pack-check: convert various uses of SHA-1 to abstract forms

Convert various explicit calls to use SHA-1 functions and constants to
references to the_hash_algo.  Make several strings more generic with
respect to the hash algorithm used.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

pack-check.c

@@ -41,7 +41,7 @@ int check_pack_crc(struct packed_git *p, struct pack_window **w_curs,
 	} while (len);
 
 	index_crc = p->index_data;
-	index_crc += 2 + 256 + p->num_objects * (20/4) + nr;
+	index_crc += 2 + 256 + p->num_objects * (the_hash_algo->rawsz/4) + nr;
 
 	return data_crc != ntohl(*index_crc);
 }
@@ -54,7 +54,7 @@ static int verify_packfile(struct packed_git *p,
 {
 	off_t index_size = p->index_size;
 	const unsigned char *index_base = p->index_data;
-	git_SHA_CTX ctx;
+	git_hash_ctx ctx;
 	unsigned char hash[GIT_MAX_RAWSZ], *pack_sig;
 	off_t offset = 0, pack_sig_ofs = 0;
 	uint32_t nr_objects, i;
@@ -64,24 +64,24 @@ static int verify_packfile(struct packed_git *p,
 	if (!is_pack_valid(p))
 		return error("packfile %s cannot be accessed", p->pack_name);
 
-	git_SHA1_Init(&ctx);
+	the_hash_algo->init_fn(&ctx);
 	do {
 		unsigned long remaining;
 		unsigned char *in = use_pack(p, w_curs, offset, &remaining);
 		offset += remaining;
 		if (!pack_sig_ofs)
-			pack_sig_ofs = p->pack_size - 20;
+			pack_sig_ofs = p->pack_size - the_hash_algo->rawsz;
 		if (offset > pack_sig_ofs)
 			remaining -= (unsigned int)(offset - pack_sig_ofs);
-		git_SHA1_Update(&ctx, in, remaining);
+		the_hash_algo->update_fn(&ctx, in, remaining);
 	} while (offset < pack_sig_ofs);
-	git_SHA1_Final(hash, &ctx);
+	the_hash_algo->final_fn(hash, &ctx);
 	pack_sig = use_pack(p, w_curs, pack_sig_ofs, NULL);
 	if (hashcmp(hash, pack_sig))
-		err = error("%s SHA1 checksum mismatch",
+		err = error("%s pack checksum mismatch",
 			    p->pack_name);
-	if (hashcmp(index_base + index_size - 40, pack_sig))
-		err = error("%s SHA1 does not match its index",
+	if (hashcmp(index_base + index_size - the_hash_algo->hexsz, pack_sig))
+		err = error("%s pack checksum does not match its index",
 			    p->pack_name);
 	unuse_pack(w_curs);
 
@@ -165,8 +165,8 @@ int verify_pack_index(struct packed_git *p)
 {
 	off_t index_size;
 	const unsigned char *index_base;
-	git_SHA_CTX ctx;
-	unsigned char sha1[20];
+	git_hash_ctx ctx;
+	unsigned char hash[GIT_MAX_RAWSZ];
 	int err = 0;
 
 	if (open_pack_index(p))
@@ -175,11 +175,11 @@ int verify_pack_index(struct packed_git *p)
 	index_base = p->index_data;
 
 	/* Verify SHA1 sum of the index file */
-	git_SHA1_Init(&ctx);
-	git_SHA1_Update(&ctx, index_base, (unsigned int)(index_size - 20));
-	git_SHA1_Final(sha1, &ctx);
-	if (hashcmp(sha1, index_base + index_size - 20))
-		err = error("Packfile index for %s SHA1 mismatch",
+	the_hash_algo->init_fn(&ctx);
+	the_hash_algo->update_fn(&ctx, index_base, (unsigned int)(index_size - the_hash_algo->rawsz));
+	the_hash_algo->final_fn(hash, &ctx);
+	if (hashcmp(hash, index_base + index_size - the_hash_algo->rawsz))
+		err = error("Packfile index for %s hash mismatch",
 			    p->pack_name);
 	return err;
 }