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authorDenys Vlasenko <dvlasenk@redhat.com>2010-10-30 00:55:02 +0200
committerDenys Vlasenko <dvlasenk@redhat.com>2010-10-30 00:55:02 +0200
commitf16727ebbbb385b1bf4d03608a04f8310469cf1f (patch)
treec606facf27e7e157cafe525b7d4a6b50d8c539e7 /archival/libunarchive
parent0c576975c87c543522ab31566139c078429dff38 (diff)
downloadbusybox-f16727ebbbb385b1bf4d03608a04f8310469cf1f.tar.gz
decompress_bunzip2: code shrink ~5 bytes
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Diffstat (limited to 'archival/libunarchive')
-rw-r--r--archival/libunarchive/decompress_bunzip2.c25
1 files changed, 13 insertions, 12 deletions
diff --git a/archival/libunarchive/decompress_bunzip2.c b/archival/libunarchive/decompress_bunzip2.c
index 2d4867220..d30166fa4 100644
--- a/archival/libunarchive/decompress_bunzip2.c
+++ b/archival/libunarchive/decompress_bunzip2.c
@@ -153,6 +153,7 @@ static int get_next_block(bunzip_data *bd)
struct group_data *hufGroup;
int dbufCount, dbufSize, groupCount, *base, *limit, selector,
i, j, t, runPos, symCount, symTotal, nSelectors, byteCount[256];
+ int runCnt = runCnt; /* for compiler */
uint8_t uc, symToByte[256], mtfSymbol[256], *selectors;
uint32_t *dbuf;
unsigned origPtr;
@@ -242,19 +243,19 @@ static int get_next_block(bunzip_data *bd)
uint8_t length[MAX_SYMBOLS];
/* 8 bits is ALMOST enough for temp[], see below */
unsigned temp[MAX_HUFCODE_BITS+1];
- int minLen, maxLen, pp;
+ int minLen, maxLen, pp, len_m1;
/* Read Huffman code lengths for each symbol. They're stored in
a way similar to mtf; record a starting value for the first symbol,
- and an offset from the previous value for everys symbol after that.
+ and an offset from the previous value for every symbol after that.
(Subtracting 1 before the loop and then adding it back at the end is
an optimization that makes the test inside the loop simpler: symbol
length 0 becomes negative, so an unsigned inequality catches it.) */
- t = get_bits(bd, 5) - 1;
+ len_m1 = get_bits(bd, 5) - 1;
for (i = 0; i < symCount; i++) {
for (;;) {
int two_bits;
- if ((unsigned)t > (MAX_HUFCODE_BITS-1))
+ if ((unsigned)len_m1 > (MAX_HUFCODE_BITS-1))
return RETVAL_DATA_ERROR;
/* If first bit is 0, stop. Else second bit indicates whether
@@ -267,11 +268,11 @@ static int get_next_block(bunzip_data *bd)
}
/* Add one if second bit 1, else subtract 1. Avoids if/else */
- t += (((two_bits+1) & 2) - 1);
+ len_m1 += (((two_bits+1) & 2) - 1);
}
/* Correct for the initial -1, to get the final symbol length */
- length[i] = t + 1;
+ length[i] = len_m1 + 1;
}
/* Find largest and smallest lengths in this group */
@@ -337,8 +338,8 @@ static int get_next_block(bunzip_data *bd)
t += temp_i;
base[++i] = pp - t;
}
- limit[maxLen+1] = INT_MAX; /* Sentinel value for reading next sym. */
limit[maxLen] = pp + temp[maxLen] - 1;
+ limit[maxLen+1] = INT_MAX; /* Sentinel value for reading next sym. */
base[minLen] = 0;
}
@@ -418,7 +419,7 @@ static int get_next_block(bunzip_data *bd)
/* If this is the start of a new run, zero out counter */
if (runPos == 0) {
runPos = 1;
- t = 0;
+ runCnt = 0;
}
/* Neat trick that saves 1 symbol: instead of or-ing 0 or 1 at
@@ -428,7 +429,7 @@ static int get_next_block(bunzip_data *bd)
the basic or 0/1 method (except all bits 0, which would use no
symbols, but a run of length 0 doesn't mean anything in this
context). Thus space is saved. */
- t += (runPos << nextSym); /* +runPos if RUNA; +2*runPos if RUNB */
+ runCnt += (runPos << nextSym); /* +runPos if RUNA; +2*runPos if RUNB */
if (runPos < dbufSize) runPos <<= 1;
goto end_of_huffman_loop;
}
@@ -439,10 +440,10 @@ static int get_next_block(bunzip_data *bd)
literal used is the one at the head of the mtfSymbol array.) */
if (runPos != 0) {
uint8_t tmp_byte;
- if (dbufCount + t >= dbufSize) return RETVAL_DATA_ERROR;
+ if (dbufCount + runCnt >= dbufSize) return RETVAL_DATA_ERROR;
tmp_byte = symToByte[mtfSymbol[0]];
- byteCount[tmp_byte] += t;
- while (--t >= 0) dbuf[dbufCount++] = tmp_byte;
+ byteCount[tmp_byte] += runCnt;
+ while (--runCnt >= 0) dbuf[dbufCount++] = (uint32_t)tmp_byte;
runPos = 0;
}