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Diffstat (limited to 'zlib/infcodes.c')
| -rw-r--r-- | zlib/infcodes.c | 257 |
1 files changed, 257 insertions, 0 deletions
diff --git a/zlib/infcodes.c b/zlib/infcodes.c new file mode 100644 index 00000000000..d4e5ee9a554 --- /dev/null +++ b/zlib/infcodes.c @@ -0,0 +1,257 @@ +/* infcodes.c -- process literals and length/distance pairs + * Copyright (C) 1995-1998 Mark Adler + * For conditions of distribution and use, see copyright notice in zlib.h + */ + +#include "zutil.h" +#include "inftrees.h" +#include "infblock.h" +#include "infcodes.h" +#include "infutil.h" +#include "inffast.h" + +/* simplify the use of the inflate_huft type with some defines */ +#define exop word.what.Exop +#define bits word.what.Bits + +typedef enum { /* waiting for "i:"=input, "o:"=output, "x:"=nothing */ + START, /* x: set up for LEN */ + LEN, /* i: get length/literal/eob next */ + LENEXT, /* i: getting length extra (have base) */ + DIST, /* i: get distance next */ + DISTEXT, /* i: getting distance extra */ + COPY, /* o: copying bytes in window, waiting for space */ + LIT, /* o: got literal, waiting for output space */ + WASH, /* o: got eob, possibly still output waiting */ + END, /* x: got eob and all data flushed */ + BADCODE} /* x: got error */ +inflate_codes_mode; + +/* inflate codes private state */ +struct inflate_codes_state { + + /* mode */ + inflate_codes_mode mode; /* current inflate_codes mode */ + + /* mode dependent information */ + uInt len; + union { + struct { + inflate_huft *tree; /* pointer into tree */ + uInt need; /* bits needed */ + } code; /* if LEN or DIST, where in tree */ + uInt lit; /* if LIT, literal */ + struct { + uInt get; /* bits to get for extra */ + uInt dist; /* distance back to copy from */ + } copy; /* if EXT or COPY, where and how much */ + } sub; /* submode */ + + /* mode independent information */ + Byte lbits; /* ltree bits decoded per branch */ + Byte dbits; /* dtree bits decoder per branch */ + inflate_huft *ltree; /* literal/length/eob tree */ + inflate_huft *dtree; /* distance tree */ + +}; + + +inflate_codes_statef *inflate_codes_new(bl, bd, tl, td, z) +uInt bl, bd; +inflate_huft *tl; +inflate_huft *td; /* need separate declaration for Borland C++ */ +z_streamp z; +{ + inflate_codes_statef *c; + + if ((c = (inflate_codes_statef *) + ZALLOC(z,1,sizeof(struct inflate_codes_state))) != Z_NULL) + { + c->mode = START; + c->lbits = (Byte)bl; + c->dbits = (Byte)bd; + c->ltree = tl; + c->dtree = td; + Tracev((stderr, "inflate: codes new\n")); + } + return c; +} + + +int inflate_codes(s, z, r) +inflate_blocks_statef *s; +z_streamp z; +int r; +{ + uInt j; /* temporary storage */ + inflate_huft *t; /* temporary pointer */ + uInt e; /* extra bits or operation */ + uLong b; /* bit buffer */ + uInt k; /* bits in bit buffer */ + Bytef *p; /* input data pointer */ + uInt n; /* bytes available there */ + Bytef *q; /* output window write pointer */ + uInt m; /* bytes to end of window or read pointer */ + Bytef *f; /* pointer to copy strings from */ + inflate_codes_statef *c = s->sub.decode.codes; /* codes state */ + + /* copy input/output information to locals (UPDATE macro restores) */ + LOAD + + /* process input and output based on current state */ + while (1) switch (c->mode) + { /* waiting for "i:"=input, "o:"=output, "x:"=nothing */ + case START: /* x: set up for LEN */ +#ifndef SLOW + if (m >= 258 && n >= 10) + { + UPDATE + r = inflate_fast(c->lbits, c->dbits, c->ltree, c->dtree, s, z); + LOAD + if (r != Z_OK) + { + c->mode = r == Z_STREAM_END ? WASH : BADCODE; + break; + } + } +#endif /* !SLOW */ + c->sub.code.need = c->lbits; + c->sub.code.tree = c->ltree; + c->mode = LEN; + case LEN: /* i: get length/literal/eob next */ + j = c->sub.code.need; + NEEDBITS(j) + t = c->sub.code.tree + ((uInt)b & inflate_mask[j]); + DUMPBITS(t->bits) + e = (uInt)(t->exop); + if (e == 0) /* literal */ + { + c->sub.lit = t->base; + Tracevv((stderr, t->base >= 0x20 && t->base < 0x7f ? + "inflate: literal '%c'\n" : + "inflate: literal 0x%02x\n", t->base)); + c->mode = LIT; + break; + } + if (e & 16) /* length */ + { + c->sub.copy.get = e & 15; + c->len = t->base; + c->mode = LENEXT; + break; + } + if ((e & 64) == 0) /* next table */ + { + c->sub.code.need = e; + c->sub.code.tree = t + t->base; + break; + } + if (e & 32) /* end of block */ + { + Tracevv((stderr, "inflate: end of block\n")); + c->mode = WASH; + break; + } + c->mode = BADCODE; /* invalid code */ + z->msg = (char*)"invalid literal/length code"; + r = Z_DATA_ERROR; + LEAVE + case LENEXT: /* i: getting length extra (have base) */ + j = c->sub.copy.get; + NEEDBITS(j) + c->len += (uInt)b & inflate_mask[j]; + DUMPBITS(j) + c->sub.code.need = c->dbits; + c->sub.code.tree = c->dtree; + Tracevv((stderr, "inflate: length %u\n", c->len)); + c->mode = DIST; + case DIST: /* i: get distance next */ + j = c->sub.code.need; + NEEDBITS(j) + t = c->sub.code.tree + ((uInt)b & inflate_mask[j]); + DUMPBITS(t->bits) + e = (uInt)(t->exop); + if (e & 16) /* distance */ + { + c->sub.copy.get = e & 15; + c->sub.copy.dist = t->base; + c->mode = DISTEXT; + break; + } + if ((e & 64) == 0) /* next table */ + { + c->sub.code.need = e; + c->sub.code.tree = t + t->base; + break; + } + c->mode = BADCODE; /* invalid code */ + z->msg = (char*)"invalid distance code"; + r = Z_DATA_ERROR; + LEAVE + case DISTEXT: /* i: getting distance extra */ + j = c->sub.copy.get; + NEEDBITS(j) + c->sub.copy.dist += (uInt)b & inflate_mask[j]; + DUMPBITS(j) + Tracevv((stderr, "inflate: distance %u\n", c->sub.copy.dist)); + c->mode = COPY; + case COPY: /* o: copying bytes in window, waiting for space */ +#ifndef __TURBOC__ /* Turbo C bug for following expression */ + f = (uInt)(q - s->window) < c->sub.copy.dist ? + s->end - (c->sub.copy.dist - (q - s->window)) : + q - c->sub.copy.dist; +#else + f = q - c->sub.copy.dist; + if ((uInt)(q - s->window) < c->sub.copy.dist) + f = s->end - (c->sub.copy.dist - (uInt)(q - s->window)); +#endif + while (c->len) + { + NEEDOUT + OUTBYTE(*f++) + if (f == s->end) + f = s->window; + c->len--; + } + c->mode = START; + break; + case LIT: /* o: got literal, waiting for output space */ + NEEDOUT + OUTBYTE(c->sub.lit) + c->mode = START; + break; + case WASH: /* o: got eob, possibly more output */ + if (k > 7) /* return unused byte, if any */ + { + Assert(k < 16, "inflate_codes grabbed too many bytes") + k -= 8; + n++; + p--; /* can always return one */ + } + FLUSH + if (s->read != s->write) + LEAVE + c->mode = END; + case END: + r = Z_STREAM_END; + LEAVE + case BADCODE: /* x: got error */ + r = Z_DATA_ERROR; + LEAVE + default: + r = Z_STREAM_ERROR; + LEAVE + } +#ifdef NEED_DUMMY_RETURN + return Z_STREAM_ERROR; /* Some dumb compilers complain without this */ +#endif +} + + +void inflate_codes_free(c, z) +inflate_codes_statef *c; +z_streamp z; +{ + ZFREE(z, c); + Tracev((stderr, "inflate: codes free\n")); +} |