LZO压缩算法(C语言).doc

/ 本程序采用 Lempel-Ziv 压缩算法, 云风没有对这个算法做深入研究/ 代码是根据 Markus Franz Xaver Johannes Oberhumer 的 LZO 改写/ 而成, 所以算法上的问题请不要问我, 如果你对这个压缩算法有兴趣,/ 请拜访 LZO 的主页 / http:/wildsau.idv.uni-linz.ac.at/mfx/lzo.html/ LZO 属于 GNU 软件, 在此声明, 本文件中的代码使用权利不同于风魂游/ 戏程序库中的其他部分, 请遵守 GNU 协议使用. /#include /#include #include #define byte unsigned charint _stdcall compress(void *src, unsigned src_len, void *dst);int _stdcall decompress(void *src, unsigned src_len,void *dst);static unsigned _do_compress (byte *in, unsigned in_len, byte *out, unsigned *out_len)static long wrkmem 16384L; register byte *ip; byte *op;byte *in_end = in + in_len; byte *ip_end = in + in_len - 13; byte *ii; byte *dict = (byte *)wrkmem; op = out;ip = in;ii = ip; ip += 4; for(;)register byte *m_pos;unsigned m_off;unsigned m_len;unsigned dindex;dindex = (0x21*(unsigned)(ip3)6)ip2)5)ip1)5) & 0x3fff;m_pos = dict dindex;if(unsigned)m_pos (unsigned)in) |(m_off = (unsigned)(unsigned)ip-(unsigned)m_pos) ) 0xbfff)goto literal;if(m_off = 0x0800 | m_pos3 = ip3)goto try_match;dindex = (dindex & 0x7ff ) 0x201f;m_pos = dictdindex;if(unsigned)(m_pos) (unsigned)(in) |(m_off = (unsigned)( (int)(unsigned)ip-(unsigned)m_pos) 0xbfff) goto literal;if (m_off = ip_end)break;continue;match:dictdindex = ip;if(ip - ii 0)register unsigned t = ip - ii;if (t = 3)op-2 |= (byte)t;else if(t 255)tt -= 255;*op+ = 0;*op+ = (byte)tt;do *op+ = *ii+; while (-t 0);ip += 3;if(m_pos3 != *ip+ | m_pos4 != *ip+ | m_pos5 != *ip+ |m_pos6 != *ip+ | m_pos7 != *ip+ | m_pos8 != *ip+ )-ip;m_len = ip - ii;if(m_off = 0x0800 )-m_off;*op+ = (byte)(m_len - 1) 5) | (m_off & 7) 3);elseif (m_off 11) | (m_len - 2);goto m3_m4_offset;elsebyte *end = in_end;byte *m = m_pos + 9;while (ip end & *m = *ip)m+, ip+;m_len = (ip - ii);if(m_off = 0x4000)-m_off;if (m_len = 33)*op+ = (byte)(32 | (m_len - 2);elsem_len -= 33;*op+=32;goto m3_m4_len;elsem_off -= 0x4000;if(m_len 11) | (m_len - 2);elsem_len -= 9;*op+ = (byte)(16 | (m_off & 0x4000) 11);m3_m4_len:while (m_len 255)m_len -= 255;*op+ = 0;*op+ = (byte)m_len;m3_m4_offset:*op+ = (byte)(m_off & 63) 6);ii = ip;if (ip = ip_end)break; *out_len = op - out; return (unsigned) (in_end - ii);int _stdcall compress(void *in, unsigned in_len, void *out) byte *op = out; unsigned t,out_len; if (in_len 0)byte *ii = (byte*)in + in_len - t;if (op = (byte*)out & t = 238)*op+ = (byte) ( 17 + t );elseif (t = 3)op-2 |= (byte)t ;elseif (t 255) tt -= 255;*op+ = 0;*op+ = (byte)tt;do *op+ = *ii+; while (-t 0); *op+ = 17; *op+ = 0; *op+ = 0; return (op - (byte*)out);int _stdcall decompress (void *in, unsigned in_len,void *out) register byte *op; register byte *ip; register unsigned t; register byte *m_pos; byte *ip_end = (byte*)in + in_len; op = out; ip = in; if(*ip 17)t = *ip+ - 17;if (t 0);goto first_literal_run; for(;)t = *ip+;if (t = 16) goto match;if (t = 0)while (*ip = 0)t += 255;ip+;t += 15 + *ip+;* (unsigned *) op = * ( unsigned *) ip;op += 4; ip += 4;if (-t 0)if (t = 4)do* (unsigned * ) op = * ( unsigned * ) ip;op += 4; ip += 4; t -= 4; while (t = 4);if (t 0) do *op+ = *ip+; while (-t 0);elsedo *op+ = *ip+; while (-t 0);first_literal_run:t = *ip+;if (t = 16)goto match;m_pos = op - 0x0801;m_pos -= t 2;m_pos -= *ip+ = 64)m_pos = op - 1;m_pos -= (t 2) & 7;m_pos -= *ip+ 5) - 1;goto copy_match;else if (t = 32)t &= 31;if (t = 0)while (*ip = 0) t += 255;ip+;t += 31 + *ip+;m_pos = op - 1;m_pos -= (* ( unsigned short * ) ip) 2;ip += 2;elseif (t = 16) m_pos = op;m_pos -= (t & 8) 2;ip += 2;if (m_pos = op)goto eof_found;m_pos -= 0x4000;else m_pos = op - 1;m_pos -= t 2;m_pos -= *ip+ = 6 & (op - m_pos) = 4) * (unsigned *) op = * ( unsigned *) m_pos;op += 4; m_pos += 4; t -= 2;do* (unsigned *) op = * ( unsigned *) m_pos;op += 4; m_pos += 4; t -= 4;while (t = 4);if (t 0)do *op+ = *m_pos+; while (-t 0);elsecopy_match:*op+ = *m_pos+; *op