t: add basic tests for our SHA-1 implementation

diff --git a/cache.h b/cache.h
index b7166e45ed8c20c627dc741e4b66fa4201c8ec53..85a8e7b10136afdf66e239bfbb5b60a52d44ef87 100644 (file)
--- a/cache.h
+++ b/cache.h
@@ -1024,16 +1024,12 @@ 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)
@@ -1041,14 +1037,30 @@ static inline int oidcmp(const struct object_id *oid1, const struct object_id *o
        return hashcmp(oid1->hash, oid2->hash);
 }
 
+static inline int hasheq(const unsigned char *sha1, const unsigned char *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)
+{
+       return hasheq(oid1->hash, oid2->hash);
+}
+
 static inline int is_null_sha1(const unsigned char *sha1)
 {
-       return !hashcmp(sha1, null_sha1);
+       return hasheq(sha1, null_sha1);
 }
 
 static inline int is_null_oid(const struct object_id *oid)
 {
-       return !hashcmp(oid->hash, null_sha1);
+       return hasheq(oid->hash, null_sha1);
 }
 
 static inline void hashcpy(unsigned char *sha_dst, const unsigned char *sha_src)
@@ -1085,22 +1097,22 @@ static inline void oidread(struct object_id *oid, const unsigned char *hash)
 
 static inline int is_empty_blob_sha1(const unsigned char *sha1)
 {
-       return !hashcmp(sha1, the_hash_algo->empty_blob->hash);
+       return hasheq(sha1, the_hash_algo->empty_blob->hash);
 }
 
 static inline int is_empty_blob_oid(const struct object_id *oid)
 {
-       return !oidcmp(oid, the_hash_algo->empty_blob);
+       return oideq(oid, the_hash_algo->empty_blob);
 }
 
 static inline int is_empty_tree_sha1(const unsigned char *sha1)
 {
-       return !hashcmp(sha1, the_hash_algo->empty_tree->hash);
+       return hasheq(sha1, the_hash_algo->empty_tree->hash);
 }
 
 static inline int is_empty_tree_oid(const struct object_id *oid)
 {
-       return !oidcmp(oid, the_hash_algo->empty_tree);
+       return oideq(oid, the_hash_algo->empty_tree);
 }
 
 const char *empty_tree_oid_hex(void);
@@ -1351,9 +1363,9 @@ 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
@@ -1361,10 +1373,13 @@ 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