Andrew's git - gitweb.git/blob

   1#ifndef SHA1_LOOKUP_H
   2#define SHA1_LOOKUP_H
   3
   4typedef const unsigned char *sha1_access_fn(size_t index, void *table);
   5
   6extern int sha1_pos(const unsigned char *sha1,
   7                    void *table,
   8                    size_t nr,
   9                    sha1_access_fn fn);
  10
  11/*
  12 * Searches for sha1 in table, using the given fanout table to determine the
  13 * interval to search, then using binary search. Returns the element index of
  14 * the position found if successful, -i-1 if not (where i is the index of the
  15 * least element that is greater than sha1).
  16 *
  17 * Takes the following parameters:
  18 *
  19 *  - sha1: the hash to search for
  20 *  - fanout: a 256-element array of NETWORK-order 32-bit integers; the integer
  21 *    at position i represents the number of elements in table whose first byte
  22 *    is less than or equal to i
  23 *  - table: a sorted list of hashes with optional extra information in between
  24 *  - stride: distance between two consecutive elements in table (should be
  25 *    GIT_MAX_RAWSZ or greater)
  26 *
  27 * This function does not verify the validity of the fanout table.
  28 */
  29extern int bsearch_hash(const unsigned char *sha1, const void *fanout,
  30                        const void *table, size_t stride);
  31#endif