The tendency of vi to auto-indent can be really annoying at times.
This commit is contained in:
Rob Landley
parent
f856eabcde
commit
2c98c40ec8
@ -71,7 +71,7 @@ struct group_data {
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typedef struct {
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/* State for interrupting output loop */
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int writeCopies,writePos,writeRunCountdown,writeCount,writeCurrent;
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/* I/O tracking data (file handles, buffers, positions, etc.) */
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@ -154,34 +154,34 @@ static int get_next_block(bunzip_data *bd)
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dbuf=bd->dbuf;
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dbufSize=bd->dbufSize;
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selectors=bd->selectors;
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/* Reset longjmp I/O error handling */
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i=setjmp(bd->jmpbuf);
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if(i) return i;
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/* Read in header signature and CRC, then validate signature.
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(last block signature means CRC is for whole file, return now) */
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i = get_bits(bd,24);
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j = get_bits(bd,24);
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bd->headerCRC=get_bits(bd,32);
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if ((i == 0x177245) && (j == 0x385090)) return RETVAL_LAST_BLOCK;
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if ((i != 0x314159) || (j != 0x265359)) return RETVAL_NOT_BZIP_DATA;
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/* We can add support for blockRandomised if anybody complains. There was
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some code for this in busybox 1.0.0-pre3, but nobody ever noticed that
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it didn't actually work. */
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if(get_bits(bd,1)) return RETVAL_OBSOLETE_INPUT;
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if((origPtr=get_bits(bd,24)) > dbufSize) return RETVAL_DATA_ERROR;
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/* mapping table: if some byte values are never used (encoding things
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like ascii text), the compression code removes the gaps to have fewer
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symbols to deal with, and writes a sparse bitfield indicating which
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values were present. We make a translation table to convert the symbols
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back to the corresponding bytes. */
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t=get_bits(bd, 16);
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symTotal=0;
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for (i=0;i<16;i++) {
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@ -191,81 +191,81 @@ static int get_next_block(bunzip_data *bd)
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if(k&(1<<(15-j))) symToByte[symTotal++]=(16*i)+j;
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}
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}
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/* How many different Huffman coding groups does this block use? */
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groupCount=get_bits(bd,3);
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if (groupCount<2 || groupCount>MAX_GROUPS) return RETVAL_DATA_ERROR;
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/* nSelectors: Every GROUP_SIZE many symbols we select a new Huffman coding
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group. Read in the group selector list, which is stored as MTF encoded
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bit runs. (MTF=Move To Front, as each value is used it's moved to the
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start of the list.) */
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if(!(nSelectors=get_bits(bd, 15))) return RETVAL_DATA_ERROR;
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for(i=0; i<groupCount; i++) mtfSymbol[i] = i;
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for(i=0; i<nSelectors; i++) {
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/* Get next value */
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for(j=0;get_bits(bd,1);j++) if (j>=groupCount) return RETVAL_DATA_ERROR;
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/* Decode MTF to get the next selector */
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uc = mtfSymbol[j];
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for(;j;j--) mtfSymbol[j] = mtfSymbol[j-1];
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mtfSymbol[0]=selectors[i]=uc;
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}
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/* Read the Huffman coding tables for each group, which code for symTotal
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literal symbols, plus two run symbols (RUNA, RUNB) */
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symCount=symTotal+2;
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for (j=0; j<groupCount; j++) {
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unsigned char length[MAX_SYMBOLS],temp[MAX_HUFCODE_BITS+1];
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int minLen, maxLen, pp;
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/* Read Huffman code lengths for each symbol. They're stored in
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a way similar to mtf; record a starting value for the first symbol,
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and an offset from the previous value for everys symbol after that.
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(Subtracting 1 before the loop and then adding it back at the end is
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an optimization that makes the test inside the loop simpler: symbol
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length 0 becomes negative, so an unsigned inequality catches it.) */
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t=get_bits(bd, 5)-1;
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for (i = 0; i < symCount; i++) {
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for(;;) {
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if (((unsigned)t) > (MAX_HUFCODE_BITS-1))
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return RETVAL_DATA_ERROR;
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/* If first bit is 0, stop. Else second bit indicates whether
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to increment or decrement the value. Optimization: grab 2
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bits and unget the second if the first was 0. */
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k = get_bits(bd,2);
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if (k < 2) {
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bd->inbufBitCount++;
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break;
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}
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/* Add one if second bit 1, else subtract 1. Avoids if/else */
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t+=(((k+1)&2)-1);
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}
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/* Correct for the initial -1, to get the final symbol length */
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length[i]=t+1;
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}
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/* Find largest and smallest lengths in this group */
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minLen=maxLen=length[0];
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for(i = 1; i < symCount; i++) {
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if(length[i] > maxLen) maxLen = length[i];
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else if(length[i] < minLen) minLen = length[i];
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}
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/* Calculate permute[], base[], and limit[] tables from length[].
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*
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* permute[] is the lookup table for converting Huffman coded symbols
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@ -276,47 +276,47 @@ static int get_next_block(bunzip_data *bd)
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* number of bits can have. This is how the Huffman codes can vary in
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* length: each code with a value>limit[length] needs another bit.
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*/
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hufGroup=bd->groups+j;
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hufGroup->minLen = minLen;
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hufGroup->maxLen = maxLen;
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/* Note that minLen can't be smaller than 1, so we adjust the base
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and limit array pointers so we're not always wasting the first
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entry. We do this again when using them (during symbol decoding).*/
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base=hufGroup->base-1;
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limit=hufGroup->limit-1;
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/* Calculate permute[]. Concurently, initialize temp[] and limit[]. */
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pp=0;
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for(i=minLen;i<=maxLen;i++) {
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temp[i]=limit[i]=0;
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for(t=0;t<symCount;t++)
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if(length[t]==i) hufGroup->permute[pp++] = t;
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}
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/* Count symbols coded for at each bit length */
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for (i=0;i<symCount;i++) temp[length[i]]++;
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/* Calculate limit[] (the largest symbol-coding value at each bit
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* length, which is (previous limit<<1)+symbols at this level), and
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* base[] (number of symbols to ignore at each bit length, which is
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* limit minus the cumulative count of symbols coded for already). */
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pp=t=0;
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for (i=minLen; i<maxLen; i++) {
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pp+=temp[i];
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/* We read the largest possible symbol size and then unget bits
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after determining how many we need, and those extra bits could
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be set to anything. (They're noise from future symbols.) At
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each level we're really only interested in the first few bits,
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so here we set all the trailing to-be-ignored bits to 1 so they
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don't affect the value>limit[length] comparison. */
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limit[i]= (pp << (maxLen - i)) - 1;
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pp<<=1;
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base[i+1]=pp-(t+=temp[i]);
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@ -325,34 +325,34 @@ static int get_next_block(bunzip_data *bd)
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limit[maxLen]=pp+temp[maxLen]-1;
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base[minLen]=0;
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}
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/* We've finished reading and digesting the block header. Now read this
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block's Huffman coded symbols from the file and undo the Huffman coding
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and run length encoding, saving the result into dbuf[dbufCount++]=uc */
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/* Initialize symbol occurrence counters and symbol Move To Front table */
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for(i=0;i<256;i++) {
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byteCount[i] = 0;
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mtfSymbol[i]=(unsigned char)i;
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}
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/* Loop through compressed symbols. */
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runPos=dbufCount=selector=0;
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for(;;) {
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/* fetch next Huffman coding group from list. */
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symCount=GROUP_SIZE-1;
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if(selector>=nSelectors) return RETVAL_DATA_ERROR;
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hufGroup=bd->groups+selectors[selector++];
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base=hufGroup->base-1;
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limit=hufGroup->limit-1;
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continue_this_group:
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/* Read next Huffman-coded symbol. */
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/* Note: It is far cheaper to read maxLen bits and back up than it is
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to read minLen bits and then an additional bit at a time, testing
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as we go. Because there is a trailing last block (with file CRC),
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@ -362,7 +362,7 @@ continue_this_group:
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dry). The following (up to got_huff_bits:) is equivalent to
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j=get_bits(bd,hufGroup->maxLen);
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*/
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while (bd->inbufBitCount<hufGroup->maxLen) {
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if(bd->inbufPos==bd->inbufCount) {
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j = get_bits(bd,hufGroup->maxLen);
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@ -373,37 +373,37 @@ continue_this_group:
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};
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bd->inbufBitCount-=hufGroup->maxLen;
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j = (bd->inbufBits>>bd->inbufBitCount)&((1<<hufGroup->maxLen)-1);
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got_huff_bits:
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/* Figure how how many bits are in next symbol and unget extras */
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i=hufGroup->minLen;
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while(j>limit[i]) ++i;
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bd->inbufBitCount += (hufGroup->maxLen - i);
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/* Huffman decode value to get nextSym (with bounds checking) */
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if ((i > hufGroup->maxLen)
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|| (((unsigned)(j=(j>>(hufGroup->maxLen-i))-base[i]))
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>= MAX_SYMBOLS))
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return RETVAL_DATA_ERROR;
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nextSym = hufGroup->permute[j];
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/* We have now decoded the symbol, which indicates either a new literal
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byte, or a repeated run of the most recent literal byte. First,
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check if nextSym indicates a repeated run, and if so loop collecting
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how many times to repeat the last literal. */
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if (((unsigned)nextSym) <= SYMBOL_RUNB) { /* RUNA or RUNB */
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/* If this is the start of a new run, zero out counter */
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if(!runPos) {
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runPos = 1;
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t = 0;
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}
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/* Neat trick that saves 1 symbol: instead of or-ing 0 or 1 at
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each bit position, add 1 or 2 instead. For example,
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1011 is 1<<0 + 1<<1 + 2<<2. 1010 is 2<<0 + 2<<1 + 1<<2.
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@ -411,17 +411,17 @@ got_huff_bits:
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the basic or 0/1 method (except all bits 0, which would use no
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symbols, but a run of length 0 doesn't mean anything in this
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context). Thus space is saved. */
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t += (runPos << nextSym); /* +runPos if RUNA; +2*runPos if RUNB */
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runPos <<= 1;
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goto end_of_huffman_loop;
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}
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/* When we hit the first non-run symbol after a run, we now know
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how many times to repeat the last literal, so append that many
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copies to our buffer of decoded symbols (dbuf) now. (The last
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literal used is the one at the head of the mtfSymbol array.) */
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if(runPos) {
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runPos=0;
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if(dbufCount+t>=dbufSize) return RETVAL_DATA_ERROR;
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@ -430,11 +430,11 @@ got_huff_bits:
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byteCount[uc] += t;
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while(t--) dbuf[dbufCount++]=uc;
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}
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/* Is this the terminating symbol? */
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if(nextSym>symTotal) break;
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/* At this point, nextSym indicates a new literal character. Subtract
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one to get the position in the MTF array at which this literal is
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currently to be found. (Note that the result can't be -1 or 0,
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@ -442,30 +442,30 @@ got_huff_bits:
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first symbol in the mtf array, position 0, would have been handled
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as part of a run above. Therefore 1 unused mtf position minus
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2 non-literal nextSym values equals -1.) */
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if(dbufCount>=dbufSize) return RETVAL_DATA_ERROR;
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i = nextSym - 1;
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uc = mtfSymbol[i];
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/* Adjust the MTF array. Since we typically expect to move only a
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* small number of symbols, and are bound by 256 in any case, using
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* memmove here would typically be bigger and slower due to function
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* call overhead and other assorted setup costs. */
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do {
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mtfSymbol[i] = mtfSymbol[i-1];
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} while (--i);
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mtfSymbol[0] = uc;
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uc=symToByte[uc];
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/* We have our literal byte. Save it into dbuf. */
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byteCount[uc]++;
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dbuf[dbufCount++] = (unsigned int)uc;
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/* Skip group initialization if we're not done with this group. Done
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* this way to avoid compiler warning. */
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end_of_huffman_loop:
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if(symCount--) goto continue_this_group;
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}
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@ -476,7 +476,7 @@ end_of_huffman_loop:
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Now undo the Burrows-Wheeler transform on dbuf.
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See http://dogma.net/markn/articles/bwt/bwt.htm
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*/
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/* Turn byteCount into cumulative occurrence counts of 0 to n-1. */
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j=0;
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@ -497,7 +497,7 @@ end_of_huffman_loop:
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/* Decode first byte by hand to initialize "previous" byte. Note that it
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doesn't get output, and if the first three characters are identical
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it doesn't qualify as a run (hence writeRunCountdown=5). */
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if(dbufCount) {
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if(origPtr>=dbufCount) return RETVAL_DATA_ERROR;
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bd->writePos=dbuf[origPtr];
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