[PATCH v2 1/2] patchbreak(), is_scissors_line(): work with a buf/len pair

[Matheus Tavares <matheus.bernardino@usp.br>]

From: René Scharfe <l.s.r@web.de>

The next patch will add calls to these two functions from code that
works with a char */size_t pair. So let's adapt the functions in
preparation.
---
 mailinfo.c | 37 +++++++++++++++++++------------------
 1 file changed, 19 insertions(+), 18 deletions(-)

diff --git a/mailinfo.c b/mailinfo.c
index 9621ba62a3..f0a690b6e8 100644
--- a/mailinfo.c
+++ b/mailinfo.c
@@ -646,32 +646,30 @@ static void decode_transfer_encoding(struct mailinfo *mi, struct strbuf *line)
 	free(ret);
 }
 
-static inline int patchbreak(const struct strbuf *line)
+static inline int patchbreak(const char *buf, size_t len)
 {
-	size_t i;
-
 	/* Beginning of a "diff -" header? */
-	if (starts_with(line->buf, "diff -"))
+	if (skip_prefix_mem(buf, len, "diff -", &buf, &len))
 		return 1;
 
 	/* CVS "Index: " line? */
-	if (starts_with(line->buf, "Index: "))
+	if (skip_prefix_mem(buf, len, "Index: ", &buf, &len))
 		return 1;
 
 	/*
 	 * "--- <filename>" starts patches without headers
 	 * "---<sp>*" is a manual separator
 	 */
-	if (line->len < 4)
+	if (len < 4)
 		return 0;
 
-	if (starts_with(line->buf, "---")) {
+	if (skip_prefix_mem(buf, len, "---", &buf, &len)) {
 		/* space followed by a filename? */
-		if (line->buf[3] == ' ' && !isspace(line->buf[4]))
+		if (len > 1 && buf[0] == ' ' && !isspace(buf[1]))
 			return 1;
 		/* Just whitespace? */
-		for (i = 3; i < line->len; i++) {
-			unsigned char c = line->buf[i];
+		for (; len; buf++, len--) {
+			unsigned char c = buf[0];
 			if (c == '\n')
 				return 1;
 			if (!isspace(c))
@@ -682,14 +680,14 @@ static inline int patchbreak(const struct strbuf *line)
 	return 0;
 }
 
-static int is_scissors_line(const char *line)
+static int is_scissors_line(const char *line, size_t len)
 {
 	const char *c;
 	int scissors = 0, gap = 0;
 	const char *first_nonblank = NULL, *last_nonblank = NULL;
 	int visible, perforation = 0, in_perforation = 0;
 
-	for (c = line; *c; c++) {
+	for (c = line; len; c++, len--) {
 		if (isspace(*c)) {
 			if (in_perforation) {
 				perforation++;
@@ -705,12 +703,14 @@ static int is_scissors_line(const char *line)
 			perforation++;
 			continue;
 		}
-		if (starts_with(c, ">8") || starts_with(c, "8<") ||
-		    starts_with(c, ">%") || starts_with(c, "%<")) {
+		if (skip_prefix_mem(c, len, ">8", &c, &len) ||
+		    skip_prefix_mem(c, len, "8<", &c, &len) ||
+		    skip_prefix_mem(c, len, ">%", &c, &len) ||
+		    skip_prefix_mem(c, len, "%<", &c, &len)) {
 			in_perforation = 1;
 			perforation += 2;
 			scissors += 2;
-			c++;
+			c--, len++;
 			continue;
 		}
 		in_perforation = 0;
@@ -747,7 +747,8 @@ static int check_inbody_header(struct mailinfo *mi, const struct strbuf *line)
 {
 	if (mi->inbody_header_accum.len &&
 	    (line->buf[0] == ' ' || line->buf[0] == '\t')) {
-		if (mi->use_scissors && is_scissors_line(line->buf)) {
+		if (mi->use_scissors &&
+		    is_scissors_line(line->buf, line->len)) {
 			/*
 			 * This is a scissors line; do not consider this line
 			 * as a header continuation line.
@@ -808,7 +809,7 @@ static int handle_commit_msg(struct mailinfo *mi, struct strbuf *line)
 	if (convert_to_utf8(mi, line, mi->charset.buf))
 		return 0; /* mi->input_error already set */
 
-	if (mi->use_scissors && is_scissors_line(line->buf)) {
+	if (mi->use_scissors && is_scissors_line(line->buf, line->len)) {
 		int i;
 
 		strbuf_setlen(&mi->log_message, 0);
@@ -826,7 +827,7 @@ static int handle_commit_msg(struct mailinfo *mi, struct strbuf *line)
 		return 0;
 	}
 
-	if (patchbreak(line)) {
+	if (patchbreak(line->buf, line->len)) {
 		if (mi->message_id)
 			strbuf_addf(&mi->log_message,
 				    "Message-Id: %s\n", mi->message_id);
-- 
2.37.2