[PATCH 8/9] vcs-svn: suppress a signed/unsigned comparison warning

[Jonathan Nieder <jrnieder@gmail.com>]

From: Jonathan Nieder <jrnieder@gmail.com>
Date: Thu, 5 Jul 2012 22:21:09 -0500

All callers pass a nonnegative delta_len, so the code is already safe.
Add an assertion to ensure that remains so and add a cast to keep
clang and gcc -Wsign-compare from worrying.

Reported-by: David Barr <davidbarr@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
v2 suppressed the warning by casting "len" to an off_t, producing an
unintentional change (breakage) in functionality on 64-bit systems
when "len" is large.

This version is longer but more conservative.

 vcs-svn/svndiff.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/vcs-svn/svndiff.c b/vcs-svn/svndiff.c
index e810d0c3..74c97c45 100644
--- a/vcs-svn/svndiff.c
+++ b/vcs-svn/svndiff.c
@@ -77,8 +77,9 @@ static int error_short_read(struct line_buffer *input)
 static int read_chunk(struct line_buffer *delta, off_t *delta_len,
 		      struct strbuf *buf, size_t len)
 {
+	assert(*delta_len >= 0);
 	strbuf_reset(buf);
-	if (len > *delta_len ||
+	if (len > (uintmax_t) *delta_len ||
 	    buffer_read_binary(delta, buf, len) != len)
 		return error_short_read(delta);
 	*delta_len -= buf->len;
@@ -290,7 +291,7 @@ error_out:
 int svndiff0_apply(struct line_buffer *delta, off_t delta_len,
 			struct sliding_view *preimage, FILE *postimage)
 {
-	assert(delta && preimage && postimage);
+	assert(delta && preimage && postimage && delta_len >= 0);
 
 	if (read_magic(delta, &delta_len))
 		return -1;
-- 
1.7.10.4