Andrew's git - gitweb.git/blob

   1#ifndef HASH_H
   2#define HASH_H
   3
   4#include "git-compat-util.h"
   5
   6#if defined(SHA1_PPC)
   7#include "ppc/sha1.h"
   8#elif defined(SHA1_APPLE)
   9#include <CommonCrypto/CommonDigest.h>
  10#elif defined(SHA1_OPENSSL)
  11#include <openssl/sha.h>
  12#elif defined(SHA1_DC)
  13#include "sha1dc_git.h"
  14#else /* SHA1_BLK */
  15#include "block-sha1/sha1.h"
  16#endif
  17
  18/*
  19 * Note that these constants are suitable for indexing the hash_algos array and
  20 * comparing against each other, but are otherwise arbitrary, so they should not
  21 * be exposed to the user or serialized to disk.  To know whether a
  22 * git_hash_algo struct points to some usable hash function, test the format_id
  23 * field for being non-zero.  Use the name field for user-visible situations and
  24 * the format_id field for fixed-length fields on disk.
  25 */
  26/* An unknown hash function. */
  27#define GIT_HASH_UNKNOWN 0
  28/* SHA-1 */
  29#define GIT_HASH_SHA1 1
  30/* Number of algorithms supported (including unknown). */
  31#define GIT_HASH_NALGOS (GIT_HASH_SHA1 + 1)
  32
  33typedef void (*git_hash_init_fn)(void *ctx);
  34typedef void (*git_hash_update_fn)(void *ctx, const void *in, size_t len);
  35typedef void (*git_hash_final_fn)(unsigned char *hash, void *ctx);
  36
  37struct git_hash_algo {
  38        /*
  39         * The name of the algorithm, as appears in the config file and in
  40         * messages.
  41         */
  42        const char *name;
  43
  44        /* A four-byte version identifier, used in pack indices. */
  45        uint32_t format_id;
  46
  47        /* The size of a hash context (e.g. git_SHA_CTX). */
  48        size_t ctxsz;
  49
  50        /* The length of the hash in binary. */
  51        size_t rawsz;
  52
  53        /* The length of the hash in hex characters. */
  54        size_t hexsz;
  55
  56        /* The hash initialization function. */
  57        git_hash_init_fn init_fn;
  58
  59        /* The hash update function. */
  60        git_hash_update_fn update_fn;
  61
  62        /* The hash finalization function. */
  63        git_hash_final_fn final_fn;
  64
  65        /* The OID of the empty tree. */
  66        const struct object_id *empty_tree;
  67
  68        /* The OID of the empty blob. */
  69        const struct object_id *empty_blob;
  70};
  71extern const struct git_hash_algo hash_algos[GIT_HASH_NALGOS];
  72
  73#endif