jinclude.h

这是一个JPEG编码源代码

#ifndef JINCLUDE_H
#define JINCLUDE_H

#include <stdio.h>

/* define basic type 
 */
typedef int   INT32;
typedef short INT16;
typedef char  INT8;
typedef unsigned int   UINT32;
typedef unsigned short UINT16;
typedef unsigned char  UINT8;

/* jpeg input sample unit 0~255 
 */
typedef UINT8 JSAMPLE;

/* define useful constant value 
 */
#define DCTSIZE   8
#define DCTSIZE2 64

#define MAX_COMPONENT  4
#define NUM_HUFF_TBLS  2  /* # of huffman table, for basic 2, for other 4.   */
#define NUM_QUANT_TBLS 4  /* # of quant table, default 4, but we just use 2. */

#define MAX_BLOCK_IN_MCU 10 /* ISO Specifid. */

/* this two value not only used in table select but also for evalute */
#define DC_HUFF_TBL 0     
#define AC_HUFF_TBL 1

typedef INT16  DCTVAL;
typedef DCTVAL DCTBLOCK[DCTSIZE2];

typedef struct {
  DCTBLOCK quantval;
} JQUANT_TBL; 

typedef struct {
  UINT8 bits[17]; /* zero not use */
  UINT8 huffval[256];
  
  UINT16 esize[256];
  UINT16 ecode[256];
} JHUFF_TBL;

typedef enum {
  JC_CREATING,
  JC_SETTING,
  JC_START,
  JC_FINISH,
  JC_DESTORING
} JC_STATE;

typedef enum {
  JCS_UNKNOWN,  /* for error */
  JCS_GRAY,
  JCS_RGB,
  JCS_CMYK,
  JCS_YCbCr,
  JCS_YUV
} JC_COLORSPACE;

/* Basic struct define start here.
 */

/* component struct */
typedef struct {
  /* component identify */
  UINT8 comp_id;    /* 0 ~ 255 */
  UINT8 comp_index; /* index in jpeg_compress_info.comp[...] */
  /* information in frame head component table */
  int h_factor;
  int v_factor;
  int quant_tbl_no; /* quant table selector */
  /* information in scan head component table */
  int dc_tbl_no;    /* DC cofficent huffman code table selector */
  int ac_tbl_no;    /* AC cofficent huffman code table selector */
  /* compress buffer used to process this 'color' compress. 
   * initialize it in jpeg_calculate_value().
   */
  int   num_dct_table;
  DCTBLOCK *dct_table;
  /* prev-value */
  DCTVAL preval;
} jpeg_component_info;

/* compress information struct */
typedef struct {
  /* Basic value, client should specified this before jpeg_set_value().
   */
  int image_width;  
  int image_height;

  FILE *output;
  
  /* basic forward DCT based config value. */
  int precision;  /* sample precision,  default to 8 */
  float quality;
  
  /* color component value */
  JC_COLORSPACE in_color_space;
  int num_comp;   /* # of color component, default to 3 for YCrCb */
  jpeg_component_info comp[MAX_COMPONENT];
                  /* components value */

  /* Value need to be calculate , in jpeg_set_value().
   */
  int mcu_per_row;  /* # of MCUs across image. */
  int mcu_rows;     /* # of MCU rows in image. */
  int block_in_mcu; /* # of blocks per MCU */
  
  int mcu_width;    /* # of pixels per MCU, horizontally */
  int mcu_height;   /* # of pixels per MCU, vertically */
  int mcu_blocks;   /* mcu_width * mcu_height */
  
  int max_h_factor;
  int max_v_factor;
  
  JHUFF_TBL *dc_huff_table[NUM_HUFF_TBLS];
  JHUFF_TBL *ac_huff_table[NUM_HUFF_TBLS];
  
  JQUANT_TBL *quant_table[NUM_QUANT_TBLS];
  
  /* We cache the image to this buffer for Color-Convent & Down-Sample. We use 
   * write_scan_line to fill value to this buffer and when this buffer full 
   * filled we make a compress of row-MCU.
   */
  JSAMPLE *inbuf;
  int inbuf_width;  /* # of pixel across buffer  */
  int inbuf_height; /* # of pixel rows in buffer */
  int inbuf_size;   /* buffer size, NOT EQUATE inbuf_width * inbuf_height ! */
  
  /* State value, will changed in processing 
   */
  JC_STATE state;
  int  next_line;
  
} jpeg_compress_info;

#endif /*JINCLUDE_H*/