From c4483576b8d30fadcae208d8f12383febd060d0a Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Wed, 1 Jun 2005 17:54:59 -0700 Subject: [PATCH] Add "unpack_sha1_header()" helper function It's for people who aren't necessarily interested in the whole unpacked file, but do want to know the header information (size, type, etc..) For example, the delta code can use this to figure out whether an object is already a delta object, and what it is a delta against, without actually bothering to unpack all of the actual data in the delta. --- cache.h | 1 + sha1_file.c | 27 +++++++++++++++------------ 2 files changed, 16 insertions(+), 12 deletions(-) diff --git a/cache.h b/cache.h index d38d9a848..69b63ba1d 100644 --- a/cache.h +++ b/cache.h @@ -151,6 +151,7 @@ extern char *sha1_file_name(const unsigned char *sha1); /* Read and unpack a sha1 file into memory, write memory to a sha1 file */ extern void * map_sha1_file(const unsigned char *sha1, unsigned long *size); +extern int unpack_sha1_header(z_stream *stream, void *map, unsigned long mapsize, void *buffer, unsigned long size); extern void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size); extern void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size); extern int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *return_sha1); diff --git a/sha1_file.c b/sha1_file.c index ac7bf9fd2..bc3d70fdd 100644 --- a/sha1_file.c +++ b/sha1_file.c @@ -307,6 +307,19 @@ void *map_sha1_file(const unsigned char *sha1, unsigned long *size) return map; } +int unpack_sha1_header(z_stream *stream, void *map, unsigned long mapsize, void *buffer, unsigned long size) +{ + /* Get the data stream */ + memset(stream, 0, sizeof(*stream)); + stream->next_in = map; + stream->avail_in = mapsize; + stream->next_out = buffer; + stream->avail_out = size; + + inflateInit(stream); + return inflate(stream, 0); +} + void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size) { int ret, bytes; @@ -314,18 +327,8 @@ void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned l char buffer[8192]; unsigned char *buf; - /* Get the data stream */ - memset(&stream, 0, sizeof(stream)); - stream.next_in = map; - stream.avail_in = mapsize; - stream.next_out = (unsigned char *)buffer; - stream.avail_out = sizeof(buffer); - - inflateInit(&stream); - ret = inflate(&stream, 0); - if (ret < Z_OK) - return NULL; - if (sscanf(buffer, "%10s %lu", type, size) != 2) + ret = unpack_sha1_header(&stream, map, mapsize, buffer, sizeof(buffer)); + if (ret < Z_OK || sscanf(buffer, "%10s %lu", type, size) != 2) return NULL; bytes = strlen(buffer) + 1; -- 2.30.2