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authorGravatar Denys Vlasenko <vda.linux@googlemail.com>2018-01-31 16:11:44 +0100
committerGravatar Denys Vlasenko <vda.linux@googlemail.com>2018-01-31 16:11:56 +0100
commit05251986c7c00b07a5a7ff0f70258e53a3f3de9e (patch)
treeea84e7fc00018c7f664434ea36dca7107c419029 /archival/gzip.c
parent8fd35a1fa629daed5e4e580e72993df7654f0a5e (diff)
downloadbusybox-05251986c7c00b07a5a7ff0f70258e53a3f3de9e.tar.gz
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gzip: code shrink
Use one memset to clear part of G1, and all of G2. function old new delta pack_gzip 838 828 -10 Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Diffstat (limited to 'archival/gzip.c')
-rw-r--r--archival/gzip.c108
1 files changed, 56 insertions, 52 deletions
diff --git a/archival/gzip.c b/archival/gzip.c
index d52167f84..9dc31e30b 100644
--- a/archival/gzip.c
+++ b/archival/gzip.c
@@ -300,6 +300,50 @@ enum {
struct globals {
+/* =========================================================================== */
+/* global buffers, allocated once */
+
+#define DECLARE(type, array, size) \
+ type * array
+#define ALLOC(type, array, size) \
+ array = xzalloc((size_t)(((size)+1L)/2) * 2*sizeof(type))
+#define FREE(array) \
+ do { free(array); array = NULL; } while (0)
+
+ /* buffer for literals or lengths */
+ /* DECLARE(uch, l_buf, LIT_BUFSIZE); */
+ DECLARE(uch, l_buf, INBUFSIZ);
+
+ DECLARE(ush, d_buf, DIST_BUFSIZE);
+ DECLARE(uch, outbuf, OUTBUFSIZ);
+
+/* Sliding window. Input bytes are read into the second half of the window,
+ * and move to the first half later to keep a dictionary of at least WSIZE
+ * bytes. With this organization, matches are limited to a distance of
+ * WSIZE-MAX_MATCH bytes, but this ensures that IO is always
+ * performed with a length multiple of the block size. Also, it limits
+ * the window size to 64K, which is quite useful on MSDOS.
+ * To do: limit the window size to WSIZE+BSZ if SMALL_MEM (the code would
+ * be less efficient).
+ */
+ DECLARE(uch, window, 2L * WSIZE);
+
+/* Link to older string with same hash index. To limit the size of this
+ * array to 64K, this link is maintained only for the last 32K strings.
+ * An index in this array is thus a window index modulo 32K.
+ */
+ /* DECLARE(Pos, prev, WSIZE); */
+ DECLARE(ush, prev, 1L << BITS);
+
+/* Heads of the hash chains or 0. */
+ /* DECLARE(Pos, head, 1<<HASH_BITS); */
+#define head (G1.prev + WSIZE) /* hash head (see deflate.c) */
+
+/* =========================================================================== */
+/* all members below are zeroed out in pack_gzip() for each next file */
+
+ uint32_t crc; /* shift register contents */
+ /*uint32_t *crc_32_tab;*/
#if ENABLE_FEATURE_GZIP_LEVELS
unsigned max_chain_length;
@@ -368,49 +412,6 @@ struct globals {
#ifdef DEBUG
ulg bits_sent; /* bit length of the compressed data */
#endif
-
- /*uint32_t *crc_32_tab;*/
- uint32_t crc; /* shift register contents */
-
-/* ===========================================================================
- */
-#define DECLARE(type, array, size) \
- type * array
-#define ALLOC(type, array, size) \
- array = xzalloc((size_t)(((size)+1L)/2) * 2*sizeof(type))
-#define FREE(array) \
- do { free(array); array = NULL; } while (0)
-
- /* global buffers */
-
- /* buffer for literals or lengths */
- /* DECLARE(uch, l_buf, LIT_BUFSIZE); */
- DECLARE(uch, l_buf, INBUFSIZ);
-
- DECLARE(ush, d_buf, DIST_BUFSIZE);
- DECLARE(uch, outbuf, OUTBUFSIZ);
-
-/* Sliding window. Input bytes are read into the second half of the window,
- * and move to the first half later to keep a dictionary of at least WSIZE
- * bytes. With this organization, matches are limited to a distance of
- * WSIZE-MAX_MATCH bytes, but this ensures that IO is always
- * performed with a length multiple of the block size. Also, it limits
- * the window size to 64K, which is quite useful on MSDOS.
- * To do: limit the window size to WSIZE+BSZ if SMALL_MEM (the code would
- * be less efficient).
- */
- DECLARE(uch, window, 2L * WSIZE);
-
-/* Link to older string with same hash index. To limit the size of this
- * array to 64K, this link is maintained only for the last 32K strings.
- * An index in this array is thus a window index modulo 32K.
- */
- /* DECLARE(Pos, prev, WSIZE); */
- DECLARE(ush, prev, 1L << BITS);
-
-/* Heads of the hash chains or 0. */
- /* DECLARE(Pos, head, 1<<HASH_BITS); */
-#define head (G1.prev + WSIZE) /* hash head (see deflate.c) */
};
#define G1 (*(ptr_to_globals - 1))
@@ -460,6 +461,7 @@ static void put_16bit(ush w)
}
*dst = (uch)w;
w >>= 8;
+ G1.outcnt = ++outcnt;
#else
*dst = (uch)w;
w >>= 8;
@@ -469,13 +471,13 @@ static void put_16bit(ush w)
G1.outcnt = outcnt + 2;
return;
}
+ G1.outcnt = ++outcnt;
#endif
/* Slowpath: we will need to do flush_outbuf() */
- G1.outcnt = ++outcnt;
if (outcnt == OUTBUFSIZ)
- flush_outbuf();
- put_8bit(w);
+ flush_outbuf(); /* here */
+ put_8bit(w); /* or here */
}
#define OPTIMIZED_PUT_32BIT (CONFIG_GZIP_FAST > 0 && BB_UNALIGNED_MEMACCESS_OK && BB_LITTLE_ENDIAN)
@@ -2056,17 +2058,20 @@ static void ct_init(void)
G2.static_ltree[n++].Len = 9;
//G2.bl_count[9]++;
}
- G2.bl_count[9] = 255 - 143;
+ //G2.bl_count[9] = 255 - 143;
while (n <= 279) {
G2.static_ltree[n++].Len = 7;
//G2.bl_count[7]++;
}
- G2.bl_count[7] = 279 - 255;
+ //G2.bl_count[7] = 279 - 255;
while (n <= 287) {
G2.static_ltree[n++].Len = 8;
//G2.bl_count[8]++;
}
- G2.bl_count[8] = 287 - 279 + (143 + 1);
+ //G2.bl_count[8] += 287 - 279;
+ G2.bl_count[7] = 279 - 255;
+ G2.bl_count[8] = (143 + 1) + (287 - 279);
+ G2.bl_count[9] = 255 - 143;
/* Codes 286 and 287 do not exist, but we must include them in the
* tree construction to get a canonical Huffman tree (longest code
* all ones)
@@ -2132,8 +2137,8 @@ static void zip(void)
static
IF_DESKTOP(long long) int FAST_FUNC pack_gzip(transformer_state_t *xstate UNUSED_PARAM)
{
- /* Reinit G1.xxx except pointers to allocated buffers */
- memset(&G1, 0, offsetof(struct globals, l_buf));
+ /* Reinit G1.xxx except pointers to allocated buffers, and entire G2 */
+ memset(&G1.crc, 0, (sizeof(G1) - offsetof(struct globals, crc)) + sizeof(G2));
/* Clear input and output buffers */
//G1.outcnt = 0;
@@ -2143,7 +2148,6 @@ IF_DESKTOP(long long) int FAST_FUNC pack_gzip(transformer_state_t *xstate UNUSED
//G1.isize = 0;
/* Reinit G2.xxx */
- memset(&G2, 0, sizeof(G2));
G2.l_desc.dyn_tree = G2.dyn_ltree;
G2.l_desc.static_tree = G2.static_ltree;
G2.l_desc.extra_bits = extra_lbits;