[rsync/rsync.git] / zlib / inflate.c

/* inflate.c -- zlib interface to inflate modules
 * Copyright (C) 1995-2002 Mark Adler
 * For conditions of distribution and use, see copyright notice in zlib.h 
 */

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

#ifdef BAD /* For AIX */
#undef BAD
#endif

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
d4286ec4	1	/* inflate.c -- zlib interface to inflate modules
be59d0ec	2	* Copyright (C) 1995-2002 Mark Adler
d4286ec4 PM	3	* For conditions of distribution and use, see copyright notice in zlib.h
	4	*/
	5
	6	#include "zutil.h"
	7	#include "infblock.h"
	8
4a2744ce WD	9	#ifdef BAD /* For AIX */
	10	#undef BAD
	11	#endif
	12
d4286ec4 PM	13	struct inflate_blocks_state {int dummy;}; /* for buggy compilers */
	14
	15	typedef enum {
	16	METHOD, /* waiting for method byte */
	17	FLAG, /* waiting for flag byte */
	18	DICT4, /* four dictionary check bytes to go */
	19	DICT3, /* three dictionary check bytes to go */
	20	DICT2, /* two dictionary check bytes to go */
	21	DICT1, /* one dictionary check byte to go */
	22	DICT0, /* waiting for inflateSetDictionary */
	23	BLOCKS, /* decompressing blocks */
	24	CHECK4, /* four check bytes to go */
	25	CHECK3, /* three check bytes to go */
	26	CHECK2, /* two check bytes to go */
	27	CHECK1, /* one check byte to go */
	28	DONE, /* finished check, done */
9819f005	29	BAD} /* got an error--stay here */
d4286ec4 PM	30	inflate_mode;
	31
	32	/* inflate private state */
	33	struct internal_state {
	34
	35	/* mode */
	36	inflate_mode mode; /* current inflate mode */
	37
	38	/* mode dependent information */
	39	union {
	40	uInt method; /* if FLAGS, method byte */
	41	struct {
	42	uLong was; /* computed check value */
	43	uLong need; /* stream check value */
	44	} check; /* if CHECK, check values to compare */
9819f005	45	uInt marker; /* if BAD, inflateSync's marker bytes count */
d4286ec4 PM	46	} sub; /* submode */
	47
	48	/* mode independent information */
	49	int nowrap; /* flag for no wrapper */
	50	uInt wbits; /* log2(window size) (8..15, defaults to 15) */
	51	inflate_blocks_statef
	52	blocks; / current inflate_blocks state */
	53
	54	};
	55
	56
	57	int ZEXPORT inflateReset(z)
	58	z_streamp z;
	59	{
	60	if (z == Z_NULL \|\| z->state == Z_NULL)
	61	return Z_STREAM_ERROR;
	62	z->total_in = z->total_out = 0;
	63	z->msg = Z_NULL;
	64	z->state->mode = z->state->nowrap ? BLOCKS : METHOD;
	65	inflate_blocks_reset(z->state->blocks, z, Z_NULL);
	66	Tracev((stderr, "inflate: reset\n"));
	67	return Z_OK;
	68	}
	69
	70
	71	int ZEXPORT inflateEnd(z)
	72	z_streamp z;
	73	{
	74	if (z == Z_NULL \|\| z->state == Z_NULL \|\| z->zfree == Z_NULL)
	75	return Z_STREAM_ERROR;
	76	if (z->state->blocks != Z_NULL)
	77	inflate_blocks_free(z->state->blocks, z);
	78	ZFREE(z, z->state);
	79	z->state = Z_NULL;
	80	Tracev((stderr, "inflate: end\n"));
	81	return Z_OK;
	82	}
	83
	84
	85	int ZEXPORT inflateInit2_(z, w, version, stream_size)
	86	z_streamp z;
	87	int w;
	88	const char *version;
	89	int stream_size;
	90	{
	91	if (version == Z_NULL \|\| version[0] != ZLIB_VERSION[0] \|\|
	92	stream_size != sizeof(z_stream))
	93	return Z_VERSION_ERROR;
	94
	95	/* initialize state */
	96	if (z == Z_NULL)
	97	return Z_STREAM_ERROR;
	98	z->msg = Z_NULL;
	99	if (z->zalloc == Z_NULL)
	100	{
	101	z->zalloc = zcalloc;
	102	z->opaque = (voidpf)0;
	103	}
	104	if (z->zfree == Z_NULL) z->zfree = zcfree;
	105	if ((z->state = (struct internal_state FAR *)
	106	ZALLOC(z,1,sizeof(struct internal_state))) == Z_NULL)
	107	return Z_MEM_ERROR;
	108	z->state->blocks = Z_NULL;
	109
110	/* handle undocumented nowrap option (no zlib header or check) */
111	z->state->nowrap = 0;
112	if (w < 0)
113	{
114	w = - w;
115	z->state->nowrap = 1;
116	}
117
118	/* set window size */
119	if (w < 8 \|\| w > 15)
120	{
121	inflateEnd(z);
122	return Z_STREAM_ERROR;
123	}
124	z->state->wbits = (uInt)w;
125
126	/* create inflate_blocks state */
127	if ((z->state->blocks =
128	inflate_blocks_new(z, z->state->nowrap ? Z_NULL : adler32, (uInt)1 << w))
129	== Z_NULL)
130	{
131	inflateEnd(z);
132	return Z_MEM_ERROR;
133	}
134	Tracev((stderr, "inflate: allocated\n"));
135
136	/* reset state */
137	inflateReset(z);
138	return Z_OK;
139	}
140
141
142	int ZEXPORT inflateInit_(z, version, stream_size)
143	z_streamp z;
144	const char *version;
145	int stream_size;
146	{
147	return inflateInit2_(z, DEF_WBITS, version, stream_size);
148	}
149
150
151	#define NEEDBYTE {if(z->avail_in==0)return r;r=f;}
152	#define NEXTBYTE (z->avail_in--,z->total_in++,*z->next_in++)
153
154	int ZEXPORT inflate(z, f)
155	z_streamp z;
156	int f;
157	{
158	int r;
159	uInt b;
160
161	if (z == Z_NULL \|\| z->state == Z_NULL \|\| z->next_in == Z_NULL)
162	return Z_STREAM_ERROR;
163	f = f == Z_FINISH ? Z_BUF_ERROR : Z_OK;
164	r = Z_BUF_ERROR;
165	while (1) switch (z->state->mode)
166	{
167	case METHOD:
168	NEEDBYTE
169	if (((z->state->sub.method = NEXTBYTE) & 0xf) != Z_DEFLATED)
170	{
9819f005	171	z->state->mode = BAD;
d4286ec4 PM	172	z->msg = (char*)"unknown compression method";
	173	z->state->sub.marker = 5; /* can't try inflateSync */
	174	break;
	175	}
	176	if ((z->state->sub.method >> 4) + 8 > z->state->wbits)
	177	{
9819f005	178	z->state->mode = BAD;
d4286ec4 PM	179	z->msg = (char*)"invalid window size";
	180	z->state->sub.marker = 5; /* can't try inflateSync */
	181	break;
	182	}
	183	z->state->mode = FLAG;
	184	case FLAG:
	185	NEEDBYTE
	186	b = NEXTBYTE;
	187	if (((z->state->sub.method << 8) + b) % 31)
	188	{
9819f005	189	z->state->mode = BAD;
d4286ec4 PM	190	z->msg = (char*)"incorrect header check";
	191	z->state->sub.marker = 5; /* can't try inflateSync */
	192	break;
	193	}
	194	Tracev((stderr, "inflate: zlib header ok\n"));
	195	if (!(b & PRESET_DICT))
	196	{
	197	z->state->mode = BLOCKS;
	198	break;
	199	}
	200	z->state->mode = DICT4;
	201	case DICT4:
	202	NEEDBYTE
	203	z->state->sub.check.need = (uLong)NEXTBYTE << 24;
	204	z->state->mode = DICT3;
	205	case DICT3:
	206	NEEDBYTE
	207	z->state->sub.check.need += (uLong)NEXTBYTE << 16;
	208	z->state->mode = DICT2;
	209	case DICT2:
	210	NEEDBYTE
	211	z->state->sub.check.need += (uLong)NEXTBYTE << 8;
	212	z->state->mode = DICT1;
	213	case DICT1:
	214	NEEDBYTE
	215	z->state->sub.check.need += (uLong)NEXTBYTE;
	216	z->adler = z->state->sub.check.need;
	217	z->state->mode = DICT0;
	218	return Z_NEED_DICT;
	219	case DICT0:
9819f005	220	z->state->mode = BAD;
d4286ec4 PM	221	z->msg = (char*)"need dictionary";
	222	z->state->sub.marker = 0; /* can try inflateSync */
	223	return Z_STREAM_ERROR;
	224	case BLOCKS:
	225	r = inflate_blocks(z->state->blocks, z, r);
	226	if (r == Z_DATA_ERROR)
	227	{
9819f005	228	z->state->mode = BAD;
d4286ec4 PM	229	z->state->sub.marker = 0; /* can try inflateSync */
	230	break;
	231	}
	232	if (r == Z_OK)
	233	r = f;
	234	if (r != Z_STREAM_END)
	235	return r;
	236	r = f;
	237	inflate_blocks_reset(z->state->blocks, z, &z->state->sub.check.was);
	238	if (z->state->nowrap)
	239	{
	240	z->state->mode = DONE;
	241	break;
	242	}
	243	z->state->mode = CHECK4;
	244	case CHECK4:
	245	NEEDBYTE
	246	z->state->sub.check.need = (uLong)NEXTBYTE << 24;
	247	z->state->mode = CHECK3;
	248	case CHECK3:
	249	NEEDBYTE
	250	z->state->sub.check.need += (uLong)NEXTBYTE << 16;
	251	z->state->mode = CHECK2;
	252	case CHECK2:
	253	NEEDBYTE
	254	z->state->sub.check.need += (uLong)NEXTBYTE << 8;
	255	z->state->mode = CHECK1;
	256	case CHECK1:
	257	NEEDBYTE
	258	z->state->sub.check.need += (uLong)NEXTBYTE;
	259
	260	if (z->state->sub.check.was != z->state->sub.check.need)
	261	{
9819f005	262	z->state->mode = BAD;
d4286ec4 PM	263	z->msg = (char*)"incorrect data check";
	264	z->state->sub.marker = 5; /* can't try inflateSync */
	265	break;
	266	}
	267	Tracev((stderr, "inflate: zlib check ok\n"));
	268	z->state->mode = DONE;
	269	case DONE:
	270	return Z_STREAM_END;
9819f005	271	case BAD:
d4286ec4 PM	272	return Z_DATA_ERROR;
	273	default:
	274	return Z_STREAM_ERROR;
	275	}
	276	#ifdef NEED_DUMMY_RETURN
	277	return Z_STREAM_ERROR; /* Some dumb compilers complain without this */
	278	#endif
	279	}
	280
	281
	282	int ZEXPORT inflateSetDictionary(z, dictionary, dictLength)
	283	z_streamp z;
	284	const Bytef *dictionary;
	285	uInt dictLength;
	286	{
	287	uInt length = dictLength;
	288
	289	if (z == Z_NULL \|\| z->state == Z_NULL \|\| z->state->mode != DICT0)
	290	return Z_STREAM_ERROR;
	291
	292	if (adler32(1L, dictionary, dictLength) != z->adler) return Z_DATA_ERROR;
	293	z->adler = 1L;
	294
	295	if (length >= ((uInt)1<<z->state->wbits))
	296	{
	297	length = (1<<z->state->wbits)-1;
	298	dictionary += dictLength - length;
	299	}
	300	inflate_set_dictionary(z->state->blocks, dictionary, length);
	301	z->state->mode = BLOCKS;
	302	return Z_OK;
	303	}
	304
	305
	306	int ZEXPORT inflateSync(z)
	307	z_streamp z;
	308	{
	309	uInt n; /* number of bytes to look at */
	310	Bytef p; / pointer to bytes */
	311	uInt m; /* number of marker bytes found in a row */
	312	uLong r, w; /* temporaries to save total_in and total_out */
	313
	314	/* set up */
	315	if (z == Z_NULL \|\| z->state == Z_NULL)
	316	return Z_STREAM_ERROR;
9819f005	317	if (z->state->mode != BAD)
d4286ec4	318	{
9819f005	319	z->state->mode = BAD;
d4286ec4 PM	320	z->state->sub.marker = 0;
	321	}
	322	if ((n = z->avail_in) == 0)
	323	return Z_BUF_ERROR;
	324	p = z->next_in;
	325	m = z->state->sub.marker;
	326
	327	/* search */
	328	while (n && m < 4)
	329	{
	330	static const Byte mark[4] = {0, 0, 0xff, 0xff};
	331	if (*p == mark[m])
	332	m++;
	333	else if (*p)
	334	m = 0;
	335	else
	336	m = 4 - m;
	337	p++, n--;
	338	}
	339
	340	/* restore */
	341	z->total_in += p - z->next_in;
	342	z->next_in = p;
	343	z->avail_in = n;
	344	z->state->sub.marker = m;
	345
	346	/* return no joy or set up to restart on a new block */
	347	if (m != 4)
	348	return Z_DATA_ERROR;
	349	r = z->total_in; w = z->total_out;
	350	inflateReset(z);
	351	z->total_in = r; z->total_out = w;
	352	z->state->mode = BLOCKS;
	353	return Z_OK;
	354	}
	355
	356
	357	/* Returns true if inflate is currently at the end of a block generated
	358	* by Z_SYNC_FLUSH or Z_FULL_FLUSH. This function is used by one PPP
	359	* implementation to provide an additional safety check. PPP uses Z_SYNC_FLUSH
	360	* but removes the length bytes of the resulting empty stored block. When
	361	* decompressing, PPP checks that at the end of input packet, inflate is
	362	* waiting for these length bytes.
	363	*/
	364	int ZEXPORT inflateSyncPoint(z)
	365	z_streamp z;
	366	{
	367	if (z == Z_NULL \|\| z->state == Z_NULL \|\| z->state->blocks == Z_NULL)
	368	return Z_STREAM_ERROR;
	369	return inflate_blocks_sync_point(z->state->blocks);
	370	}