/* * jpeg.h * * Basic jpeg data structure definitions. *//* * $Id: jpeg.h,v 1.2 2002/10/15 00:04:29 enlf Exp $ */#ifndef _JPEG#define _JPEGtypedef unsigned char   Uchar;typedef unsigned short  Ushort;typedef unsigned int    Uint;typedef FILE *          StreamIN ;/* * The following structure stores basic information about one component. */typedef struct JpegComponentInfo {    /*     * These values are fixed over the whole image.     * They are read from the SOF marker.     */    short componentId;          /* identifier for this component (0..255) */    short componentIndex;       /* its index in SOF or cPtr->compInfo[]   */    /*     * Downsampling is not normally used in lossless JPEG, although     * it is permitted by the JPEG standard (DIS). We set all sampling      * factors to 1 in this program.     */    short hSampFactor;          /* horizontal sampling factor */    short vSampFactor;          /* vertical sampling factor   */    /*     * Huffman table selector (0..3). The value may vary     * between scans. It is read from the SOS marker.     */    short dcTblNo;} JpegComponentInfo;/* * One of the following structures is created for each huffman coding * table.  We use the same structure for encoding and decoding, so there * may be some extra fields for encoding that aren't used in the decoding * and vice-versa. */typedef struct HuffmanTable {    /*     * These two fields directly represent the contents of a JPEG DHT     * marker     */    Uchar bits[17];    Uchar huffval[256];    /*     * This field is used only during compression.  It's initialized     * FALSE when the table is created, and set TRUE when it's been     * output to the file.     */    int sentTable;    /*     * The remaining fields are computed from the above to allow more     * efficient coding and decoding.  These fields should be considered     * private to the Huffman compression & decompression modules.     */    Ushort ehufco[256];    char ehufsi[256];    Ushort mincode[17];    int maxcode[18];    short valptr[17];    int numbits[256];    int value[256];} HuffmanTable;/* * One of the following structures is used to pass around the * compression information. *//* * One of the following structures is used to pass around the * decompression information. */typedef struct DecompressInfo {    /*     * Image width, height, and image data precision (bits/sample)     * These fields are set by ReadFileHeader or ReadScanHeader     */     int imageWidth;    int imageHeight;    int dataPrecision;    /*     * compInfo[i] describes component that appears i'th in SOF     * numComponents is the # of color components in JPEG image.     */    JpegComponentInfo compInfo[4];    short numComponents;    /*     * *curCompInfo[i] describes component that appears i'th in SOS.     * compsInScan is the # of color components in current scan.     */    JpegComponentInfo *curCompInfo[4];    short compsInScan;    /*     * MCUmembership[i] indexes the i'th component of MCU into the     * curCompInfo array.     */    short MCUmembership[10];    /*     * ptrs to Huffman coding tables, or NULL if not defined     */    HuffmanTable *dcHuffTblPtrs[4];    /*      * prediction seletion value (PSV) and point transform parameter (Pt)     */    int Ss;    int Pt;    /*     * In lossless JPEG, restart interval shall be an integer     * multiple of the number of MCU in a MCU row.     */    int restartInterval;/* MCUs per restart interval, 0 = no restart */    int restartInRows; /*if > 0, MCU rows per restart interval; 0 = no restart*/    /*     * these fields are private data for the entropy decoder     */    int restartRowsToGo;        /* MCUs rows left in this restart interval */    short nextRestartNum;       /* # of next RSTn marker (0..7) */    int  error;                 /* an ERROR flag */} DecompressInfo;/* *-------------------------------------------------------------- * * swap -- * *      Swap the contents stored in a and b. *      "type" is the variable type of a and b. * * Results: *      The values in a and b are swapped. * * Side effects: *      None. * *-------------------------------------------------------------- */#define swap(type,a,b) {type c; c=(a); (a)=(b); (b)=c;}#define MEMSET(s,c,n) memset((void *)(s),(int)(c),(int)(n))#define MEMCPY(s1,s2,n) memcpy((void *)(s1),(void *)(s2),(int)(n))/* * Lossless JPEG specifies data precision to be from 2 to 16 bits/sample. */ #define MinPrecisionBits 2#define MaxPrecisionBits 16#define MinPrecisionValue 2#define MaxPrecisionValue 65535#endif /* _JPEG */