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authorGravatar Denys Vlasenko <vda.linux@googlemail.com>2018-01-31 15:32:32 +0100
committerGravatar Denys Vlasenko <vda.linux@googlemail.com>2018-01-31 15:32:32 +0100
commit468731a86b850f6f1430a81b87cd7e2288300101 (patch)
tree1882f9969b19d398928fc3978b416ea77a484d26 /archival/gzip.c
parent631c16855a05f0699149502bba93a3ad8f88608e (diff)
downloadbusybox-468731a86b850f6f1430a81b87cd7e2288300101.tar.gz
busybox-468731a86b850f6f1430a81b87cd7e2288300101.tar.bz2
gzip: code shrink and speedup
function old new delta pack_gzip 908 861 -47 Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Diffstat (limited to 'archival/gzip.c')
-rw-r--r--archival/gzip.c29
1 files changed, 17 insertions, 12 deletions
diff --git a/archival/gzip.c b/archival/gzip.c
index 5812f4b27..fa7a79b04 100644
--- a/archival/gzip.c
+++ b/archival/gzip.c
@@ -478,15 +478,14 @@ static void put_16bit(ush w)
put_8bit(w);
}
+#define OPTIMIZED_PUT_32BIT (CONFIG_GZIP_FAST > 0 && BB_UNALIGNED_MEMACCESS_OK && BB_LITTLE_ENDIAN)
static void put_32bit(ulg n)
{
-#if CONFIG_GZIP_FAST > 0 \
- && BB_UNALIGNED_MEMACCESS_OK && BB_LITTLE_ENDIAN
+#if OPTIMIZED_PUT_32BIT
unsigned outcnt = G1.outcnt;
if (outcnt < OUTBUFSIZ-4) {
/* Common case */
- uch *dst = &G1.outbuf[outcnt];
- ulg *dst32 = (void*) dst;
+ ulg *dst32 = (void*) &G1.outbuf[outcnt];
*dst32 = n; /* unaligned LSB 32-bit store */
G1.outcnt = outcnt + 4;
return;
@@ -1951,7 +1950,7 @@ static void bi_init(void)
/* ===========================================================================
* Initialize the "longest match" routines for a new file
*/
-static void lm_init(ush * flagsp)
+static void lm_init(unsigned *flags16p)
{
unsigned j;
@@ -1960,7 +1959,7 @@ static void lm_init(ush * flagsp)
/* prev will be initialized on the fly */
/* speed options for the general purpose bit flag */
- *flagsp |= 2; /* FAST 4, SLOW 2 */
+ *flags16p |= 2; /* FAST 4, SLOW 2 */
/* ??? reduce max_chain_length for binary files */
//G1.strstart = 0; // globals are zeroed in pack_gzip()
@@ -2044,9 +2043,8 @@ static void ct_init(void)
Assert(dist == 256, "ct_init: 256+dist != 512");
/* Construct the codes of the static literal tree */
- /* already zeroed - it's in bss
- for (n = 0; n <= MAX_BITS; n++)
- G2.bl_count[n] = 0; */
+ //for (n = 0; n <= MAX_BITS; n++) // globals are zeroed in pack_gzip()
+ // G2.bl_count[n] = 0;
n = 0;
while (n <= 143) {
@@ -2088,7 +2086,7 @@ static void ct_init(void)
*/
static void zip(void)
{
- ush deflate_flags = 0; /* pkzip -es, -en or -ex equivalent */
+ unsigned deflate_flags;
//G1.outcnt = 0; // globals are zeroed in pack_gzip()
@@ -2104,10 +2102,17 @@ static void zip(void)
bi_init();
ct_init();
+ deflate_flags = 0; /* pkzip -es, -en or -ex equivalent */
lm_init(&deflate_flags);
- put_8bit(deflate_flags); /* extra flags */
- put_8bit(3); /* OS identifier = 3 (Unix) */
+ put_16bit(deflate_flags | 0x300); /* extra flags. OS id = 3 (Unix) */
+
+#if OPTIMIZED_PUT_32BIT
+ /* put_32bit() performs 32bit stores. If we use it in send_bits()... */
+ if (BUF_SIZE > 16)
+ /* then all stores are misaligned, unless we flush the buffer now */
+ flush_outbuf();
+#endif
deflate();