ungif.h File Reference

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Classes
struct	GifColorType
struct	ColorMapObject
struct	GifImageDesc
struct	ExtensionBlock
struct	Extensions
struct	GifFileType
struct	SavedImage

Macros
#define	GIF_ERROR   0
#define	GIF_OK   1
#define	TRUE   1
#define	FALSE   0
#define	NULL   0
#define	GIF_STAMP   "GIFVER" /* First chars in file - GIF stamp. */
#define	GIF_STAMP_LEN   sizeof(GIF_STAMP) - 1
#define	GIF_VERSION_POS   3 /* Version first character in stamp. */
#define	GIF87_STAMP   "GIF87a" /* First chars in file - GIF stamp. */
#define	GIF89_STAMP   "GIF89a" /* First chars in file - GIF stamp. */
#define	GIF_FILE_BUFFER_SIZE   16384 /* Files uses bigger buffers than usual. */
#define	COMMENT_EXT_FUNC_CODE   0xfe /* comment */
#define	GRAPHICS_EXT_FUNC_CODE   0xf9 /* graphics control */
#define	PLAINTEXT_EXT_FUNC_CODE   0x01 /* plaintext */
#define	APPLICATION_EXT_FUNC_CODE   0xff /* application block */
#define	D_GIF_ERR_OPEN_FAILED   101 /* And DGif possible errors. */
#define	D_GIF_ERR_READ_FAILED   102
#define	D_GIF_ERR_NOT_GIF_FILE   103
#define	D_GIF_ERR_NO_SCRN_DSCR   104
#define	D_GIF_ERR_NO_IMAG_DSCR   105
#define	D_GIF_ERR_NO_COLOR_MAP   106
#define	D_GIF_ERR_WRONG_RECORD   107
#define	D_GIF_ERR_DATA_TOO_BIG   108
#define	D_GIF_ERR_NOT_ENOUGH_MEM   109
#define	D_GIF_ERR_CLOSE_FAILED   110
#define	D_GIF_ERR_NOT_READABLE   111
#define	D_GIF_ERR_IMAGE_DEFECT   112
#define	D_GIF_ERR_EOF_TOO_SOON   113

Typedefs
typedef int	GifBooleanType
typedef unsigned char	GifPixelType
typedef unsigned char *	GifRowType
typedef unsigned char	GifByteType
typedef unsigned int	GifPrefixType
typedef int	GifWord
typedef struct GifColorType	GifColorType
typedef struct ColorMapObject	ColorMapObject
typedef struct GifImageDesc	GifImageDesc
typedef struct GifFileType	GifFileType
typedef int(*	InputFunc) (GifFileType *, GifByteType *, int)
typedef struct SavedImage	SavedImage

Enumerations
enum	GifRecordType {   UNDEFINED_RECORD_TYPE, SCREEN_DESC_RECORD_TYPE, IMAGE_DESC_RECORD_TYPE, EXTENSION_RECORD_TYPE,   TERMINATE_RECORD_TYPE }

Functions
int	DGifSlurp (GifFileType *GifFile) DECLSPEC_HIDDEN
GifFileType *	DGifOpen (void *userPtr, InputFunc readFunc) DECLSPEC_HIDDEN
int	DGifCloseFile (GifFileType *GifFile) DECLSPEC_HIDDEN

Macro Definition Documentation

APPLICATION_EXT_FUNC_CODE

#define APPLICATION_EXT_FUNC_CODE   0xff /* application block */

Definition at line 144 of file ungif.h.

COMMENT_EXT_FUNC_CODE

#define COMMENT_EXT_FUNC_CODE   0xfe /* comment */

Definition at line 141 of file ungif.h.

D_GIF_ERR_CLOSE_FAILED

#define D_GIF_ERR_CLOSE_FAILED   110

Definition at line 160 of file ungif.h.

D_GIF_ERR_DATA_TOO_BIG

#define D_GIF_ERR_DATA_TOO_BIG   108

Definition at line 158 of file ungif.h.

D_GIF_ERR_EOF_TOO_SOON

#define D_GIF_ERR_EOF_TOO_SOON   113

Definition at line 163 of file ungif.h.

D_GIF_ERR_IMAGE_DEFECT

#define D_GIF_ERR_IMAGE_DEFECT   112

Definition at line 162 of file ungif.h.

D_GIF_ERR_NO_COLOR_MAP

#define D_GIF_ERR_NO_COLOR_MAP   106

Definition at line 156 of file ungif.h.

D_GIF_ERR_NO_IMAG_DSCR

#define D_GIF_ERR_NO_IMAG_DSCR   105

Definition at line 155 of file ungif.h.

D_GIF_ERR_NO_SCRN_DSCR

#define D_GIF_ERR_NO_SCRN_DSCR   104

Definition at line 154 of file ungif.h.

D_GIF_ERR_NOT_ENOUGH_MEM

#define D_GIF_ERR_NOT_ENOUGH_MEM   109

Definition at line 159 of file ungif.h.

D_GIF_ERR_NOT_GIF_FILE

#define D_GIF_ERR_NOT_GIF_FILE   103

Definition at line 153 of file ungif.h.

D_GIF_ERR_NOT_READABLE

#define D_GIF_ERR_NOT_READABLE   111

Definition at line 161 of file ungif.h.

D_GIF_ERR_OPEN_FAILED

#define D_GIF_ERR_OPEN_FAILED   101 /* And DGif possible errors. */

Definition at line 151 of file ungif.h.

D_GIF_ERR_READ_FAILED

#define D_GIF_ERR_READ_FAILED   102

Definition at line 152 of file ungif.h.

D_GIF_ERR_WRONG_RECORD

#define D_GIF_ERR_WRONG_RECORD   107

Definition at line 157 of file ungif.h.

FALSE

#define FALSE   0

Definition at line 62 of file ungif.h.

GIF87_STAMP

#define GIF87_STAMP   "GIF87a" /* First chars in file - GIF stamp. */

Definition at line 72 of file ungif.h.

GIF89_STAMP

#define GIF89_STAMP   "GIF89a" /* First chars in file - GIF stamp. */

Definition at line 73 of file ungif.h.

GIF_ERROR

#define GIF_ERROR   0

Definition at line 55 of file ungif.h.

GIF_FILE_BUFFER_SIZE

#define GIF_FILE_BUFFER_SIZE   16384 /* Files uses bigger buffers than usual. */

Definition at line 75 of file ungif.h.

GIF_OK

#define GIF_OK   1

Definition at line 56 of file ungif.h.

GIF_STAMP

#define GIF_STAMP   "GIFVER" /* First chars in file - GIF stamp. */

Definition at line 69 of file ungif.h.

GIF_STAMP_LEN

#define GIF_STAMP_LEN   sizeof(GIF_STAMP) - 1

Definition at line 70 of file ungif.h.

GIF_VERSION_POS

#define GIF_VERSION_POS   3 /* Version first character in stamp. */

Definition at line 71 of file ungif.h.

GRAPHICS_EXT_FUNC_CODE

#define GRAPHICS_EXT_FUNC_CODE   0xf9 /* graphics control */

Definition at line 142 of file ungif.h.

NULL

#define NULL   0

Definition at line 66 of file ungif.h.

PLAINTEXT_EXT_FUNC_CODE

#define PLAINTEXT_EXT_FUNC_CODE   0x01 /* plaintext */

Definition at line 143 of file ungif.h.

TRUE

#define TRUE   1

Definition at line 59 of file ungif.h.

Typedef Documentation

ColorMapObject

typedef struct ColorMapObject ColorMapObject

GifBooleanType

typedef int GifBooleanType

Definition at line 77 of file ungif.h.

GifByteType

typedef unsigned char GifByteType

Definition at line 80 of file ungif.h.

GifColorType

typedef struct GifColorType GifColorType

GifFileType

typedef struct GifFileType GifFileType

GifImageDesc

typedef struct GifImageDesc GifImageDesc

GifPixelType

typedef unsigned char GifPixelType

Definition at line 78 of file ungif.h.

GifPrefixType

typedef unsigned int GifPrefixType

Definition at line 81 of file ungif.h.

GifRowType

typedef unsigned char* GifRowType

Definition at line 79 of file ungif.h.

GifWord

typedef int GifWord

Definition at line 82 of file ungif.h.

InputFunc

typedef int(* InputFunc) (GifFileType *, GifByteType *, int)

Definition at line 137 of file ungif.h.

SavedImage

typedef struct SavedImage SavedImage

Enumeration Type Documentation

GifRecordType

enum GifRecordType

Enumerator
UNDEFINED_RECORD_TYPE
SCREEN_DESC_RECORD_TYPE
IMAGE_DESC_RECORD_TYPE
EXTENSION_RECORD_TYPE
TERMINATE_RECORD_TYPE

Definition at line 128 of file ungif.h.

             {
    UNDEFINED_RECORD_TYPE,
    SCREEN_DESC_RECORD_TYPE,
    IMAGE_DESC_RECORD_TYPE, /* Begin with ',' */
    EXTENSION_RECORD_TYPE,  /* Begin with '!' */
    TERMINATE_RECORD_TYPE   /* Begin with ';' */
} GifRecordType;

Function Documentation

DGifCloseFile()

int DGifCloseFile

(

GifFileType *

GifFile

)

Definition at line 1047 of file ungif.c.

                                     {

    GifFilePrivateType *Private;

    if (GifFile == NULL)
        return GIF_ERROR;

    Private = GifFile->Private;

    if (GifFile->Image.ColorMap) {
        FreeMapObject(GifFile->Image.ColorMap);
        GifFile->Image.ColorMap = NULL;
    }

    if (GifFile->SColorMap) {
        FreeMapObject(GifFile->SColorMap);
        GifFile->SColorMap = NULL;
    }

    ungif_free(Private);
    Private = NULL;

    if (GifFile->SavedImages) {
        FreeSavedImages(GifFile);
        GifFile->SavedImages = NULL;
    }

    FreeExtension(&GifFile->Extensions);

    ungif_free(GifFile);

    return GIF_OK;
}

Referenced by GifDecoder_Release().

DGifOpen()

GifFileType* DGifOpen	(	void *	userPtr,
		InputFunc	readFunc
	)

Definition at line 993 of file ungif.c.

                             {

    unsigned char Buf[GIF_STAMP_LEN + 1];
    GifFileType *GifFile;
    GifFilePrivateType *Private;

    GifFile = ungif_alloc(sizeof(GifFileType));
    if (GifFile == NULL) {
        return NULL;
    }

    memset(GifFile, '\0', sizeof(GifFileType));

    Private = ungif_alloc(sizeof(GifFilePrivateType));
    if (!Private) {
        ungif_free(GifFile);
        return NULL;
    }

    GifFile->Private = (void*)Private;

    Private->Read = readFunc;    /* TVT */
    GifFile->UserData = userData;    /* TVT */

    /* Lets see if this is a GIF file: */
    if (READ(GifFile, Buf, GIF_STAMP_LEN) != GIF_STAMP_LEN) {
        ungif_free(Private);
        ungif_free(GifFile);
        return NULL;
    }

    /* The GIF Version number is ignored at this time. Maybe we should do
     * something more useful with it. */
    Buf[GIF_STAMP_LEN] = 0;
    if (memcmp(GIF_STAMP, Buf, GIF_VERSION_POS) != 0) {
        ungif_free(Private);
        ungif_free(GifFile);
        return NULL;
    }

    if (DGifGetScreenDesc(GifFile) == GIF_ERROR) {
        ungif_free(Private);
        ungif_free(GifFile);
        return NULL;
    }

    return GifFile;
}

Referenced by GifDecoder_Initialize().

DGifSlurp()

int DGifSlurp

(

GifFileType *

GifFile

)

Definition at line 876 of file ungif.c.

                                 {

    int ImageSize;
    GifRecordType RecordType;
    SavedImage *sp;
    GifByteType *ExtData;
    Extensions temp_save;

    temp_save.ExtensionBlocks = NULL;
    temp_save.ExtensionBlockCount = 0;

    do {
        if (DGifGetRecordType(GifFile, &RecordType) == GIF_ERROR)
            return (GIF_ERROR);

        switch (RecordType) {
          case IMAGE_DESC_RECORD_TYPE:
              if (DGifGetImageDesc(GifFile) == GIF_ERROR)
                  return (GIF_ERROR);

              sp = &GifFile->SavedImages[GifFile->ImageCount - 1];
              ImageSize = sp->ImageDesc.Width * sp->ImageDesc.Height;

              sp->RasterBits = ungif_alloc(ImageSize * sizeof(GifPixelType));
              if (sp->RasterBits == NULL) {
                  return GIF_ERROR;
              }
              if (DGifGetLine(GifFile, sp->RasterBits, ImageSize) ==
                  GIF_ERROR)
                  return (GIF_ERROR);
              if (temp_save.ExtensionBlocks) {
                  sp->Extensions.ExtensionBlocks = temp_save.ExtensionBlocks;
                  sp->Extensions.ExtensionBlockCount = temp_save.ExtensionBlockCount;

                  temp_save.ExtensionBlocks = NULL;
                  temp_save.ExtensionBlockCount = 0;

                  /* FIXME: The following is wrong.  It is left in only for
                   * backwards compatibility.  Someday it should go away. Use
                   * the sp->ExtensionBlocks->Function variable instead. */
                  sp->Extensions.Function = sp->Extensions.ExtensionBlocks[0].Function;
              }
              break;

          case EXTENSION_RECORD_TYPE:
          {
              int Function;
              Extensions *Extensions;

              if (DGifGetExtension(GifFile, &Function, &ExtData) == GIF_ERROR)
                  return (GIF_ERROR);

              if (GifFile->ImageCount || Function == GRAPHICS_EXT_FUNC_CODE)
                  Extensions = &temp_save;
              else
                  Extensions = &GifFile->Extensions;

              Extensions->Function = Function;

              if (ExtData)
              {
                  /* Create an extension block with our data */
                  if (AddExtensionBlock(Extensions, ExtData[0], &ExtData[1]) == GIF_ERROR)
                      return (GIF_ERROR);
              }
              else /* Empty extension block */
              {
                  if (AddExtensionBlock(Extensions, 0, NULL) == GIF_ERROR)
                      return (GIF_ERROR);
              }

              while (ExtData != NULL) {
                  int Len;
                  GifByteType *Data;

                  if (DGifGetExtensionNext(GifFile, &ExtData) == GIF_ERROR)
                      return (GIF_ERROR);

                  if (ExtData)
                  {
                      Len = ExtData[0];
                      Data = &ExtData[1];
                  }
                  else
                  {
                      Len = 0;
                      Data = NULL;
                  }

                  if (AppendExtensionBlock(Extensions, Len, Data) == GIF_ERROR)
                      return (GIF_ERROR);
              }
              break;
          }

          case TERMINATE_RECORD_TYPE:
              break;

          default:    /* Should be trapped by DGifGetRecordType */
              break;
        }
    } while (RecordType != TERMINATE_RECORD_TYPE);

    /* Just in case the Gif has an extension block without an associated
     * image... (Should we save this into a savefile structure with no image
     * instead? Have to check if the present writing code can handle that as
     * well.... */
    if (temp_save.ExtensionBlocks)
        FreeExtension(&temp_save);

    return (GIF_OK);
}

Referenced by GifDecoder_Initialize().