WebSVN - shark - Blame - Rev 1618 - /shark/branches/xen/ports/zlib/infcodes.c

Rev	Author	Line No.	Line
107	pj	1	/* infcodes.c -- process literals and length/distance pairs
		2	* Copyright (C) 1995-2002 Mark Adler
		3	* For conditions of distribution and use, see copyright notice in zlib.h
		4	*/
		5
		6	#include "zutil.h"
		7	#include "inftrees.h"
		8	#include "infblock.h"
		9	#include "infcodes.h"
		10	#include "infutil.h"
		11	#include "inffast.h"
		12
		13	/* simplify the use of the inflate_huft type with some defines */
		14	#define exop word.what.Exop
		15	#define bits word.what.Bits
		16
		17	typedef enum { /* waiting for "i:"=input, "o:"=output, "x:"=nothing */
		18	START, /* x: set up for LEN */
		19	LEN, /* i: get length/literal/eob next */
		20	LENEXT, /* i: getting length extra (have base) */
		21	DIST, /* i: get distance next */
		22	DISTEXT, /* i: getting distance extra */
		23	COPY, /* o: copying bytes in window, waiting for space */
		24	LIT, /* o: got literal, waiting for output space */
		25	WASH, /* o: got eob, possibly still output waiting */
		26	END, /* x: got eob and all data flushed */
		27	BADCODE} /* x: got error */
		28	inflate_codes_mode;
		29
		30	/* inflate codes private state */
		31	struct inflate_codes_state {
		32
		33	/* mode */
		34	inflate_codes_mode mode; /* current inflate_codes mode */
		35
		36	/* mode dependent information */
		37	uInt len;
		38	union {
		39	struct {
		40	inflate_huft tree; / pointer into tree */
		41	uInt need; /* bits needed */
		42	} code; /* if LEN or DIST, where in tree */
		43	uInt lit; /* if LIT, literal */
		44	struct {
		45	uInt get; /* bits to get for extra */
		46	uInt dist; /* distance back to copy from */
		47	} copy; /* if EXT or COPY, where and how much */
		48	} sub; /* submode */
		49
		50	/* mode independent information */
		51	Byte lbits; /* ltree bits decoded per branch */
		52	Byte dbits; /* dtree bits decoder per branch */
		53	inflate_huft ltree; / literal/length/eob tree */
		54	inflate_huft dtree; / distance tree */
		55
		56	};
		57
		58
		59	inflate_codes_statef *inflate_codes_new(bl, bd, tl, td, z)
		60	uInt bl, bd;
		61	inflate_huft *tl;
		62	inflate_huft td; / need separate declaration for Borland C++ */
		63	z_streamp z;
		64	{
		65	inflate_codes_statef *c;
		66
		67	if ((c = (inflate_codes_statef *)
		68	ZALLOC(z,1,sizeof(struct inflate_codes_state))) != Z_NULL)
		69	{
		70	c->mode = START;
		71	c->lbits = (Byte)bl;
		72	c->dbits = (Byte)bd;
		73	c->ltree = tl;
		74	c->dtree = td;
		75	Tracev((stderr, "inflate: codes new\n"));
		76	}
		77	return c;
		78	}
		79
		80
		81	int inflate_codes(s, z, r)
		82	inflate_blocks_statef *s;
		83	z_streamp z;
		84	int r;
		85	{
		86	uInt j; /* temporary storage */
		87	inflate_huft t; / temporary pointer */
		88	uInt e; /* extra bits or operation */
		89	uLong b; /* bit buffer */
		90	uInt k; /* bits in bit buffer */
		91	Bytef p; / input data pointer */
		92	uInt n; /* bytes available there */
		93	Bytef q; / output window write pointer */
		94	uInt m; /* bytes to end of window or read pointer */
		95	Bytef f; / pointer to copy strings from */
		96	inflate_codes_statef c = s->sub.decode.codes; / codes state */
		97
		98	/* copy input/output information to locals (UPDATE macro restores) */
		99	LOAD
		100
		101	/* process input and output based on current state */
		102	while (1) switch (c->mode)
		103	{ /* waiting for "i:"=input, "o:"=output, "x:"=nothing */
		104	case START: /* x: set up for LEN */
		105	#ifndef SLOW
		106	if (m >= 258 && n >= 10)
		107	{
		108	UPDATE
		109	r = inflate_fast(c->lbits, c->dbits, c->ltree, c->dtree, s, z);
		110	LOAD
		111	if (r != Z_OK)
		112	{
		113	c->mode = r == Z_STREAM_END ? WASH : BADCODE;
		114	break;
		115	}
		116	}
		117	#endif /* !SLOW */
		118	c->sub.code.need = c->lbits;
		119	c->sub.code.tree = c->ltree;
		120	c->mode = LEN;
		121	case LEN: /* i: get length/literal/eob next */
		122	j = c->sub.code.need;
		123	NEEDBITS(j)
		124	t = c->sub.code.tree + ((uInt)b & inflate_mask[j]);
		125	DUMPBITS(t->bits)
		126	e = (uInt)(t->exop);
		127	if (e == 0) /* literal */
		128	{
		129	c->sub.lit = t->base;
		130	Tracevv((stderr, t->base >= 0x20 && t->base < 0x7f ?
		131	"inflate: literal '%c'\n" :
		132	"inflate: literal 0x%02x\n", t->base));
		133	c->mode = LIT;
		134	break;
		135	}
		136	if (e & 16) /* length */
		137	{
		138	c->sub.copy.get = e & 15;
		139	c->len = t->base;
		140	c->mode = LENEXT;
		141	break;
		142	}
		143	if ((e & 64) == 0) /* next table */
		144	{
		145	c->sub.code.need = e;
		146	c->sub.code.tree = t + t->base;
		147	break;
		148	}
		149	if (e & 32) /* end of block */
		150	{
		151	Tracevv((stderr, "inflate: end of block\n"));
		152	c->mode = WASH;
		153	break;
		154	}
		155	c->mode = BADCODE; /* invalid code */
		156	z->msg = (char*)"invalid literal/length code";
		157	r = Z_DATA_ERROR;
		158	LEAVE
		159	case LENEXT: /* i: getting length extra (have base) */
		160	j = c->sub.copy.get;
		161	NEEDBITS(j)
		162	c->len += (uInt)b & inflate_mask[j];
		163	DUMPBITS(j)
		164	c->sub.code.need = c->dbits;
		165	c->sub.code.tree = c->dtree;
		166	Tracevv((stderr, "inflate: length %u\n", c->len));
		167	c->mode = DIST;
		168	case DIST: /* i: get distance next */
		169	j = c->sub.code.need;
		170	NEEDBITS(j)
		171	t = c->sub.code.tree + ((uInt)b & inflate_mask[j]);
		172	DUMPBITS(t->bits)
		173	e = (uInt)(t->exop);
		174	if (e & 16) /* distance */
		175	{
		176	c->sub.copy.get = e & 15;
		177	c->sub.copy.dist = t->base;
		178	c->mode = DISTEXT;
		179	break;
		180	}
		181	if ((e & 64) == 0) /* next table */
		182	{
		183	c->sub.code.need = e;
		184	c->sub.code.tree = t + t->base;
		185	break;
		186	}
		187	c->mode = BADCODE; /* invalid code */
		188	z->msg = (char*)"invalid distance code";
		189	r = Z_DATA_ERROR;
		190	LEAVE
		191	case DISTEXT: /* i: getting distance extra */
		192	j = c->sub.copy.get;
		193	NEEDBITS(j)
		194	c->sub.copy.dist += (uInt)b & inflate_mask[j];
		195	DUMPBITS(j)
		196	Tracevv((stderr, "inflate: distance %u\n", c->sub.copy.dist));
		197	c->mode = COPY;
		198	case COPY: /* o: copying bytes in window, waiting for space */
		199	f = q - c->sub.copy.dist;
		200	while (f < s->window) /* modulo window size-"while" instead */
		201	f += s->end - s->window; /* of "if" handles invalid distances */
		202	while (c->len)
		203	{
		204	NEEDOUT
		205	OUTBYTE(*f++)
		206	if (f == s->end)
		207	f = s->window;
		208	c->len--;
		209	}
		210	c->mode = START;
		211	break;
		212	case LIT: /* o: got literal, waiting for output space */
		213	NEEDOUT
		214	OUTBYTE(c->sub.lit)
		215	c->mode = START;
		216	break;
		217	case WASH: /* o: got eob, possibly more output */
		218	if (k > 7) /* return unused byte, if any */
		219	{
		220	Assert(k < 16, "inflate_codes grabbed too many bytes")
		221	k -= 8;
		222	n++;
		223	p--; /* can always return one */
		224	}
		225	FLUSH
		226	if (s->read != s->write)
		227	LEAVE
		228	c->mode = END;
		229	case END:
		230	r = Z_STREAM_END;
		231	LEAVE
		232	case BADCODE: /* x: got error */
		233	r = Z_DATA_ERROR;
		234	LEAVE
		235	default:
		236	r = Z_STREAM_ERROR;
		237	LEAVE
		238	}
		239	#ifdef NEED_DUMMY_RETURN
		240	return Z_STREAM_ERROR; /* Some dumb compilers complain without this */
		241	#endif
		242	}
		243
		244
		245	void inflate_codes_free(c, z)
		246	inflate_codes_statef *c;
		247	z_streamp z;
		248	{
		249	ZFREE(z, c);
		250	Tracev((stderr, "inflate: codes free\n"));
		251	}

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