svn commit: trunk/busybox/archival/libunarchive
vda at busybox.net
vda at busybox.net
Wed Oct 10 20:53:41 UTC 2007
Author: vda
Date: 2007-10-10 13:53:41 -0700 (Wed, 10 Oct 2007)
New Revision: 20217
Log:
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
Modified:
trunk/busybox/archival/libunarchive/decompress_bunzip2.c
Changeset:
Modified: trunk/busybox/archival/libunarchive/decompress_bunzip2.c
===================================================================
--- trunk/busybox/archival/libunarchive/decompress_bunzip2.c 2007-10-10 14:43:03 UTC (rev 20216)
+++ trunk/busybox/archival/libunarchive/decompress_bunzip2.c 2007-10-10 20:53:41 UTC (rev 20217)
@@ -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)
@@ -54,23 +54,28 @@
/* 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 @@
/* 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 @@
/* 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 @@
/* 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 @@
/* 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 @@
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 @@
/* 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 @@
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 @@
/* 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 @@
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 @@
} 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);
}
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