[PATCH 12/21] Use prefixcmp() instead of memcmp() for cleaner code with less magic numbers

[Johan Herland <johan@herland.net>]

Signed-off-by: Johan Herland <johan@herland.net>
---
 tag.c |   15 +++++++++++----
 1 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/tag.c b/tag.c
index c7c75b3..ac76ec0 100644
--- a/tag.c
+++ b/tag.c
@@ -51,6 +51,13 @@ static int verify_object(unsigned char *sha1, const char *expected_type)
 	return ret;
 }
 
+/*
+ * Perform parsing and verification of tag object data.
+ *
+ * The 'item' parameter may be set to NULL if only verification is desired.
+ *
+ * The given data _must_ be null-terminated.
+ */
 int parse_and_verify_tag_buffer(struct tag *item,
 		const char *data, const unsigned long size, int thorough_verify)
 {
@@ -75,7 +82,7 @@ int parse_and_verify_tag_buffer(struct tag *item,
 		return error("Tag object failed preliminary size check");
 
 	/* Verify object line */
-	if (memcmp(data, "object ", 7))
+	if (prefixcmp(data, "object "))
 		return error("Tag object (@ char 0): "
 			"Does not start with \"object \"");
 
@@ -84,7 +91,7 @@ int parse_and_verify_tag_buffer(struct tag *item,
 
 	/* Verify type line */
 	type_line = data + 48;
-	if (memcmp(type_line - 1, "\ntype ", 6))
+	if (prefixcmp(type_line - 1, "\ntype "))
 		return error("Tag object (@ char 47): "
 			"Could not find \"\\ntype \"");
 
@@ -94,7 +101,7 @@ int parse_and_verify_tag_buffer(struct tag *item,
 		return error("Tag object (@ char " PD_FMT "): "
 			"Could not find \"\\n\" after \"type\"",
 			type_line - data);
-	if (memcmp(tag_line, "tag ", 4) || tag_line[4] == '\n')
+	if (prefixcmp(tag_line, "tag ") || tag_line[4] == '\n')
 		return error("Tag object (@ char " PD_FMT "): "
 			"Could not find \"tag \"", tag_line - data);
 
@@ -105,7 +112,7 @@ int parse_and_verify_tag_buffer(struct tag *item,
 			"Could not find \"\\n\" after \"tag\"",
 			tag_line - data);
 	if (thorough_verify) {
-		if (memcmp(tagger_line, "tagger ", 7) || (tagger_line[7] == '\n'))
+		if (prefixcmp(tagger_line, "tagger ") || (tagger_line[7] == '\n'))
 			return error("Tag object (@ char " PD_FMT "): "
 				"Could not find \"tagger \"",
 				tagger_line - data);
-- 
1.5.2