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Revision ce163c793d2058056ccc57563c350fd6415397ca authored by René Scharfe on 02 March 2009, 23:00:55 UTC, committed by Junio C Hamano on 03 March 2009, 02:28:03 UTC 
diffcore-pickaxe: use memmem()
 
Use memmem() instead of open-coding it.  The system libraries usually have a
much faster version than the memcmp()-loop here.  Even our own fall-back in
compat/, which is used on Windows, is slightly faster.

The following commands were run in a Linux kernel repository and timed, the
best of five results is shown:

  $ STRING='Ensure that the real time constraints are schedulable.'
  $ git log -S"$STRING" HEAD -- kernel/sched.c >/dev/null

On Ubuntu 8.10 x64, before (v1.6.2-rc2):

  8.09user 0.04system 0:08.14elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
  0inputs+0outputs (0major+30952minor)pagefaults 0swaps

And with the patch:

  1.50user 0.04system 0:01.54elapsed 100%CPU (0avgtext+0avgdata 0maxresident)k
  0inputs+0outputs (0major+30645minor)pagefaults 0swaps

On Fedora 10 x64, before:

  8.34user 0.05system 0:08.39elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
  0inputs+0outputs (0major+29268minor)pagefaults 0swaps

And with the patch:

  1.15user 0.05system 0:01.20elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
  0inputs+0outputs (0major+32253minor)pagefaults 0swaps

On Windows Vista x64, before:

  real    0m9.204s
  user    0m0.000s
  sys     0m0.000s

And with the patch:

  real    0m8.470s
  user    0m0.000s
  sys     0m0.000s

Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 parent f474c52
Raw File
blob.c 
#include "cache.h"
#include "blob.h"

const char *blob_type = "blob";

struct blob *lookup_blob(const unsigned char *sha1)
{
	struct object *obj = lookup_object(sha1);
	if (!obj)
		return create_object(sha1, OBJ_BLOB, alloc_blob_node());
	if (!obj->type)
		obj->type = OBJ_BLOB;
	if (obj->type != OBJ_BLOB) {
		error("Object %s is a %s, not a blob",
		      sha1_to_hex(sha1), typename(obj->type));
		return NULL;
	}
	return (struct blob *) obj;
}

int parse_blob_buffer(struct blob *item, void *buffer, unsigned long size)
{
	item->object.parsed = 1;
	return 0;
}

int parse_blob(struct blob *item)
{
        enum object_type type;
        void *buffer;
        unsigned long size;
	int ret;

        if (item->object.parsed)
                return 0;
        buffer = read_sha1_file(item->object.sha1, &type, &size);
        if (!buffer)
                return error("Could not read %s",
                             sha1_to_hex(item->object.sha1));
        if (type != OBJ_BLOB)
                return error("Object %s not a blob",
                             sha1_to_hex(item->object.sha1));
	ret = parse_blob_buffer(item, buffer, size);
	free(buffer);
	return ret;
}
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