diff options
| -rw-r--r-- | archival/libunarchive/decompress_bunzip2.c | 25 |
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; } |