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54 lines
1.5 KiB
54 lines
1.5 KiB
/* $Id: codelength.h,v 1.3 2011/07/30 13:10:05 nanard Exp $ */ |
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/* Project : miniupnp |
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* Author : Thomas BERNARD |
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* copyright (c) 2005-2015 Thomas Bernard |
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* This software is subjet to the conditions detailed in the |
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* provided LICENCE file. */ |
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#ifndef CODELENGTH_H_INCLUDED |
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#define CODELENGTH_H_INCLUDED |
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/* Encode length by using 7bit per Byte : |
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* Most significant bit of each byte specifies that the |
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* following byte is part of the code */ |
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/* n : unsigned |
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* p : unsigned char * |
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*/ |
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#define DECODELENGTH(n, p) n = 0; \ |
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do { n = (n << 7) | (*p & 0x7f); } \ |
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while((*(p++)&0x80) && (n<(1<<25))); |
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/* n : unsigned |
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* READ : function/macro to read one byte (unsigned char) |
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*/ |
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#define DECODELENGTH_READ(n, READ) \ |
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n = 0; \ |
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do { \ |
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unsigned char c; \ |
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READ(c); \ |
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n = (n << 7) | (c & 0x07f); \ |
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if(!(c&0x80)) break; \ |
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} while(n<(1<<25)); |
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/* n : unsigned |
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* p : unsigned char * |
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* p_limit : unsigned char * |
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*/ |
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#define DECODELENGTH_CHECKLIMIT(n, p, p_limit) \ |
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n = 0; \ |
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do { \ |
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if((p) >= (p_limit)) break; \ |
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n = (n << 7) | (*(p) & 0x7f); \ |
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} while((*((p)++)&0x80) && (n<(1<<25))); |
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/* n : unsigned |
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* p : unsigned char * |
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*/ |
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#define CODELENGTH(n, p) if(n>=268435456) *(p++) = (n >> 28) | 0x80; \ |
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if(n>=2097152) *(p++) = (n >> 21) | 0x80; \ |
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if(n>=16384) *(p++) = (n >> 14) | 0x80; \ |
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if(n>=128) *(p++) = (n >> 7) | 0x80; \ |
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*(p++) = n & 0x7f; |
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#endif /* CODELENGTH_H_INCLUDED */
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