algorithm - C++ LZSS Compression -


can find compression algorithm decompression code. algorithms not forte , friend made code didn't put comments in , somehow lost compression code before leaving. haa.

static inline unsigned char getbit_le(unsigned char byte, unsigned int pos) {     return !!(byte & (1 << pos)); }  static inline unsigned char getbyte_le(unsigned char byte) {     return byte; }  static int lzss_decompress(byte *uncompr, dword uncomprlen,                            byte *compr, dword comprlen) {     unsigned int act_uncomprlen = 0;     unsigned int curbyte = 0;     unsigned int ncurwindowbyte = 0xfee;     unsigned char window[4096];     unsigned int win_size = 4096;      memset(window, 0, win_size);         while (1) {         unsigned char bitmap;          if (curbyte >= comprlen)             break;          bitmap = getbyte_le(compr[curbyte++]);         (unsigned int curbit_bitmap = 0; curbit_bitmap < 8; curbit_bitmap++) {             if (getbit_le(bitmap, curbit_bitmap)) {                 unsigned char data;                  if (curbyte >= comprlen)                     goto out;                  if (act_uncomprlen >= uncomprlen)                     goto out;                  data = ~getbyte_le(compr[curbyte++]);                 uncompr[act_uncomprlen++] = data;                        window[ncurwindowbyte++] = data;                 ncurwindowbyte &= win_size - 1;             } else {                 unsigned int copy_bytes, win_offset;                  if (curbyte >= comprlen)                     goto out;                 win_offset = getbyte_le(compr[curbyte++]);                  if (curbyte >= comprlen)                     goto out;                 copy_bytes = getbyte_le(compr[curbyte++]);                  win_offset |= (copy_bytes >> 4) << 8;                 copy_bytes &= 0x0f;                 copy_bytes += 3;                 (unsigned int = 0; < copy_bytes; i++) {                     unsigned char data;                      if (act_uncomprlen >= uncomprlen)                         goto out;                      data = window[(win_offset + i) & (win_size - 1)];                     uncompr[act_uncomprlen++] = data;                            window[ncurwindowbyte++] = data;                     ncurwindowbyte &= win_size - 1;                      }             }         }     } out:     return act_uncomprlen;   }


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