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434 lines
16 KiB
C
434 lines
16 KiB
C
/*
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* puff.c
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* Copyright (C) 2002-2013 Mark Adler
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* For conditions of distribution and use, see copyright notice in puff.h
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* version 2.3, 21 Jan 2013
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*/
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#include <setjmp.h> /* for setjmp(), longjmp(), and jmp_buf */
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#include "puff.h" /* prototype for puff() */
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#define local static /* for local function definitions */
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#define MAXBITS 15 /* maximum bits in a code */
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#define MAXLCODES 286 /* maximum number of literal/length codes */
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#define MAXDCODES 30 /* maximum number of distance codes */
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#define MAXCODES (MAXLCODES+MAXDCODES) /* maximum codes lengths to read */
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#define FIXLCODES 288 /* number of fixed literal/length codes */
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/* input and output state */
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struct state {
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/* output state */
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unsigned char *out; /* output buffer */
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unsigned long outlen; /* available space at out */
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unsigned long outcnt; /* bytes written to out so far */
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/* input state */
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const unsigned char *in; /* input buffer */
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unsigned long inlen; /* available input at in */
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unsigned long incnt; /* bytes read so far */
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int bitbuf; /* bit buffer */
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int bitcnt; /* number of bits in bit buffer */
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/* input limit error return state for bits() and decode() */
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jmp_buf env;
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};
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local int bits(struct state *s, int need)
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{
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long val; /* bit accumulator (can use up to 20 bits) */
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/* load at least need bits into val */
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val = s->bitbuf;
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while (s->bitcnt < need) {
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if (s->incnt == s->inlen)
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longjmp(s->env, 1); /* out of input */
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val |= (long)(s->in[s->incnt++]) << s->bitcnt; /* load eight bits */
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s->bitcnt += 8;
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}
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/* drop need bits and update buffer, always zero to seven bits left */
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s->bitbuf = (int)(val >> need);
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s->bitcnt -= need;
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/* return need bits, zeroing the bits above that */
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return (int)(val & ((1L << need) - 1));
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}
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local int stored(struct state *s)
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{
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unsigned len; /* length of stored block */
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/* discard leftover bits from current byte (assumes s->bitcnt < 8) */
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s->bitbuf = 0;
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s->bitcnt = 0;
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/* get length and check against its one's complement */
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if (s->incnt + 4 > s->inlen)
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return 2; /* not enough input */
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len = s->in[s->incnt++];
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len |= s->in[s->incnt++] << 8;
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if (s->in[s->incnt++] != (~len & 0xff) ||
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s->in[s->incnt++] != ((~len >> 8) & 0xff))
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return -2; /* didn't match complement! */
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/* copy len bytes from in to out */
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if (s->incnt + len > s->inlen)
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return 2; /* not enough input */
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if (s->out != NIL) {
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if (s->outcnt + len > s->outlen)
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return 1; /* not enough output space */
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while (len--)
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s->out[s->outcnt++] = s->in[s->incnt++];
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}
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else { /* just scanning */
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s->outcnt += len;
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s->incnt += len;
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}
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/* done with a valid stored block */
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return 0;
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}
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struct huffman {
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short *count; /* number of symbols of each length */
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short *symbol; /* canonically ordered symbols */
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};
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local int decode(struct state *s, const struct huffman *h)
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{
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int len; /* current number of bits in code */
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int code; /* len bits being decoded */
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int first; /* first code of length len */
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int count; /* number of codes of length len */
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int index; /* index of first code of length len in symbol table */
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int bitbuf; /* bits from stream */
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int left; /* bits left in next or left to process */
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short *next; /* next number of codes */
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bitbuf = s->bitbuf;
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left = s->bitcnt;
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code = first = index = 0;
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len = 1;
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next = h->count + 1;
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while (1) {
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while (left--) {
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code |= bitbuf & 1;
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bitbuf >>= 1;
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count = *next++;
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if (code - count < first) { /* if length len, return symbol */
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s->bitbuf = bitbuf;
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s->bitcnt = (s->bitcnt - len) & 7;
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return h->symbol[index + (code - first)];
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}
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index += count; /* else update for next length */
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first += count;
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first <<= 1;
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code <<= 1;
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len++;
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}
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left = (MAXBITS+1) - len;
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if (left == 0)
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break;
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if (s->incnt == s->inlen)
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longjmp(s->env, 1); /* out of input */
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bitbuf = s->in[s->incnt++];
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if (left > 8)
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left = 8;
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}
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return -10; /* ran out of codes */
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}
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local int construct(struct huffman *h, const short *length, int n)
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{
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int symbol; /* current symbol when stepping through length[] */
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int len; /* current length when stepping through h->count[] */
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int left; /* number of possible codes left of current length */
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short offs[MAXBITS+1]; /* offsets in symbol table for each length */
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/* count number of codes of each length */
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for (len = 0; len <= MAXBITS; len++)
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h->count[len] = 0;
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for (symbol = 0; symbol < n; symbol++)
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(h->count[length[symbol]])++; /* assumes lengths are within bounds */
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if (h->count[0] == n) /* no codes! */
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return 0; /* complete, but decode() will fail */
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/* check for an over-subscribed or incomplete set of lengths */
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left = 1; /* one possible code of zero length */
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for (len = 1; len <= MAXBITS; len++) {
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left <<= 1; /* one more bit, double codes left */
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left -= h->count[len]; /* deduct count from possible codes */
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if (left < 0)
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return left; /* over-subscribed--return negative */
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} /* left > 0 means incomplete */
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/* generate offsets into symbol table for each length for sorting */
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offs[1] = 0;
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for (len = 1; len < MAXBITS; len++)
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offs[len + 1] = offs[len] + h->count[len];
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/*
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* put symbols in table sorted by length, by symbol order within each
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* length
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*/
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for (symbol = 0; symbol < n; symbol++)
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if (length[symbol] != 0)
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h->symbol[offs[length[symbol]]++] = (short)symbol;
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/* return zero for complete set, positive for incomplete set */
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return left;
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}
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local int codes(struct state *s,
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const struct huffman *lencode,
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const struct huffman *distcode)
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{
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int symbol; /* decoded symbol */
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int len; /* length for copy */
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unsigned dist; /* distance for copy */
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static const short lens[29] = { /* Size base for length codes 257..285 */
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3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
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35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258};
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static const short lext[29] = { /* Extra bits for length codes 257..285 */
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0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2,
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3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0};
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static const short dists[30] = { /* Offset base for distance codes 0..29 */
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1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
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257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
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8193, 12289, 16385, 24577};
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static const short dext[30] = { /* Extra bits for distance codes 0..29 */
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0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6,
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7, 7, 8, 8, 9, 9, 10, 10, 11, 11,
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12, 12, 13, 13};
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/* decode literals and length/distance pairs */
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do {
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symbol = decode(s, lencode);
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if (symbol < 0)
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return symbol; /* invalid symbol */
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if (symbol < 256) { /* literal: symbol is the byte */
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/* write out the literal */
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if (s->out != NIL) {
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if (s->outcnt == s->outlen)
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return 1;
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s->out[s->outcnt] = (unsigned char)symbol;
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}
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s->outcnt++;
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}
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else if (symbol > 256) { /* length */
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/* get and compute length */
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symbol -= 257;
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if (symbol >= 29)
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return -10; /* invalid fixed code */
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len = lens[symbol] + bits(s, lext[symbol]);
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/* get and check distance */
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symbol = decode(s, distcode);
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if (symbol < 0)
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return symbol; /* invalid symbol */
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dist = dists[symbol] + bits(s, dext[symbol]);
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#ifndef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR
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if (dist > s->outcnt)
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return -11; /* distance too far back */
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#endif
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/* copy length bytes from distance bytes back */
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if (s->out != NIL) {
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if (s->outcnt + len > s->outlen)
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return 1;
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while (len--) {
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s->out[s->outcnt] =
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#ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR
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dist > s->outcnt ?
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0 :
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#endif
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s->out[s->outcnt - dist];
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s->outcnt++;
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}
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}
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else
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s->outcnt += len;
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}
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} while (symbol != 256); /* end of block symbol */
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/* done with a valid fixed or dynamic block */
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return 0;
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}
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local int fixed(struct state *s)
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{
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static int virgin = 1;
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static short lencnt[MAXBITS+1], lensym[FIXLCODES];
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static short distcnt[MAXBITS+1], distsym[MAXDCODES];
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static struct huffman lencode, distcode;
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/* build fixed huffman tables if first call (may not be thread safe) */
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if (virgin) {
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int symbol;
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short lengths[FIXLCODES];
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/* construct lencode and distcode */
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lencode.count = lencnt;
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lencode.symbol = lensym;
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distcode.count = distcnt;
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distcode.symbol = distsym;
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/* literal/length table */
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for (symbol = 0; symbol < 144; symbol++)
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lengths[symbol] = 8;
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for (; symbol < 256; symbol++)
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lengths[symbol] = 9;
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for (; symbol < 280; symbol++)
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lengths[symbol] = 7;
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for (; symbol < FIXLCODES; symbol++)
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lengths[symbol] = 8;
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construct(&lencode, lengths, FIXLCODES);
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/* distance table */
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for (symbol = 0; symbol < MAXDCODES; symbol++)
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lengths[symbol] = 5;
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construct(&distcode, lengths, MAXDCODES);
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/* do this just once */
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virgin = 0;
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}
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/* decode data until end-of-block code */
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return codes(s, &lencode, &distcode);
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}
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local int dynamic(struct state *s)
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{
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int nlen, ndist, ncode; /* number of lengths in descriptor */
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int index; /* index of lengths[] */
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int err; /* construct() return value */
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short lengths[MAXCODES]; /* descriptor code lengths */
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short lencnt[MAXBITS+1], lensym[MAXLCODES]; /* lencode memory */
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short distcnt[MAXBITS+1], distsym[MAXDCODES]; /* distcode memory */
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struct huffman lencode, distcode; /* length and distance codes */
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static const short order[19] = /* permutation of code length codes */
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{16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
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/* construct lencode and distcode */
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lencode.count = lencnt;
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lencode.symbol = lensym;
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distcode.count = distcnt;
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distcode.symbol = distsym;
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/* get number of lengths in each table, check lengths */
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nlen = bits(s, 5) + 257;
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ndist = bits(s, 5) + 1;
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ncode = bits(s, 4) + 4;
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if (nlen > MAXLCODES || ndist > MAXDCODES)
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return -3; /* bad counts */
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/* read code length code lengths (really), missing lengths are zero */
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for (index = 0; index < ncode; index++)
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lengths[order[index]] = (short)bits(s, 3);
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for (; index < 19; index++)
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lengths[order[index]] = 0;
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/* build huffman table for code lengths codes (use lencode temporarily) */
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err = construct(&lencode, lengths, 19);
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if (err != 0) /* require complete code set here */
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return -4;
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/* read length/literal and distance code length tables */
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index = 0;
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while (index < nlen + ndist) {
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int symbol; /* decoded value */
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int len; /* last length to repeat */
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symbol = decode(s, &lencode);
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if (symbol < 0)
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return symbol; /* invalid symbol */
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if (symbol < 16) /* length in 0..15 */
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lengths[index++] = (short)symbol;
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else { /* repeat instruction */
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len = 0; /* assume repeating zeros */
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if (symbol == 16) { /* repeat last length 3..6 times */
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if (index == 0)
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return -5; /* no last length! */
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len = lengths[index - 1]; /* last length */
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symbol = 3 + bits(s, 2);
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}
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else if (symbol == 17) /* repeat zero 3..10 times */
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symbol = 3 + bits(s, 3);
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else /* == 18, repeat zero 11..138 times */
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symbol = 11 + bits(s, 7);
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if (index + symbol > nlen + ndist)
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return -6; /* too many lengths! */
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while (symbol--) /* repeat last or zero symbol times */
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lengths[index++] = (short)len;
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}
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}
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/* check for end-of-block code -- there better be one! */
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if (lengths[256] == 0)
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return -9;
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/* build huffman table for literal/length codes */
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err = construct(&lencode, lengths, nlen);
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if (err && (err < 0 || nlen != lencode.count[0] + lencode.count[1]))
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return -7; /* incomplete code ok only for single length 1 code */
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/* build huffman table for distance codes */
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err = construct(&distcode, lengths + nlen, ndist);
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if (err && (err < 0 || ndist != distcode.count[0] + distcode.count[1]))
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return -8; /* incomplete code ok only for single length 1 code */
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/* decode data until end-of-block code */
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return codes(s, &lencode, &distcode);
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}
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int puff(unsigned long dictlen, // length of custom dictionary
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unsigned char *dest, /* pointer to destination pointer */
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unsigned long *destlen, /* amount of output space */
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const unsigned char *source, /* pointer to source data pointer */
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unsigned long *sourcelen) /* amount of input available */
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{
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struct state s; /* input/output state */
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int last, type; /* block information */
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int err; /* return value */
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/* initialize output state */
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s.out = dest;
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s.outlen = *destlen; /* ignored if dest is NIL */
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s.outcnt = dictlen;
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/* initialize input state */
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s.in = source;
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s.inlen = *sourcelen;
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s.incnt = 0;
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s.bitbuf = 0;
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s.bitcnt = 0;
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/* return if bits() or decode() tries to read past available input */
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if (setjmp(s.env) != 0) /* if came back here via longjmp() */
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err = 2; /* then skip do-loop, return error */
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else {
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/* process blocks until last block or error */
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do {
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last = bits(&s, 1); /* one if last block */
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type = bits(&s, 2); /* block type 0..3 */
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err = type == 0 ?
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stored(&s) :
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(type == 1 ?
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fixed(&s) :
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(type == 2 ?
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dynamic(&s) :
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-1)); /* type == 3, invalid */
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if (err != 0)
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break; /* return with error */
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} while (!last);
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}
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/* update the lengths and return */
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if (err <= 0) {
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*destlen = s.outcnt - dictlen;
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*sourcelen = s.incnt;
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}
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return err;
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}
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