fb_gfx_lzw.h

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/* tiny LZW codec,
   Based on code by Mark Nelson, Dr. Dobb's Journal October, 1989 */

#ifndef __FB_GFX_LZW_H__
#define __FB_GFX_LZW_H__


#define MAX_CODE        4095
#define TABLE_SIZE      5021

#define OUTPUT_CODE(c)                                          \
{                                                                                       \
        if (bit) {                                                              \
                *out_buffer++ |= (c & 0xF) << 4;        \
                *out_buffer++ = c >> 4;                         \
                size++;                                                         \
        }                                                                               \
        else {                                                                  \
                *out_buffer++ = c & 0xFF;                       \
                *out_buffer = c >> 8;                           \
        }                                                                               \
        size++;                                                                 \
        if (size >= *out_size)                                  \
                return -1;                                                      \
        bit ^= 1;                                                               \
}

#define INPUT_CODE(c)                                           \
{                                                                                       \
        if (bit) {                                                              \
                c = *in_buffer++ >> 4;                          \
                c |= *in_buffer++ << 4;                         \
                in_size--;                                                      \
        }                                                                               \
        else {                                                                  \
                c = *in_buffer++;                                       \
                c |= (*in_buffer & 0xF) << 8;           \
        }                                                                               \
        in_size--;                                                              \
        bit ^= 1;                                                               \
}


typedef struct LZW_ENTRY
{
        short code;
        unsigned short prefix;
        unsigned char value;
} LZW_ENTRY;

extern LZW_ENTRY fb_lzw_entry[TABLE_SIZE];

#endif