gzip: code shrink
function old new delta
fill_window_if_needed - 238 +238
deflate 924 907 -17
pack_gzip 809 790 -19
fill_window 216 - -216
------------------------------------------------------------------------------
(add/remove: 1/1 grow/shrink: 0/2 up/down: 238/-252) Total: -14 bytes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/archival/gzip.c b/archival/gzip.c
index 10eda7a..8ef6639 100644
--- a/archival/gzip.c
+++ b/archival/gzip.c
@@ -312,25 +312,24 @@
#define nice_match (G1.nice_match)
#endif
- lng block_start;
-
/* window position at the beginning of the current output block. Gets
* negative when the window is moved backwards.
*/
+ lng block_start;
+
unsigned ins_h; /* hash index of string to be inserted */
-#define H_SHIFT ((HASH_BITS+MIN_MATCH-1) / MIN_MATCH)
/* Number of bits by which ins_h and del_h must be shifted at each
* input step. It must be such that after MIN_MATCH steps, the oldest
* byte no longer takes part in the hash key, that is:
* H_SHIFT * MIN_MATCH >= HASH_BITS
*/
-
- unsigned prev_length;
+#define H_SHIFT ((HASH_BITS+MIN_MATCH-1) / MIN_MATCH)
/* Length of the best match at previous step. Matches not greater than this
* are discarded. This is used in the lazy match evaluation.
*/
+ unsigned prev_length;
unsigned strstart; /* start of string to insert */
unsigned match_start; /* start of matching string */
@@ -347,18 +346,17 @@
unsigned insize; /* valid bytes in l_buf */
#endif
unsigned outcnt; /* bytes in output buffer */
-
smallint eofile; /* flag set at end of input file */
/* ===========================================================================
* Local data used by the "bit string" routines.
*/
- unsigned short bi_buf;
-
/* Output buffer. bits are inserted starting at the bottom (least significant
* bits).
*/
+ unsigned short bi_buf;
+
#undef BUF_SIZE
#define BUF_SIZE (8 * sizeof(G1.bi_buf))
@@ -368,7 +366,7 @@
int bi_valid;
#ifdef DEBUG
- ulg bits_sent; /* bit length of the compressed data */
+ ulg bits_sent; /* bit length of the compressed data */
#endif
/*uint32_t *crc_32_tab;*/
@@ -662,6 +660,12 @@
}
}
}
+/* Both users fill window with the same loop: */
+static void fill_window_if_needed(void)
+{
+ while (G1.lookahead < MIN_LOOKAHEAD && !G1.eofile)
+ fill_window();
+}
/* ===========================================================================
@@ -1894,8 +1898,7 @@
* for the next match, plus MIN_MATCH bytes to insert the
* string following the next match.
*/
- while (G1.lookahead < MIN_LOOKAHEAD && !G1.eofile)
- fill_window();
+ fill_window_if_needed();
}
if (match_available)
ct_tally(0, G1.window[G1.strstart - 1]);
@@ -1948,8 +1951,7 @@
/* Make sure that we always have enough lookahead. This is important
* if input comes from a device such as a tty.
*/
- while (G1.lookahead < MIN_LOOKAHEAD && !G1.eofile)
- fill_window();
+ fill_window_if_needed();
//G1.ins_h = 0; // globals are zeroed in pack_gzip()
for (j = 0; j < MIN_MATCH - 1; j++)