From dcde55bc58ae845307efbdce3a1071f75ccd758e Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Wed, 29 Jun 2005 02:49:56 -0400 Subject: [PATCH] assorted delta code cleanup This is a wrap-up patch including all the cleanups I've done to the delta code and its usage. The most important change is the factorization of the delta header handling code. Signed-off-by: Nicolas Pitre Signed-off-by: Linus Torvalds --- delta.h | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'delta.h') diff --git a/delta.h b/delta.h index bc3a220179..31d1820f80 100644 --- a/delta.h +++ b/delta.h @@ -9,4 +9,26 @@ extern void *patch_delta(void *src_buf, unsigned long src_size, void *delta_buf, unsigned long delta_size, unsigned long *dst_size); +/* the smallest possible delta size is 4 bytes */ +#define DELTA_SIZE_MIN 4 + +/* + * This must be called twice on the delta data buffer, first to get the + * expected reference buffer size, and again to get the result buffer size. + */ +static inline unsigned long get_delta_hdr_size(const unsigned char **datap) +{ + const unsigned char *data = *datap; + unsigned char cmd = *data++; + unsigned long size = cmd & ~0x80; + int i = 7; + while (cmd & 0x80) { + cmd = *data++; + size |= (cmd & ~0x80) << i; + i += 7; + } + *datap = data; + return size; +} + #endif -- cgit v1.3-5-g9baa