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148 lines
2.6 KiB
C
148 lines
2.6 KiB
C
/* copyright (c) 2007 magnus auvinen, see licence.txt for more info */
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#include "e_system.h"
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#include <string.h>
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/* Format: ESDDDDDD EDDDDDDD EDD... Extended, Data, Sign */
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unsigned char *vint_pack(unsigned char *dst, int i)
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{
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*dst = (i>>25)&0x40; /* set sign bit if i<0 */
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i = i^(i>>31); /* if(i<0) i = ~i */
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*dst |= i&0x3F; /* pack 6bit into dst */
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i >>= 6; /* discard 6 bits */
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if(i)
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{
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*dst |= 0x80; /* set extend bit */
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while(1)
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{
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dst++;
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*dst = i&(0x7F); /* pack 7bit */
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i >>= 7; /* discard 7 bits */
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*dst |= (i!=0)<<7; /* set extend bit (may branch) */
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if(!i)
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break;
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}
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}
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dst++;
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return dst;
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}
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const unsigned char *vint_unpack(const unsigned char *src, int *i)
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{
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int sign = (*src>>6)&1;
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*i = *src&0x3F;
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do
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{
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if(!(*src&0x80)) break;
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src++;
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*i |= (*src&(0x7F))<<(6);
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if(!(*src&0x80)) break;
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src++;
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*i |= (*src&(0x7F))<<(6+7);
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if(!(*src&0x80)) break;
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src++;
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*i |= (*src&(0x7F))<<(6+7+7);
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if(!(*src&0x80)) break;
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src++;
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*i |= (*src&(0x7F))<<(6+7+7+7);
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} while(0);
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src++;
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*i ^= -sign; /* if(sign) *i = ~(*i) */
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return src;
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}
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long intpack_decompress(const void *src_, int size, void *dst_)
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{
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const unsigned char *src = (unsigned char *)src_;
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const unsigned char *end = src + size;
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int *dst = (int *)dst_;
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while(src < end)
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{
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src = vint_unpack(src, dst);
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dst++;
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}
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return (long)((unsigned char *)dst-(unsigned char *)dst_);
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}
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long intpack_compress(const void *src_, int size, void *dst_)
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{
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int *src = (int *)src_;
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unsigned char *dst = (unsigned char *)dst_;
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size /= 4;
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while(size)
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{
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dst = vint_pack(dst, *src);
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size--;
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src++;
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}
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return (long)(dst-(unsigned char *)dst_);
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}
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/* */
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long zerobit_compress(const void *src_, int size, void *dst_)
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{
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unsigned char *src = (unsigned char *)src_;
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unsigned char *dst = (unsigned char *)dst_;
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while(size)
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{
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unsigned char bit = 0x80;
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unsigned char mask = 0;
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int dst_move = 1;
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int chunk = size < 8 ? size : 8;
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int b;
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size -= chunk;
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for(b = 0; b < chunk; b++, bit>>=1)
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{
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if(*src)
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{
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dst[dst_move] = *src;
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mask |= bit;
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dst_move++;
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}
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src++;
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}
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*dst = mask;
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dst += dst_move;
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}
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return (long)(dst-(unsigned char *)dst_);
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}
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long zerobit_decompress(const void *src_, int size, void *dst_)
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{
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unsigned char *src = (unsigned char *)src_;
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unsigned char *dst = (unsigned char *)dst_;
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unsigned char *end = src + size;
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while(src != end)
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{
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unsigned char bit = 0x80;
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unsigned char mask = *src++;
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int b;
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for(b = 0; b < 8; b++, bit>>=1)
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{
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if(mask&bit)
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*dst++ = *src++;
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else
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*dst++ = 0;
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}
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}
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return (long)(dst-(unsigned char *)dst_);
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}
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