crccache/crccache.h

   1 /*
   2  * crccache.h
   3  *
   4  *  Created on: 21/02/2009
   5  *      Author: tcollett
   6  */
   7
   8 #ifndef CRCCACHE_H_
   9 #define CRCCACHE_H_
  10
  11 const char * CRCCACHE_ENCODING = "crccache";
  12 // hashes per file, 20x5 gives us 100 bytes, acceptable overhead
  13 #define BLOCK_COUNT 20
  14 const int HASH_SIZE=30; // bits per has, 30 bits is 5 bytes base 64
  15 const int HASH_BASE64_SIZE_TX=5; //HASH_SIZE/6;
  16 const int HASH_BASE64_SIZE_ACTUAL=8; // decoded/coded in blocks of 4 into three bytes
  17 const int HASH_BASE64_SIZE_PADDING=3; // decoded/coded in blocks of 4 into three bytes
  18
  19 const int HASH_HEADER_SIZE=100;//BLOCK_COUNT*HASH_BASE64_SIZE;
  20
  21
  22 const unsigned char ENCODING_LITERAL='L';
  23 const unsigned char ENCODING_BLOCK='B';
  24
  25 const int ENCODING_LITERAL_HEADER_SIZE = 1+4;// 1 byte indicator + 4 bytes length
  26 const int ENCODING_BLOCK_HEADER_SIZE = 1+1;// 1 byte indicator + 1 byte block
  27
  28 unsigned decode_30bithash(const char * source);
  29 char * encode_30bithash(unsigned hash, char * target);
  30
  31
  32
  33 #endif /* CRCCACHE_H_ */