From 52a4388d95436c268a3488c6ff00e4641afd12d3 Mon Sep 17 00:00:00 2001 From: Denis Vlasenko Date: Wed, 10 Oct 2007 20:53:41 +0000 Subject: bunzip: small code shrink and consmetics read_bunzip 276 283 +7 get_bits 184 162 -22 get_next_block 1833 1810 -23 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 1/2 up/down: 7/-45) Total: -38 bytes --- archival/libunarchive/decompress_bunzip2.c | 50 +++++++++++++++++------------- 1 file changed, 28 insertions(+), 22 deletions(-) (limited to 'archival') diff --git a/archival/libunarchive/decompress_bunzip2.c b/archival/libunarchive/decompress_bunzip2.c index 17b87e2c1..c1b12732c 100644 --- a/archival/libunarchive/decompress_bunzip2.c +++ b/archival/libunarchive/decompress_bunzip2.c @@ -44,7 +44,7 @@ #define RETVAL_LAST_BLOCK (-1) #define RETVAL_NOT_BZIP_DATA (-2) #define RETVAL_UNEXPECTED_INPUT_EOF (-3) -#define RETVAL_UNEXPECTED_OUTPUT_EOF (-4) +#define RETVAL_SHORT_WRITE (-4) #define RETVAL_DATA_ERROR (-5) #define RETVAL_OUT_OF_MEMORY (-6) #define RETVAL_OBSOLETE_INPUT (-7) @@ -54,22 +54,27 @@ /* This is what we know about each Huffman coding group */ struct group_data { - /* We have an extra slot at the end of limit[] for a sentinal value. */ + /* We have an extra slot at the end of limit[] for a sentinel value. */ int limit[MAX_HUFCODE_BITS+1], base[MAX_HUFCODE_BITS], permute[MAX_SYMBOLS]; int minLen, maxLen; }; /* Structure holding all the housekeeping data, including IO buffers and - memory that persists between calls to bunzip */ + * memory that persists between calls to bunzip + * Found the most used member: + * cat this_file.c | sed -e 's/"/ /g' -e "s/'/ /g" | xargs -n1 \ + * | grep 'bd->' | sed 's/^.*bd->/bd->/' | sort | $PAGER + * and moved it (inbufBitCount) to offset 0. + */ struct bunzip_data { - /* State for interrupting output loop */ - int writeCopies, writePos, writeRunCountdown, writeCount, writeCurrent; - /* I/O tracking data (file handles, buffers, positions, etc.) */ + unsigned inbufBitCount, inbufBits; int in_fd, out_fd, inbufCount, inbufPos /*, outbufPos*/; unsigned char *inbuf /*,*outbuf*/; - unsigned inbufBitCount, inbufBits; + + /* State for interrupting output loop */ + int writeCopies, writePos, writeRunCountdown, writeCount, writeCurrent; /* The CRC values stored in the block header and calculated from the data */ uint32_t headerCRC, totalCRC, writeCRC; @@ -80,7 +85,7 @@ struct bunzip_data { /* For I/O error handling */ jmp_buf jmpbuf; - /* Big things go last (register-relative addressing can be larger for big offsets */ + /* Big things go last (register-relative addressing can be larger for big offsets) */ uint32_t crc32Table[256]; unsigned char selectors[32768]; /* nSelectors=15 bits */ struct group_data groups[MAX_GROUPS]; /* Huffman coding tables */ @@ -91,7 +96,7 @@ struct bunzip_data { /* Return the next nnn bits of input. All reads from the compressed input are done through this function. All reads are big endian */ -static unsigned get_bits(bunzip_data *bd, char bits_wanted) +static unsigned get_bits(bunzip_data *bd, int bits_wanted) { unsigned bits = 0; @@ -121,7 +126,7 @@ static unsigned get_bits(bunzip_data *bd, char bits_wanted) /* Grab next 8 bits of input from buffer. */ - bd->inbufBits = (bd->inbufBits<<8) | bd->inbuf[bd->inbufPos++]; + bd->inbufBits = (bd->inbufBits << 8) | bd->inbuf[bd->inbufPos++]; bd->inbufBitCount += 8; } @@ -205,7 +210,7 @@ static int get_next_block(bunzip_data *bd) /* Get next value */ for (j = 0; get_bits(bd, 1); j++) - if (j>=groupCount) return RETVAL_DATA_ERROR; + if (j >= groupCount) return RETVAL_DATA_ERROR; /* Decode MTF to get the next selector */ @@ -320,19 +325,20 @@ static int get_next_block(bunzip_data *bd) t += temp[i]; base[i+1] = pp - t; } - limit[maxLen+1] = INT_MAX; /* Sentinal value for reading next sym. */ + limit[maxLen+1] = INT_MAX; /* Sentinel value for reading next sym. */ limit[maxLen] = pp + temp[maxLen] - 1; base[minLen] = 0; } /* We've finished reading and digesting the block header. Now read this block's Huffman coded symbols from the file and undo the Huffman coding - and run length encoding, saving the result into dbuf[dbufCount++]=uc */ + and run length encoding, saving the result into dbuf[dbufCount++] = uc */ /* Initialize symbol occurrence counters and symbol Move To Front table */ + memset(byteCount, 0, sizeof(byteCount)); /* smaller, maybe slower? */ for (i = 0; i < 256; i++) { - byteCount[i] = 0; + //byteCount[i] = 0; mtfSymbol[i] = (unsigned char)i; } @@ -547,7 +553,7 @@ int read_bunzip(bunzip_data *bd, char *outbuf, int len) /* If the output buffer is full, snapshot state and return */ if (gotcount >= len) { - bd->writePos =pos; + bd->writePos = pos; bd->writeCurrent = current; bd->writeCopies++; return len; @@ -573,8 +579,8 @@ int read_bunzip(bunzip_data *bd, char *outbuf, int len) current = pos & 0xff; pos >>= 8; - /* After 3 consecutive copies of the same byte, the 4th is a repeat - count. We count down from 4 instead + /* After 3 consecutive copies of the same byte, the 4th + * is a repeat count. We count down from 4 instead * of counting up because testing for non-zero is faster */ if (--bd->writeRunCountdown) { @@ -606,7 +612,7 @@ int read_bunzip(bunzip_data *bd, char *outbuf, int len) /* If this block had a CRC error, force file level CRC error. */ if (bd->writeCRC != bd->headerCRC) { - bd->totalCRC = bd->headerCRC+1; + bd->totalCRC = bd->headerCRC + 1; return RETVAL_LAST_BLOCK; } } @@ -713,8 +719,8 @@ unpack_bz2_stream(int src_fd, int dst_fd) for (;;) { i = read_bunzip(bd, outbuf, IOBUF_SIZE); if (i <= 0) break; - if (i != safe_write(dst_fd, outbuf, i)) { - i = RETVAL_UNEXPECTED_OUTPUT_EOF; + if (i != full_write(dst_fd, outbuf, i)) { + i = RETVAL_SHORT_WRITE; break; } USE_DESKTOP(total_written += i;) @@ -729,8 +735,8 @@ unpack_bz2_stream(int src_fd, int dst_fd) } else { i = RETVAL_OK; } - } else if (i == RETVAL_UNEXPECTED_OUTPUT_EOF) { - bb_error_msg("unexpected EOF"); + } else if (i == RETVAL_SHORT_WRITE) { + bb_error_msg("short write"); } else { bb_error_msg("bunzip error %d", i); } -- cgit v1.2.3