[PATCH] Add "--compression-level=N" option to git-pack-objects
Setting the compression level for objects in the pack is useful in some
cases; in particular, disabling compression of the individual objects and
then compressing the whole pack can improve the overall compression ratio.
Signed-off-by: Sergey Vlasov <[EMAIL PROTECTED]>
---
Documentation/git-pack-objects.txt | 14 +++++++++++++-
csum-file.c | 5 +++--
csum-file.h | 2 +-
pack-objects.c | 15 +++++++++++++--
4 files changed, 30 insertions(+), 6 deletions(-)
e54e13c2f057e71998ed39299545717311c7678d
diff --git a/Documentation/git-pack-objects.txt
b/Documentation/git-pack-objects.txt
--- a/Documentation/git-pack-objects.txt
+++ b/Documentation/git-pack-objects.txt
@@ -9,7 +9,7 @@ git-pack-objects - Create a packed archi
SYNOPSIS
--------
-'git-pack-objects' [--incremental] [--window=N] [--depth=N] {--stdout |
base-name} < object-list
+'git-pack-objects' [--incremental] [--window=N] [--depth=N]
[--compression-level=N] {--stdout | base-name} < object-list
DESCRIPTION
@@ -61,6 +61,18 @@ base-name::
side, because delta data needs to be applied that many
times to get to the necessary object.
+--compression-level::
+ Set zlib compression level for the object data. The
+ compression level is a number from 0 to 9, where 0 means
+ no compression, 1 indicates the fastest compression
+ method (less compression), and 9 indicates the slowest
+ compression method (best compression). The default
+ compression level is 6. Setting the compression level
+ to 0 may be useful when the pack will be compressed as a
+ whole at a later stage (in the pack format every object
+ is compressed separately to allow random access, which
+ is less efficient than compressing the whole file).
+
--incremental::
This flag causes an object already in a pack ignored
even if it appears in the standard input.
diff --git a/csum-file.c b/csum-file.c
--- a/csum-file.c
+++ b/csum-file.c
@@ -117,14 +117,15 @@ struct sha1file *sha1fd(int fd, const ch
return f;
}
-int sha1write_compressed(struct sha1file *f, void *in, unsigned int size)
+int sha1write_compressed(struct sha1file *f, void *in, unsigned int size,
+ int compression_level)
{
z_stream stream;
unsigned long maxsize;
void *out;
memset(&stream, 0, sizeof(stream));
- deflateInit(&stream, Z_DEFAULT_COMPRESSION);
+ deflateInit(&stream, compression_level);
maxsize = deflateBound(&stream, size);
out = xmalloc(maxsize);
diff --git a/csum-file.h b/csum-file.h
--- a/csum-file.h
+++ b/csum-file.h
@@ -14,6 +14,6 @@ extern struct sha1file *sha1fd(int fd, c
extern struct sha1file *sha1create(const char *fmt, ...) __attribute__((format
(printf, 1, 2)));
extern int sha1close(struct sha1file *, unsigned char *, int);
extern int sha1write(struct sha1file *, void *, unsigned int);
-extern int sha1write_compressed(struct sha1file *, void *, unsigned int);
+extern int sha1write_compressed(struct sha1file *, void *, unsigned int, int);
#endif
diff --git a/pack-objects.c b/pack-objects.c
--- a/pack-objects.c
+++ b/pack-objects.c
@@ -5,7 +5,7 @@
#include "pack.h"
#include "csum-file.h"
-static const char pack_usage[] = "git-pack-objects [--incremental]
[--window=N] [--depth=N] {--stdout | base-name} < object-list";
+static const char pack_usage[] = "git-pack-objects [--incremental]
[--window=N] [--depth=N] [--compression-level=N] {--stdout | base-name} <
object-list";
struct object_entry {
unsigned char sha1[20];
@@ -21,6 +21,7 @@ struct object_entry {
static unsigned char object_list_sha1[20];
static int non_empty = 0;
static int incremental = 0;
+static int compression_level = Z_DEFAULT_COMPRESSION;
static struct object_entry **sorted_by_sha, **sorted_by_type;
static struct object_entry *objects = NULL;
static int nr_objects = 0, nr_alloc = 0;
@@ -103,7 +104,7 @@ static unsigned long write_object(struct
sha1write(f, entry->delta, 20);
hdrlen += 20;
}
- datalen = sha1write_compressed(f, buf, size);
+ datalen = sha1write_compressed(f, buf, size, compression_level);
free(buf);
return hdrlen + datalen;
}
@@ -421,6 +422,16 @@ int main(int argc, char **argv)
usage(pack_usage);
continue;
}
+ if (!strncmp("--compression-level=", arg, 20)) {
+ char *end;
+ compression_level = strtoul(arg+20, &end, 0);
+ if (!arg[20] || *end)
+ usage(pack_usage);
+ if (compression_level < Z_NO_COMPRESSION
+ || compression_level > Z_BEST_COMPRESSION)
+ die("invalid compression level");
+ continue;
+ }
if (!strcmp("--stdout", arg)) {
pack_to_stdout = 1;
continue;
-
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