src/zlib/inflate.c

/* inflate.c -- zlib interface to inflate modules
 * Copyright (C) 1995-1998 Mark Adler
 * For conditions of distribution and use, see copyright notice in zlib.h
 */

#include "zutil.h"
#include "infblock.h"

struct inflate_blocks_state {int dummy;}; /* for buggy compilers */

typedef enum {
      METHOD,   /* waiting for method byte */
      FLAG,     /* waiting for flag byte */
      DICT4,    /* four dictionary check bytes to go */
      DICT3,    /* three dictionary check bytes to go */
      DICT2,    /* two dictionary check bytes to go */
      DICT1,    /* one dictionary check byte to go */
      DICT0,    /* waiting for inflateSetDictionary */
      BLOCKS,   /* decompressing blocks */
      CHECK4,   /* four check bytes to go */
      CHECK3,   /* three check bytes to go */
      CHECK2,   /* two check bytes to go */
      CHECK1,   /* one check byte to go */
      DONE,     /* finished check, done */
      BAD}      /* got an error--stay here */
inflate_mode;

/* inflate private state */
struct internal_state {

  /* mode */
  inflate_mode  mode;   /* current inflate mode */

  /* mode dependent information */
  union {
    uInt method;        /* if FLAGS, method byte */
    struct {
      uLong was;                /* computed check value */
      uLong need;               /* stream check value */
    } check;            /* if CHECK, check values to compare */
    uInt marker;        /* if BAD, inflateSync's marker bytes count */
  } sub;        /* submode */

  /* mode independent information */
  int  nowrap;          /* flag for no wrapper */
  uInt wbits;           /* log2(window size)  (8..15, defaults to 15) */
  inflate_blocks_statef
    *blocks;            /* current inflate_blocks state */

};


int ZEXPORT inflateReset(z)
z_streamp z;
{
  if (z == Z_NULL || z->state == Z_NULL)
    return Z_STREAM_ERROR;
  z->total_in = z->total_out = 0;
  z->msg = Z_NULL;
  z->state->mode = z->state->nowrap ? BLOCKS : METHOD;
  inflate_blocks_reset(z->state->blocks, z, Z_NULL);
  Tracev((stderr, "inflate: reset\n"));
  return Z_OK;
}


int ZEXPORT inflateEnd(z)
z_streamp z;
{
  if (z == Z_NULL || z->state == Z_NULL || z->zfree == Z_NULL)
    return Z_STREAM_ERROR;
  if (z->state->blocks != Z_NULL)
    inflate_blocks_free(z->state->blocks, z);
  ZFREE(z, z->state);
  z->state = Z_NULL;
  Tracev((stderr, "inflate: end\n"));
  return Z_OK;
}


int ZEXPORT inflateInit2_(z, w, version, stream_size)
z_streamp z;
int w;
const char *version;
int stream_size;
{
  if (version == Z_NULL || version[0] != ZLIB_VERSION[0] ||
      stream_size != sizeof(z_stream))
      return Z_VERSION_ERROR;

  /* initialize state */
  if (z == Z_NULL)
    return Z_STREAM_ERROR;
  z->msg = Z_NULL;
  if (z->zalloc == Z_NULL)
  {
    z->zalloc = zcalloc;
    z->opaque = (voidpf)0;
  }
  if (z->zfree == Z_NULL) z->zfree = zcfree;
  if ((z->state = (struct internal_state FAR *)
       ZALLOC(z,1,sizeof(struct internal_state))) == Z_NULL)
    return Z_MEM_ERROR;
  z->state->blocks = Z_NULL;

  /* handle undocumented nowrap option (no zlib header or check) */
  z->state->nowrap = 0;
  if (w < 0)
  {
    w = - w;
    z->state->nowrap = 1;
  }

  /* set window size */
  if (w < 8 || w > 15)
  {
    inflateEnd(z);
    return Z_STREAM_ERROR;
  }
  z->state->wbits = (uInt)w;

  /* create inflate_blocks state */
  if ((z->state->blocks =
      inflate_blocks_new(z, z->state->nowrap ? Z_NULL : adler32, (uInt)1 << w))
      == Z_NULL)
  {
    inflateEnd(z);
    return Z_MEM_ERROR;
  }
  Tracev((stderr, "inflate: allocated\n"));

  /* reset state */
  inflateReset(z);
  return Z_OK;
}


int ZEXPORT inflateInit_(z, version, stream_size)
z_streamp z;
const char *version;
int stream_size;
{
  return inflateInit2_(z, DEF_WBITS, version, stream_size);
}


#define NEEDBYTE {if(z->avail_in==0)return r;r=f;}
#define NEXTBYTE (z->avail_in--,z->total_in++,*z->next_in++)

int ZEXPORT inflate(z, f)
z_streamp z;
int f;
{
  int r;
  uInt b;

  if (z == Z_NULL || z->state == Z_NULL || z->next_in == Z_NULL)
    return Z_STREAM_ERROR;
  f = f == Z_FINISH ? Z_BUF_ERROR : Z_OK;
  r = Z_BUF_ERROR;
  while (1) switch (z->state->mode)
  {
    case METHOD:
      NEEDBYTE
      if (((z->state->sub.method = NEXTBYTE) & 0xf) != Z_DEFLATED)
      {
        z->state->mode = BAD;
        z->msg = (char*)"unknown compression method";
        z->state->sub.marker = 5;       /* can't try inflateSync */
        break;
      }
      if ((z->state->sub.method >> 4) + 8 > z->state->wbits)
      {
        z->state->mode = BAD;
        z->msg = (char*)"invalid window size";
        z->state->sub.marker = 5;       /* can't try inflateSync */
        break;
      }
      z->state->mode = FLAG;
    case FLAG:
      NEEDBYTE
      b = NEXTBYTE;
      if (((z->state->sub.method << 8) + b) % 31)
      {
        z->state->mode = BAD;
        z->msg = (char*)"incorrect header check";
        z->state->sub.marker = 5;       /* can't try inflateSync */
        break;
      }
      Tracev((stderr, "inflate: zlib header ok\n"));
      if (!(b & PRESET_DICT))
      {
        z->state->mode = BLOCKS;
        break;
      }
      z->state->mode = DICT4;
    case DICT4:
      NEEDBYTE
      z->state->sub.check.need = (uLong)NEXTBYTE << 24;
      z->state->mode = DICT3;
    case DICT3:
      NEEDBYTE
      z->state->sub.check.need += (uLong)NEXTBYTE << 16;
      z->state->mode = DICT2;
    case DICT2:
      NEEDBYTE
      z->state->sub.check.need += (uLong)NEXTBYTE << 8;
      z->state->mode = DICT1;
    case DICT1:
      NEEDBYTE
      z->state->sub.check.need += (uLong)NEXTBYTE;
      z->adler = z->state->sub.check.need;
      z->state->mode = DICT0;
      return Z_NEED_DICT;
    case DICT0:
      z->state->mode = BAD;
      z->msg = (char*)"need dictionary";
      z->state->sub.marker = 0;       /* can try inflateSync */
      return Z_STREAM_ERROR;
    case BLOCKS:
      r = inflate_blocks(z->state->blocks, z, r);
      if (r == Z_DATA_ERROR)
      {
        z->state->mode = BAD;
        z->state->sub.marker = 0;       /* can try inflateSync */
        break;
      }
      if (r == Z_OK)
        r = f;
      if (r != Z_STREAM_END)
        return r;
      r = f;
      inflate_blocks_reset(z->state->blocks, z, &z->state->sub.check.was);
      if (z->state->nowrap)
      {
        z->state->mode = DONE;
        break;
      }
      z->state->mode = CHECK4;
    case CHECK4:
      NEEDBYTE
      z->state->sub.check.need = (uLong)NEXTBYTE << 24;
      z->state->mode = CHECK3;
    case CHECK3:
      NEEDBYTE
      z->state->sub.check.need += (uLong)NEXTBYTE << 16;
      z->state->mode = CHECK2;
    case CHECK2:
      NEEDBYTE
      z->state->sub.check.need += (uLong)NEXTBYTE << 8;
      z->state->mode = CHECK1;
    case CHECK1:
      NEEDBYTE
      z->state->sub.check.need += (uLong)NEXTBYTE;

      if (z->state->sub.check.was != z->state->sub.check.need)
      {
        z->state->mode = BAD;
        z->msg = (char*)"incorrect data check";
        z->state->sub.marker = 5;       /* can't try inflateSync */
        break;
      }
      Tracev((stderr, "inflate: zlib check ok\n"));
      z->state->mode = DONE;
    case DONE:
      return Z_STREAM_END;
    case BAD:
      return Z_DATA_ERROR;
    default:
      return Z_STREAM_ERROR;
  }
#ifdef NEED_DUMMY_RETURN
  return Z_STREAM_ERROR;  /* Some dumb compilers complain without this */
#endif
}


int ZEXPORT inflateSetDictionary(z, dictionary, dictLength)
z_streamp z;
const Bytef *dictionary;
uInt  dictLength;
{
  uInt length = dictLength;

  if (z == Z_NULL || z->state == Z_NULL || z->state->mode != DICT0)
    return Z_STREAM_ERROR;

  if (adler32(1L, dictionary, dictLength) != z->adler) return Z_DATA_ERROR;
  z->adler = 1L;

  if (length >= ((uInt)1<<z->state->wbits))
  {
    length = (1<<z->state->wbits)-1;
    dictionary += dictLength - length;
  }
  inflate_set_dictionary(z->state->blocks, dictionary, length);
  z->state->mode = BLOCKS;
  return Z_OK;
}


int ZEXPORT inflateSync(z)
z_streamp z;
{
  uInt n;       /* number of bytes to look at */
  Bytef *p;     /* pointer to bytes */
  uInt m;       /* number of marker bytes found in a row */
  uLong r, w;   /* temporaries to save total_in and total_out */

  /* set up */
  if (z == Z_NULL || z->state == Z_NULL)
    return Z_STREAM_ERROR;
  if (z->state->mode != BAD)
  {
    z->state->mode = BAD;
    z->state->sub.marker = 0;
  }
  if ((n = z->avail_in) == 0)
    return Z_BUF_ERROR;
  p = z->next_in;
  m = z->state->sub.marker;

  /* search */
  while (n && m < 4)
  {
    static const Byte mark[4] = {0, 0, 0xff, 0xff};
    if (*p == mark[m])
      m++;
    else if (*p)
      m = 0;
    else
      m = 4 - m;
    p++, n--;
  }

  /* restore */
  z->total_in += p - z->next_in;
  z->next_in = p;
  z->avail_in = n;
  z->state->sub.marker = m;

  /* return no joy or set up to restart on a new block */
  if (m != 4)
    return Z_DATA_ERROR;
  r = z->total_in;  w = z->total_out;
  inflateReset(z);
  z->total_in = r;  z->total_out = w;
  z->state->mode = BLOCKS;
  return Z_OK;
}


/* Returns true if inflate is currently at the end of a block generated
 * by Z_SYNC_FLUSH or Z_FULL_FLUSH. This function is used by one PPP
 * implementation to provide an additional safety check. PPP uses Z_SYNC_FLUSH
 * but removes the length bytes of the resulting empty stored block. When
 * decompressing, PPP checks that at the end of input packet, inflate is
 * waiting for these length bytes.
 */
int ZEXPORT inflateSyncPoint(z)
z_streamp z;
{
  if (z == Z_NULL || z->state == Z_NULL || z->state->blocks == Z_NULL)
    return Z_STREAM_ERROR;
  return inflate_blocks_sync_point(z->state->blocks);
}
Commit	Line	Data
	1	/* inflate.c -- zlib interface to inflate modules
	2	* Copyright (C) 1995-1998 Mark Adler
	3	* For conditions of distribution and use, see copyright notice in zlib.h
	4	*/
	5
	6	#include "zutil.h"
	7	#include "infblock.h"
	8
	9	struct inflate_blocks_state {int dummy;}; /* for buggy compilers */
	10
	11	typedef enum {
	12	METHOD, /* waiting for method byte */
	13	FLAG, /* waiting for flag byte */
	14	DICT4, /* four dictionary check bytes to go */
	15	DICT3, /* three dictionary check bytes to go */
	16	DICT2, /* two dictionary check bytes to go */
	17	DICT1, /* one dictionary check byte to go */
	18	DICT0, /* waiting for inflateSetDictionary */
	19	BLOCKS, /* decompressing blocks */
	20	CHECK4, /* four check bytes to go */
	21	CHECK3, /* three check bytes to go */
	22	CHECK2, /* two check bytes to go */
	23	CHECK1, /* one check byte to go */
	24	DONE, /* finished check, done */
	25	BAD} /* got an error--stay here */
	26	inflate_mode;
	27
	28	/* inflate private state */
	29	struct internal_state {
	30
	31	/* mode */
	32	inflate_mode mode; /* current inflate mode */
	33
	34	/* mode dependent information */
	35	union {
	36	uInt method; /* if FLAGS, method byte */
	37	struct {
	38	uLong was; /* computed check value */
	39	uLong need; /* stream check value */
	40	} check; /* if CHECK, check values to compare */
	41	uInt marker; /* if BAD, inflateSync's marker bytes count */
	42	} sub; /* submode */
	43
	44	/* mode independent information */
	45	int nowrap; /* flag for no wrapper */
	46	uInt wbits; /* log2(window size) (8..15, defaults to 15) */
	47	inflate_blocks_statef
	48	blocks; / current inflate_blocks state */
	49
	50	};
	51
	52
	53	int ZEXPORT inflateReset(z)
	54	z_streamp z;
	55	{
	56	if (z == Z_NULL \|\| z->state == Z_NULL)
	57	return Z_STREAM_ERROR;
	58	z->total_in = z->total_out = 0;
	59	z->msg = Z_NULL;
	60	z->state->mode = z->state->nowrap ? BLOCKS : METHOD;
	61	inflate_blocks_reset(z->state->blocks, z, Z_NULL);
	62	Tracev((stderr, "inflate: reset\n"));
	63	return Z_OK;
	64	}
	65
	66
	67	int ZEXPORT inflateEnd(z)
	68	z_streamp z;
	69	{
	70	if (z == Z_NULL \|\| z->state == Z_NULL \|\| z->zfree == Z_NULL)
	71	return Z_STREAM_ERROR;
	72	if (z->state->blocks != Z_NULL)
	73	inflate_blocks_free(z->state->blocks, z);
	74	ZFREE(z, z->state);
	75	z->state = Z_NULL;
	76	Tracev((stderr, "inflate: end\n"));
	77	return Z_OK;
	78	}
	79
	80
	81	int ZEXPORT inflateInit2_(z, w, version, stream_size)
	82	z_streamp z;
	83	int w;
	84	const char *version;
	85	int stream_size;
	86	{
	87	if (version == Z_NULL \|\| version[0] != ZLIB_VERSION[0] \|\|
	88	stream_size != sizeof(z_stream))
	89	return Z_VERSION_ERROR;
	90
	91	/* initialize state */
	92	if (z == Z_NULL)
	93	return Z_STREAM_ERROR;
	94	z->msg = Z_NULL;
	95	if (z->zalloc == Z_NULL)
	96	{
	97	z->zalloc = zcalloc;
	98	z->opaque = (voidpf)0;
	99	}
	100	if (z->zfree == Z_NULL) z->zfree = zcfree;
	101	if ((z->state = (struct internal_state FAR *)
	102	ZALLOC(z,1,sizeof(struct internal_state))) == Z_NULL)
	103	return Z_MEM_ERROR;
	104	z->state->blocks = Z_NULL;
	105
	106	/* handle undocumented nowrap option (no zlib header or check) */
	107	z->state->nowrap = 0;
	108	if (w < 0)
	109	{
	110	w = - w;
	111	z->state->nowrap = 1;
	112	}
	113
	114	/* set window size */
	115	if (w < 8 \|\| w > 15)
	116	{
	117	inflateEnd(z);
	118	return Z_STREAM_ERROR;
	119	}
	120	z->state->wbits = (uInt)w;
	121
	122	/* create inflate_blocks state */
	123	if ((z->state->blocks =
	124	inflate_blocks_new(z, z->state->nowrap ? Z_NULL : adler32, (uInt)1 << w))
	125	== Z_NULL)
	126	{
	127	inflateEnd(z);
	128	return Z_MEM_ERROR;
	129	}
	130	Tracev((stderr, "inflate: allocated\n"));
	131
	132	/* reset state */
	133	inflateReset(z);
	134	return Z_OK;
	135	}
	136
	137
	138	int ZEXPORT inflateInit_(z, version, stream_size)
	139	z_streamp z;
	140	const char *version;
	141	int stream_size;
	142	{
	143	return inflateInit2_(z, DEF_WBITS, version, stream_size);
	144	}
	145
	146
	147	#define NEEDBYTE {if(z->avail_in==0)return r;r=f;}
	148	#define NEXTBYTE (z->avail_in--,z->total_in++,*z->next_in++)
	149
	150	int ZEXPORT inflate(z, f)
	151	z_streamp z;
	152	int f;
	153	{
	154	int r;
	155	uInt b;
	156
	157	if (z == Z_NULL \|\| z->state == Z_NULL \|\| z->next_in == Z_NULL)
	158	return Z_STREAM_ERROR;
	159	f = f == Z_FINISH ? Z_BUF_ERROR : Z_OK;
	160	r = Z_BUF_ERROR;
	161	while (1) switch (z->state->mode)
	162	{
	163	case METHOD:
	164	NEEDBYTE
	165	if (((z->state->sub.method = NEXTBYTE) & 0xf) != Z_DEFLATED)
	166	{
	167	z->state->mode = BAD;
	168	z->msg = (char*)"unknown compression method";
	169	z->state->sub.marker = 5; /* can't try inflateSync */
	170	break;
	171	}
	172	if ((z->state->sub.method >> 4) + 8 > z->state->wbits)
	173	{
	174	z->state->mode = BAD;
	175	z->msg = (char*)"invalid window size";
	176	z->state->sub.marker = 5; /* can't try inflateSync */
	177	break;
	178	}
	179	z->state->mode = FLAG;
	180	case FLAG:
	181	NEEDBYTE
	182	b = NEXTBYTE;
	183	if (((z->state->sub.method << 8) + b) % 31)
	184	{
	185	z->state->mode = BAD;
	186	z->msg = (char*)"incorrect header check";
	187	z->state->sub.marker = 5; /* can't try inflateSync */
	188	break;
	189	}
	190	Tracev((stderr, "inflate: zlib header ok\n"));
	191	if (!(b & PRESET_DICT))
	192	{
	193	z->state->mode = BLOCKS;
	194	break;
	195	}
	196	z->state->mode = DICT4;
	197	case DICT4:
	198	NEEDBYTE
	199	z->state->sub.check.need = (uLong)NEXTBYTE << 24;
	200	z->state->mode = DICT3;
	201	case DICT3:
	202	NEEDBYTE
	203	z->state->sub.check.need += (uLong)NEXTBYTE << 16;
	204	z->state->mode = DICT2;
	205	case DICT2:
	206	NEEDBYTE
	207	z->state->sub.check.need += (uLong)NEXTBYTE << 8;
	208	z->state->mode = DICT1;
	209	case DICT1:
	210	NEEDBYTE
	211	z->state->sub.check.need += (uLong)NEXTBYTE;
	212	z->adler = z->state->sub.check.need;
	213	z->state->mode = DICT0;
	214	return Z_NEED_DICT;
	215	case DICT0:
	216	z->state->mode = BAD;
	217	z->msg = (char*)"need dictionary";
	218	z->state->sub.marker = 0; /* can try inflateSync */
	219	return Z_STREAM_ERROR;
	220	case BLOCKS:
	221	r = inflate_blocks(z->state->blocks, z, r);
	222	if (r == Z_DATA_ERROR)
	223	{
	224	z->state->mode = BAD;
	225	z->state->sub.marker = 0; /* can try inflateSync */
	226	break;
	227	}
	228	if (r == Z_OK)
	229	r = f;
	230	if (r != Z_STREAM_END)
	231	return r;
	232	r = f;
	233	inflate_blocks_reset(z->state->blocks, z, &z->state->sub.check.was);
	234	if (z->state->nowrap)
	235	{
	236	z->state->mode = DONE;
	237	break;
	238	}
	239	z->state->mode = CHECK4;
	240	case CHECK4:
	241	NEEDBYTE
	242	z->state->sub.check.need = (uLong)NEXTBYTE << 24;
	243	z->state->mode = CHECK3;
	244	case CHECK3:
	245	NEEDBYTE
	246	z->state->sub.check.need += (uLong)NEXTBYTE << 16;
	247	z->state->mode = CHECK2;
	248	case CHECK2:
	249	NEEDBYTE
	250	z->state->sub.check.need += (uLong)NEXTBYTE << 8;
	251	z->state->mode = CHECK1;
	252	case CHECK1:
	253	NEEDBYTE
	254	z->state->sub.check.need += (uLong)NEXTBYTE;
	255
	256	if (z->state->sub.check.was != z->state->sub.check.need)
	257	{
	258	z->state->mode = BAD;
	259	z->msg = (char*)"incorrect data check";
	260	z->state->sub.marker = 5; /* can't try inflateSync */
	261	break;
	262	}
	263	Tracev((stderr, "inflate: zlib check ok\n"));
	264	z->state->mode = DONE;
	265	case DONE:
	266	return Z_STREAM_END;
	267	case BAD:
	268	return Z_DATA_ERROR;
	269	default:
	270	return Z_STREAM_ERROR;
	271	}
	272	#ifdef NEED_DUMMY_RETURN
	273	return Z_STREAM_ERROR; /* Some dumb compilers complain without this */
	274	#endif
	275	}
	276
	277
	278	int ZEXPORT inflateSetDictionary(z, dictionary, dictLength)
	279	z_streamp z;
	280	const Bytef *dictionary;
	281	uInt dictLength;
	282	{
	283	uInt length = dictLength;
	284
	285	if (z == Z_NULL \|\| z->state == Z_NULL \|\| z->state->mode != DICT0)
	286	return Z_STREAM_ERROR;
	287
	288	if (adler32(1L, dictionary, dictLength) != z->adler) return Z_DATA_ERROR;
	289	z->adler = 1L;
	290
	291	if (length >= ((uInt)1<<z->state->wbits))
	292	{
	293	length = (1<<z->state->wbits)-1;
	294	dictionary += dictLength - length;
	295	}
	296	inflate_set_dictionary(z->state->blocks, dictionary, length);
	297	z->state->mode = BLOCKS;
	298	return Z_OK;
	299	}
	300
	301
	302	int ZEXPORT inflateSync(z)
	303	z_streamp z;
	304	{
	305	uInt n; /* number of bytes to look at */
	306	Bytef p; / pointer to bytes */
	307	uInt m; /* number of marker bytes found in a row */
	308	uLong r, w; /* temporaries to save total_in and total_out */
	309
	310	/* set up */
	311	if (z == Z_NULL \|\| z->state == Z_NULL)
	312	return Z_STREAM_ERROR;
	313	if (z->state->mode != BAD)
	314	{
	315	z->state->mode = BAD;
	316	z->state->sub.marker = 0;
	317	}
	318	if ((n = z->avail_in) == 0)
	319	return Z_BUF_ERROR;
	320	p = z->next_in;
	321	m = z->state->sub.marker;
	322
	323	/* search */
	324	while (n && m < 4)
	325	{
	326	static const Byte mark[4] = {0, 0, 0xff, 0xff};
	327	if (*p == mark[m])
	328	m++;
	329	else if (*p)
	330	m = 0;
	331	else
	332	m = 4 - m;
	333	p++, n--;
	334	}
	335
	336	/* restore */
	337	z->total_in += p - z->next_in;
	338	z->next_in = p;
	339	z->avail_in = n;
	340	z->state->sub.marker = m;
	341
	342	/* return no joy or set up to restart on a new block */
	343	if (m != 4)
	344	return Z_DATA_ERROR;
	345	r = z->total_in; w = z->total_out;
	346	inflateReset(z);
	347	z->total_in = r; z->total_out = w;
	348	z->state->mode = BLOCKS;
	349	return Z_OK;
	350	}
	351
	352
	353	/* Returns true if inflate is currently at the end of a block generated
	354	* by Z_SYNC_FLUSH or Z_FULL_FLUSH. This function is used by one PPP
	355	* implementation to provide an additional safety check. PPP uses Z_SYNC_FLUSH
	356	* but removes the length bytes of the resulting empty stored block. When
	357	* decompressing, PPP checks that at the end of input packet, inflate is
	358	* waiting for these length bytes.
	359	*/
	360	int ZEXPORT inflateSyncPoint(z)
	361	z_streamp z;
	362	{
	363	if (z == Z_NULL \|\| z->state == Z_NULL \|\| z->state->blocks == Z_NULL)
	364	return Z_STREAM_ERROR;
	365	return inflate_blocks_sync_point(z->state->blocks);
	366	}