coef_arrays[ci], dst_blk_y,
     (JDIMENSION) compptr->v_samp_factor, TRUE);
      if (dstinfo->jpeg_height > srcinfo->output_height) {
    if (dst_blk_y < y_crop_blocks ||
        dst_blk_y >= y_crop_blocks + comp_height) {
      for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
        FMEMZERO(dst_buffer[offset_y],
             compptr->width_in_blocks * SIZEOF(JBLOCK));
      }
      continue;
    }
    src_buffer = (*srcinfo->mem->access_virt_barray)
      ((j_common_ptr) srcinfo, src_coef_arrays[ci],
       dst_blk_y - y_crop_blocks,
       (JDIMENSION) compptr->v_samp_factor, FALSE);
      } else {
    src_buffer = (*srcinfo->mem->access_virt_barray)
      ((j_common_ptr) srcinfo, src_coef_arrays[ci],
       dst_blk_y + y_crop_blocks,
       (JDIMENSION) compptr->v_samp_factor, FALSE);
      }
      for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
    /* Copy source region */
    jcopy_block_row(src_buffer[offset_y],
            dst_buffer[offset_y] + x_crop_blocks,
            comp_width);
    if (x_crop_blocks > 0) {
      /* Reflect to left */
      dst_row_ptr = dst_buffer[offset_y] + x_crop_blocks;
      for (dst_blk_x = x_crop_blocks; dst_blk_x > 0;) {
        src_row_ptr = dst_row_ptr;     /* (re)set axis of reflection */
        for (src_blk_x = comp_width; src_blk_x > 0 && dst_blk_x > 0;
         src_blk_x--, dst_blk_x--) {
          dst_ptr = *--dst_row_ptr;    /* destination goes left */
          src_ptr = *src_row_ptr++;    /* source goes right */
          /* this unrolled loop doesn't need to know which row it's on... */
          for (k = 0; k < DCTSIZE2; k += 2) {
        *dst_ptr++ = *src_ptr++;   /* copy even column */
        *dst_ptr++ = - *src_ptr++; /* copy odd column with sign change */
          }
        }
      }
    }
    if (compptr->width_in_blocks > x_crop_blocks + comp_width) {
      /* Reflect to right */
      dst_row_ptr = dst_buffer[offset_y] + x_crop_blocks + comp_width;
      for (dst_blk_x = compptr->width_in_blocks - x_crop_blocks - comp_width;
           dst_blk_x > 0;) {
        src_row_ptr = dst_row_ptr;     /* (re)set axis of reflection */
        for (src_blk_x = comp_width; src_blk_x > 0 && dst_blk_x > 0;
         src_blk_x--, dst_blk_x--) {
          dst_ptr = *dst_row_ptr++;    /* destination goes right */
          src_ptr = *--src_row_ptr;    /* source goes left */
          /* this unrolled loop doesn't need to know which row it's on... */
          for (k = 0; k < DCTSIZE2; k += 2) {
        *dst_ptr++ = *src_ptr++;   /* copy even column */
        *dst_ptr++ = - *src_ptr++; /* copy odd column with sign change */
          }
        }
      }
    }
      }
    }
  }
}
 
 
LOCAL(void)
do_wipe (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
     JDIMENSION x_crop_offset, JDIMENSION y_crop_offset,
     jvirt_barray_ptr *src_coef_arrays,
     JDIMENSION drop_width, JDIMENSION drop_height)
/* Wipe - drop content of specified area, fill with zero (neutral gray) */
{
  JDIMENSION x_wipe_blocks, wipe_width;
  JDIMENSION y_wipe_blocks, wipe_bottom;
  int ci, offset_y;
  JBLOCKARRAY buffer;
  jpeg_component_info *compptr;
 
  for (ci = 0; ci < dstinfo->num_components; ci++) {
    compptr = dstinfo->comp_info + ci;
    x_wipe_blocks = x_crop_offset * compptr->h_samp_factor;
    wipe_width = drop_width * compptr->h_samp_factor;
    y_wipe_blocks = y_crop_offset * compptr->v_samp_factor;
    wipe_bottom = drop_height * compptr->v_samp_factor + y_wipe_blocks;
    for (; y_wipe_blocks < wipe_bottom;
     y_wipe_blocks += compptr->v_samp_factor) {
      buffer = (*srcinfo->mem->access_virt_barray)
    ((j_common_ptr) srcinfo, src_coef_arrays[ci], y_wipe_blocks,
     (JDIMENSION) compptr->v_samp_factor, TRUE);
      for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
    FMEMZERO(buffer[offset_y] + x_wipe_blocks,
         wipe_width * SIZEOF(JBLOCK));
      }
    }
  }
}
 
 
LOCAL(void)
do_flatten (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
        JDIMENSION x_crop_offset, JDIMENSION y_crop_offset,
        jvirt_barray_ptr *src_coef_arrays,
        JDIMENSION drop_width, JDIMENSION drop_height)
/* Flatten - drop content of specified area, similar to wipe,
 * but fill with average of adjacent blocks, instead of zero.
 */
{
  JDIMENSION x_wipe_blocks, wipe_width, wipe_right;
  JDIMENSION y_wipe_blocks, wipe_bottom, blk_x;
  int ci, offset_y, dc_left_value, dc_right_value, average;
  JBLOCKARRAY buffer;
  jpeg_component_info *compptr;
 
  for (ci = 0; ci < dstinfo->num_components; ci++) {
    compptr = dstinfo->comp_info + ci;
    x_wipe_blocks = x_crop_offset * compptr->h_samp_factor;
    wipe_width = drop_width * compptr->h_samp_factor;
    wipe_right = wipe_width + x_wipe_blocks;
    y_wipe_blocks = y_crop_offset * compptr->v_samp_factor;
    wipe_bottom = drop_height * compptr->v_samp_factor + y_wipe_blocks;
    for (; y_wipe_blocks < wipe_bottom;
     y_wipe_blocks += compptr->v_samp_factor) {
      buffer = (*srcinfo->mem->access_virt_barray)
    ((j_common_ptr) srcinfo, src_coef_arrays[ci], y_wipe_blocks,
     (JDIMENSION) compptr->v_samp_factor, TRUE);
      for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
    FMEMZERO(buffer[offset_y] + x_wipe_blocks,
         wipe_width * SIZEOF(JBLOCK));
    if (x_wipe_blocks > 0) {
      dc_left_value = buffer[offset_y][x_wipe_blocks - 1][0];
      if (wipe_right < compptr->width_in_blocks) {
        dc_right_value = buffer[offset_y][wipe_right][0];
        average = (dc_left_value + dc_right_value) >> 1;
      } else {
        average = dc_left_value;
      }
    } else if (wipe_right < compptr->width_in_blocks) {
      average = buffer[offset_y][wipe_right][0];
    } else continue;
    for (blk_x = x_wipe_blocks; blk_x < wipe_right; blk_x++) {
      buffer[offset_y][blk_x][0] = (JCOEF) average;
    }
      }
    }
  }
}
 
 
LOCAL(void)
do_reflect (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
        JDIMENSION x_crop_offset,
        jvirt_barray_ptr *src_coef_arrays,
        JDIMENSION drop_width, JDIMENSION drop_height)
/* Reflect - drop content of specified area, similar to wipe, but
 * fill with repeated reflections of the outside area, instead of zero.
 * NB: y_crop_offset is assumed to be zero.
 */
{
  JDIMENSION x_wipe_blocks, wipe_width;
  JDIMENSION y_wipe_blocks, wipe_bottom;
  JDIMENSION src_blk_x, dst_blk_x;
  int ci, k, offset_y;
  JBLOCKARRAY buffer;
  JBLOCKROW src_row_ptr, dst_row_ptr;
  JCOEFPTR src_ptr, dst_ptr;
  jpeg_component_info *compptr;
 
  for (ci = 0; ci < dstinfo->num_components; ci++) {
    compptr = dstinfo->comp_info + ci;
    x_wipe_blocks = x_crop_offset * compptr->h_samp_factor;
    wipe_width = drop_width * compptr->h_samp_factor;
    wipe_bottom = drop_height * compptr->v_samp_factor;
    for (y_wipe_blocks = 0; y_wipe_blocks < wipe_bottom;
     y_wipe_blocks += compptr->v_samp_factor) {
      buffer = (*srcinfo->mem->access_virt_barray)
    ((j_common_ptr) srcinfo, src_coef_arrays[ci], y_wipe_blocks,
     (JDIMENSION) compptr->v_samp_factor, TRUE);
      for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
    if (x_wipe_blocks > 0) {
      /* Reflect from left */
      dst_row_ptr = buffer[offset_y] + x_wipe_blocks;
      for (dst_blk_x = wipe_width; dst_blk_x > 0;) {
        src_row_ptr = dst_row_ptr;     /* (re)set axis of reflection */
        for (src_blk_x = x_wipe_blocks;
         src_blk_x > 0 && dst_blk_x > 0; src_blk_x--, dst_blk_x--) {
          dst_ptr = *dst_row_ptr++;    /* destination goes right */
          src_ptr = *--src_row_ptr;    /* source goes left */
          /* this unrolled loop doesn't need to know which row it's on... */
          for (k = 0; k < DCTSIZE2; k += 2) {
        *dst_ptr++ = *src_ptr++;   /* copy even column */
        *dst_ptr++ = - *src_ptr++; /* copy odd column with sign change */
          }
        }
      }
    } else if (compptr->width_in_blocks > x_wipe_blocks + wipe_width) {
      /* Reflect from right */
      dst_row_ptr = buffer[offset_y] + x_wipe_blocks + wipe_width;
      for (dst_blk_x = wipe_width; dst_blk_x > 0;) {
        src_row_ptr = dst_row_ptr;     /* (re)set axis of reflection */
        src_blk_x = compptr->width_in_blocks - x_wipe_blocks - wipe_width;
        for (; src_blk_x > 0 && dst_blk_x > 0; src_blk_x--, dst_blk_x--) {
          dst_ptr = *--dst_row_ptr;    /* destination goes left */
          src_ptr = *src_row_ptr++;    /* source goes right */
          /* this unrolled loop doesn't need to know which row it's on... */
          for (k = 0; k < DCTSIZE2; k += 2) {
        *dst_ptr++ = *src_ptr++;   /* copy even column */
        *dst_ptr++ = - *src_ptr++; /* copy odd column with sign change */
          }
        }
      }
    } else {
      FMEMZERO(buffer[offset_y] + x_wipe_blocks,
           wipe_width * SIZEOF(JBLOCK));
    }
      }
    }
  }
}
 
 
LOCAL(void)
do_flip_h_no_crop (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
           JDIMENSION x_crop_offset,
           jvirt_barray_ptr *src_coef_arrays)
/* Horizontal flip; done in-place, so no separate dest array is required.
 * NB: this only works when y_crop_offset is zero.
 */
{
  JDIMENSION MCU_cols, comp_width, blk_x, blk_y, x_crop_blocks;
  int ci, k, offset_y;
  JBLOCKARRAY buffer;
  JCOEFPTR ptr1, ptr2;
  JCOEF temp1, temp2;
  jpeg_component_info *compptr;
 
  /* Horizontal mirroring of DCT blocks is accomplished by swapping
   * pairs of blocks in-place.  Within a DCT block, we perform horizontal
   * mirroring by changing the signs of odd-numbered columns.
   * Partial iMCUs at the right edge are left untouched.
   */
  MCU_cols = srcinfo->output_width /
    (dstinfo->max_h_samp_factor * dstinfo->min_DCT_h_scaled_size);
 
  for (ci = 0; ci < dstinfo->num_components; ci++) {
    compptr = dstinfo->comp_info + ci;
    comp_width = MCU_cols * compptr->h_samp_factor;
    x_crop_blocks = x_crop_offset * compptr->h_samp_factor;
    for (blk_y = 0; blk_y < compptr->height_in_blocks;
     blk_y += compptr->v_samp_factor) {
      buffer = (*srcinfo->mem->access_virt_barray)
    ((j_common_ptr) srcinfo, src_coef_arrays[ci], blk_y,
     (JDIMENSION) compptr->v_samp_factor, TRUE);
      for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
    /* Do the mirroring */
    for (blk_x = 0; blk_x * 2 < comp_width; blk_x++) {
      ptr1 = buffer[offset_y][blk_x];
      ptr2 = buffer[offset_y][comp_width - blk_x - 1];
      /* this unrolled loop doesn't need to know which row it's on... */
      for (k = 0; k < DCTSIZE2; k += 2) {
        temp1 = *ptr1;  /* swap even column */
        temp2 = *ptr2;
        *ptr1++ = temp2;
        *ptr2++ = temp1;
        temp1 = *ptr1;  /* swap odd column with sign change */
        temp2 = *ptr2;
        *ptr1++ = -temp2;
        *ptr2++ = -temp1;
      }
    }
    if (x_crop_blocks > 0) {
      /* Now left-justify the portion of the data to be kept.
       * We can't use a single jcopy_block_row() call because that routine
       * depends on memcpy(), whose behavior is unspecified for overlapping
       * source and destination areas.  Sigh.
       */
      for (blk_x = 0; blk_x < compptr->width_in_blocks; blk_x++) {
        jcopy_block_row(buffer[offset_y] + blk_x + x_crop_blocks,
                buffer[offset_y] + blk_x,
                (JDIMENSION) 1);
      }
    }
      }
    }
  }
}
 
 
LOCAL(void)
do_flip_h (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
       JDIMENSION x_crop_offset, JDIMENSION y_crop_offset,
       jvirt_barray_ptr *src_coef_arrays,
       jvirt_barray_ptr *dst_coef_arrays)
/* Horizontal flip in general cropping case */
{
  JDIMENSION MCU_cols, comp_width, dst_blk_x, dst_blk_y;
  JDIMENSION x_crop_blocks, y_crop_blocks;
  int ci, k, offset_y;
  JBLOCKARRAY src_buffer, dst_buffer;
  JBLOCKROW src_row_ptr, dst_row_ptr;
  JCOEFPTR src_ptr, dst_ptr;
  jpeg_component_info *compptr;
 
  /* Here we must output into a separate array because we can't touch
   * different rows of a single virtual array simultaneously.  Otherwise,
   * this is essentially the same as the routine above.
   */
  MCU_cols = srcinfo->output_width /
    (dstinfo->max_h_samp_factor * dstinfo->min_DCT_h_scaled_size);
 
  for (ci = 0; ci < dstinfo->num_components; ci++) {
    compptr = dstinfo->comp_info + ci;
    comp_width = MCU_cols * compptr->h_samp_factor;
    x_crop_blocks = x_crop_offset * compptr->h_samp_factor;
    y_crop_blocks = y_crop_offset * compptr->v_samp_factor;
    for (dst_blk_y = 0; dst_blk_y < compptr->height_in_blocks;
     dst_blk_y += compptr->v_samp_factor) {
      dst_buffer = (*srcinfo->mem->access_virt_barray)
    ((j_common_ptr) srcinfo, dst_coef_arrays[ci], dst_blk_y,
     (JDIMENSION) compptr->v_samp_factor, TRUE);
      src_buffer = (*srcinfo->mem->access_virt_barray)
    ((j_common_ptr) srcinfo, src_coef_arrays[ci],
     dst_blk_y + y_crop_blocks,
     (JDIMENSION) compptr->v_samp_factor, FALSE);
      for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
    dst_row_ptr = dst_buffer[offset_y];
    src_row_ptr = src_buffer[offset_y];
    for (dst_blk_x = 0; dst_blk_x < compptr->width_in_blocks; dst_blk_x++) {
      if (x_crop_blocks + dst_blk_x < comp_width) {
        /* Do the mirrorable blocks */
        dst_ptr = dst_row_ptr[dst_blk_x];
        src_ptr = src_row_ptr[comp_width - x_crop_blocks - dst_blk_x - 1];
        /* this unrolled loop doesn't need to know which row it's on... */
        for (k = 0; k < DCTSIZE2; k += 2) {
          *dst_ptr++ = *src_ptr++;   /* copy even column */
          *dst_ptr++ = - *src_ptr++; /* copy odd column with sign change */
        }
      } else {
        /* Copy last partial block(s) verbatim */
        jcopy_block_row(src_row_ptr + dst_blk_x + x_crop_blocks,
                dst_row_ptr + dst_blk_x,
                (JDIMENSION) 1);
      }
    }
      }
    }
  }
}
 
 
LOCAL(void)
do_flip_v (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
       JDIMENSION x_crop_offset, JDIMENSION y_crop_offset,
       jvirt_barray_ptr *src_coef_arrays,
       jvirt_barray_ptr *dst_coef_arrays)
/* Vertical flip */
{
  JDIMENSION MCU_rows, comp_height, dst_blk_x, dst_blk_y;
  JDIMENSION x_crop_blocks, y_crop_blocks;
  int ci, i, j, offset_y;
  JBLOCKARRAY src_buffer, dst_buffer;
  JBLOCKROW src_row_ptr, dst_row_ptr;
  JCOEFPTR src_ptr, dst_ptr;
  jpeg_component_info *compptr;
 
  /* We output into a separate array because we can't touch different
   * rows of the source virtual array simultaneously.  Otherwise, this
   * is a pretty straightforward analog of horizontal flip.
   * Within a DCT block, vertical mirroring is done by changing the signs
   * of odd-numbered rows.
   * Partial iMCUs at the bottom edge are copied verbatim.
   */
  MCU_rows = srcinfo->output_height /
    (dstinfo->max_v_samp_factor * dstinfo->min_DCT_v_scaled_size);
 
  for (ci = 0; ci < dstinfo->num_components; ci++) {
    compptr = dstinfo->comp_info + ci;
    comp_height = MCU_rows * compptr->v_samp_factor;
    x_crop_blocks = x_crop_offset * compptr->h_samp_factor;
    y_crop_blocks = y_crop_offset * compptr->v_samp_factor;
    for (dst_blk_y = 0; dst_blk_y < compptr->height_in_blocks;
     dst_blk_y += compptr->v_samp_factor) {
      dst_buffer = (*srcinfo->mem->access_virt_barray)
    ((j_common_ptr) srcinfo, dst_coef_arrays[ci], dst_blk_y,
     (JDIMENSION) compptr->v_samp_factor, TRUE);
      if (y_crop_blocks + dst_blk_y < comp_height) {
    /* Row is within the mirrorable area. */
    src_buffer = (*srcinfo->mem->access_virt_barray)
      ((j_common_ptr) srcinfo, src_coef_arrays[ci],
       comp_height - y_crop_blocks - dst_blk_y -
       (JDIMENSION) compptr->v_samp_factor,
       (JDIMENSION) compptr->v_samp_factor, FALSE);
      } else {
    /* Bottom-edge blocks will be copied verbatim. */
    src_buffer = (*srcinfo->mem->access_virt_barray)
      ((j_common_ptr) srcinfo, src_coef_arrays[ci],
       dst_blk_y + y_crop_blocks,
       (JDIMENSION) compptr->v_samp_factor, FALSE);
      }
      for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
    if (y_crop_blocks + dst_blk_y < comp_height) {
      /* Row is within the mirrorable area. */
      dst_row_ptr = dst_buffer[offset_y];
      src_row_ptr = src_buffer[compptr->v_samp_factor - offset_y - 1];
      src_row_ptr += x_crop_blocks;
      for (dst_blk_x = 0; dst_blk_x < compptr->width_in_blocks;
           dst_blk_x++) {
        dst_ptr = dst_row_ptr[dst_blk_x];
        src_ptr = src_row_ptr[dst_blk_x];
        for (i = 0; i < DCTSIZE; i += 2) {
          /* copy even row */
          for (j = 0; j < DCTSIZE; j++)
        *dst_ptr++ = *src_ptr++;
          /* copy odd row with sign change */
          for (j = 0; j < DCTSIZE; j++)
        *dst_ptr++ = - *src_ptr++;
        }
      }
    } else {
      /* Just copy row verbatim. */
      jcopy_block_row(src_buffer[offset_y] + x_crop_blocks,
              dst_buffer[offset_y],
              compptr->width_in_blocks);
    }
      }
    }
  }
}
 
 
LOCAL(void)
do_transpose (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
          JDIMENSION x_crop_offset, JDIMENSION y_crop_offset,
          jvirt_barray_ptr *src_coef_arrays,
          jvirt_barray_ptr *dst_coef_arrays)
/* Transpose source into destination */
{
  JDIMENSION dst_blk_x, dst_blk_y, x_crop_blocks, y_crop_blocks;
  int ci, i, j, offset_x, offset_y;
  JBLOCKARRAY src_buffer, dst_buffer;
  JCOEFPTR src_ptr, dst_ptr;
  jpeg_component_info *compptr;
 
  /* Transposing pixels within a block just requires transposing the
   * DCT coefficients.
   * Partial iMCUs at the edges require no special treatment; we simply
   * process all the available DCT blocks for every component.
   */
  for (ci = 0; ci < dstinfo->num_components; ci++) {
    compptr = dstinfo->comp_info + ci;
    x_crop_blocks = x_crop_offset * compptr->h_samp_factor;
    y_crop_blocks = y_crop_offset * compptr->v_samp_factor;
    for (dst_blk_y = 0; dst_blk_y < compptr->height_in_blocks;
     dst_blk_y += compptr->v_samp_factor) {
      dst_buffer = (*srcinfo->mem->access_virt_barray)
    ((j_common_ptr) srcinfo, dst_coef_arrays[ci], dst_blk_y,
     (JDIMENSION) compptr->v_samp_factor, TRUE);
      for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
    for (dst_blk_x = 0; dst_blk_x < compptr->width_in_blocks;
         dst_blk_x += compptr->h_samp_factor) {
      src_buffer = (*srcinfo->mem->access_virt_barray)
        ((j_common_ptr) srcinfo, src_coef_arrays[ci],
         dst_blk_x + x_crop_blocks,
         (JDIMENSION) compptr->h_samp_factor, FALSE);
      for (offset_x = 0; offset_x < compptr->h_samp_factor; offset_x++) {
        dst_ptr = dst_buffer[offset_y][dst_blk_x + offset_x];
        src_ptr = src_buffer[offset_x][dst_blk_y + offset_y + y_crop_blocks];
        for (i = 0; i < DCTSIZE; i++)
          for (j = 0; j < DCTSIZE; j++)
        dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
      }
    }
      }
    }
  }
}
 
 
LOCAL(void)
do_rot_90 (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
       JDIMENSION x_crop_offset, JDIMENSION y_crop_offset,
       jvirt_barray_ptr *src_coef_arrays,
       jvirt_barray_ptr *dst_coef_arrays)
/* 90 degree rotation is equivalent to
 *   1. Transposing the image;
 *   2. Horizontal mirroring.
 * These two steps are merged into a single processing routine.
 */
{
  JDIMENSION MCU_cols, comp_width, dst_blk_x, dst_blk_y;
  JDIMENSION x_crop_blocks, y_crop_blocks;
  int ci, i, j, offset_x, offset_y;
  JBLOCKARRAY src_buffer, dst_buffer;
  JCOEFPTR src_ptr, dst_ptr;
  jpeg_component_info *compptr;
 
  /* Because of the horizontal mirror step, we can't process partial iMCUs
   * at the (output) right edge properly.  They just get transposed and
   * not mirrored.
   */
  MCU_cols = srcinfo->output_height /
    (dstinfo->max_h_samp_factor * dstinfo->min_DCT_h_scaled_size);
 
  for (ci = 0; ci < dstinfo->num_components; ci++) {
    compptr = dstinfo->comp_info + ci;
    comp_width = MCU_cols * compptr->h_samp_factor;
    x_crop_blocks = x_crop_offset * compptr->h_samp_factor;
    y_crop_blocks = y_crop_offset * compptr->v_samp_factor;
    for (dst_blk_y = 0; dst_blk_y < compptr->height_in_blocks;
     dst_blk_y += compptr->v_samp_factor) {
      dst_buffer = (*srcinfo->mem->access_virt_barray)
    ((j_common_ptr) srcinfo, dst_coef_arrays[ci], dst_blk_y,
     (JDIMENSION) compptr->v_samp_factor, TRUE);
      for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
    for (dst_blk_x = 0; dst_blk_x < compptr->width_in_blocks;
         dst_blk_x += compptr->h_samp_factor) {
      if (x_crop_blocks + dst_blk_x < comp_width) {
        /* Block is within the mirrorable area. */
        src_buffer = (*srcinfo->mem->access_virt_barray)
          ((j_common_ptr) srcinfo, src_coef_arrays[ci],
           comp_width - x_crop_blocks - dst_blk_x -
           (JDIMENSION) compptr->h_samp_factor,
           (JDIMENSION) compptr->h_samp_factor, FALSE);
      } else {
        /* Edge blocks are transposed but not mirrored. */
        src_buffer = (*srcinfo->mem->access_virt_barray)
          ((j_common_ptr) srcinfo, src_coef_arrays[ci],
           dst_blk_x + x_crop_blocks,
           (JDIMENSION) compptr->h_samp_factor, FALSE);
      }
      for (offset_x = 0; offset_x < compptr->h_samp_factor; offset_x++) {
        dst_ptr = dst_buffer[offset_y][dst_blk_x + offset_x];
        if (x_crop_blocks + dst_blk_x < comp_width) {
          /* Block is within the mirrorable area. */
          src_ptr = src_buffer[compptr->h_samp_factor - offset_x - 1]
        [dst_blk_y + offset_y + y_crop_blocks];
          for (i = 0; i < DCTSIZE; i++) {
        for (j = 0; j < DCTSIZE; j++)
          dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
        i++;
        for (j = 0; j < DCTSIZE; j++)
          dst_ptr[j*DCTSIZE+i] = -src_ptr[i*DCTSIZE+j];
          }
        } else {
          /* Edge blocks are transposed but not mirrored. */
          src_ptr = src_buffer[offset_x]
        [dst_blk_y + offset_y + y_crop_blocks];
          for (i = 0; i < DCTSIZE; i++)
        for (j = 0; j < DCTSIZE; j++)
          dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
        }
      }
    }
      }
    }
  }
}
 
 
LOCAL(void)
do_rot_270 (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
        JDIMENSION x_crop_offset, JDIMENSION y_crop_offset,
        jvirt_barray_ptr *src_coef_arrays,
        jvirt_barray_ptr *dst_coef_arrays)
/* 270 degree rotation is equivalent to
 *   1. Horizontal mirroring;
 *   2. Transposing the image.
 * These two steps are merged into a single processing routine.
 */
{
  JDIMENSION MCU_rows, comp_height, dst_blk_x, dst_blk_y;
  JDIMENSION x_crop_blocks, y_crop_blocks;
  int ci, i, j, offset_x, offset_y;
  JBLOCKARRAY src_buffer, dst_buffer;
  JCOEFPTR src_ptr, dst_ptr;
  jpeg_component_info *compptr;
 
  /* Because of the horizontal mirror step, we can't process partial iMCUs
   * at the (output) bottom edge properly.  They just get transposed and
   * not mirrored.
   */
  MCU_rows = srcinfo->output_width /
    (dstinfo->max_v_samp_factor * dstinfo->min_DCT_v_scaled_size);
 
  for (ci = 0; ci < dstinfo->num_components; ci++) {
    compptr = dstinfo->comp_info + ci;
    comp_height = MCU_rows * compptr->v_samp_factor;
    x_crop_blocks = x_crop_offset * compptr->h_samp_factor;
    y_crop_blocks = y_crop_offset * compptr->v_samp_factor;
    for (dst_blk_y = 0; dst_blk_y < compptr->height_in_blocks;
     dst_blk_y += compptr->v_samp_factor) {
      dst_buffer = (*srcinfo->mem->access_virt_barray)
    ((j_common_ptr) srcinfo, dst_coef_arrays[ci], dst_blk_y,
     (JDIMENSION) compptr->v_samp_factor, TRUE);
      for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
    for (dst_blk_x = 0; dst_blk_x < compptr->width_in_blocks;
         dst_blk_x += compptr->h_samp_factor) {
      src_buffer = (*srcinfo->mem->access_virt_barray)
        ((j_common_ptr) srcinfo, src_coef_arrays[ci],
         dst_blk_x + x_crop_blocks,
         (JDIMENSION) compptr->h_samp_factor, FALSE);
      for (offset_x = 0; offset_x < compptr->h_samp_factor; offset_x++) {
        dst_ptr = dst_buffer[offset_y][dst_blk_x + offset_x];
        if (y_crop_blocks + dst_blk_y < comp_height) {
          /* Block is within the mirrorable area. */
          src_ptr = src_buffer[offset_x]
        [comp_height - y_crop_blocks - dst_blk_y - offset_y - 1];
          for (i = 0; i < DCTSIZE; i++) {
        for (j = 0; j < DCTSIZE; j++) {
          dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
          j++;
          dst_ptr[j*DCTSIZE+i] = -src_ptr[i*DCTSIZE+j];
        }
          }
        } else {
          /* Edge blocks are transposed but not mirrored. */
          src_ptr = src_buffer[offset_x]
        [dst_blk_y + offset_y + y_crop_blocks];
          for (i = 0; i < DCTSIZE; i++)
        for (j = 0; j < DCTSIZE; j++)
          dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
        }
      }
    }
      }
    }
  }
}
 
 
LOCAL(void)
do_rot_180 (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
        JDIMENSION x_crop_offset, JDIMENSION y_crop_offset,
        jvirt_barray_ptr *src_coef_arrays,
        jvirt_barray_ptr *dst_coef_arrays)
/* 180 degree rotation is equivalent to
 *   1. Vertical mirroring;
 *   2. Horizontal mirroring.
 * These two steps are merged into a single processing routine.
 */
{
  JDIMENSION MCU_cols, MCU_rows, comp_width, comp_height, dst_blk_x, dst_blk_y;
  JDIMENSION x_crop_blocks, y_crop_blocks;
  int ci, i, j, offset_y;
  JBLOCKARRAY src_buffer, dst_buffer;
  JBLOCKROW src_row_ptr, dst_row_ptr;
  JCOEFPTR src_ptr, dst_ptr;
  jpeg_component_info *compptr;
 
  MCU_cols = srcinfo->output_width /
    (dstinfo->max_h_samp_factor * dstinfo->min_DCT_h_scaled_size);
  MCU_rows = srcinfo->output_height /
    (dstinfo->max_v_samp_factor * dstinfo->min_DCT_v_scaled_size);
 
  for (ci = 0; ci < dstinfo->num_components; ci++) {
    compptr = dstinfo->comp_info + ci;
    comp_width = MCU_cols * compptr->h_samp_factor;
    comp_height = MCU_rows * compptr->v_samp_factor;
    x_crop_blocks = x_crop_offset * compptr->h_samp_factor;
    y_crop_blocks = y_crop_offset * compptr->v_samp_factor;
    for (dst_blk_y = 0; dst_blk_y < compptr->height_in_blocks;
     dst_blk_y += compptr->v_samp_factor) {
      dst_buffer = (*srcinfo->mem->access_virt_barray)
    ((j_common_ptr) srcinfo, dst_coef_arrays[ci], dst_blk_y,
     (JDIMENSION) compptr->v_samp_factor, TRUE);
      if (y_crop_blocks + dst_blk_y < comp_height) {
    /* Row is within the vertically mirrorable area. */
    src_buffer = (*srcinfo->mem->access_virt_barray)
      ((j_common_ptr) srcinfo, src_coef_arrays[ci],
       comp_height - y_crop_blocks - dst_blk_y -
       (JDIMENSION) compptr->v_samp_factor,
       (JDIMENSION) compptr->v_samp_factor, FALSE);
      } else {
    /* Bottom-edge rows are only mirrored horizontally. */
    src_buffer = (*srcinfo->mem->access_virt_barray)
      ((j_common_ptr) srcinfo, src_coef_arrays[ci],
       dst_blk_y + y_crop_blocks,
       (JDIMENSION) compptr->v_samp_factor, FALSE);
      }
      for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
    dst_row_ptr = dst_buffer[offset_y];
    if (y_crop_blocks + dst_blk_y < comp_height) {
      /* Row is within the mirrorable area. */
      src_row_ptr = src_buffer[compptr->v_samp_factor - offset_y - 1];
      for (dst_blk_x = 0; dst_blk_x < compptr->width_in_blocks; dst_blk_x++) {
        dst_ptr = dst_row_ptr[dst_blk_x];
        if (x_crop_blocks + dst_blk_x < comp_width) {
          /* Process the blocks that can be mirrored both ways. */
          src_ptr = src_row_ptr[comp_width - x_crop_blocks - dst_blk_x - 1];
          for (i = 0; i < DCTSIZE; i += 2) {
        /* For even row, negate every odd column. */
        for (j = 0; j < DCTSIZE; j += 2) {
          *dst_ptr++ = *src_ptr++;
          *dst_ptr++ = - *src_ptr++;
        }
        /* For odd row, negate every even column. */
        for (j = 0; j < DCTSIZE; j += 2) {
          *dst_ptr++ = - *src_ptr++;
          *dst_ptr++ = *src_ptr++;
        }
          }
        } else {
          /* Any remaining right-edge blocks are only mirrored vertically. */
          src_ptr = src_row_ptr[x_crop_blocks + dst_blk_x];
          for (i = 0; i < DCTSIZE; i += 2) {
        for (j = 0; j < DCTSIZE; j++)
          *dst_ptr++ = *src_ptr++;
        for (j = 0; j < DCTSIZE; j++)
          *dst_ptr++ = - *src_ptr++;
          }
        }
      }
    } else {
      /* Remaining rows are just mirrored horizontally. */
      src_row_ptr = src_buffer[offset_y];
      for (dst_blk_x = 0; dst_blk_x < compptr->width_in_blocks; dst_blk_x++) {
        if (x_crop_blocks + dst_blk_x < comp_width) {
          /* Process the blocks that can be mirrored. */
          dst_ptr = dst_row_ptr[dst_blk_x];
          src_ptr = src_row_ptr[comp_width - x_crop_blocks - dst_blk_x - 1];
          for (i = 0; i < DCTSIZE2; i += 2) {
        *dst_ptr++ = *src_ptr++;
        *dst_ptr++ = - *src_ptr++;
          }
        } else {
          /* Any remaining right-edge blocks are only copied. */
          jcopy_block_row(src_row_ptr + dst_blk_x + x_crop_blocks,
                  dst_row_ptr + dst_blk_x,
                  (JDIMENSION) 1);
        }
      }
    }
      }
    }
  }
}
 
 
LOCAL(void)
do_transverse (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
           JDIMENSION x_crop_offset, JDIMENSION y_crop_offset,
           jvirt_barray_ptr *src_coef_arrays,
           jvirt_barray_ptr *dst_coef_arrays)
/* Transverse transpose is equivalent to
 *   1. 180 degree rotation;
 *   2. Transposition;
 * or
 *   1. Horizontal mirroring;
 *   2. Transposition;
 *   3. Horizontal mirroring.
 * These steps are merged into a single processing routine.
 */
{
  JDIMENSION MCU_cols, MCU_rows, comp_width, comp_height, dst_blk_x, dst_blk_y;
  JDIMENSION x_crop_blocks, y_crop_blocks;
  int ci, i, j, offset_x, offset_y;
  JBLOCKARRAY src_buffer, dst_buffer;
  JCOEFPTR src_ptr, dst_ptr;
  jpeg_component_info *compptr;
 
  MCU_cols = srcinfo->output_height /
    (dstinfo->max_h_samp_factor * dstinfo->min_DCT_h_scaled_size);
  MCU_rows = srcinfo->output_width /
    (dstinfo->max_v_samp_factor * dstinfo->min_DCT_v_scaled_size);
 
  for (ci = 0; ci < dstinfo->num_components; ci++) {
    compptr = dstinfo->comp_info + ci;
    comp_width = MCU_cols * compptr->h_samp_factor;
    comp_height = MCU_rows * compptr->v_samp_factor;
    x_crop_blocks = x_crop_offset * compptr->h_samp_factor;
    y_crop_blocks = y_crop_offset * compptr->v_samp_factor;
    for (dst_blk_y = 0; dst_blk_y < compptr->height_in_blocks;
     dst_blk_y += compptr->v_samp_factor) {
      dst_buffer = (*srcinfo->mem->access_virt_barray)
    ((j_common_ptr) srcinfo, dst_coef_arrays[ci], dst_blk_y,
     (JDIMENSION) compptr->v_samp_factor, TRUE);
      for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
    for (dst_blk_x = 0; dst_blk_x < compptr->width_in_blocks;
         dst_blk_x += compptr->h_samp_factor) {
      if (x_crop_blocks + dst_blk_x < comp_width) {
        /* Block is within the mirrorable area. */
        src_buffer = (*srcinfo->mem->access_virt_barray)
          ((j_common_ptr) srcinfo, src_coef_arrays[ci],
           comp_width - x_crop_blocks - dst_blk_x -
           (JDIMENSION) compptr->h_samp_factor,
           (JDIMENSION) compptr->h_samp_factor, FALSE);
      } else {
        src_buffer = (*srcinfo->mem->access_virt_barray)
          ((j_common_ptr) srcinfo, src_coef_arrays[ci],
           dst_blk_x + x_crop_blocks,
           (JDIMENSION) compptr->h_samp_factor, FALSE);
      }
      for (offset_x = 0; offset_x < compptr->h_samp_factor; offset_x++) {
        dst_ptr = dst_buffer[offset_y][dst_blk_x + offset_x];
        if (y_crop_blocks + dst_blk_y < comp_height) {
          if (x_crop_blocks + dst_blk_x < comp_width) {
        /* Block is within the mirrorable area. */
        src_ptr = src_buffer[compptr->h_samp_factor - offset_x - 1]
          [comp_height - y_crop_blocks - dst_blk_y - offset_y - 1];
        for (i = 0; i < DCTSIZE; i++) {
          for (j = 0; j < DCTSIZE; j++) {
            dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
            j++;
            dst_ptr[j*DCTSIZE+i] = -src_ptr[i*DCTSIZE+j];
          }
          i++;
          for (j = 0; j < DCTSIZE; j++) {
            dst_ptr[j*DCTSIZE+i] = -src_ptr[i*DCTSIZE+j];
            j++;
            dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
          }
        }
          } else {
        /* Right-edge blocks are mirrored in y only */
        src_ptr = src_buffer[offset_x]
          [comp_height - y_crop_blocks - dst_blk_y - offset_y - 1];
        for (i = 0; i < DCTSIZE; i++) {
          for (j = 0; j < DCTSIZE; j++) {
            dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
            j++;
            dst_ptr[j*DCTSIZE+i] = -src_ptr[i*DCTSIZE+j];
          }
        }
          }
        } else {
          if (x_crop_blocks + dst_blk_x < comp_width) {
        /* Bottom-edge blocks are mirrored in x only */
        src_ptr = src_buffer[compptr->h_samp_factor - offset_x - 1]
          [dst_blk_y + offset_y + y_crop_blocks];
        for (i = 0; i < DCTSIZE; i++) {
          for (j = 0; j < DCTSIZE; j++)
            dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
          i++;
          for (j = 0; j < DCTSIZE; j++)
            dst_ptr[j*DCTSIZE+i] = -src_ptr[i*DCTSIZE+j];
        }
          } else {
        /* At lower right corner, just transpose, no mirroring */
        src_ptr = src_buffer[offset_x]
          [dst_blk_y + offset_y + y_crop_blocks];
        for (i = 0; i < DCTSIZE; i++)
          for (j = 0; j < DCTSIZE; j++)
            dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
          }
        }
      }
    }
      }
    }
  }
}
 
 
/* Parse an unsigned integer: subroutine for jtransform_parse_crop_spec.
 * Returns TRUE if valid integer found, FALSE if not.
 * *strptr is advanced over the digit string, and *result is set to its value.
 */
 
LOCAL(boolean)
jt_read_integer (const char ** strptr, JDIMENSION * result)
{
  const char * ptr = *strptr;
  JDIMENSION val = 0;
 
  for (; isdigit(*ptr); ptr++) {
    val = val * 10 + (JDIMENSION) (*ptr - '0');
  }
  *result = val;
  if (ptr == *strptr)
    return FALSE;       /* oops, no digits */
  *strptr = ptr;
  return TRUE;
}
 
 
/* Parse a crop specification (written in X11 geometry style).
 * The routine returns TRUE if the spec string is valid, FALSE if not.
 *
 * The crop spec string should have the format
 *  <width>[{fr}]x<height>[{fr}]{+-}<xoffset>{+-}<yoffset>
 * where width, height, xoffset, and yoffset are unsigned integers.
 * Each of the elements can be omitted to indicate a default value.
 * (A weakness of this style is that it is not possible to omit xoffset
 * while specifying yoffset, since they look alike.)
 *
 * This code is loosely based on XParseGeometry from the X11 distribution.
 */
 
GLOBAL(boolean)
jtransform_parse_crop_spec (jpeg_transform_info *info, const char *spec)
{
  info->crop = FALSE;
  info->crop_width_set = JCROP_UNSET;
  info->crop_height_set = JCROP_UNSET;
  info->crop_xoffset_set = JCROP_UNSET;
  info->crop_yoffset_set = JCROP_UNSET;
 
  if (isdigit(*spec)) {
    /* fetch width */
    if (! jt_read_integer(&spec, &info->crop_width))
      return FALSE;
    if (*spec == 'f' || *spec == 'F') {
      spec++;
      info->crop_width_set = JCROP_FORCE;
    } else if (*spec == 'r' || *spec == 'R') {
      spec++;
      info->crop_width_set = JCROP_REFLECT;
    } else
      info->crop_width_set = JCROP_POS;
  }
  if (*spec == 'x' || *spec == 'X') {
    /* fetch height */
    spec++;
    if (! jt_read_integer(&spec, &info->crop_height))
      return FALSE;
    if (*spec == 'f' || *spec == 'F') {
      spec++;
      info->crop_height_set = JCROP_FORCE;
    } else if (*spec == 'r' || *spec == 'R') {
      spec++;
      info->crop_height_set = JCROP_REFLECT;
    } else
      info->crop_height_set = JCROP_POS;
  }
  if (*spec == '+' || *spec == '-') {
    /* fetch xoffset */
    info->crop_xoffset_set = (*spec == '-') ? JCROP_NEG : JCROP_POS;
    spec++;
    if (! jt_read_integer(&spec, &info->crop_xoffset))
      return FALSE;
  }
  if (*spec == '+' || *spec == '-') {
    /* fetch yoffset */
    info->crop_yoffset_set = (*spec == '-') ? JCROP_NEG : JCROP_POS;
    spec++;
    if (! jt_read_integer(&spec, &info->crop_yoffset))
      return FALSE;
  }
  /* We had better have gotten to the end of the string. */
  if (*spec != '\0')
    return FALSE;
  info->crop = TRUE;
  return TRUE;
}
 
 
/* Trim off any partial iMCUs on the indicated destination edge */
 
LOCAL(void)
trim_right_edge (jpeg_transform_info *info, JDIMENSION full_width)
{
  JDIMENSION MCU_cols;
 
  MCU_cols = info->output_width / info->iMCU_sample_width;
  if (MCU_cols > 0 && info->x_crop_offset + MCU_cols ==
      full_width / info->iMCU_sample_width)
    info->output_width = MCU_cols * info->iMCU_sample_width;
}
 
LOCAL(void)
trim_bottom_edge (jpeg_transform_info *info, JDIMENSION full_height)
{
  JDIMENSION MCU_rows;
 
  MCU_rows = info->output_height / info->iMCU_sample_height;
  if (MCU_rows > 0 && info->y_crop_offset + MCU_rows ==
      full_height / info->iMCU_sample_height)
    info->output_height = MCU_rows * info->iMCU_sample_height;
}
 
 
/* Request any required workspace.
 *
 * This routine figures out the size that the output image will be
 * (which implies that all the transform parameters must be set before
 * it is called).
 *
 * We allocate the workspace virtual arrays from the source decompression
 * object, so that all the arrays (both the original data and the workspace)
 * will be taken into account while making memory management decisions.
 * Hence, this routine must be called after jpeg_read_header (which reads
 * the image dimensions) and before jpeg_read_coefficients (which realizes
 * the source's virtual arrays).
 *
 * This function returns FALSE right away if -perfect is given
 * and transformation is not perfect.  Otherwise returns TRUE.
 */
 
GLOBAL(boolean)
jtransform_request_workspace (j_decompress_ptr srcinfo,
                  jpeg_transform_info *info)
{
  jvirt_barray_ptr *coef_arrays;
  boolean need_workspace, transpose_it;
  jpeg_component_info *compptr;
  JDIMENSION xoffset, yoffset, dtemp;
  JDIMENSION width_in_iMCUs, height_in_iMCUs;
  JDIMENSION width_in_blocks, height_in_blocks;
  int itemp, ci, h_samp_factor, v_samp_factor;
 
  /* Determine number of components in output image */
  if (info->force_grayscale &&
      (srcinfo->jpeg_color_space == JCS_YCbCr ||
       srcinfo->jpeg_color_space == JCS_BG_YCC) &&
      srcinfo->num_components == 3)
    /* We'll only process the first component */
    info->num_components = 1;
  else
    /* Process all the components */
    info->num_components = srcinfo->num_components;
 
  /* Compute output image dimensions and related values. */
  jpeg_core_output_dimensions(srcinfo);
 
  /* Return right away if -perfect is given and transformation is not perfect.
   */
  if (info->perfect) {
    if (info->num_components == 1) {
      if (!jtransform_perfect_transform(srcinfo->output_width,
      srcinfo->output_height,
      srcinfo->min_DCT_h_scaled_size,
      srcinfo->min_DCT_v_scaled_size,
      info->transform))
    return FALSE;
    } else {
      if (!jtransform_perfect_transform(srcinfo->output_width,
      srcinfo->output_height,
      srcinfo->max_h_samp_factor * srcinfo->min_DCT_h_scaled_size,
      srcinfo->max_v_samp_factor * srcinfo->min_DCT_v_scaled_size,
      info->transform))
    return FALSE;
    }
  }
 
  /* If there is only one output component, force the iMCU size to be 1;
   * else use the source iMCU size.  (This allows us to do the right thing
   * when reducing color to grayscale, and also provides a handy way of
   * cleaning up "funny" grayscale images whose sampling factors are not 1x1.)
   */
  switch (info->transform) {
  case JXFORM_TRANSPOSE:
  case JXFORM_TRANSVERSE:
  case JXFORM_ROT_90:
  case JXFORM_ROT_270:
    info->output_width = srcinfo->output_height;
    info->output_height = srcinfo->output_width;
    if (info->num_components == 1) {
      info->iMCU_sample_width = srcinfo->min_DCT_v_scaled_size;
      info->iMCU_sample_height = srcinfo->min_DCT_h_scaled_size;
    } else {
      info->iMCU_sample_width =
    srcinfo->max_v_samp_factor * srcinfo->min_DCT_v_scaled_size;
      info->iMCU_sample_height =
    srcinfo->max_h_samp_factor * srcinfo->min_DCT_h_scaled_size;
    }
    break;
  default:
    info->output_width = srcinfo->output_width;
    info->output_height = srcinfo->output_height;
    if (info->num_components == 1) {
      info->iMCU_sample_width = srcinfo->min_DCT_h_scaled_size;
      info->iMCU_sample_height = srcinfo->min_DCT_v_scaled_size;
    } else {
      info->iMCU_sample_width =
    srcinfo->max_h_samp_factor * srcinfo->min_DCT_h_scaled_size;
      info->iMCU_sample_height =
    srcinfo->max_v_samp_factor * srcinfo->min_DCT_v_scaled_size;
    }
  }
 
  /* If cropping has been requested, compute the crop area's position and
   * dimensions, ensuring that its upper left corner falls at an iMCU boundary.
   */
  if (info->crop) {
    /* Insert default values for unset crop parameters */
    if (info->crop_xoffset_set == JCROP_UNSET)
      info->crop_xoffset = 0;   /* default to +0 */
    if (info->crop_yoffset_set == JCROP_UNSET)
      info->crop_yoffset = 0;   /* default to +0 */
    if (info->crop_width_set == JCROP_UNSET) {
      if (info->crop_xoffset >= info->output_width)
    ERREXIT(srcinfo, JERR_BAD_CROP_SPEC);
      info->crop_width = info->output_width - info->crop_xoffset;
    } else {
      /* Check for crop extension */
      if (info->crop_width > info->output_width) {
    /* Crop extension does not work when transforming! */
    if (info->transform != JXFORM_NONE ||
        info->crop_xoffset >= info->crop_width ||
        info->crop_xoffset > info->crop_width - info->output_width)
      ERREXIT(srcinfo, JERR_BAD_CROP_SPEC);
      } else {
    if (info->crop_xoffset >= info->output_width ||
        info->crop_width <= 0 ||
        info->crop_xoffset > info->output_width - info->crop_width)
      ERREXIT(srcinfo, JERR_BAD_CROP_SPEC);
      }
    }
    if (info->crop_height_set == JCROP_UNSET) {
      if (info->crop_yoffset >= info->output_height)
    ERREXIT(srcinfo, JERR_BAD_CROP_SPEC);
      info->crop_height = info->output_height - info->crop_yoffset;
    } else {
      /* Check for crop extension */
      if (info->crop_height > info->output_height) {
    /* Crop extension does not work when transforming! */
    if (info->transform != JXFORM_NONE ||
        info->crop_yoffset >= info->crop_height ||
        info->crop_yoffset > info->crop_height - info->output_height)
      ERREXIT(srcinfo, JERR_BAD_CROP_SPEC);
      } else {
    if (info->crop_yoffset >= info->output_height ||
        info->crop_height <= 0 ||
        info->crop_yoffset > info->output_height - info->crop_height)
      ERREXIT(srcinfo, JERR_BAD_CROP_SPEC);
      }
    }
    /* Convert negative crop offsets into regular offsets */
    if (info->crop_xoffset_set != JCROP_NEG)
      xoffset = info->crop_xoffset;
    else if (info->crop_width > info->output_width) /* crop extension */
      xoffset = info->crop_width - info->output_width - info->crop_xoffset;
    else
      xoffset = info->output_width - info->crop_width - info->crop_xoffset;
    if (info->crop_yoffset_set != JCROP_NEG)
      yoffset = info->crop_yoffset;
    else if (info->crop_height > info->output_height) /* crop extension */
      yoffset = info->crop_height - info->output_height - info->crop_yoffset;
    else
      yoffset = info->output_height - info->crop_height - info->crop_yoffset;
    /* Now adjust so that upper left corner falls at an iMCU boundary */
    switch (info->transform) {
    case JXFORM_DROP:
      /* Ensure the effective drop region will not exceed the requested */
      itemp = info->iMCU_sample_width;
      dtemp = itemp - 1 - ((xoffset + itemp - 1) % itemp);
      xoffset += dtemp;
      if (info->crop_width <= dtemp)
    info->drop_width = 0;
      else if (xoffset + info->crop_width - dtemp == info->output_width)
    /* Matching right edge: include partial iMCU */
    info->drop_width = (info->crop_width - dtemp + itemp - 1) / itemp;
      else
    info->drop_width = (info->crop_width - dtemp) / itemp;
      itemp = info->iMCU_sample_height;
      dtemp = itemp - 1 - ((yoffset + itemp - 1) % itemp);
      yoffset += dtemp;
      if (info->crop_height <= dtemp)
    info->drop_height = 0;
      else if (yoffset + info->crop_height - dtemp == info->output_height)
    /* Matching bottom edge: include partial iMCU */
    info->drop_height = (info->crop_height - dtemp + itemp - 1) / itemp;
      else
    info->drop_height = (info->crop_height - dtemp) / itemp;
      /* Check if sampling factors match for dropping */
      if (info->drop_width != 0 && info->drop_height != 0)
    for (ci = 0; ci < info->num_components &&
             ci < info->drop_ptr->num_components; ci++) {
      if (info->drop_ptr->comp_info[ci].h_samp_factor *
          srcinfo->max_h_samp_factor !=
          srcinfo->comp_info[ci].h_samp_factor *
          info->drop_ptr->max_h_samp_factor)
        ERREXIT6(srcinfo, JERR_BAD_DROP_SAMPLING, ci,
          info->drop_ptr->comp_info[ci].h_samp_factor,
          info->drop_ptr->max_h_samp_factor,
          srcinfo->comp_info[ci].h_samp_factor,
          srcinfo->max_h_samp_factor, 'h');
      if (info->drop_ptr->comp_info[ci].v_samp_factor *
          srcinfo->max_v_samp_factor !=
          srcinfo->comp_info[ci].v_samp_factor *
          info->drop_ptr->max_v_samp_factor)
        ERREXIT6(srcinfo, JERR_BAD_DROP_SAMPLING, ci,
          info->drop_ptr->comp_info[ci].v_samp_factor,
          info->drop_ptr->max_v_samp_factor,
          srcinfo->comp_info[ci].v_samp_factor,
          srcinfo->max_v_samp_factor, 'v');
    }
      break;
    case JXFORM_WIPE:
      /* Ensure the effective wipe region will cover the requested */
      info->drop_width = (JDIMENSION) jdiv_round_up
    ((long) (info->crop_width + (xoffset % info->iMCU_sample_width)),
     (long) info->iMCU_sample_width);
      info->drop_height = (JDIMENSION) jdiv_round_up
    ((long) (info->crop_height + (yoffset % info->iMCU_sample_height)),
     (long) info->iMCU_sample_height);
      break;
    default:
      /* Ensure the effective crop region will cover the requested */
      if (info->crop_width_set == JCROP_FORCE ||
      info->crop_width > info->output_width)
    info->output_width = info->crop_width;
      else
    info->output_width =
      info->crop_width + (xoffset % info->iMCU_sample_width);
      if (info->crop_height_set == JCROP_FORCE ||
      info->crop_height > info->output_height)
    info->output_height = info->crop_height;
      else
    info->output_height =
      info->crop_height + (yoffset % info->iMCU_sample_height);
    }
    /* Save x/y offsets measured in iMCUs */
    info->x_crop_offset = xoffset / info->iMCU_sample_width;
    info->y_crop_offset = yoffset / info->iMCU_sample_height;
  } else {
    info->x_crop_offset = 0;
    info->y_crop_offset = 0;
  }
 
  /* Figure out whether we need workspace arrays,
   * and if so whether they are transposed relative to the source.
   */
  need_workspace = FALSE;
  transpose_it = FALSE;
  switch (info->transform) {
  case JXFORM_NONE:
    if (info->x_crop_offset != 0 || info->y_crop_offset != 0 ||
    info->output_width > srcinfo->output_width ||
    info->output_height > srcinfo->output_height)
      need_workspace = TRUE;
    /* No workspace needed if neither cropping nor transforming */
    break;
  case JXFORM_FLIP_H:
    if (info->trim)
      trim_right_edge(info, srcinfo->output_width);
    if (info->y_crop_offset != 0)
      need_workspace = TRUE;
    /* do_flip_h_no_crop doesn't need a workspace array */
    break;
  case JXFORM_FLIP_V:
    if (info->trim)
      trim_bottom_edge(info, srcinfo->output_height);
    /* Need workspace arrays having same dimensions as source image. */
    need_workspace = TRUE;
    break;
  case JXFORM_TRANSPOSE:
    /* transpose does NOT have to trim anything */
    /* Need workspace arrays having transposed dimensions. */
    need_workspace = TRUE;
    transpose_it = TRUE;
    break;
  case JXFORM_TRANSVERSE:
    if (info->trim) {
      trim_right_edge(info, srcinfo->output_height);
      trim_bottom_edge(info, srcinfo->output_width);
    }
    /* Need workspace arrays having transposed dimensions. */
    need_workspace = TRUE;
    transpose_it = TRUE;
    break;
  case JXFORM_ROT_90:
    if (info->trim)
      trim_right_edge(info, srcinfo->output_height);
    /* Need workspace arrays having transposed dimensions. */
    need_workspace = TRUE;
    transpose_it = TRUE;
    break;
  case JXFORM_ROT_180:
    if (info->trim) {
      trim_right_edge(info, srcinfo->output_width);
      trim_bottom_edge(info, srcinfo->output_height);
    }
    /* Need workspace arrays having same dimensions as source image. */
    need_workspace = TRUE;
    break;
  case JXFORM_ROT_270:
    if (info->trim)
      trim_bottom_edge(info, srcinfo->output_width);
    /* Need workspace arrays having transposed dimensions. */
    need_workspace = TRUE;
    transpose_it = TRUE;
    break;
  case JXFORM_WIPE:
    break;
  case JXFORM_DROP:
#if DROP_REQUEST_FROM_SRC
    drop_request_from_src(info->drop_ptr, srcinfo);
#endif
    break;
  }
 
  /* Allocate workspace if needed.
   * Note that we allocate arrays padded out to the next iMCU boundary,
   * so that transform routines need not worry about missing edge blocks.
   */
  if (need_workspace) {
    coef_arrays = (jvirt_barray_ptr *) (*srcinfo->mem->alloc_small)
      ((j_common_ptr) srcinfo, JPOOL_IMAGE,
       SIZEOF(jvirt_barray_ptr) * info->num_components);
    width_in_iMCUs = (JDIMENSION) jdiv_round_up
      ((long) info->output_width, (long) info->iMCU_sample_width);
    height_in_iMCUs = (JDIMENSION) jdiv_round_up
      ((long) info->output_height, (long) info->iMCU_sample_height);
    for (ci = 0; ci < info->num_components; ci++) {
      compptr = srcinfo->comp_info + ci;
      if (info->num_components == 1) {
    /* we're going to force samp factors to 1x1 in this case */
    h_samp_factor = v_samp_factor = 1;
      } else if (transpose_it) {
    h_samp_factor = compptr->v_samp_factor;
    v_samp_factor = compptr->h_samp_factor;
      } else {
    h_samp_factor = compptr->h_samp_factor;
    v_samp_factor = compptr->v_samp_factor;
      }
      width_in_blocks = width_in_iMCUs * h_samp_factor;
      height_in_blocks = height_in_iMCUs * v_samp_factor;
      coef_arrays[ci] = (*srcinfo->mem->request_virt_barray)
    ((j_common_ptr) srcinfo, JPOOL_IMAGE, FALSE,
     width_in_blocks, height_in_blocks, (JDIMENSION) v_samp_factor);
    }
    info->workspace_coef_arrays = coef_arrays;
  } else
    info->workspace_coef_arrays = NULL;
 
  return TRUE;
}
 
 
/* Transpose destination image parameters */
 
LOCAL(void)
transpose_critical_parameters (j_compress_ptr dstinfo)
{
  int tblno, i, j, ci, itemp;
  jpeg_component_info *compptr;
  JQUANT_TBL *qtblptr;
  JDIMENSION jtemp;
  UINT16 qtemp;
 
  /* Transpose image dimensions */
  jtemp = dstinfo->image_width;
  dstinfo->image_width = dstinfo->image_height;
  dstinfo->image_height = jtemp;
  itemp = dstinfo->min_DCT_h_scaled_size;
  dstinfo->min_DCT_h_scaled_size = dstinfo->min_DCT_v_scaled_size;
  dstinfo->min_DCT_v_scaled_size = itemp;
 
  /* Transpose sampling factors */
  for (ci = 0; ci < dstinfo->num_components; ci++) {
    compptr = dstinfo->comp_info + ci;
    itemp = compptr->h_samp_factor;
    compptr->h_samp_factor = compptr->v_samp_factor;
    compptr->v_samp_factor = itemp;
  }
 
  /* Transpose quantization tables */
  for (tblno = 0; tblno < NUM_QUANT_TBLS; tblno++) {
    qtblptr = dstinfo->quant_tbl_ptrs[tblno];
    if (qtblptr != NULL) {
      for (i = 0; i < DCTSIZE; i++) {
    for (j = 0; j < i; j++) {
      qtemp = qtblptr->quantval[i*DCTSIZE+j];
      qtblptr->quantval[i*DCTSIZE+j] = qtblptr->quantval[j*DCTSIZE+i];
      qtblptr->quantval[j*DCTSIZE+i] = qtemp;
    }
      }
    }
  }
}
 
 
/* Adjust Exif image parameters.
 *
 * We try to adjust the Tags ExifImageWidth and ExifImageHeight if possible.
 */
 
LOCAL(void)
adjust_exif_parameters (JOCTET FAR * data, unsigned int length,
            JDIMENSION new_width, JDIMENSION new_height)
{
  boolean is_motorola; /* Flag for byte order */
  unsigned int number_of_tags, tagnum;
  unsigned int firstoffset, offset;
  JDIMENSION new_value;
 
  if (length < 12) return; /* Length of an IFD entry */
 
  /* Discover byte order */
  if (GETJOCTET(data[0]) == 0x49 && GETJOCTET(data[1]) == 0x49)
    is_motorola = FALSE;
  else if (GETJOCTET(data[0]) == 0x4D && GETJOCTET(data[1]) == 0x4D)
    is_motorola = TRUE;
  else
    return;
 
  /* Check Tag Mark */
  if (is_motorola) {
    if (GETJOCTET(data[2]) != 0) return;
    if (GETJOCTET(data[3]) != 0x2A) return;
  } else {
    if (GETJOCTET(data[3]) != 0) return;
    if (GETJOCTET(data[2]) != 0x2A) return;
  }
 
  /* Get first IFD offset (offset to IFD0) */
  if (is_motorola) {
    if (GETJOCTET(data[4]) != 0) return;
    if (GETJOCTET(data[5]) != 0) return;
    firstoffset = GETJOCTET(data[6]);
    firstoffset <<= 8;
    firstoffset += GETJOCTET(data[7]);
  } else {
    if (GETJOCTET(data[7]) != 0) return;
    if (GETJOCTET(data[6]) != 0) return;
    firstoffset = GETJOCTET(data[5]);
    firstoffset <<= 8;
    firstoffset += GETJOCTET(data[4]);
  }
  if (firstoffset > length - 2) return; /* check end of data segment */
 
  /* Get the number of directory entries contained in this IFD */
  if (is_motorola) {
    number_of_tags = GETJOCTET(data[firstoffset]);
    number_of_tags <<= 8;
    number_of_tags += GETJOCTET(data[firstoffset+1]);
  } else {
    number_of_tags = GETJOCTET(data[firstoffset+1]);
    number_of_tags <<= 8;
    number_of_tags += GETJOCTET(data[firstoffset]);
  }
  if (number_of_tags == 0) return;
  firstoffset += 2;
 
  /* Search for ExifSubIFD offset Tag in IFD0 */
  for (;;) {
    if (firstoffset > length - 12) return; /* check end of data segment */
    /* Get Tag number */
    if (is_motorola) {
      tagnum = GETJOCTET(data[firstoffset]);
      tagnum <<= 8;
      tagnum += GETJOCTET(data[firstoffset+1]);
    } else {
      tagnum = GETJOCTET(data[firstoffset+1]);
      tagnum <<= 8;
      tagnum += GETJOCTET(data[firstoffset]);
    }
    if (tagnum == 0x8769) break; /* found ExifSubIFD offset Tag */
    if (--number_of_tags == 0) return;
    firstoffset += 12;
  }
 
  /* Get the ExifSubIFD offset */
  if (is_motorola) {
    if (GETJOCTET(data[firstoffset+8]) != 0) return;
    if (GETJOCTET(data[firstoffset+9]) != 0) return;
    offset = GETJOCTET(data[firstoffset+10]);
    offset <<= 8;
    offset += GETJOCTET(data[firstoffset+11]);
  } else {
    if (GETJOCTET(data[firstoffset+11]) != 0) return;
    if (GETJOCTET(data[firstoffset+10]) != 0) return;
    offset = GETJOCTET(data[firstoffset+9]);
    offset <<= 8;
    offset += GETJOCTET(data[firstoffset+8]);
  }
  if (offset > length - 2) return; /* check end of data segment */
 
  /* Get the number of directory entries contained in this SubIFD */
  if (is_motorola) {
    number_of_tags = GETJOCTET(data[offset]);
    number_of_tags <<= 8;
    number_of_tags += GETJOCTET(data[offset+1]);
  } else {
    number_of_tags = GETJOCTET(data[offset+1]);
    number_of_tags <<= 8;
    number_of_tags += GETJOCTET(data[offset]);
  }
  if (number_of_tags < 2) return;
  offset += 2;
 
  /* Search for ExifImageWidth and ExifImageHeight Tags in this SubIFD */
  do {
    if (offset > length - 12) return; /* check end of data segment */
    /* Get Tag number */
    if (is_motorola) {
      tagnum = GETJOCTET(data[offset]);
      tagnum <<= 8;
      tagnum += GETJOCTET(data[offset+1]);
    } else {
      tagnum = GETJOCTET(data[offset+1]);
      tagnum <<= 8;
      tagnum += GETJOCTET(data[offset]);
    }
    if (tagnum == 0xA002 || tagnum == 0xA003) {
      if (tagnum == 0xA002)
    new_value = new_width; /* ExifImageWidth Tag */
      else
    new_value = new_height; /* ExifImageHeight Tag */
      if (is_motorola) {
    data[offset+2] = 0; /* Format = unsigned long (4 octets) */
    data[offset+3] = 4;
    data[offset+4] = 0; /* Number Of Components = 1 */
    data[offset+5] = 0;
    data[offset+6] = 0;
    data[offset+7] = 1;
    data[offset+8] = 0;
    data[offset+9] = 0;
    data[offset+10] = (JOCTET)((new_value >> 8) & 0xFF);
    data[offset+11] = (JOCTET)(new_value & 0xFF);
      } else {
    data[offset+2] = 4; /* Format = unsigned long (4 octets) */
    data[offset+3] = 0;
    data[offset+4] = 1; /* Number Of Components = 1 */
    data[offset+5] = 0;
    data[offset+6] = 0;
    data[offset+7] = 0;
    data[offset+8] = (JOCTET)(new_value & 0xFF);
    data[offset+9] = (JOCTET)((new_value >> 8) & 0xFF);
    data[offset+10] = 0;
    data[offset+11] = 0;
      }
    }
    offset += 12;
  } while (--number_of_tags);
}
 
 
/* Adjust output image parameters as needed.
 *
 * This must be called after jpeg_copy_critical_parameters()
 * and before jpeg_write_coefficients().
 *
 * The return value is the set of virtual coefficient arrays to be written
 * (either the ones allocated by jtransform_request_workspace, or the
 * original source data arrays).  The caller will need to pass this value
 * to jpeg_write_coefficients().
 */
 
GLOBAL(jvirt_barray_ptr *)
jtransform_adjust_parameters (j_decompress_ptr srcinfo,
                  j_compress_ptr dstinfo,
                  jvirt_barray_ptr *src_coef_arrays,
                  jpeg_transform_info *info)
{
  /* If force-to-grayscale is requested, adjust destination parameters */
  if (info->force_grayscale) {
    /* First, ensure we have YCC or grayscale data, and that the source's
     * Y channel is full resolution.  (No reasonable person would make Y
     * be less than full resolution, so actually coping with that case
     * isn't worth extra code space.  But we check it to avoid crashing.)
     */
    if ((((dstinfo->jpeg_color_space == JCS_YCbCr ||
       dstinfo->jpeg_color_space == JCS_BG_YCC) &&
      dstinfo->num_components == 3) ||
     (dstinfo->jpeg_color_space == JCS_GRAYSCALE &&
      dstinfo->num_components == 1)) &&
    srcinfo->comp_info[0].h_samp_factor == srcinfo->max_h_samp_factor &&
    srcinfo->comp_info[0].v_samp_factor == srcinfo->max_v_samp_factor) {
      /* We use jpeg_set_colorspace to make sure subsidiary settings get fixed
       * properly.  Among other things, it sets the target h_samp_factor &
       * v_samp_factor to 1, which typically won't match the source.
       * We have to preserve the source's quantization table number, however.
       */
      int sv_quant_tbl_no = dstinfo->comp_info[0].quant_tbl_no;
      jpeg_set_colorspace(dstinfo, JCS_GRAYSCALE);
      dstinfo->comp_info[0].quant_tbl_no = sv_quant_tbl_no;
    } else {
      /* Sorry, can't do it */
      ERREXIT(dstinfo, JERR_CONVERSION_NOTIMPL);
    }
  } else if (info->num_components == 1) {
    /* For a single-component source, we force the destination sampling factors
     * to 1x1, with or without force_grayscale.  This is useful because some
     * decoders choke on grayscale images with other sampling factors.
     */
    dstinfo->comp_info[0].h_samp_factor = 1;
    dstinfo->comp_info[0].v_samp_factor = 1;
  }
 
  /* Correct the destination's image dimensions as necessary
   * for rotate/flip, resize, and crop operations.
   */
  dstinfo->jpeg_width = info->output_width;
  dstinfo->jpeg_height = info->output_height;
 
  /* Transpose destination image parameters, adjust quantization */
  switch (info->transform) {
  case JXFORM_TRANSPOSE:
  case JXFORM_TRANSVERSE:
  case JXFORM_ROT_90:
  case JXFORM_ROT_270:
    transpose_critical_parameters(dstinfo);
    break;
  case JXFORM_DROP:
    if (info->drop_width != 0 && info->drop_height != 0)
      adjust_quant(srcinfo, src_coef_arrays,
           info->drop_ptr, info->drop_coef_arrays,
           info->trim, dstinfo);
    break;
  default:
    break;
  }
 
  /* Adjust Exif properties */
  if (srcinfo->marker_list != NULL &&
      srcinfo->marker_list->marker == JPEG_APP0+1 &&
      srcinfo->marker_list->data_length >= 6 &&
      GETJOCTET(srcinfo->marker_list->data[0]) == 0x45 &&
      GETJOCTET(srcinfo->marker_list->data[1]) == 0x78 &&
      GETJOCTET(srcinfo->marker_list->data[2]) == 0x69 &&
      GETJOCTET(srcinfo->marker_list->data[3]) == 0x66 &&
      GETJOCTET(srcinfo->marker_list->data[4]) == 0 &&
      GETJOCTET(srcinfo->marker_list->data[5]) == 0) {
    /* Suppress output of JFIF marker */
    dstinfo->write_JFIF_header = FALSE;
    /* Adjust Exif image parameters */
    if (dstinfo->jpeg_width != srcinfo->image_width ||
    dstinfo->jpeg_height != srcinfo->image_height)
      /* Align data segment to start of TIFF structure for parsing */
      adjust_exif_parameters(srcinfo->marker_list->data + 6,
    srcinfo->marker_list->data_length - 6,
    dstinfo->jpeg_width, dstinfo->jpeg_height);
  }
 
  /* Return the appropriate output data set */
  if (info->workspace_coef_arrays != NULL)
    return info->workspace_coef_arrays;
  return src_coef_arrays;
}
 
 
/* Execute the actual transformation, if any.
 *
 * This must be called *after* jpeg_write_coefficients, because it depends
 * on jpeg_write_coefficients to have computed subsidiary values such as
 * the per-component width and height fields in the destination object.
 *
 * Note that some transformations will modify the source data arrays!
 */
 
GLOBAL(void)
jtransform_execute_transform (j_decompress_ptr srcinfo,
                  j_compress_ptr dstinfo,
                  jvirt_barray_ptr *src_coef_arrays,
                  jpeg_transform_info *info)
{
  jvirt_barray_ptr *dst_coef_arrays = info->workspace_coef_arrays;
 
  /* Note: conditions tested here should match those in switch statement
   * in jtransform_request_workspace()
   */
  switch (info->transform) {
  case JXFORM_NONE:
    if (info->output_width > srcinfo->output_width ||
    info->output_height > srcinfo->output_height) {
      if (info->output_width > srcinfo->output_width &&
      info->crop_width_set == JCROP_REFLECT)
    do_crop_ext_reflect(srcinfo, dstinfo,
                info->x_crop_offset, info->y_crop_offset,
                src_coef_arrays, dst_coef_arrays);
      else if (info->output_width > srcinfo->output_width &&
           info->crop_width_set == JCROP_FORCE)
    do_crop_ext_flat(srcinfo, dstinfo,
             info->x_crop_offset, info->y_crop_offset,
             src_coef_arrays, dst_coef_arrays);
      else
    do_crop_ext_zero(srcinfo, dstinfo,
             info->x_crop_offset, info->y_crop_offset,
             src_coef_arrays, dst_coef_arrays);
    } else if (info->x_crop_offset != 0 || info->y_crop_offset != 0)
      do_crop(srcinfo, dstinfo, info->x_crop_offset, info->y_crop_offset,
          src_coef_arrays, dst_coef_arrays);
    break;
  case JXFORM_FLIP_H:
    if (info->y_crop_offset != 0)
      do_flip_h(srcinfo, dstinfo, info->x_crop_offset, info->y_crop_offset,
        src_coef_arrays, dst_coef_arrays);
    else
      do_flip_h_no_crop(srcinfo, dstinfo, info->x_crop_offset,
            src_coef_arrays);
    break;
  case JXFORM_FLIP_V:
    do_flip_v(srcinfo, dstinfo, info->x_crop_offset, info->y_crop_offset,
          src_coef_arrays, dst_coef_arrays);
    break;
  case JXFORM_TRANSPOSE:
    do_transpose(srcinfo, dstinfo, info->x_crop_offset, info->y_crop_offset,
         src_coef_arrays, dst_coef_arrays);
    break;
  case JXFORM_TRANSVERSE:
    do_transverse(srcinfo, dstinfo, info->x_crop_offset, info->y_crop_offset,
          src_coef_arrays, dst_coef_arrays);
    break;
  case JXFORM_ROT_90:
    do_rot_90(srcinfo, dstinfo, info->x_crop_offset, info->y_crop_offset,
          src_coef_arrays, dst_coef_arrays);
    break;
  case JXFORM_ROT_180:
    do_rot_180(srcinfo, dstinfo, info->x_crop_offset, info->y_crop_offset,
           src_coef_arrays, dst_coef_arrays);
    break;
  case JXFORM_ROT_270:
    do_rot_270(srcinfo, dstinfo, info->x_crop_offset, info->y_crop_offset,
           src_coef_arrays, dst_coef_arrays);
    break;
  case JXFORM_WIPE:
    if (info->crop_width_set == JCROP_REFLECT &&
    info->y_crop_offset == 0 && info->drop_height ==
    (JDIMENSION) jdiv_round_up
      ((long) info->output_height, (long) info->iMCU_sample_height) &&
    (info->x_crop_offset == 0 ||
     info->x_crop_offset + info->drop_width ==
     (JDIMENSION) jdiv_round_up
       ((long) info->output_width, (long) info->iMCU_sample_width)))
      do_reflect(srcinfo, dstinfo, info->x_crop_offset,
         src_coef_arrays, info->drop_width, info->drop_height);
    else if (info->crop_width_set == JCROP_FORCE)
      do_flatten(srcinfo, dstinfo, info->x_crop_offset, info->y_crop_offset,
         src_coef_arrays, info->drop_width, info->drop_height);
    else
      do_wipe(srcinfo, dstinfo, info->x_crop_offset, info->y_crop_offset,
          src_coef_arrays, info->drop_width, info->drop_height);
    break;
  case JXFORM_DROP:
    if (info->drop_width != 0 && info->drop_height != 0)
      do_drop(srcinfo, dstinfo, info->x_crop_offset, info->y_crop_offset,
          src_coef_arrays, info->drop_ptr, info->drop_coef_arrays,
          info->drop_width, info->drop_height);
    break;
  }
}
 
/* jtransform_perfect_transform
 *
 * Determine whether lossless transformation is perfectly
 * possible for a specified image and transformation.
 *
 * Inputs:
 *   image_width, image_height: source image dimensions.
 *   MCU_width, MCU_height: pixel dimensions of MCU.
 *   transform: transformation identifier.
 * Parameter sources from initialized jpeg_struct
 * (after reading source header):
 *   image_width = cinfo.image_width
 *   image_height = cinfo.image_height
 *   MCU_width = cinfo.max_h_samp_factor * cinfo.block_size
 *   MCU_height = cinfo.max_v_samp_factor * cinfo.block_size
 * Result:
 *   TRUE = perfect transformation possible
 *   FALSE = perfect transformation not possible
 *           (may use custom action then)
 */
 
GLOBAL(boolean)
jtransform_perfect_transform(JDIMENSION image_width, JDIMENSION image_height,
                 int MCU_width, int MCU_height,
                 JXFORM_CODE transform)
{
  boolean result = TRUE; /* initialize TRUE */
 
  switch (transform) {
  case JXFORM_FLIP_H:
  case JXFORM_ROT_270:
    if (image_width % (JDIMENSION) MCU_width)
      result = FALSE;
    break;
  case JXFORM_FLIP_V:
  case JXFORM_ROT_90:
    if (image_height % (JDIMENSION) MCU_height)
      result = FALSE;
    break;
  case JXFORM_TRANSVERSE:
  case JXFORM_ROT_180:
    if (image_width % (JDIMENSION) MCU_width)
      result = FALSE;
    if (image_height % (JDIMENSION) MCU_height)
      result = FALSE;
    break;
  default:
    break;
  }
 
  return result;
}
 
#endif /* TRANSFORMS_SUPPORTED */
 
 
/* Setup decompression object to save desired markers in memory.
 * This must be called before jpeg_read_header() to have the desired effect.
 */
 
GLOBAL(void)
jcopy_markers_setup (j_decompress_ptr srcinfo, JCOPY_OPTION option)
{
#ifdef SAVE_MARKERS_SUPPORTED
  int m;
 
  /* Save comments except under NONE option */
  if (option != JCOPYOPT_NONE) {
    jpeg_save_markers(srcinfo, JPEG_COM, 0xFFFF);
  }
  /* Save all types of APPn markers iff ALL option */
  if (option == JCOPYOPT_ALL) {
    for (m = 0; m < 16; m++)
      jpeg_save_markers(srcinfo, JPEG_APP0 + m, 0xFFFF);
  }
#endif /* SAVE_MARKERS_SUPPORTED */
}
 
/* Copy markers saved in the given source object to the destination object.
 * This should be called just after jpeg_start_compress() or
 * jpeg_write_coefficients().
 * Note that those routines will have written the SOI, and also the
 * JFIF APP0 or Adobe APP14 markers if selected.
 */
 
GLOBAL(void)
jcopy_markers_execute (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
               JCOPY_OPTION option)
{
  jpeg_saved_marker_ptr marker;
 
  /* In the current implementation, we don't actually need to examine the
   * option flag here; we just copy everything that got saved.
   * But to avoid confusion, we do not output JFIF and Adobe APP14 markers
   * if the encoder library already wrote one.
   */
  for (marker = srcinfo->marker_list; marker != NULL; marker = marker->next) {
    if (dstinfo->write_JFIF_header &&
    marker->marker == JPEG_APP0 &&
    marker->data_length >= 5 &&
    GETJOCTET(marker->data[0]) == 0x4A &&
    GETJOCTET(marker->data[1]) == 0x46 &&
    GETJOCTET(marker->data[2]) == 0x49 &&
    GETJOCTET(marker->data[3]) == 0x46 &&
    GETJOCTET(marker->data[4]) == 0)
      continue;         /* reject duplicate JFIF */
    if (dstinfo->write_Adobe_marker &&
    marker->marker == JPEG_APP0+14 &&
    marker->data_length >= 5 &&
    GETJOCTET(marker->data[0]) == 0x41 &&
    GETJOCTET(marker->data[1]) == 0x64 &&
    GETJOCTET(marker->data[2]) == 0x6F &&
    GETJOCTET(marker->data[3]) == 0x62 &&
    GETJOCTET(marker->data[4]) == 0x65)
      continue;         /* reject duplicate Adobe */
#ifdef NEED_FAR_POINTERS
    /* We could use jpeg_write_marker if the data weren't FAR... */
    {
      unsigned int i;
      jpeg_write_m_header(dstinfo, marker->marker, marker->data_length);
      for (i = 0; i < marker->data_length; i++)
    jpeg_write_m_byte(dstinfo, marker->data[i]);
    }
#else
    jpeg_write_marker(dstinfo, marker->marker,
              marker->data, marker->data_length);
#endif
  }
}