jddctmgr.c File Reference

#include "jinclude.h"
#include "jpeglib.h"
#include "jdct.h"

Include dependency graph for jddctmgr.c:

Go to the source code of this file.

Classes
struct	my_idct_controller
union	multiplier_table

Macros
#define	JPEG_INTERNALS

Typedefs
typedef my_idct_controller *	my_idct_ptr

Functions
	start_pass (j_decompress_ptr cinfo)
	jinit_inverse_dct (j_decompress_ptr cinfo)

Macro Definition Documentation

JPEG_INTERNALS

#define JPEG_INTERNALS

Definition at line 19 of file jddctmgr.c.

Typedef Documentation

my_idct_ptr

typedef my_idct_controller* my_idct_ptr

Definition at line 55 of file jddctmgr.c.

Function Documentation

jinit_inverse_dct()

jinit_inverse_dct

(

j_decompress_ptr

cinfo

)

Definition at line 376 of file jddctmgr.c.

{
  my_idct_ptr idct;
  int ci;
  jpeg_component_info *compptr;
 
  idct = (my_idct_ptr) (*cinfo->mem->alloc_small)
    ((j_common_ptr) cinfo, JPOOL_IMAGE, SIZEOF(my_idct_controller));
  cinfo->idct = &idct->pub;
  idct->pub.start_pass = start_pass;
 
  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
       ci++, compptr++) {
    /* Allocate and pre-zero a multiplier table for each component */
    compptr->dct_table = (*cinfo->mem->alloc_small)
      ((j_common_ptr) cinfo, JPOOL_IMAGE, SIZEOF(multiplier_table));
    MEMZERO(compptr->dct_table, SIZEOF(multiplier_table));
    /* Mark multiplier table not yet set up for any method */
    idct->cur_method[ci] = -1;
  }
}

Referenced by master_selection().

start_pass()

start_pass

(

j_decompress_ptr

cinfo

)

Definition at line 78 of file jddctmgr.c.

{
  my_idct_ptr idct = (my_idct_ptr) cinfo->idct;
  int ci, i;
  jpeg_component_info *compptr;
  int method = 0;
  inverse_DCT_method_ptr method_ptr = NULL;
  JQUANT_TBL * qtbl;
 
  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
       ci++, compptr++) {
    /* Select the proper IDCT routine for this component's scaling */
    switch ((compptr->DCT_h_scaled_size << 8) + compptr->DCT_v_scaled_size) {
#ifdef IDCT_SCALING_SUPPORTED
/*
 * The current scaled-IDCT routines require ISLOW-style multiplier tables,
 * so be sure to compile that code if either ISLOW or SCALING is requested.
 */
#ifndef PROVIDE_ISLOW_TABLES
#define PROVIDE_ISLOW_TABLES
#endif
    case ((1 << 8) + 1):
      method_ptr = jpeg_idct_1x1;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((2 << 8) + 2):
      method_ptr = jpeg_idct_2x2;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((3 << 8) + 3):
      method_ptr = jpeg_idct_3x3;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((4 << 8) + 4):
      method_ptr = jpeg_idct_4x4;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((5 << 8) + 5):
      method_ptr = jpeg_idct_5x5;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((6 << 8) + 6):
      method_ptr = jpeg_idct_6x6;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((7 << 8) + 7):
      method_ptr = jpeg_idct_7x7;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((9 << 8) + 9):
      method_ptr = jpeg_idct_9x9;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((10 << 8) + 10):
      method_ptr = jpeg_idct_10x10;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((11 << 8) + 11):
      method_ptr = jpeg_idct_11x11;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((12 << 8) + 12):
      method_ptr = jpeg_idct_12x12;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((13 << 8) + 13):
      method_ptr = jpeg_idct_13x13;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((14 << 8) + 14):
      method_ptr = jpeg_idct_14x14;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((15 << 8) + 15):
      method_ptr = jpeg_idct_15x15;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((16 << 8) + 16):
      method_ptr = jpeg_idct_16x16;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((16 << 8) + 8):
      method_ptr = jpeg_idct_16x8;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((14 << 8) + 7):
      method_ptr = jpeg_idct_14x7;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((12 << 8) + 6):
      method_ptr = jpeg_idct_12x6;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((10 << 8) + 5):
      method_ptr = jpeg_idct_10x5;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((8 << 8) + 4):
      method_ptr = jpeg_idct_8x4;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((6 << 8) + 3):
      method_ptr = jpeg_idct_6x3;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((4 << 8) + 2):
      method_ptr = jpeg_idct_4x2;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((2 << 8) + 1):
      method_ptr = jpeg_idct_2x1;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((8 << 8) + 16):
      method_ptr = jpeg_idct_8x16;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((7 << 8) + 14):
      method_ptr = jpeg_idct_7x14;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((6 << 8) + 12):
      method_ptr = jpeg_idct_6x12;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((5 << 8) + 10):
      method_ptr = jpeg_idct_5x10;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((4 << 8) + 8):
      method_ptr = jpeg_idct_4x8;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((3 << 8) + 6):
      method_ptr = jpeg_idct_3x6;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((2 << 8) + 4):
      method_ptr = jpeg_idct_2x4;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
    case ((1 << 8) + 2):
      method_ptr = jpeg_idct_1x2;
      method = JDCT_ISLOW;  /* jidctint uses islow-style table */
      break;
#endif
    case ((DCTSIZE << 8) + DCTSIZE):
      switch (cinfo->dct_method) {
#ifdef DCT_ISLOW_SUPPORTED
      case JDCT_ISLOW:
#ifndef PROVIDE_ISLOW_TABLES
#define PROVIDE_ISLOW_TABLES
#endif
    method_ptr = jpeg_idct_islow;
    method = JDCT_ISLOW;
    break;
#endif
#ifdef DCT_IFAST_SUPPORTED
      case JDCT_IFAST:
    method_ptr = jpeg_idct_ifast;
    method = JDCT_IFAST;
    break;
#endif
#ifdef DCT_FLOAT_SUPPORTED
      case JDCT_FLOAT:
    method_ptr = jpeg_idct_float;
    method = JDCT_FLOAT;
    break;
#endif
      default:
    ERREXIT(cinfo, JERR_NOT_COMPILED);
      }
      break;
    default:
      ERREXIT2(cinfo, JERR_BAD_DCTSIZE,
           compptr->DCT_h_scaled_size, compptr->DCT_v_scaled_size);
    }
    idct->pub.inverse_DCT[ci] = method_ptr;
    /* Create multiplier table from quant table.
     * However, we can skip this if the component is uninteresting
     * or if we already built the table.  Also, if no quant table
     * has yet been saved for the component, we leave the
     * multiplier table all-zero; we'll be reading zeroes
     * from the coefficient controller's buffer anyway.
     */
    if (! compptr->component_needed || idct->cur_method[ci] == method)
      continue;
    qtbl = compptr->quant_table;
    if (qtbl == NULL)       /* happens if no data yet for component */
      continue;
    idct->cur_method[ci] = method;
    switch (method) {
#ifdef PROVIDE_ISLOW_TABLES
    case JDCT_ISLOW:
      {
    /* For LL&M IDCT method, multipliers are equal to raw quantization
     * coefficients, but are stored as ints to ensure access efficiency.
     */
    ISLOW_MULT_TYPE * ismtbl = (ISLOW_MULT_TYPE *) compptr->dct_table;
    for (i = 0; i < DCTSIZE2; i++) {
      ismtbl[i] = (ISLOW_MULT_TYPE) qtbl->quantval[i];
    }
      }
      break;
#endif
#ifdef DCT_IFAST_SUPPORTED
    case JDCT_IFAST:
      {
    /* For AA&N IDCT method, multipliers are equal to quantization
     * coefficients scaled by scalefactor[row]*scalefactor[col], where
     *   scalefactor[0] = 1
     *   scalefactor[k] = cos(k*PI/16) * sqrt(2)    for k=1..7
     * For integer operation, the multiplier table is to be scaled by
     * IFAST_SCALE_BITS.
     */
    IFAST_MULT_TYPE * ifmtbl = (IFAST_MULT_TYPE *) compptr->dct_table;
#define CONST_BITS 14
    static const INT16 aanscales[DCTSIZE2] = {
      /* precomputed values scaled up by 14 bits */
      16384, 22725, 21407, 19266, 16384, 12873,  8867,  4520,
      22725, 31521, 29692, 26722, 22725, 17855, 12299,  6270,
      21407, 29692, 27969, 25172, 21407, 16819, 11585,  5906,
      19266, 26722, 25172, 22654, 19266, 15137, 10426,  5315,
      16384, 22725, 21407, 19266, 16384, 12873,  8867,  4520,
      12873, 17855, 16819, 15137, 12873, 10114,  6967,  3552,
       8867, 12299, 11585, 10426,  8867,  6967,  4799,  2446,
       4520,  6270,  5906,  5315,  4520,  3552,  2446,  1247
    };
    SHIFT_TEMPS
 
    for (i = 0; i < DCTSIZE2; i++) {
      ifmtbl[i] = (IFAST_MULT_TYPE)
        DESCALE(MULTIPLY16V16((INT32) qtbl->quantval[i],
                  (INT32) aanscales[i]),
            CONST_BITS-IFAST_SCALE_BITS);
    }
      }
      break;
#endif
#ifdef DCT_FLOAT_SUPPORTED
    case JDCT_FLOAT:
      {
    /* For float AA&N IDCT method, multipliers are equal to quantization
     * coefficients scaled by scalefactor[row]*scalefactor[col], where
     *   scalefactor[0] = 1
     *   scalefactor[k] = cos(k*PI/16) * sqrt(2)    for k=1..7
     * We apply a further scale factor of 1/8
     * with adjustment if necessary.
     */
    FLOAT_MULT_TYPE * fmtbl = (FLOAT_MULT_TYPE *) compptr->dct_table;
    int row, col;
    static const double aanscalefactor[DCTSIZE] = {
      1.0, 1.387039845, 1.306562965, 1.175875602,
      1.0, 0.785694958, 0.541196100, 0.275899379
    };
#if JPEG_DATA_PRECISION == BITS_IN_JSAMPLE
 
    i = 0;
    for (row = 0; row < DCTSIZE; row++) {
      for (col = 0; col < DCTSIZE; col++) {
        fmtbl[i] = (FLOAT_MULT_TYPE) ((double) qtbl->quantval[i] *
          aanscalefactor[row] * aanscalefactor[col] * 0.125);
#else
    double extrafactor = 0.125;
 
    /* Adjust extra factor */
#if JPEG_DATA_PRECISION < BITS_IN_JSAMPLE
    i = BITS_IN_JSAMPLE - JPEG_DATA_PRECISION;
    do { extrafactor *= 2.0; } while (--i);
#else
    i = JPEG_DATA_PRECISION - BITS_IN_JSAMPLE;
    do { extrafactor *= 0.5; } while (--i);
#endif
 
    i = 0;
    for (row = 0; row < DCTSIZE; row++) {
      for (col = 0; col < DCTSIZE; col++) {
        fmtbl[i] = (FLOAT_MULT_TYPE) ((double) qtbl->quantval[i] *
          aanscalefactor[row] * aanscalefactor[col] * extrafactor);
#endif
        i++;
      }
    }
      }
      break;
#endif
    default:
      ERREXIT(cinfo, JERR_NOT_COMPILED);
    }
  }
}

Referenced by jinit_inverse_dct().