File gzip-code-shrink-2.patch of Package busybox.20467
From: Denys Vlasenko <vda.linux@googlemail.com>
Date: Sat Oct 19 18:52:41 2019 +0200
Subject: gzip: code shrink
Patch-mainline: 6572ef6e1e4822f785b7139ef166586c444dc01e
Git-repo: https://git.busybox.net/busybox
Git-commit: de5e8dce4ffde011ece77f864ca326a9c98b50c1
References:
huft_build() still has way too many params
function old new delta
lit - 94 +94
dist - 94 +94
huft_build 1058 1054 -4
inflate_block 1281 1254 -27
cpdext 30 - -30
cplext 31 - -31
cpdist 60 - -60
cplens 62 - -62
------------------------------------------------------------------------------
(add/remove: 2/4 grow/shrink: 0/2 up/down: 188/-214) Total: -26 bytes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Signed-off-by: Egbert Eich <eich@suse.de>
---
archival/libarchive/decompress_gunzip.c | 55 ++++++++++++++++-----------------
1 file changed, 26 insertions(+), 29 deletions(-)
diff --git a/archival/libarchive/decompress_gunzip.c b/archival/libarchive/decompress_gunzip.c
index 8f23a7307..6571b23d7 100644
--- a/archival/libarchive/decompress_gunzip.c
+++ b/archival/libarchive/decompress_gunzip.c
@@ -186,29 +186,26 @@ static const uint16_t mask_bits[] ALIGN2 = {
0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
};
-/* Copy lengths for literal codes 257..285 */
-static const uint16_t cplens[] ALIGN2 = {
- 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, 35, 43, 51, 59,
- 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0
+/* Put lengths/offsets and extra bits in a struct of arrays
+ * to make calls to huft_build() have one fewer parameter.
+ */
+struct cp_ext {
+ uint16_t cp[31];
+ uint8_t ext[31];
};
-
+/* Copy lengths and extra bits for literal codes 257..285 */
/* note: see note #13 above about the 258 in this list. */
-/* Extra bits for literal codes 257..285 */
-static const uint8_t cplext[] ALIGN1 = {
- 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5,
- 5, 5, 5, 0, 99, 99
-}; /* 99 == invalid */
-
-/* Copy offsets for distance codes 0..29 */
-static const uint16_t cpdist[] ALIGN2 = {
- 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, 257, 385, 513,
- 769, 1025, 1537, 2049, 3073, 4097, 6145, 8193, 12289, 16385, 24577
+static const struct cp_ext lit = {
+ /*257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 */
+ /*0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 */
+ { 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0 },
+ { 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 99, 99 } /* 99 == invalid */
};
-
-/* Extra bits for distance codes */
-static const uint8_t cpdext[] ALIGN1 = {
- 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10,
- 11, 11, 12, 12, 13, 13
+/* Copy offsets and extra bits for distance codes 0..29 */
+static const struct cp_ext dist = {
+ /*0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 */
+ { 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, 257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145, 8193, 12289, 16385, 24577 },
+ { 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13 }
};
/* Tables for deflate from PKZIP's appnote.txt. */
@@ -290,8 +287,8 @@ static unsigned fill_bitbuffer(STATE_PARAM unsigned bitbuffer, unsigned *current
* result: starting table
*/
static huft_t* huft_build(const unsigned *b, const unsigned n,
- const unsigned s, const uint16_t *d,
- const uint8_t *e, unsigned *m)
+ const unsigned s, const struct cp_ext *cp_ext,
+ unsigned *m)
{
unsigned a; /* counter for codes of length k */
unsigned c[BMAX + 1]; /* bit length count table */
@@ -449,8 +446,8 @@ static huft_t* huft_build(const unsigned *b, const unsigned n,
r.e = (unsigned char) (*p < 256 ? 16 : 15); /* 256 is EOB code */
r.v.n = (unsigned short) (*p++); /* simple code is just the value */
} else {
- r.e = (unsigned char) e[*p - s]; /* non-simple--look up in lists */
- r.v.n = d[*p++ - s];
+ r.e = (unsigned char) cp_ext->ext[*p - s]; /* non-simple--look up in lists */
+ r.v.n = cp_ext->cp[*p++ - s];
}
/* fill code-like entries with r */
@@ -779,14 +776,14 @@ static int inflate_block(STATE_PARAM smallint *e)
for (; i < 288; i++) /* make a complete, but wrong code set */
ll[i] = 8;
bl = 7;
- inflate_codes_tl = huft_build(ll, 288, 257, cplens, cplext, &bl);
+ inflate_codes_tl = huft_build(ll, 288, 257, &lit, &bl);
/* huft_build() never returns error here - we use known data */
/* set up distance table */
for (i = 0; i < 30; i++) /* make an incomplete code set */
ll[i] = 5;
bd = 5;
- inflate_codes_td = huft_build(ll, 30, 0, cpdist, cpdext, &bd);
+ inflate_codes_td = huft_build(ll, 30, 0, &dist, &bd);
/* set up data for inflate_codes() */
inflate_codes_setup(PASS_STATE bl, bd);
@@ -852,7 +849,7 @@ static int inflate_block(STATE_PARAM smallint *e)
/* build decoding table for trees - single level, 7 bit lookup */
bl = 7;
- inflate_codes_tl = huft_build(ll, 19, 19, NULL, NULL, &bl);
+ inflate_codes_tl = huft_build(ll, 19, 19, NULL, &bl);
if (!inflate_codes_tl) {
abort_unzip(PASS_STATE_ONLY); /* incomplete code set */
}
@@ -917,12 +914,12 @@ static int inflate_block(STATE_PARAM smallint *e)
/* build the decoding tables for literal/length and distance codes */
bl = lbits;
- inflate_codes_tl = huft_build(ll, nl, 257, cplens, cplext, &bl);
+ inflate_codes_tl = huft_build(ll, nl, 257, &lit, &bl);
if (!inflate_codes_tl) {
abort_unzip(PASS_STATE_ONLY);
}
bd = dbits;
- inflate_codes_td = huft_build(ll + nl, nd, 0, cpdist, cpdext, &bd);
+ inflate_codes_td = huft_build(ll + nl, nd, 0, &dist, &bd);
if (!inflate_codes_td) {
abort_unzip(PASS_STATE_ONLY);
}
