t/helper: add a test helper to compute hash speed

diff --git a/cache.h b/cache.h
index b1fd3d58ab20b6fd4460c6475c0eb0390c3ab9ac..5d969727f96d33c5b723c9179cb11c16605ab25d 100644 (file)
--- a/cache.h
+++ b/cache.h
@@ -45,10 +45,14 @@ 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 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
+/* The largest possible block size for any supported hash. */
+#define GIT_MAX_BLKSZ GIT_SHA1_BLKSZ
 
 struct object_id {
        unsigned char hash[GIT_MAX_RAWSZ];
@@ -1023,7 +1027,13 @@ extern const struct object_id null_oid;
 
 static inline int hashcmp(const unsigned char *sha1, const unsigned char *sha2)
 {
-       return memcmp(sha1, sha2, the_hash_algo->rawsz);
+       /*
+        * 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 == 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)
@@ -1031,14 +1041,30 @@ 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)
@@ -1075,22 +1101,22 @@ 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);
@@ -1341,9 +1367,9 @@ 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
@@ -1351,10 +1377,13 @@ 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
@@ -1508,6 +1537,7 @@ struct checkout {
        unsigned force:1,
                 quiet:1,
                 not_new:1,
+                clone:1,
                 refresh_cache:1;
 };
 #define CHECKOUT_INIT { NULL, "" }