From 9c499a5af48bd4d9d635c8021e6ad14fd4e939dc Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Tue, 30 Jan 2018 18:15:39 +0100 Subject: 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 --- archival/gzip.c | 28 +++++++++++++++------------- 1 file changed, 15 insertions(+), 13 deletions(-) (limited to 'archival/gzip.c') diff --git a/archival/gzip.c b/archival/gzip.c index 10eda7aa3..8ef66390a 100644 --- a/archival/gzip.c +++ b/archival/gzip.c @@ -312,25 +312,24 @@ struct globals { #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 @@ struct globals { 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 @@ struct globals { 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 @@ static void fill_window(void) } } } +/* 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 @@ static NOINLINE ulg deflate(void) * 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 @@ static void lm_init(ush * flagsp) /* 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++) -- cgit v1.2.3