diff options
author | Junio C Hamano <gitster@pobox.com> | 2019-01-29 23:47:55 +0300 |
---|---|---|
committer | Junio C Hamano <gitster@pobox.com> | 2019-01-29 23:47:55 +0300 |
commit | 33e4ae9c509e0ecdc6508475f2974d275539616e (patch) | |
tree | 93aa27f2902d3257932d64962f724c66b7a50ef6 /cache.h | |
parent | 5d3635db19c6dff4fb063fabfa4161fd3b8285f0 (diff) | |
parent | 4b4e2918099600c1eefe7b5a71bf647803905b7e (diff) |
Merge branch 'bc/sha-256'
Add sha-256 hash and plug it through the code to allow building Git
with the "NewHash".
* bc/sha-256:
hash: add an SHA-256 implementation using OpenSSL
sha256: add an SHA-256 implementation using libgcrypt
Add a base implementation of SHA-256 support
commit-graph: convert to using the_hash_algo
t/helper: add a test helper to compute hash speed
sha1-file: add a constant for hash block size
t: make the sha1 test-tool helper generic
t: add basic tests for our SHA-1 implementation
cache: make hashcmp and hasheq work with larger hashes
hex: introduce functions to print arbitrary hashes
sha1-file: provide functions to look up hash algorithms
sha1-file: rename algorithm to "sha1"
Diffstat (limited to 'cache.h')
-rw-r--r-- | cache.h | 51 |
1 files changed, 33 insertions, 18 deletions
@@ -45,10 +45,20 @@ unsigned long git_deflate_bound(git_zstream *, unsigned long); /* The length in bytes and in hex digits of an object name (SHA-1 value). */ #define GIT_SHA1_RAWSZ 20 #define GIT_SHA1_HEXSZ (2 * GIT_SHA1_RAWSZ) +/* The block size of SHA-1. */ +#define GIT_SHA1_BLKSZ 64 + +/* The length in bytes and in hex digits of an object name (SHA-256 value). */ +#define GIT_SHA256_RAWSZ 32 +#define GIT_SHA256_HEXSZ (2 * GIT_SHA256_RAWSZ) +/* The block size of SHA-256. */ +#define GIT_SHA256_BLKSZ 64 /* The length in byte and in hex digits of the largest possible hash value. */ -#define GIT_MAX_RAWSZ GIT_SHA1_RAWSZ -#define GIT_MAX_HEXSZ GIT_SHA1_HEXSZ +#define GIT_MAX_RAWSZ GIT_SHA256_RAWSZ +#define GIT_MAX_HEXSZ GIT_SHA256_HEXSZ +/* The largest possible block size for any supported hash. */ +#define GIT_MAX_BLKSZ GIT_SHA256_BLKSZ struct object_id { unsigned char hash[GIT_MAX_RAWSZ]; @@ -1028,16 +1038,12 @@ extern const struct object_id null_oid; static inline int hashcmp(const unsigned char *sha1, const unsigned char *sha2) { /* - * This is a temporary optimization hack. By asserting the size here, - * we let the compiler know that it's always going to be 20, which lets - * it turn this fixed-size memcmp into a few inline instructions. - * - * This will need to be extended or ripped out when we learn about - * hashes of different sizes. + * Teach the compiler that there are only two possibilities of hash size + * here, so that it can optimize for this case as much as possible. */ - if (the_hash_algo->rawsz != 20) - BUG("hash size not yet supported by hashcmp"); - return memcmp(sha1, sha2, the_hash_algo->rawsz); + if (the_hash_algo->rawsz == GIT_MAX_RAWSZ) + return memcmp(sha1, sha2, GIT_MAX_RAWSZ); + return memcmp(sha1, sha2, GIT_SHA1_RAWSZ); } static inline int oidcmp(const struct object_id *oid1, const struct object_id *oid2) @@ -1047,7 +1053,13 @@ static inline int oidcmp(const struct object_id *oid1, const struct object_id *o static inline int hasheq(const unsigned char *sha1, const unsigned char *sha2) { - return !hashcmp(sha1, sha2); + /* + * We write this here instead of deferring to hashcmp so that the + * compiler can properly inline it and avoid calling memcmp. + */ + if (the_hash_algo->rawsz == GIT_MAX_RAWSZ) + return !memcmp(sha1, sha2, GIT_MAX_RAWSZ); + return !memcmp(sha1, sha2, GIT_SHA1_RAWSZ); } static inline int oideq(const struct object_id *oid1, const struct object_id *oid2) @@ -1365,9 +1377,9 @@ extern int get_oid_hex(const char *hex, struct object_id *sha1); extern int hex_to_bytes(unsigned char *binary, const char *hex, size_t len); /* - * Convert a binary sha1 to its hex equivalent. The `_r` variant is reentrant, + * Convert a binary hash to its hex equivalent. The `_r` variant is reentrant, * and writes the NUL-terminated output to the buffer `out`, which must be at - * least `GIT_SHA1_HEXSZ + 1` bytes, and returns a pointer to out for + * least `GIT_MAX_HEXSZ + 1` bytes, and returns a pointer to out for * convenience. * * The non-`_r` variant returns a static buffer, but uses a ring of 4 @@ -1375,10 +1387,13 @@ extern int hex_to_bytes(unsigned char *binary, const char *hex, size_t len); * * printf("%s -> %s", sha1_to_hex(one), sha1_to_hex(two)); */ -extern char *sha1_to_hex_r(char *out, const unsigned char *sha1); -extern char *oid_to_hex_r(char *out, const struct object_id *oid); -extern char *sha1_to_hex(const unsigned char *sha1); /* static buffer result! */ -extern char *oid_to_hex(const struct object_id *oid); /* same static buffer as sha1_to_hex */ +char *hash_to_hex_algop_r(char *buffer, const unsigned char *hash, const struct git_hash_algo *); +char *sha1_to_hex_r(char *out, const unsigned char *sha1); +char *oid_to_hex_r(char *out, const struct object_id *oid); +char *hash_to_hex_algop(const unsigned char *hash, const struct git_hash_algo *); /* static buffer result! */ +char *sha1_to_hex(const unsigned char *sha1); /* same static buffer */ +char *hash_to_hex(const unsigned char *hash); /* same static buffer */ +char *oid_to_hex(const struct object_id *oid); /* same static buffer */ /* * Parse a 40-character hexadecimal object ID starting from hex, updating the |