Mechanical conversion to use prefixcmp()

This mechanically converts strncmp() to use prefixcmp(), but only when
the parameters match specific patterns, so that they can be verified
easily.  Leftover from this will be fixed in a separate step, including
idiotic conversions like

    if (!strncmp("foo", arg, 3))

  =>

    if (!(-prefixcmp(arg, "foo")))

This was done by using this script in px.perl

   #!/usr/bin/perl -i.bak -p
   if (/strncmp\(([^,]+), "([^\\"]*)", (\d+)\)/ && (length($2) == $3)) {
           s|strncmp\(([^,]+), "([^\\"]*)", (\d+)\)|prefixcmp($1, "$2")|;
   }
   if (/strncmp\("([^\\"]*)", ([^,]+), (\d+)\)/ && (length($1) == $3)) {
           s|strncmp\("([^\\"]*)", ([^,]+), (\d+)\)|(-prefixcmp($2, "$1"))|;
   }

and running:

   $ git grep -l strncmp -- '*.c' | xargs perl px.perl

Signed-off-by: Junio C Hamano <junkio@cox.net>

builtin-apply.c

@@ -1129,11 +1129,11 @@ static struct fragment *parse_binary_hunk(char **buf_p,
 
 	*status_p = 0;
 
-	if (!strncmp(buffer, "delta ", 6)) {
+	if (!prefixcmp(buffer, "delta ")) {
 		patch_method = BINARY_DELTA_DEFLATED;
 		origlen = strtoul(buffer + 6, NULL, 10);
 	}
-	else if (!strncmp(buffer, "literal ", 8)) {
+	else if (!prefixcmp(buffer, "literal ")) {
 		patch_method = BINARY_LITERAL_DEFLATED;
 		origlen = strtoul(buffer + 8, NULL, 10);
 	}
@@ -2608,14 +2608,14 @@ int cmd_apply(int argc, const char **argv, const char *unused_prefix)
 			read_stdin = 0;
 			continue;
 		}
-		if (!strncmp(arg, "--exclude=", 10)) {
+		if (!prefixcmp(arg, "--exclude=")) {
 			struct excludes *x = xmalloc(sizeof(*x));
 			x->path = arg + 10;
 			x->next = excludes;
 			excludes = x;
 			continue;
 		}
-		if (!strncmp(arg, "-p", 2)) {
+		if (!prefixcmp(arg, "-p")) {
 			p_value = atoi(arg + 2);
 			continue;
 		}
@@ -2669,13 +2669,13 @@ int cmd_apply(int argc, const char **argv, const char *unused_prefix)
 			line_termination = 0;
 			continue;
 		}
-		if (!strncmp(arg, "-C", 2)) {
+		if (!prefixcmp(arg, "-C")) {
 			p_context = strtoul(arg + 2, &end, 0);
 			if (*end != '\0')
 				die("unrecognized context count '%s'", arg + 2);
 			continue;
 		}
-		if (!strncmp(arg, "--whitespace=", 13)) {
+		if (!prefixcmp(arg, "--whitespace=")) {
 			whitespace_option = arg + 13;
 			parse_whitespace_option(arg + 13);
 			continue;

builtin-archive.c

@@ -35,7 +35,7 @@ static int run_remote_archiver(const char *remote, int argc,
 
 	for (i = 1; i < argc; i++) {
 		const char *arg = argv[i];
-		if (!strncmp("--exec=", arg, 7)) {
+		if (!(-prefixcmp(arg, "--exec="))) {
 			if (exec_at)
 				die("multiple --exec specified");
 			exec = arg + 7;
@@ -62,7 +62,7 @@ static int run_remote_archiver(const char *remote, int argc,
 	if (buf[len-1] == '\n')
 		buf[--len] = 0;
 	if (strcmp(buf, "ACK")) {
-		if (len > 5 && !strncmp(buf, "NACK ", 5))
+		if (len > 5 && !prefixcmp(buf, "NACK "))
 			die("git-archive: NACK %s", buf + 5);
 		die("git-archive: protocol error");
 	}
@@ -166,11 +166,11 @@ int parse_archive_args(int argc, const char **argv, struct archiver *ar)
 			verbose = 1;
 			continue;
 		}
-		if (!strncmp(arg, "--format=", 9)) {
+		if (!prefixcmp(arg, "--format=")) {
 			format = arg + 9;
 			continue;
 		}
-		if (!strncmp(arg, "--prefix=", 9)) {
+		if (!prefixcmp(arg, "--prefix=")) {
 			base = arg + 9;
 			continue;
 		}
@@ -218,7 +218,7 @@ static const char *extract_remote_arg(int *ac, const char **av)
 		if (!strcmp(arg, "--"))
 			no_more_options = 1;
 		if (!no_more_options) {
-			if (!strncmp(arg, "--remote=", 9)) {
+			if (!prefixcmp(arg, "--remote=")) {
 				if (remote)
 					die("Multiple --remote specified");
 				remote = arg + 9;

builtin-blame.c

@@ -2097,17 +2097,17 @@ int cmd_blame(int argc, const char **argv, const char *prefix)
 			output_option |= OUTPUT_LONG_OBJECT_NAME;
 		else if (!strcmp("-S", arg) && ++i < argc)
 			revs_file = argv[i];
-		else if (!strncmp("-M", arg, 2)) {
+		else if (!(-prefixcmp(arg, "-M"))) {
 			opt |= PICKAXE_BLAME_MOVE;
 			blame_move_score = parse_score(arg+2);
 		}
-		else if (!strncmp("-C", arg, 2)) {
+		else if (!(-prefixcmp(arg, "-C"))) {
 			if (opt & PICKAXE_BLAME_COPY)
 				opt |= PICKAXE_BLAME_COPY_HARDER;
 			opt |= PICKAXE_BLAME_COPY | PICKAXE_BLAME_MOVE;
 			blame_copy_score = parse_score(arg+2);
 		}
-		else if (!strncmp("-L", arg, 2)) {
+		else if (!(-prefixcmp(arg, "-L"))) {
 			if (!arg[2]) {
 				if (++i >= argc)
 					usage(blame_usage);

builtin-branch.c

@@ -59,7 +59,7 @@ int git_branch_config(const char *var, const char *value)
 		branch_use_color = git_config_colorbool(var, value);
 		return 0;
 	}
-	if (!strncmp(var, "color.branch.", 13)) {
+	if (!prefixcmp(var, "color.branch.")) {
 		int slot = parse_branch_color_slot(var, 13);
 		color_parse(value, var, branch_colors[slot]);
 		return 0;
@@ -178,13 +178,13 @@ static int append_ref(const char *refname, const unsigned char *sha1, int flags,
 	int len;
 
 	/* Detect kind */
-	if (!strncmp(refname, "refs/heads/", 11)) {
+	if (!prefixcmp(refname, "refs/heads/")) {
 		kind = REF_LOCAL_BRANCH;
 		refname += 11;
-	} else if (!strncmp(refname, "refs/remotes/", 13)) {
+	} else if (!prefixcmp(refname, "refs/remotes/")) {
 		kind = REF_REMOTE_BRANCH;
 		refname += 13;
-	} else if (!strncmp(refname, "refs/tags/", 10)) {
+	} else if (!prefixcmp(refname, "refs/tags/")) {
 		kind = REF_TAG;
 		refname += 10;
 	}
@@ -446,7 +446,7 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 			reflog = 1;
 			continue;
 		}
-		if (!strncmp(arg, "--abbrev=", 9)) {
+		if (!prefixcmp(arg, "--abbrev=")) {
 			abbrev = atoi(arg+9);
 			continue;
 		}
@@ -476,7 +476,7 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 		detached = 1;
 	}
 	else {
-		if (strncmp(head, "refs/heads/", 11))
+		if (prefixcmp(head, "refs/heads/"))
 			die("HEAD not found below refs/heads!");
 		head += 11;
 	}

builtin-checkout-index.c

@@ -223,12 +223,12 @@ int cmd_checkout_index(int argc, const char **argv, const char *prefix)
 			to_tempfile = 1;
 			continue;
 		}
-		if (!strncmp(arg, "--prefix=", 9)) {
+		if (!prefixcmp(arg, "--prefix=")) {
 			state.base_dir = arg+9;
 			state.base_dir_len = strlen(state.base_dir);
 			continue;
 		}
-		if (!strncmp(arg, "--stage=", 8)) {
+		if (!prefixcmp(arg, "--stage=")) {
 			if (!strcmp(arg + 8, "all")) {
 				to_tempfile = 1;
 				checkout_stage = CHECKOUT_ALL;

builtin-describe.c

@@ -52,7 +52,7 @@ static int get_name(const char *path, const unsigned char *sha1, int flag, void
 	 * If --tags, then any tags are used.
 	 * Otherwise only annotated tags are used.
 	 */
-	if (!strncmp(path, "refs/tags/", 10)) {
+	if (!prefixcmp(path, "refs/tags/")) {
 		if (object->type == OBJ_TAG)
 			prio = 2;
 		else
@@ -254,12 +254,12 @@ int cmd_describe(int argc, const char **argv, const char *prefix)
 			all = 1;
 		else if (!strcmp(arg, "--tags"))
 			tags = 1;
-		else if (!strncmp(arg, "--abbrev=", 9)) {
+		else if (!prefixcmp(arg, "--abbrev=")) {
 			abbrev = strtoul(arg + 9, NULL, 10);
 			if (abbrev != 0 && (abbrev < MINIMUM_ABBREV || 40 < abbrev))
 				abbrev = DEFAULT_ABBREV;
 		}
-		else if (!strncmp(arg, "--candidates=", 13)) {
+		else if (!prefixcmp(arg, "--candidates=")) {
 			max_candidates = strtoul(arg + 13, NULL, 10);
 			if (max_candidates < 1)
 				max_candidates = 1;

builtin-fmt-merge-msg.c

@@ -81,7 +81,7 @@ static int handle_line(char *line)
 	if (len < 43 || line[40] != '\t')
 		return 1;
 
-	if (!strncmp(line + 41, "not-for-merge", 13))
+	if (!prefixcmp(line + 41, "not-for-merge"))
 		return 0;
 
 	if (line[41] != '\t')
@@ -119,15 +119,15 @@ static int handle_line(char *line)
 	if (pulling_head) {
 		origin = xstrdup(src);
 		src_data->head_status |= 1;
-	} else if (!strncmp(line, "branch ", 7)) {
+	} else if (!prefixcmp(line, "branch ")) {
 		origin = xstrdup(line + 7);
 		append_to_list(&src_data->branch, origin, NULL);
 		src_data->head_status |= 2;
-	} else if (!strncmp(line, "tag ", 4)) {
+	} else if (!prefixcmp(line, "tag ")) {
 		origin = line;
 		append_to_list(&src_data->tag, xstrdup(origin + 4), NULL);
 		src_data->head_status |= 2;
-	} else if (!strncmp(line, "remote branch ", 14)) {
+	} else if (!prefixcmp(line, "remote branch ")) {
 		origin = xstrdup(line + 14);
 		append_to_list(&src_data->r_branch, origin, NULL);
 		src_data->head_status |= 2;
@@ -280,7 +280,7 @@ int cmd_fmt_merge_msg(int argc, const char **argv, const char *prefix)
 	current_branch = resolve_ref("HEAD", head_sha1, 1, NULL);
 	if (!current_branch)
 		die("No current branch");
-	if (!strncmp(current_branch, "refs/heads/", 11))
+	if (!prefixcmp(current_branch, "refs/heads/"))
 		current_branch += 11;
 
 	while (fgets(line, sizeof(line), in)) {

builtin-for-each-ref.c

@@ -814,7 +814,7 @@ int cmd_for_each_ref(int ac, const char **av, char *prefix)
 			i++;
 			break;
 		}
-		if (!strncmp(arg, "--format=", 9)) {
+		if (!prefixcmp(arg, "--format=")) {
 			if (format)
 				die("more than one --format?");
 			format = arg + 9;
@@ -844,7 +844,7 @@ int cmd_for_each_ref(int ac, const char **av, char *prefix)
 			quote_style = QUOTE_TCL;
 			continue;
 		}
-		if (!strncmp(arg, "--count=", 8)) {
+		if (!prefixcmp(arg, "--count=")) {
 			if (maxcount)
 				die("more than one --count?");
 			maxcount = atoi(arg + 8);
@@ -852,7 +852,7 @@ int cmd_for_each_ref(int ac, const char **av, char *prefix)
 				die("The number %s did not parse", arg);
 			continue;
 		}
-		if (!strncmp(arg, "--sort=", 7)) {
+		if (!prefixcmp(arg, "--sort=")) {
 			struct ref_sort *s = xcalloc(1, sizeof(*s));
 			int len;
 

builtin-fsck.c

@@ -546,7 +546,7 @@ static int fsck_head_link(void)
 
 	if (!head_points_at || !(flag & REF_ISSYMREF))
 		return error("HEAD is not a symbolic ref");
-	if (strncmp(head_points_at, "refs/heads/", 11))
+	if (prefixcmp(head_points_at, "refs/heads/"))
 		return error("HEAD points to something strange (%s)",
 			     head_points_at);
 	if (is_null_sha1(sha1))

builtin-grep.c

@@ -527,9 +527,9 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 			opt.word_regexp = 1;
 			continue;
 		}
-		if (!strncmp("-A", arg, 2) ||
-		    !strncmp("-B", arg, 2) ||
-		    !strncmp("-C", arg, 2) ||
+		if (!(-prefixcmp(arg, "-A")) ||
+		    !(-prefixcmp(arg, "-B")) ||
+		    !(-prefixcmp(arg, "-C")) ||
 		    (arg[0] == '-' && '1' <= arg[1] && arg[1] <= '9')) {
 			unsigned num;
 			const char *scan;

builtin-init-db.c

@@ -283,11 +283,11 @@ int cmd_init_db(int argc, const char **argv, const char *prefix)
 
 	for (i = 1; i < argc; i++, argv++) {
 		const char *arg = argv[1];
-		if (!strncmp(arg, "--template=", 11))
+		if (!prefixcmp(arg, "--template="))
 			template_dir = arg+11;
 		else if (!strcmp(arg, "--shared"))
 			shared_repository = PERM_GROUP;
-		else if (!strncmp(arg, "--shared=", 9))
+		else if (!prefixcmp(arg, "--shared="))
 			shared_repository = git_config_perm("arg", arg+9);
 		else
 			usage(init_db_usage);

builtin-log.c

@@ -32,7 +32,7 @@ static void cmd_log_init(int argc, const char **argv, const char *prefix,
 		rev->always_show_header = 0;
 	for (i = 1; i < argc; i++) {
 		const char *arg = argv[i];
-		if (!strncmp(arg, "--encoding=", 11)) {
+		if (!prefixcmp(arg, "--encoding=")) {
 			arg += 11;
 			if (strcmp(arg, "none"))
 				git_log_output_encoding = strdup(arg);
@@ -287,7 +287,7 @@ static void reopen_stdout(struct commit *commit, int nr, int keep_subject)
 
 		sol += 2;
 		/* strip [PATCH] or [PATCH blabla] */
-		if (!keep_subject && !strncmp(sol, "[PATCH", 6)) {
+		if (!keep_subject && !prefixcmp(sol, "[PATCH")) {
 			char *eos = strchr(sol + 6, ']');
 			if (eos) {
 				while (isspace(*eos))
@@ -435,7 +435,7 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 		else if (!strcmp(argv[i], "-n") ||
 				!strcmp(argv[i], "--numbered"))
 			numbered = 1;
-		else if (!strncmp(argv[i], "--start-number=", 15))
+		else if (!prefixcmp(argv[i], "--start-number="))
 			start_number = strtol(argv[i] + 15, NULL, 10);
 		else if (!strcmp(argv[i], "--start-number")) {
 			i++;
@@ -471,13 +471,13 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 		}
 		else if (!strcmp(argv[i], "--attach"))
 			rev.mime_boundary = git_version_string;
-		else if (!strncmp(argv[i], "--attach=", 9))
+		else if (!prefixcmp(argv[i], "--attach="))
 			rev.mime_boundary = argv[i] + 9;
 		else if (!strcmp(argv[i], "--ignore-if-in-upstream"))
 			ignore_if_in_upstream = 1;
 		else if (!strcmp(argv[i], "--thread"))
 			thread = 1;
-		else if (!strncmp(argv[i], "--in-reply-to=", 14))
+		else if (!prefixcmp(argv[i], "--in-reply-to="))
 			in_reply_to = argv[i] + 14;
 		else if (!strcmp(argv[i], "--in-reply-to")) {
 			i++;
@@ -485,7 +485,7 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 				die("Need a Message-Id for --in-reply-to");
 			in_reply_to = argv[i];
 		}
-		else if (!strncmp(argv[i], "--suffix=", 9))
+		else if (!prefixcmp(argv[i], "--suffix="))
 			fmt_patch_suffix = argv[i] + 9;
 		else
 			argv[j++] = argv[i];

builtin-ls-files.c

@@ -406,7 +406,7 @@ int cmd_ls_files(int argc, const char **argv, const char *prefix)
 			add_exclude(argv[++i], "", 0, &dir.exclude_list[EXC_CMDL]);
 			continue;
 		}
-		if (!strncmp(arg, "--exclude=", 10)) {
+		if (!prefixcmp(arg, "--exclude=")) {
 			exc_given = 1;
 			add_exclude(arg+10, "", 0, &dir.exclude_list[EXC_CMDL]);
 			continue;
@@ -416,12 +416,12 @@ int cmd_ls_files(int argc, const char **argv, const char *prefix)
 			add_excludes_from_file(&dir, argv[++i]);
 			continue;
 		}
-		if (!strncmp(arg, "--exclude-from=", 15)) {
+		if (!prefixcmp(arg, "--exclude-from=")) {
 			exc_given = 1;
 			add_excludes_from_file(&dir, arg+15);
 			continue;
 		}
-		if (!strncmp(arg, "--exclude-per-directory=", 24)) {
+		if (!prefixcmp(arg, "--exclude-per-directory=")) {
 			exc_given = 1;
 			dir.exclude_per_dir = arg + 24;
 			continue;
@@ -434,7 +434,7 @@ int cmd_ls_files(int argc, const char **argv, const char *prefix)
 			error_unmatch = 1;
 			continue;
 		}
-		if (!strncmp(arg, "--abbrev=", 9)) {
+		if (!prefixcmp(arg, "--abbrev=")) {
 			abbrev = strtoul(arg+9, NULL, 10);
 			if (abbrev && abbrev < MINIMUM_ABBREV)
 				abbrev = MINIMUM_ABBREV;

builtin-mailinfo.c

@@ -811,7 +811,7 @@ int cmd_mailinfo(int argc, const char **argv, const char *prefix)
 			metainfo_charset = def_charset;
 		else if (!strcmp(argv[1], "-n"))
 			metainfo_charset = NULL;
-		else if (!strncmp(argv[1], "--encoding=", 11))
+		else if (!prefixcmp(argv[1], "--encoding="))
 			metainfo_charset = argv[1] + 11;
 		else
 			usage(mailinfo_usage);

builtin-name-rev.c

@@ -85,7 +85,7 @@ static int name_ref(const char *path, const unsigned char *sha1, int flags, void
 	struct name_ref_data *data = cb_data;
 	int deref = 0;
 
-	if (data->tags_only && strncmp(path, "refs/tags/", 10))
+	if (data->tags_only && prefixcmp(path, "refs/tags/"))
 		return 0;
 
 	if (data->ref_filter && fnmatch(data->ref_filter, path, 0))
@@ -101,9 +101,9 @@ static int name_ref(const char *path, const unsigned char *sha1, int flags, void
 	if (o && o->type == OBJ_COMMIT) {
 		struct commit *commit = (struct commit *)o;
 
-		if (!strncmp(path, "refs/heads/", 11))
+		if (!prefixcmp(path, "refs/heads/"))
 			path = path + 11;
-		else if (!strncmp(path, "refs/", 5))
+		else if (!prefixcmp(path, "refs/"))
 			path = path + 5;
 
 		name_rev(commit, xstrdup(path), 0, 0, deref);
@@ -156,7 +156,7 @@ int cmd_name_rev(int argc, const char **argv, const char *prefix)
 			} else if (!strcmp(*argv, "--tags")) {
 				data.tags_only = 1;
 				continue;
-			} else  if (!strncmp(*argv, "--refs=", 7)) {
+			} else  if (!prefixcmp(*argv, "--refs=")) {
 				data.ref_filter = *argv + 7;
 				continue;
 			} else if (!strcmp(*argv, "--all")) {

builtin-pack-objects.c

@@ -1579,14 +1579,14 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix)
 			incremental = 1;
 			continue;
 		}
-		if (!strncmp("--window=", arg, 9)) {
+		if (!(-prefixcmp(arg, "--window="))) {
 			char *end;
 			window = strtoul(arg+9, &end, 0);
 			if (!arg[9] || *end)
 				usage(pack_usage);
 			continue;
 		}
-		if (!strncmp("--depth=", arg, 8)) {
+		if (!(-prefixcmp(arg, "--depth="))) {
 			char *end;
 			depth = strtoul(arg+8, &end, 0);
 			if (!arg[8] || *end)
@@ -1622,7 +1622,7 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix)
 			continue;
 		}
 		if (!strcmp("--unpacked", arg) ||
-		    !strncmp("--unpacked=", arg, 11) ||
+		    !(-prefixcmp(arg, "--unpacked=")) ||
 		    !strcmp("--reflog", arg) ||
 		    !strcmp("--all", arg)) {
 			use_internal_rev_list = 1;

builtin-pack-refs.c

@@ -36,7 +36,7 @@ static int handle_one_ref(const char *path, const unsigned char *sha1,
 	/* Do not pack the symbolic refs */
 	if ((flags & REF_ISSYMREF))
 		return 0;
-	is_tag_ref = !strncmp(path, "refs/tags/", 10);
+	is_tag_ref = !prefixcmp(path, "refs/tags/");
 
 	/* ALWAYS pack refs that were already packed or are tags */
 	if (!cb->all && !is_tag_ref && !(flags & REF_ISPACKED))

builtin-push.c

@@ -32,7 +32,7 @@ static int expand_one_ref(const char *ref, const unsigned char *sha1, int flag,
 	/* Ignore the "refs/" at the beginning of the refname */
 	ref += 5;
 
-	if (!strncmp(ref, "tags/", 5))
+	if (!prefixcmp(ref, "tags/"))
 		add_refspec(xstrdup(ref));
 	return 0;
 }
@@ -149,10 +149,10 @@ static int get_remotes_uri(const char *repo, const char *uri[MAX_URI])
 		int is_refspec;
 		char *s, *p;
 
-		if (!strncmp("URL:", buffer, 4)) {
+		if (!(-prefixcmp(buffer, "URL:"))) {
 			is_refspec = 0;
 			s = buffer + 4;
-		} else if (!strncmp("Push:", buffer, 5)) {
+		} else if (!(-prefixcmp(buffer, "Push:"))) {
 			is_refspec = 1;
 			s = buffer + 5;
 		} else
@@ -195,7 +195,7 @@ static int config_get_receivepack;
 
 static int get_remote_config(const char* key, const char* value)
 {
-	if (!strncmp(key, "remote.", 7) &&
+	if (!prefixcmp(key, "remote.") &&
 	    !strncmp(key + 7, config_repo, config_repo_len)) {
 		if (!strcmp(key + 7 + config_repo_len, ".url")) {
 			if (config_current_uri < MAX_URI)
@@ -324,8 +324,8 @@ static int do_push(const char *repo)
 		const char **dest_refspec = refspec;
 		const char *dest = uri[i];
 		const char *sender = "git-send-pack";
-		if (!strncmp(dest, "http://", 7) ||
-		    !strncmp(dest, "https://", 8))
+		if (!prefixcmp(dest, "http://") ||
+		    !prefixcmp(dest, "https://"))
 			sender = "git-http-push";
 		else if (thin)
 			argv[dest_argc++] = "--thin";
@@ -373,7 +373,7 @@ int cmd_push(int argc, const char **argv, const char *prefix)
 			verbose=1;
 			continue;
 		}
-		if (!strncmp(arg, "--repo=", 7)) {
+		if (!prefixcmp(arg, "--repo=")) {
 			repo = arg+7;
 			continue;
 		}
@@ -397,11 +397,11 @@ int cmd_push(int argc, const char **argv, const char *prefix)
 			thin = 0;
 			continue;
 		}
-		if (!strncmp(arg, "--receive-pack=", 15)) {
+		if (!prefixcmp(arg, "--receive-pack=")) {
 			receivepack = arg;
 			continue;
 		}
-		if (!strncmp(arg, "--exec=", 7)) {
+		if (!prefixcmp(arg, "--exec=")) {
 			receivepack = arg;
 			continue;
 		}

builtin-read-tree.c

@@ -133,7 +133,7 @@ int cmd_read_tree(int argc, const char **argv, const char *unused_prefix)
 		 *  entries and put the entries from the tree under the
 		 * given subdirectory.
 		 */
-		if (!strncmp(arg, "--prefix=", 9)) {
+		if (!prefixcmp(arg, "--prefix=")) {
 			if (stage || opts.merge || opts.prefix)
 				usage(read_tree_usage);
 			opts.prefix = arg + 9;
@@ -179,7 +179,7 @@ int cmd_read_tree(int argc, const char **argv, const char *unused_prefix)
 			continue;
 		}
 
-		if (!strncmp(arg, "--exclude-per-directory=", 24)) {
+		if (!prefixcmp(arg, "--exclude-per-directory=")) {
 			struct dir_struct *dir;
 
 			if (opts.dir)

builtin-reflog.c

@@ -321,9 +321,9 @@ static int cmd_reflog_expire(int argc, const char **argv, const char *prefix)
 		const char *arg = argv[i];
 		if (!strcmp(arg, "--dry-run") || !strcmp(arg, "-n"))
 			cb.dry_run = 1;
-		else if (!strncmp(arg, "--expire=", 9))
+		else if (!prefixcmp(arg, "--expire="))
 			cb.expire_total = approxidate(arg + 9);
-		else if (!strncmp(arg, "--expire-unreachable=", 21))
+		else if (!prefixcmp(arg, "--expire-unreachable="))
 			cb.expire_unreachable = approxidate(arg + 21);
 		else if (!strcmp(arg, "--stale-fix"))
 			cb.stalefix = 1;

builtin-rerere.c

@@ -105,11 +105,11 @@ static int handle_file(const char *path,
 		SHA1_Init(&ctx);
 
 	while (fgets(buf, sizeof(buf), f)) {
-		if (!strncmp("<<<<<<< ", buf, 8))
+		if (!(-prefixcmp(buf, "<<<<<<< ")))
 			hunk = 1;
-		else if (!strncmp("=======", buf, 7))
+		else if (!(-prefixcmp(buf, "=======")))
 			hunk = 2;
-		else if (!strncmp(">>>>>>> ", buf, 8)) {
+		else if (!(-prefixcmp(buf, ">>>>>>> "))) {
 			hunk_no++;
 			hunk = 0;
 			if (memcmp(one->ptr, two->ptr, one->nr < two->nr ?

builtin-rev-parse.c

@@ -274,7 +274,7 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix)
 				continue;
 			}
 			if (!strcmp(arg, "--short") ||
-			    !strncmp(arg, "--short=", 8)) {
+			    !prefixcmp(arg, "--short=")) {
 				filter &= ~(DO_FLAGS|DO_NOREV);
 				verify = 1;
 				abbrev = DEFAULT_ABBREV;
@@ -352,19 +352,19 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix)
 						: "false");
 				continue;
 			}
-			if (!strncmp(arg, "--since=", 8)) {
+			if (!prefixcmp(arg, "--since=")) {
 				show_datestring("--max-age=", arg+8);
 				continue;
 			}
-			if (!strncmp(arg, "--after=", 8)) {
+			if (!prefixcmp(arg, "--after=")) {
 				show_datestring("--max-age=", arg+8);
 				continue;
 			}
-			if (!strncmp(arg, "--before=", 9)) {
+			if (!prefixcmp(arg, "--before=")) {
 				show_datestring("--min-age=", arg+9);
 				continue;
 			}
-			if (!strncmp(arg, "--until=", 8)) {
+			if (!prefixcmp(arg, "--until=")) {
 				show_datestring("--min-age=", arg+8);
 				continue;
 			}

builtin-shortlog.c

@@ -124,7 +124,7 @@ static void insert_author_oneline(struct path_list *list,
 	else
 		free(buffer);
 
-	if (!strncmp(oneline, "[PATCH", 6)) {
+	if (!prefixcmp(oneline, "[PATCH")) {
 		char *eob = strchr(oneline, ']');
 
 		if (eob) {
@@ -179,7 +179,7 @@ static void read_from_stdin(struct path_list *list)
 	while (fgets(buffer, sizeof(buffer), stdin) != NULL) {
 		char *bob;
 		if ((buffer[0] == 'A' || buffer[0] == 'a') &&
-				!strncmp(buffer + 1, "uthor: ", 7) &&
+				!prefixcmp(buffer + 1, "uthor: ") &&
 				(bob = strchr(buffer + 7, '<')) != NULL) {
 			char buffer2[1024], offset = 0;
 
@@ -230,7 +230,7 @@ static void get_from_rev(struct rev_info *rev, struct path_list *list)
 			else
 				eol++;
 
-			if (!strncmp(buffer, "author ", 7)) {
+			if (!prefixcmp(buffer, "author ")) {
 				char *bracket = strchr(buffer, '<');
 
 				if (bracket == NULL || bracket > eol)

builtin-show-branch.c

@@ -266,7 +266,7 @@ static void show_one_commit(struct commit *commit, int no_name)
 				    pretty, sizeof(pretty), 0, NULL, NULL, 0);
 	else
 		strcpy(pretty, "(unavailable)");
-	if (!strncmp(pretty, "[PATCH] ", 8))
+	if (!prefixcmp(pretty, "[PATCH] "))
 		cp = pretty + 8;
 	else
 		cp = pretty;
@@ -404,7 +404,7 @@ static int append_remote_ref(const char *refname, const unsigned char *sha1, int
 
 static int append_tag_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 {
-	if (strncmp(refname, "refs/tags/", 10))
+	if (prefixcmp(refname, "refs/tags/"))
 		return 0;
 	return append_ref(refname + 5, sha1, 0);
 }
@@ -435,9 +435,9 @@ static int append_matching_ref(const char *refname, const unsigned char *sha1, i
 		return 0;
 	if (fnmatch(match_ref_pattern, tail, 0))
 		return 0;
-	if (!strncmp("refs/heads/", refname, 11))
+	if (!(-prefixcmp(refname, "refs/heads/")))
 		return append_head_ref(refname, sha1, flag, cb_data);
-	if (!strncmp("refs/tags/", refname, 10))
+	if (!(-prefixcmp(refname, "refs/tags/")))
 		return append_tag_ref(refname, sha1, flag, cb_data);
 	return append_ref(refname, sha1, 0);
 }
@@ -462,11 +462,11 @@ static int rev_is_head(char *head, int headlen, char *name,
 	if ((!head[0]) ||
 	    (head_sha1 && sha1 && hashcmp(head_sha1, sha1)))
 		return 0;
-	if (!strncmp(head, "refs/heads/", 11))
+	if (!prefixcmp(head, "refs/heads/"))
 		head += 11;
-	if (!strncmp(name, "refs/heads/", 11))
+	if (!prefixcmp(name, "refs/heads/"))
 		name += 11;
-	else if (!strncmp(name, "heads/", 6))
+	else if (!prefixcmp(name, "heads/"))
 		name += 6;
 	return !strcmp(head, name);
 }
@@ -635,7 +635,7 @@ int cmd_show_branch(int ac, const char **av, const char *prefix)
 			with_current_branch = 1;
 		else if (!strcmp(arg, "--sha1-name"))
 			sha1_name = 1;
-		else if (!strncmp(arg, "--more=", 7))
+		else if (!prefixcmp(arg, "--more="))
 			extra = atoi(arg + 7);
 		else if (!strcmp(arg, "--merge-base"))
 			merge_base = 1;
@@ -652,9 +652,9 @@ int cmd_show_branch(int ac, const char **av, const char *prefix)
 		else if (!strcmp(arg, "--reflog") || !strcmp(arg, "-g")) {
 			reflog = DEFAULT_REFLOG;
 		}
-		else if (!strncmp(arg, "--reflog=", 9))
+		else if (!prefixcmp(arg, "--reflog="))
 			parse_reflog_param(arg + 9, &reflog, &reflog_base);
-		else if (!strncmp(arg, "-g=", 3))
+		else if (!prefixcmp(arg, "-g="))
 			parse_reflog_param(arg + 3, &reflog, &reflog_base);
 		else
 			usage(show_branch_usage);

builtin-show-ref.c

@@ -28,8 +28,8 @@ static int show_ref(const char *refname, const unsigned char *sha1, int flag, vo
 	if (tags_only || heads_only) {
 		int match;
 
-		match = heads_only && !strncmp(refname, "refs/heads/", 11);
-		match |= tags_only && !strncmp(refname, "refs/tags/", 10);
+		match = heads_only && !prefixcmp(refname, "refs/heads/");
+		match |= tags_only && !prefixcmp(refname, "refs/tags/");
 		if (!match)
 			return 0;
 	}
@@ -178,8 +178,8 @@ int cmd_show_ref(int argc, const char **argv, const char *prefix)
 			hash_only = 1;
 			continue;
 		}
-		if (!strncmp(arg, "--hash=", 7) ||
-		    (!strncmp(arg, "--abbrev", 8) &&
+		if (!prefixcmp(arg, "--hash=") ||
+		    (!prefixcmp(arg, "--abbrev") &&
 		     (arg[8] == '=' || arg[8] == '\0'))) {
 			if (arg[2] != 'h' && !arg[8])
 				/* --abbrev only */
@@ -215,7 +215,7 @@ int cmd_show_ref(int argc, const char **argv, const char *prefix)
 		}
 		if (!strcmp(arg, "--exclude-existing"))
 			return exclude_existing(NULL);
-		if (!strncmp(arg, "--exclude-existing=", 19))
+		if (!prefixcmp(arg, "--exclude-existing="))
 			return exclude_existing(arg + 19);
 		usage(show_ref_usage);
 	}
@@ -224,7 +224,7 @@ int cmd_show_ref(int argc, const char **argv, const char *prefix)
 		unsigned char sha1[20];
 
 		while (*pattern) {
-			if (!strncmp(*pattern, "refs/", 5) &&
+			if (!prefixcmp(*pattern, "refs/") &&
 			    resolve_ref(*pattern, sha1, 1, NULL)) {
 				if (!quiet)
 					show_one(*pattern, sha1);

builtin-tar-tree.c

@@ -31,7 +31,7 @@ int cmd_tar_tree(int argc, const char **argv, const char *prefix)
 	nargv[nargc++] = "git-archive";
 	nargv[nargc++] = "--format=tar";
 
-	if (2 <= argc && !strncmp("--remote=", argv[1], 9)) {
+	if (2 <= argc && !(-prefixcmp(argv[1], "--remote="))) {
 		nargv[nargc++] = argv[1];
 		argv++;
 		argc--;

builtin-unpack-objects.c

@@ -369,7 +369,7 @@ int cmd_unpack_objects(int argc, const char **argv, const char *prefix)
 				recover = 1;
 				continue;
 			}
-			if (!strncmp(arg, "--pack_header=", 14)) {
+			if (!prefixcmp(arg, "--pack_header=")) {
 				struct pack_header *hdr;
 				char *c;
 

builtin-write-tree.c

@@ -70,7 +70,7 @@ int cmd_write_tree(int argc, const char **argv, const char *unused_prefix)
 		const char *arg = argv[1];
 		if (!strcmp(arg, "--missing-ok"))
 			missing_ok = 1;
-		else if (!strncmp(arg, "--prefix=", 9))
+		else if (!prefixcmp(arg, "--prefix="))
 			prefix = arg + 9;
 		else
 			usage(write_tree_usage);

connect.c

@@ -96,7 +96,7 @@ int get_ack(int fd, unsigned char *result_sha1)
 		line[--len] = 0;
 	if (!strcmp(line, "NAK"))
 		return 0;
-	if (!strncmp(line, "ACK ", 4)) {
+	if (!prefixcmp(line, "ACK ")) {
 		if (!get_sha1_hex(line+4, result_sha1)) {
 			if (strstr(line+45, "continue"))
 				return 2;
@@ -196,8 +196,8 @@ static int count_refspec_match(const char *pattern,
 		 */
 		if (namelen != patlen &&
 		    patlen != namelen - 5 &&
-		    strncmp(name, "refs/heads/", 11) &&
-		    strncmp(name, "refs/tags/", 10)) {
+		    prefixcmp(name, "refs/heads/") &&
+		    prefixcmp(name, "refs/tags/")) {
 			/* We want to catch the case where only weak
 			 * matches are found and there are multiple
 			 * matches, and where more than one strong

daemon.c

@@ -286,7 +286,7 @@ static int service_enabled;
 
 static int git_daemon_config(const char *var, const char *value)
 {
-	if (!strncmp(var, "daemon.", 7) &&
+	if (!prefixcmp(var, "daemon.") &&
 	    !strcmp(var + 7, service_looking_at->config_name)) {
 		service_enabled = git_config_bool(var, value);
 		return 0;
@@ -562,7 +562,7 @@ static int execute(struct sockaddr *addr)
 	for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 		struct daemon_service *s = &(daemon_service[i]);
 		int namelen = strlen(s->name);
-		if (!strncmp("git-", line, 4) &&
+		if (!(-prefixcmp(line, "git-")) &&
 		    !strncmp(s->name, line + 4, namelen) &&
 		    line[namelen + 4] == ' ') {
 			/*
@@ -1011,7 +1011,7 @@ int main(int argc, char **argv)
 	for (i = 1; i < argc; i++) {
 		char *arg = argv[i];
 
-		if (!strncmp(arg, "--listen=", 9)) {
+		if (!prefixcmp(arg, "--listen=")) {
 		    char *p = arg + 9;
 		    char *ph = listen_addr = xmalloc(strlen(arg + 9) + 1);
 		    while (*p)
@@ -1019,7 +1019,7 @@ int main(int argc, char **argv)
 		    *ph = 0;
 		    continue;
 		}
-		if (!strncmp(arg, "--port=", 7)) {
+		if (!prefixcmp(arg, "--port=")) {
 			char *end;
 			unsigned long n;
 			n = strtoul(arg+7, &end, 0);
@@ -1045,11 +1045,11 @@ int main(int argc, char **argv)
 			export_all_trees = 1;
 			continue;
 		}
-		if (!strncmp(arg, "--timeout=", 10)) {
+		if (!prefixcmp(arg, "--timeout=")) {
 			timeout = atoi(arg+10);
 			continue;
 		}
-		if (!strncmp(arg, "--init-timeout=", 15)) {
+		if (!prefixcmp(arg, "--init-timeout=")) {
 			init_timeout = atoi(arg+15);
 			continue;
 		}
@@ -1057,11 +1057,11 @@ int main(int argc, char **argv)
 			strict_paths = 1;
 			continue;
 		}
-		if (!strncmp(arg, "--base-path=", 12)) {
+		if (!prefixcmp(arg, "--base-path=")) {
 			base_path = arg+12;
 			continue;
 		}
-		if (!strncmp(arg, "--interpolated-path=", 20)) {
+		if (!prefixcmp(arg, "--interpolated-path=")) {
 			interpolated_path = arg+20;
 			continue;
 		}
@@ -1073,11 +1073,11 @@ int main(int argc, char **argv)
 			user_path = "";
 			continue;
 		}
-		if (!strncmp(arg, "--user-path=", 12)) {
+		if (!prefixcmp(arg, "--user-path=")) {
 			user_path = arg + 12;
 			continue;
 		}
-		if (!strncmp(arg, "--pid-file=", 11)) {
+		if (!prefixcmp(arg, "--pid-file=")) {
 			pid_file = arg + 11;
 			continue;
 		}
@@ -1086,27 +1086,27 @@ int main(int argc, char **argv)
 			log_syslog = 1;
 			continue;
 		}
-		if (!strncmp(arg, "--user=", 7)) {
+		if (!prefixcmp(arg, "--user=")) {
 			user_name = arg + 7;
 			continue;
 		}
-		if (!strncmp(arg, "--group=", 8)) {
+		if (!prefixcmp(arg, "--group=")) {
 			group_name = arg + 8;
 			continue;
 		}
-		if (!strncmp(arg, "--enable=", 9)) {
+		if (!prefixcmp(arg, "--enable=")) {
 			enable_service(arg + 9, 1);
 			continue;
 		}
-		if (!strncmp(arg, "--disable=", 10)) {
+		if (!prefixcmp(arg, "--disable=")) {
 			enable_service(arg + 10, 0);
 			continue;
 		}
-		if (!strncmp(arg, "--allow-override=", 17)) {
+		if (!prefixcmp(arg, "--allow-override=")) {
 			make_service_overridable(arg + 17, 1);
 			continue;
 		}
-		if (!strncmp(arg, "--forbid-override=", 18)) {
+		if (!prefixcmp(arg, "--forbid-override=")) {
 			make_service_overridable(arg + 18, 0);
 			continue;
 		}

diff.c

@@ -77,7 +77,7 @@ int git_diff_ui_config(const char *var, const char *value)
 			diff_detect_rename_default = DIFF_DETECT_RENAME;
 		return 0;
 	}
-	if (!strncmp(var, "diff.color.", 11) || !strncmp(var, "color.diff.", 11)) {
+	if (!prefixcmp(var, "diff.color.") || !strncmp(var, "color.diff.", 11)) {
 		int slot = parse_diff_color_slot(var, 11);
 		color_parse(value, var, diff_colors[slot]);
 		return 0;
@@ -1119,9 +1119,9 @@ static void builtin_diff(const char *name_a,
 		xecfg.flags = XDL_EMIT_FUNCNAMES;
 		if (!diffopts)
 			;
-		else if (!strncmp(diffopts, "--unified=", 10))
+		else if (!prefixcmp(diffopts, "--unified="))
 			xecfg.ctxlen = strtoul(diffopts + 10, NULL, 10);
-		else if (!strncmp(diffopts, "-u", 2))
+		else if (!prefixcmp(diffopts, "-u"))
 			xecfg.ctxlen = strtoul(diffopts + 2, NULL, 10);
 		ecb.outf = xdiff_outf;
 		ecb.priv = &ecbdata;
@@ -1957,7 +1957,7 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
 	else if (!strcmp(arg, "--shortstat")) {
 		options->output_format |= DIFF_FORMAT_SHORTSTAT;
 	}
-	else if (!strncmp(arg, "--stat", 6)) {
+	else if (!prefixcmp(arg, "--stat")) {
 		char *end;
 		int width = options->stat_width;
 		int name_width = options->stat_name_width;
@@ -1966,9 +1966,9 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
 
 		switch (*arg) {
 		case '-':
-			if (!strncmp(arg, "-width=", 7))
+			if (!prefixcmp(arg, "-width="))
 				width = strtoul(arg + 7, &end, 10);
-			else if (!strncmp(arg, "-name-width=", 12))
+			else if (!prefixcmp(arg, "-name-width="))
 				name_width = strtoul(arg + 12, &end, 10);
 			break;
 		case '=':
@@ -1993,7 +1993,7 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
 	}
 	else if (!strcmp(arg, "-z"))
 		options->line_termination = 0;
-	else if (!strncmp(arg, "-l", 2))
+	else if (!prefixcmp(arg, "-l"))
 		options->rename_limit = strtoul(arg+2, NULL, 10);
 	else if (!strcmp(arg, "--full-index"))
 		options->full_index = 1;
@@ -2010,31 +2010,31 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
 		options->output_format |= DIFF_FORMAT_NAME_STATUS;
 	else if (!strcmp(arg, "-R"))
 		options->reverse_diff = 1;
-	else if (!strncmp(arg, "-S", 2))
+	else if (!prefixcmp(arg, "-S"))
 		options->pickaxe = arg + 2;
 	else if (!strcmp(arg, "-s")) {
 		options->output_format |= DIFF_FORMAT_NO_OUTPUT;
 	}
-	else if (!strncmp(arg, "-O", 2))
+	else if (!prefixcmp(arg, "-O"))
 		options->orderfile = arg + 2;
-	else if (!strncmp(arg, "--diff-filter=", 14))
+	else if (!prefixcmp(arg, "--diff-filter="))
 		options->filter = arg + 14;
 	else if (!strcmp(arg, "--pickaxe-all"))
 		options->pickaxe_opts = DIFF_PICKAXE_ALL;
 	else if (!strcmp(arg, "--pickaxe-regex"))
 		options->pickaxe_opts = DIFF_PICKAXE_REGEX;
-	else if (!strncmp(arg, "-B", 2)) {
+	else if (!prefixcmp(arg, "-B")) {
 		if ((options->break_opt =
 		     diff_scoreopt_parse(arg)) == -1)
 			return -1;
 	}
-	else if (!strncmp(arg, "-M", 2)) {
+	else if (!prefixcmp(arg, "-M")) {
 		if ((options->rename_score =
 		     diff_scoreopt_parse(arg)) == -1)
 			return -1;
 		options->detect_rename = DIFF_DETECT_RENAME;
 	}
-	else if (!strncmp(arg, "-C", 2)) {
+	else if (!prefixcmp(arg, "-C")) {
 		if ((options->rename_score =
 		     diff_scoreopt_parse(arg)) == -1)
 			return -1;
@@ -2044,7 +2044,7 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
 		options->find_copies_harder = 1;
 	else if (!strcmp(arg, "--abbrev"))
 		options->abbrev = DEFAULT_ABBREV;
-	else if (!strncmp(arg, "--abbrev=", 9)) {
+	else if (!prefixcmp(arg, "--abbrev=")) {
 		options->abbrev = strtoul(arg + 9, NULL, 10);
 		if (options->abbrev < MINIMUM_ABBREV)
 			options->abbrev = MINIMUM_ABBREV;
@@ -2553,7 +2553,7 @@ static void patch_id_consume(void *priv, char *line, unsigned long len)
 	int new_len;
 
 	/* Ignore line numbers when computing the SHA1 of the patch */
-	if (!strncmp(line, "@@ -", 4))
+	if (!prefixcmp(line, "@@ -"))
 		return;
 
 	new_len = remove_space(line, len);

exec_cmd.c

@@ -56,7 +56,7 @@ int execv_git_cmd(const char **argv)
 			len = strlen(git_command);
 
 			/* Trivial cleanup */
-			while (!strncmp(exec_dir, "./", 2)) {
+			while (!prefixcmp(exec_dir, "./")) {
 				exec_dir += 2;
 				while (*exec_dir == '/')
 					exec_dir++;

fast-import.c

@@ -1392,7 +1392,7 @@ static void read_next_command(void)
 
 static void cmd_mark(void)
 {
-	if (!strncmp("mark :", command_buf.buf, 6)) {
+	if (!(-prefixcmp(command_buf.buf, "mark :"))) {
 		next_mark = strtoumax(command_buf.buf + 6, NULL, 10);
 		read_next_command();
 	}
@@ -1405,10 +1405,10 @@ static void *cmd_data (size_t *size)
 	size_t length;
 	char *buffer;
 
-	if (strncmp("data ", command_buf.buf, 5))
+	if ((-prefixcmp(command_buf.buf, "data ")))
 		die("Expected 'data n' command, found: %s", command_buf.buf);
 
-	if (!strncmp("<<", command_buf.buf + 5, 2)) {
+	if (!(-prefixcmp(command_buf.buf + 5, "<<"))) {
 		char *term = xstrdup(command_buf.buf + 5 + 2);
 		size_t sz = 8192, term_len = command_buf.len - 5 - 2;
 		length = 0;
@@ -1595,7 +1595,7 @@ static void file_change_m(struct branch *b)
 		oe = find_mark(strtoumax(p + 1, &x, 10));
 		hashcpy(sha1, oe->sha1);
 		p = x;
-	} else if (!strncmp("inline", p, 6)) {
+	} else if (!(-prefixcmp(p, "inline"))) {
 		inline_data = 1;
 		p += 6;
 	} else {
@@ -1668,7 +1668,7 @@ static void cmd_from(struct branch *b)
 	const char *from;
 	struct branch *s;
 
-	if (strncmp("from ", command_buf.buf, 5))
+	if ((-prefixcmp(command_buf.buf, "from ")))
 		return;
 
 	if (b->branch_tree.tree) {
@@ -1734,7 +1734,7 @@ static struct hash_list *cmd_merge(unsigned int *count)
 	struct branch *s;
 
 	*count = 0;
-	while (!strncmp("merge ", command_buf.buf, 6)) {
+	while (!(-prefixcmp(command_buf.buf, "merge "))) {
 		from = strchr(command_buf.buf, ' ') + 1;
 		n = xmalloc(sizeof(*n));
 		s = lookup_branch(from);
@@ -1780,11 +1780,11 @@ static void cmd_new_commit(void)
 
 	read_next_command();
 	cmd_mark();
-	if (!strncmp("author ", command_buf.buf, 7)) {
+	if (!(-prefixcmp(command_buf.buf, "author "))) {
 		author = parse_ident(command_buf.buf + 7);
 		read_next_command();
 	}
-	if (!strncmp("committer ", command_buf.buf, 10)) {
+	if (!(-prefixcmp(command_buf.buf, "committer "))) {
 		committer = parse_ident(command_buf.buf + 10);
 		read_next_command();
 	}
@@ -1805,9 +1805,9 @@ static void cmd_new_commit(void)
 	for (;;) {
 		if (1 == command_buf.len)
 			break;
-		else if (!strncmp("M ", command_buf.buf, 2))
+		else if (!(-prefixcmp(command_buf.buf, "M ")))
 			file_change_m(b);
-		else if (!strncmp("D ", command_buf.buf, 2))
+		else if (!(-prefixcmp(command_buf.buf, "D ")))
 			file_change_d(b);
 		else if (!strcmp("deleteall", command_buf.buf))
 			file_change_deleteall(b);
@@ -1877,7 +1877,7 @@ static void cmd_new_tag(void)
 	read_next_command();
 
 	/* from ... */
-	if (strncmp("from ", command_buf.buf, 5))
+	if ((-prefixcmp(command_buf.buf, "from ")))
 		die("Expected from command, got %s", command_buf.buf);
 	from = strchr(command_buf.buf, ' ') + 1;
 	s = lookup_branch(from);
@@ -1904,7 +1904,7 @@ static void cmd_new_tag(void)
 	read_next_command();
 
 	/* tagger ... */
-	if (strncmp("tagger ", command_buf.buf, 7))
+	if ((-prefixcmp(command_buf.buf, "tagger ")))
 		die("Expected tagger command, got %s", command_buf.buf);
 	tagger = parse_ident(command_buf.buf + 7);
 
@@ -1981,7 +1981,7 @@ int main(int argc, const char **argv)
 
 		if (*a != '-' || !strcmp(a, "--"))
 			break;
-		else if (!strncmp(a, "--date-format=", 14)) {
+		else if (!prefixcmp(a, "--date-format=")) {
 			const char *fmt = a + 14;
 			if (!strcmp(fmt, "raw"))
 				whenspec = WHENSPEC_RAW;
@@ -1992,15 +1992,15 @@ int main(int argc, const char **argv)
 			else
 				die("unknown --date-format argument %s", fmt);
 		}
-		else if (!strncmp(a, "--max-pack-size=", 16))
+		else if (!prefixcmp(a, "--max-pack-size="))
 			max_packsize = strtoumax(a + 16, NULL, 0) * 1024 * 1024;
-		else if (!strncmp(a, "--depth=", 8))
+		else if (!prefixcmp(a, "--depth="))
 			max_depth = strtoul(a + 8, NULL, 0);
-		else if (!strncmp(a, "--active-branches=", 18))
+		else if (!prefixcmp(a, "--active-branches="))
 			max_active_branches = strtoul(a + 18, NULL, 0);
-		else if (!strncmp(a, "--export-marks=", 15))
+		else if (!prefixcmp(a, "--export-marks="))
 			mark_file = a + 15;
-		else if (!strncmp(a, "--export-pack-edges=", 20)) {
+		else if (!prefixcmp(a, "--export-pack-edges=")) {
 			if (pack_edges)
 				fclose(pack_edges);
 			pack_edges = fopen(a + 20, "a");
@@ -2033,11 +2033,11 @@ int main(int argc, const char **argv)
 			break;
 		else if (!strcmp("blob", command_buf.buf))
 			cmd_new_blob();
-		else if (!strncmp("commit ", command_buf.buf, 7))
+		else if (!(-prefixcmp(command_buf.buf, "commit ")))
 			cmd_new_commit();
-		else if (!strncmp("tag ", command_buf.buf, 4))
+		else if (!(-prefixcmp(command_buf.buf, "tag ")))
 			cmd_new_tag();
-		else if (!strncmp("reset ", command_buf.buf, 6))
+		else if (!(-prefixcmp(command_buf.buf, "reset ")))
 			cmd_reset_branch();
 		else if (!strcmp("checkpoint", command_buf.buf))
 			cmd_checkpoint();

fetch-pack.c

@@ -198,13 +198,13 @@ static int find_common(int fd[2], unsigned char *result_sha1,
 		int len;
 
 		while ((len = packet_read_line(fd[0], line, sizeof(line)))) {
-			if (!strncmp("shallow ", line, 8)) {
+			if (!(-prefixcmp(line, "shallow "))) {
 				if (get_sha1_hex(line + 8, sha1))
 					die("invalid shallow line: %s", line);
 				register_shallow(sha1);
 				continue;
 			}
-			if (!strncmp("unshallow ", line, 10)) {
+			if (!(-prefixcmp(line, "unshallow "))) {
 				if (get_sha1_hex(line + 10, sha1))
 					die("invalid unshallow line: %s", line);
 				if (!lookup_object(sha1))
@@ -346,7 +346,7 @@ static void filter_refs(struct ref **refs, int nr_match, char **match)
 		    check_ref_format(ref->name + 5))
 			; /* trash */
 		else if (fetch_all &&
-			 (!depth || strncmp(ref->name, "refs/tags/", 10) )) {
+			 (!depth || prefixcmp(ref->name, "refs/tags/") )) {
 			*newtail = ref;
 			ref->next = NULL;
 			newtail = &ref->next;
@@ -683,11 +683,11 @@ int main(int argc, char **argv)
 		char *arg = argv[i];
 
 		if (*arg == '-') {
-			if (!strncmp("--upload-pack=", arg, 14)) {
+			if (!(-prefixcmp(arg, "--upload-pack="))) {
 				uploadpack = arg + 14;
 				continue;
 			}
-			if (!strncmp("--exec=", arg, 7)) {
+			if (!(-prefixcmp(arg, "--exec="))) {
 				uploadpack = arg + 7;
 				continue;
 			}
@@ -712,7 +712,7 @@ int main(int argc, char **argv)
 				verbose = 1;
 				continue;
 			}
-			if (!strncmp("--depth=", arg, 8)) {
+			if (!(-prefixcmp(arg, "--depth="))) {
 				depth = strtol(arg + 8, NULL, 0);
 				if (stat(git_path("shallow"), &st))
 					st.st_mtime = 0;

git.c

@@ -48,7 +48,7 @@ static int handle_options(const char*** argv, int* argc)
 		/*
 		 * Check remaining flags.
 		 */
-		if (!strncmp(cmd, "--exec-path", 11)) {
+		if (!prefixcmp(cmd, "--exec-path")) {
 			cmd += 11;
 			if (*cmd == '=')
 				git_set_exec_path(cmd + 1);
@@ -66,7 +66,7 @@ static int handle_options(const char*** argv, int* argc)
 			setenv(GIT_DIR_ENVIRONMENT, (*argv)[1], 1);
 			(*argv)++;
 			(*argc)--;
-		} else if (!strncmp(cmd, "--git-dir=", 10)) {
+		} else if (!prefixcmp(cmd, "--git-dir=")) {
 			setenv(GIT_DIR_ENVIRONMENT, cmd + 10, 1);
 		} else if (!strcmp(cmd, "--bare")) {
 			static char git_dir[PATH_MAX+1];
@@ -88,7 +88,7 @@ static char *alias_string;
 
 static int git_alias_config(const char *var, const char *value)
 {
-	if (!strncmp(var, "alias.", 6) && !strcmp(var + 6, alias_command)) {
+	if (!prefixcmp(var, "alias.") && !strcmp(var + 6, alias_command)) {
 		alias_string = xstrdup(value);
 	}
 	return 0;
@@ -348,7 +348,7 @@ int main(int argc, const char **argv, char **envp)
 	 * So we just directly call the internal command handler, and
 	 * die if that one cannot handle it.
 	 */
-	if (!strncmp(cmd, "git-", 4)) {
+	if (!prefixcmp(cmd, "git-")) {
 		cmd += 4;
 		argv[0] = cmd;
 		handle_internal_command(argc, argv, envp);
@@ -360,7 +360,7 @@ int main(int argc, const char **argv, char **envp)
 	argc--;
 	handle_options(&argv, &argc);
 	if (argc > 0) {
-		if (!strncmp(argv[0], "--", 2))
+		if (!prefixcmp(argv[0], "--"))
 			argv[0] += 2;
 	} else {
 		/* Default command: "help" */

help.c

@@ -130,7 +130,7 @@ static void list_commands(const char *exec_path, const char *pattern)
 		struct stat st;
 		int entlen;
 
-		if (strncmp(de->d_name, "git-", 4))
+		if (prefixcmp(de->d_name, "git-"))
 			continue;
 		strcpy(path+dirlen, de->d_name);
 		if (stat(path, &st) || /* stat, not lstat */
@@ -179,7 +179,7 @@ static void show_man_page(const char *git_cmd)
 {
 	const char *page;
 
-	if (!strncmp(git_cmd, "git", 3))
+	if (!prefixcmp(git_cmd, "git"))
 		page = git_cmd;
 	else {
 		int page_len = strlen(git_cmd) + 4;

http-fetch.c

@@ -717,7 +717,7 @@ static int fetch_indices(struct alt_base *repo)
 		case 'P':
 			i++;
 			if (i + 52 <= buffer.posn &&
-			    !strncmp(data + i, " pack-", 6) &&
+			    !prefixcmp(data + i, " pack-") &&
 			    !strncmp(data + i + 46, ".pack\n", 6)) {
 				get_sha1_hex(data + i + 6, sha1);
 				setup_index(repo, sha1);

http-push.c

@@ -1060,7 +1060,7 @@ static int fetch_indices(void)
 		case 'P':
 			i++;
 			if (i + 52 < buffer.posn &&
-			    !strncmp(data + i, " pack-", 6) &&
+			    !prefixcmp(data + i, " pack-") &&
 			    !strncmp(data + i + 46, ".pack\n", 6)) {
 				get_sha1_hex(data + i + 6, sha1);
 				setup_index(sha1);
@@ -1206,11 +1206,11 @@ static void handle_new_lock_ctx(struct xml_ctx *ctx, int tag_closed)
 			lock->owner = xmalloc(strlen(ctx->cdata) + 1);
 			strcpy(lock->owner, ctx->cdata);
 		} else if (!strcmp(ctx->name, DAV_ACTIVELOCK_TIMEOUT)) {
-			if (!strncmp(ctx->cdata, "Second-", 7))
+			if (!prefixcmp(ctx->cdata, "Second-"))
 				lock->timeout =
 					strtol(ctx->cdata + 7, NULL, 10);
 		} else if (!strcmp(ctx->name, DAV_ACTIVELOCK_TOKEN)) {
-			if (!strncmp(ctx->cdata, "opaquelocktoken:", 16)) {
+			if (!prefixcmp(ctx->cdata, "opaquelocktoken:")) {
 				lock->token = xmalloc(strlen(ctx->cdata) - 15);
 				strcpy(lock->token, ctx->cdata + 16);
 			}
@@ -2168,7 +2168,7 @@ static void fetch_symref(const char *path, char **symref, unsigned char *sha1)
 		return;
 
 	/* If it's a symref, set the refname; otherwise try for a sha1 */
-	if (!strncmp((char *)buffer.buffer, "ref: ", 5)) {
+	if (!prefixcmp((char *)buffer.buffer, "ref: ")) {
 		*symref = xmalloc(buffer.posn - 5);
 		strlcpy(*symref, (char *)buffer.buffer + 5, buffer.posn - 5);
 	} else {

index-pack.c

@@ -849,9 +849,9 @@ int main(int argc, char **argv)
 				fix_thin_pack = 1;
 			} else if (!strcmp(arg, "--keep")) {
 				keep_msg = "";
-			} else if (!strncmp(arg, "--keep=", 7)) {
+			} else if (!prefixcmp(arg, "--keep=")) {
 				keep_msg = arg + 7;
-			} else if (!strncmp(arg, "--pack_header=", 14)) {
+			} else if (!prefixcmp(arg, "--pack_header=")) {
 				struct pack_header *hdr;
 				char *c;
 

peek-remote.c

@@ -35,11 +35,11 @@ int main(int argc, char **argv)
 		char *arg = argv[i];
 
 		if (*arg == '-') {
-			if (!strncmp("--upload-pack=", arg, 14)) {
+			if (!(-prefixcmp(arg, "--upload-pack="))) {
 				uploadpack = arg + 14;
 				continue;
 			}
-			if (!strncmp("--exec=", arg, 7)) {
+			if (!(-prefixcmp(arg, "--exec="))) {
 				uploadpack = arg + 7;
 				continue;
 			}

receive-pack.c

@@ -109,7 +109,7 @@ static int update(struct command *cmd)
 	struct ref_lock *lock;
 
 	cmd->error_string = NULL;
-	if (!strncmp(name, "refs/", 5) && check_ref_format(name + 5)) {
+	if (!prefixcmp(name, "refs/") && check_ref_format(name + 5)) {
 		cmd->error_string = "funny refname";
 		return error("refusing to create funny ref '%s' locally",
 			     name);
@@ -125,7 +125,7 @@ static int update(struct command *cmd)
 	}
 	if (deny_non_fast_forwards && !is_null_sha1(new_sha1) &&
 	    !is_null_sha1(old_sha1) &&
-	    !strncmp(name, "refs/heads/", 11)) {
+	    !prefixcmp(name, "refs/heads/")) {
 		struct commit *old_commit, *new_commit;
 		struct commit_list *bases, *ent;
 

refs.c

@@ -828,8 +828,8 @@ int rename_ref(const char *oldref, const char *newref, const char *logmsg)
 		goto rollback;
 	}
 
-	if (!strncmp(oldref, "refs/heads/", 11) &&
-			!strncmp(newref, "refs/heads/", 11)) {
+	if (!prefixcmp(oldref, "refs/heads/") &&
+			!prefixcmp(newref, "refs/heads/")) {
 		char oldsection[1024], newsection[1024];
 
 		snprintf(oldsection, 1024, "branch.%s", oldref + 11);
@@ -894,8 +894,8 @@ static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
 	log_file = git_path("logs/%s", ref_name);
 
 	if (log_all_ref_updates &&
-	    (!strncmp(ref_name, "refs/heads/", 11) ||
-	     !strncmp(ref_name, "refs/remotes/", 13) ||
+	    (!prefixcmp(ref_name, "refs/heads/") ||
+	     !prefixcmp(ref_name, "refs/remotes/") ||
 	     !strcmp(ref_name, "HEAD"))) {
 		if (safe_create_leading_directories(log_file) < 0)
 			return error("unable to create directory for %s",

revision.c

@@ -813,11 +813,11 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, const ch
 		const char *arg = argv[i];
 		if (*arg == '-') {
 			int opts;
-			if (!strncmp(arg, "--max-count=", 12)) {
+			if (!prefixcmp(arg, "--max-count=")) {
 				revs->max_count = atoi(arg + 12);
 				continue;
 			}
-			if (!strncmp(arg, "--skip=", 7)) {
+			if (!prefixcmp(arg, "--skip=")) {
 				revs->skip_count = atoi(arg + 7);
 				continue;
 			}
@@ -836,27 +836,27 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, const ch
 				revs->max_count = atoi(arg + 2);
 				continue;
 			}
-			if (!strncmp(arg, "--max-age=", 10)) {
+			if (!prefixcmp(arg, "--max-age=")) {
 				revs->max_age = atoi(arg + 10);
 				continue;
 			}
-			if (!strncmp(arg, "--since=", 8)) {
+			if (!prefixcmp(arg, "--since=")) {
 				revs->max_age = approxidate(arg + 8);
 				continue;
 			}
-			if (!strncmp(arg, "--after=", 8)) {
+			if (!prefixcmp(arg, "--after=")) {
 				revs->max_age = approxidate(arg + 8);
 				continue;
 			}
-			if (!strncmp(arg, "--min-age=", 10)) {
+			if (!prefixcmp(arg, "--min-age=")) {
 				revs->min_age = atoi(arg + 10);
 				continue;
 			}
-			if (!strncmp(arg, "--before=", 9)) {
+			if (!prefixcmp(arg, "--before=")) {
 				revs->min_age = approxidate(arg + 9);
 				continue;
 			}
-			if (!strncmp(arg, "--until=", 8)) {
+			if (!prefixcmp(arg, "--until=")) {
 				revs->min_age = approxidate(arg + 8);
 				continue;
 			}
@@ -944,7 +944,7 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, const ch
 				revs->num_ignore_packed = 0;
 				continue;
 			}
-			if (!strncmp(arg, "--unpacked=", 11)) {
+			if (!prefixcmp(arg, "--unpacked=")) {
 				revs->unpacked = 1;
 				add_ignore_packed(revs, arg+11);
 				continue;
@@ -980,7 +980,7 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, const ch
 				revs->verbose_header = 1;
 				continue;
 			}
-			if (!strncmp(arg, "--pretty", 8)) {
+			if (!prefixcmp(arg, "--pretty")) {
 				revs->verbose_header = 1;
 				revs->commit_format = get_commit_format(arg+8);
 				continue;
@@ -1005,7 +1005,7 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, const ch
 				revs->abbrev = DEFAULT_ABBREV;
 				continue;
 			}
-			if (!strncmp(arg, "--abbrev=", 9)) {
+			if (!prefixcmp(arg, "--abbrev=")) {
 				revs->abbrev = strtoul(arg + 9, NULL, 10);
 				if (revs->abbrev < MINIMUM_ABBREV)
 					revs->abbrev = MINIMUM_ABBREV;
@@ -1034,15 +1034,15 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, const ch
 			/*
 			 * Grepping the commit log
 			 */
-			if (!strncmp(arg, "--author=", 9)) {
+			if (!prefixcmp(arg, "--author=")) {
 				add_header_grep(revs, "author", arg+9);
 				continue;
 			}
-			if (!strncmp(arg, "--committer=", 12)) {
+			if (!prefixcmp(arg, "--committer=")) {
 				add_header_grep(revs, "committer", arg+12);
 				continue;
 			}
-			if (!strncmp(arg, "--grep=", 7)) {
+			if (!prefixcmp(arg, "--grep=")) {
 				add_message_grep(revs, arg+7);
 				continue;
 			}
@@ -1050,7 +1050,7 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, const ch
 				all_match = 1;
 				continue;
 			}
-			if (!strncmp(arg, "--encoding=", 11)) {
+			if (!prefixcmp(arg, "--encoding=")) {
 				arg += 11;
 				if (strcmp(arg, "none"))
 					git_log_output_encoding = strdup(arg);

send-pack.c

@@ -379,11 +379,11 @@ int main(int argc, char **argv)
 		char *arg = *argv;
 
 		if (*arg == '-') {
-			if (!strncmp(arg, "--receive-pack=", 15)) {
+			if (!prefixcmp(arg, "--receive-pack=")) {
 				receivepack = arg + 15;
 				continue;
 			}
-			if (!strncmp(arg, "--exec=", 7)) {
+			if (!prefixcmp(arg, "--exec=")) {
 				receivepack = arg + 7;
 				continue;
 			}

setup.c

@@ -251,7 +251,7 @@ const char *setup_git_directory_gently(int *nongit_ok)
 	offset++;
 	cwd[len++] = '/';
 	cwd[len] = 0;
-	inside_git_dir = !strncmp(cwd + offset, ".git/", 5);
+	inside_git_dir = !prefixcmp(cwd + offset, ".git/");
 	return cwd + offset;
 }
 

shell.c

@@ -8,7 +8,7 @@ static int do_generic_cmd(const char *me, char *arg)
 
 	if (!arg || !(arg = sq_dequote(arg)))
 		die("bad argument");
-	if (strncmp(me, "git-", 4))
+	if (prefixcmp(me, "git-"))
 		die("bad command");
 
 	my_argv[0] = me + 4;

upload-pack.c

@@ -455,7 +455,7 @@ static int get_common_commits(void)
 			continue;
 		}
 		len = strip(line, len);
-		if (!strncmp(line, "have ", 5)) {
+		if (!prefixcmp(line, "have ")) {
 			switch (got_sha1(line+5, sha1)) {
 			case -1: /* they have what we do not */
 				if (multi_ack && ok_to_give_up())
@@ -502,7 +502,7 @@ static void receive_needs(void)
 		if (!len)
 			break;
 
-		if (!strncmp("shallow ", line, 8)) {
+		if (!(-prefixcmp(line, "shallow "))) {
 			unsigned char sha1[20];
 			struct object *object;
 			use_thin_pack = 0;
@@ -515,7 +515,7 @@ static void receive_needs(void)
 			add_object_array(object, NULL, &shallows);
 			continue;
 		}
-		if (!strncmp("deepen ", line, 7)) {
+		if (!(-prefixcmp(line, "deepen "))) {
 			char *end;
 			use_thin_pack = 0;
 			depth = strtol(line + 7, &end, 0);
@@ -523,7 +523,7 @@ static void receive_needs(void)
 				die("Invalid deepen: %s", line);
 			continue;
 		}
-		if (strncmp("want ", line, 5) ||
+		if ((-prefixcmp(line, "want ")) ||
 		    get_sha1_hex(line+5, sha1_buf))
 			die("git-upload-pack: protocol error, "
 			    "expected to get sha, not '%s'", line);
@@ -656,7 +656,7 @@ int main(int argc, char **argv)
 			strict = 1;
 			continue;
 		}
-		if (!strncmp(arg, "--timeout=", 10)) {
+		if (!prefixcmp(arg, "--timeout=")) {
 			timeout = atoi(arg+10);
 			continue;
 		}

wt-status.c

@@ -298,7 +298,7 @@ void wt_status_print(struct wt_status *s)
 	if (s->branch) {
 		const char *on_what = "On branch ";
 		const char *branch_name = s->branch;
-		if (!strncmp(branch_name, "refs/heads/", 11))
+		if (!prefixcmp(branch_name, "refs/heads/"))
 			branch_name += 11;
 		else if (!strcmp(branch_name, "HEAD")) {
 			branch_name = "";
@@ -344,7 +344,7 @@ int git_status_config(const char *k, const char *v)
 		wt_status_use_color = git_config_colorbool(k, v);
 		return 0;
 	}
-	if (!strncmp(k, "status.color.", 13) || !strncmp(k, "color.status.", 13)) {
+	if (!prefixcmp(k, "status.color.") || !strncmp(k, "color.status.", 13)) {
 		int slot = parse_status_slot(k, 13);
 		color_parse(v, k, wt_status_colors[slot]);
 	}