/* inflate.c -- zlib decompression

* Copyright (C) 1995-2022 Mark Adler

* For conditions of distribution and use, see copyright notice in zlib.h

*/

/*

* Change history:

*

* 1.2.beta0 24 Nov 2002

* - First version -- complete rewrite of inflate to simplify code, avoid

* creation of window when not needed, minimize use of window when it is

* needed, make inffast.c even faster, implement gzip decoding, and to

* improve code readability and style over the previous zlib inflate code

*

* 1.2.beta1 25 Nov 2002

* - Use pointers for available input and output checking in inffast.c

* - Remove input and output counters in inffast.c

* - Change inffast.c entry and loop from avail_in >= 7 to >= 6

* - Remove unnecessary second byte pull from length extra in inffast.c

* - Unroll direct copy to three copies per loop in inffast.c

*

* 1.2.beta2 4 Dec 2002

* - Change external routine names to reduce potential conflicts

* - Correct filename to inffixed.h for fixed tables in inflate.c

* - Make hbuf[] unsigned char to match parameter type in inflate.c

* - Change strm->next_out[-state->offset] to *(strm->next_out - state->offset)

* to avoid negation problem on Alphas (64 bit) in inflate.c

*

* 1.2.beta3 22 Dec 2002

* - Add comments on state->bits assertion in inffast.c

* - Add comments on op field in inftrees.h

* - Fix bug in reuse of allocated window after inflateReset()

* - Remove bit fields--back to byte structure for speed

* - Remove distance extra == 0 check in inflate_fast()--only helps for lengths

* - Change post-increments to pre-increments in inflate_fast(), PPC biased?

* - Add compile time option, POSTINC, to use post-increments instead (Intel?)

* - Make MATCH copy in inflate() much faster for when inflate_fast() not used

* - Use local copies of stream next and avail values, as well as local bit

* buffer and bit count in inflate()--for speed when inflate_fast() not used

*

* 1.2.beta4 1 Jan 2003

* - Split ptr - 257 statements in inflate_table() to avoid compiler warnings

* - Move a comment on output buffer sizes from inffast.c to inflate.c

* - Add comments in inffast.c to introduce the inflate_fast() routine

* - Rearrange window copies in inflate_fast() for speed and simplification

* - Unroll last copy for window match in inflate_fast()

* - Use local copies of window variables in inflate_fast() for speed

* - Pull out common wnext == 0 case for speed in inflate_fast()

* - Make op and len in inflate_fast() unsigned for consistency

* - Add FAR to lcode and dcode declarations in inflate_fast()

* - Simplified bad distance check in inflate_fast()

* - Added inflateBackInit(), inflateBack(), and inflateBackEnd() in new

* source file infback.c to provide a call-back interface to inflate for

* programs like gzip and unzip -- uses window as output buffer to avoid

* window copying

*

* 1.2.beta5 1 Jan 2003

* - Improved inflateBack() interface to allow the caller to provide initial

* input in strm.

* - Fixed stored blocks bug in inflateBack()

*

* 1.2.beta6 4 Jan 2003

* - Added comments in inffast.c on effectiveness of POSTINC

* - Typecasting all around to reduce compiler warnings

* - Changed loops from while (1) or do {} while (1) to for (;;), again to

* make compilers happy

* - Changed type of window in inflateBackInit() to unsigned char *

*

* 1.2.beta7 27 Jan 2003

* - Changed many types to unsigned or unsigned short to avoid warnings

* - Added inflateCopy() function

*

* 1.2.0 9 Mar 2003

* - Changed inflateBack() interface to provide separate opaque descriptors

* for the in() and out() functions

* - Changed inflateBack() argument and in_func typedef to swap the length

* and buffer address return values for the input function

* - Check next_in and next_out for Z_NULL on entry to inflate()

*

* The history for versions after 1.2.0 are in ChangeLog in zlib distribution.

*/

#include "zutil.h"

#include "inftrees.h"

#include "inflate.h"

#include "inffast.h"

#ifdef MAKEFIXED

# ifndef BUILDFIXED

# define BUILDFIXED

# endif

#endif

local int inflateStateCheck(z_streamp strm) {

struct inflate_state FAR *state;

if (strm == Z_NULL ||

strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0)

return 1;

state = (struct inflate_state FAR *)strm->state;

if (state == Z_NULL || state->strm != strm ||

state->mode < HEAD || state->mode > SYNC)

return 1;

return 0;

}

int ZEXPORT inflateResetKeep(z_streamp strm) {

struct inflate_state FAR *state;

if (inflateStateCheck(strm)) return Z_STREAM_ERROR;

state = (struct inflate_state FAR *)strm->state;

strm->total_in = strm->total_out = state->total = 0;

strm->msg = Z_NULL;

if (state->wrap) /* to support ill-conceived Java test suite */

strm->adler = state->wrap & 1;

state->mode = HEAD;

state->last = 0;

state->havedict = 0;

state->flags = -1;

state->dmax = 32768U;

state->head = Z_NULL;

state->hold = 0;

state->bits = 0;

state->lencode = state->distcode = state->next = state->codes;

state->sane = 1;

state->back = -1;

Tracev((stderr, "inflate: reset\n"));

return Z_OK;

}

int ZEXPORT inflateReset(z_streamp strm) {

struct inflate_state FAR *state;

if (inflateStateCheck(strm)) return Z_STREAM_ERROR;

state = (struct inflate_state FAR *)strm->state;

state->wsize = 0;

state->whave = 0;

state->wnext = 0;

return inflateResetKeep(strm);

}

int ZEXPORT inflateReset2(z_streamp strm, int windowBits) {

int wrap;

struct inflate_state FAR *state;

/* get the state */

if (inflateStateCheck(strm)) return Z_STREAM_ERROR;

state = (struct inflate_state FAR *)strm->state;

/* extract wrap request from windowBits parameter */

if (windowBits < 0) {

if (windowBits < -15)

return Z_STREAM_ERROR;

wrap = 0;

windowBits = -windowBits;

}

else {

wrap = (windowBits >> 4) + 5;

#ifdef GUNZIP

if (windowBits < 48)

windowBits &= 15;

#endif

}

/* set number of window bits, free window if different */

if (windowBits && (windowBits < 8 || windowBits > 15))

return Z_STREAM_ERROR;

if (state->window != Z_NULL && state->wbits != (unsigned)windowBits) {

ZFREE(strm, state->window);

state->window = Z_NULL;

}

/* update state and reset the rest of it */

state->wrap = wrap;

state->wbits = (unsigned)windowBits;

return inflateReset(strm);

}

int ZEXPORT inflateInit2_(z_streamp strm, int windowBits,

const char *version, int stream_size) {

int ret;

struct inflate_state FAR *state;

if (version == Z_NULL || version[0] != ZLIB_VERSION[0] ||

stream_size != (int)(sizeof(z_stream)))

return Z_VERSION_ERROR;

if (strm == Z_NULL) return Z_STREAM_ERROR;

strm->msg = Z_NULL; /* in case we return an error */

if (strm->zalloc == (alloc_func)0) {

#ifdef Z_SOLO

return Z_STREAM_ERROR;

#else

strm->zalloc = zcalloc;

strm->opaque = (voidpf)0;

#endif

}

if (strm->zfree == (free_func)0)

#ifdef Z_SOLO

return Z_STREAM_ERROR;

#else

strm->zfree = zcfree;

#endif

state = (struct inflate_state FAR *)

ZALLOC(strm, 1, sizeof(struct inflate_state));

if (state == Z_NULL) return Z_MEM_ERROR;

Tracev((stderr, "inflate: allocated\n"));

strm->state = (struct internal_state FAR *)state;

state->strm = strm;

state->window = Z_NULL;

state->mode = HEAD; /* to pass state test in inflateReset2() */

state->check = 1L; /* 1L is the result of adler32() zero length data */

ret = inflateReset2(strm, windowBits);

if (ret != Z_OK) {

ZFREE(strm, state);

strm->state = Z_NULL;

}

return ret;

}

int ZEXPORT inflateInit_(z_streamp strm, const char *version,

int stream_size) {

return inflateInit2_(strm, DEF_WBITS, version, stream_size);

}

int ZEXPORT inflatePrime(z_streamp strm, int bits, int value) {

struct inflate_state FAR *state;

if (inflateStateCheck(strm)) return Z_STREAM_ERROR;

if (bits == 0)

return Z_OK;

state = (struct inflate_state FAR *)strm->state;

if (bits < 0) {

state->hold = 0;

state->bits = 0;

return Z_OK;

}

if (bits > 16 || state->bits + (uInt)bits > 32) return Z_STREAM_ERROR;

value &= (1L << bits) - 1;

state->hold += (unsigned)value << state->bits;

state->bits += (uInt)bits;

return Z_OK;

}

/*

Return state with length and distance decoding tables and index sizes set to

fixed code decoding. Normally this returns fixed tables from inffixed.h.

If BUILDFIXED is defined, then instead this routine builds the tables the

first time it's called, and returns those tables the first time and

thereafter. This reduces the size of the code by about 2K bytes, in

exchange for a little execution time. However, BUILDFIXED should not be

used for threaded applications, since the rewriting of the tables and virgin

may not be thread-safe.

*/

local void fixedtables(struct inflate_state FAR *state) {

#ifdef BUILDFIXED

static int virgin = 1;

static code *lenfix, *distfix;

static code fixed[544];

/* build fixed huffman tables if first call (may not be thread safe) */

if (virgin) {

unsigned sym, bits;

static code *next;

/* literal/length table */

sym = 0;

while (sym < 144) state->lens[sym++] = 8;

while (sym < 256) state->lens[sym++] = 9;

while (sym < 280) state->lens[sym++] = 7;

while (sym < 288) state->lens[sym++] = 8;

next = fixed;

lenfix = next;

bits = 9;

inflate_table(LENS, state->lens, 288, &(next), &(bits), state->work);

/* distance table */

sym = 0;

while (sym < 32) state->lens[sym++] = 5;

distfix = next;

bits = 5;

inflate_table(DISTS, state->lens, 32, &(next), &(bits), state->work);

/* do this just once */

virgin = 0;

}

#else /* !BUILDFIXED */

# include "inffixed.h"

#endif /* BUILDFIXED */

state->lencode = lenfix;

state->lenbits = 9;

state->distcode = distfix;

state->distbits = 5;

}

#ifdef MAKEFIXED

#include <stdio.h>

/*

Write out the inffixed.h that is #include'd above. Defining MAKEFIXED also

defines BUILDFIXED, so the tables are built on the fly. makefixed() writes

those tables to stdout, which would be piped to inffixed.h. A small program

can simply call makefixed to do this:

void makefixed(void);

int main(void)

{

makefixed();

return 0;

}

Then that can be linked with zlib built with MAKEFIXED defined and run:

a.out > inffixed.h

*/

void makefixed(void)

{

unsigned low, size;

struct inflate_state state;

fixedtables(&state);

puts(" /* inffixed.h -- table for decoding fixed codes");

puts(" * Generated automatically by makefixed().");

puts(" */");

puts("");

puts(" /* WARNING: this file should *not* be used by applications.");

puts(" It is part of the implementation of this library and is");

puts(" subject to change. Applications should only use zlib.h.");

puts(" */");

puts("");

size = 1U << 9;

printf(" static const code lenfix[%u] = {", size);

low = 0;

for (;;) {

if ((low % 7) == 0) printf("\n ");

printf("{%u,%u,%d}", (low & 127) == 99 ? 64 : state.lencode[low].op,

state.lencode[low].bits, state.lencode[low].val);

if (++low == size) break;

putchar(',');

}

puts("\n };");

size = 1U << 5;

printf("\n static const code distfix[%u] = {", size);

low = 0;

for (;;) {

if ((low % 6) == 0) printf("\n ");

printf("{%u,%u,%d}", state.distcode[low].op, state.distcode[low].bits,

state.distcode[low].val);

if (++low == size) break;

putchar(',');

}

puts("\n };");

}

#endif /* MAKEFIXED */

/*

Update the window with the last wsize (normally 32K) bytes written before

returning. If window does not exist yet, create it. This is only called

when a window is already in use, or when output has been written during this

inflate call, but the end of the deflate stream has not been reached yet.

It is also called to create a window for dictionary data when a dictionary

is loaded.

Providing output buffers larger than 32K to inflate() should provide a speed

advantage, since only the last 32K of output is copied to the sliding window

upon return from inflate(), and since all distances after the first 32K of

output will fall in the output data, making match copies simpler and faster.

The advantage may be dependent on the size of the processor's data caches.

*/

local int updatewindow(z_streamp strm, const Bytef *end, unsigned copy) {

struct inflate_state FAR *state;

unsigned dist;

state = (struct inflate_state FAR *)strm->state;

/* if it hasn't been done already, allocate space for the window */

if (state->window == Z_NULL) {

state->window = (unsigned char FAR *)

ZALLOC(strm, 1U << state->wbits,

sizeof(unsigned char));

if (state->window == Z_NULL) return 1;

}

/* if window not in use yet, initialize */

if (state->wsize == 0) {

state->wsize = 1U << state->wbits;

state->wnext = 0;

state->whave = 0;

}

/* copy state->wsize or less output bytes into the circular window */

if (copy >= state->wsize) {

zmemcpy(state->window, end - state->wsize, state->wsize);

state->wnext = 0;

state->whave = state->wsize;

}

else {

dist = state->wsize - state->wnext;

if (dist > copy) dist = copy;

zmemcpy(state->window + state->wnext, end - copy, dist);

copy -= dist;

if (copy) {

zmemcpy(state->window, end - copy, copy);

state->wnext = copy;

state->whave = state->wsize;

}

else {

state->wnext += dist;

if (state->wnext == state->wsize) state->wnext = 0;

if (state->whave < state->wsize) state->whave += dist;

}

}

return 0;

}

/* Macros for inflate(): */

/* check function to use adler32() for zlib or crc32() for gzip */

#ifdef GUNZIP

# define UPDATE_CHECK(check, buf, len) \

(state->flags ? crc32(check, buf, len) : adler32(check, buf, len))

#else

# define UPDATE_CHECK(check, buf, len) adler32(check, buf, len)

#endif

/* check macros for header crc */

#ifdef GUNZIP

# define CRC2(check, word) \

do { \

hbuf[0] = (unsigned char)(word); \

hbuf[1] = (unsigned char)((word) >> 8); \

check = crc32(check, hbuf, 2); \

} while (0)

# define CRC4(check, word) \

do { \

hbuf[0] = (unsigned char)(word); \

hbuf[1] = (unsigned char)((word) >> 8); \

hbuf[2] = (unsigned char)((word) >> 16); \

hbuf[3] = (unsigned char)((word) >> 24); \

check = crc32(check, hbuf, 4); \

} while (0)

#endif

/* Load registers with state in inflate() for speed */

#define LOAD() \

do { \

put = strm->next_out; \

left = strm->avail_out; \

next = strm->next_in; \

have = strm->avail_in; \

hold = state->hold; \

bits = state->bits; \

} while (0)

/* Restore state from registers in inflate() */

#define RESTORE() \

do { \

strm->next_out = put; \

strm->avail_out = left; \

strm->next_in = next; \

strm->avail_in = have; \

state->hold = hold; \

state->bits = bits; \

} while (0)

/* Clear the input bit accumulator */

#define INITBITS() \

do { \

hold = 0; \

bits = 0; \

} while (0)

/* Get a byte of input into the bit accumulator, or return from inflate()

if there is no input available. */

#define PULLBYTE() \

do { \

if (have == 0) goto inf_leave; \

have--; \

hold += (unsigned long)(*next++) << bits; \

bits += 8; \

} while (0)

/* Assure that there are at least n bits in the bit accumulator. If there is

not enough available input to do that, then return from inflate(). */

#define NEEDBITS(n) \

do { \

while (bits < (unsigned)(n)) \

PULLBYTE(); \

} while (0)

/* Return the low n bits of the bit accumulator (n < 16) */

#define BITS(n) \

((unsigned)hold & ((1U << (n)) - 1))

/* Remove n bits from the bit accumulator */

#define DROPBITS(n) \

do { \

hold >>= (n); \

bits -= (unsigned)(n); \

} while (0)

/* Remove zero to seven bits as needed to go to a byte boundary */

#define BYTEBITS() \

do { \

hold >>= bits & 7; \

bits -= bits & 7; \

} while (0)

/*

inflate() uses a state machine to process as much input data and generate as

much output data as possible before returning. The state machine is

structured roughly as follows:

for (;;) switch (state) {

...

case STATEn:

if (not enough input data or output space to make progress)

return;

... make progress ...

state = STATEm;

break;

...

}

so when inflate() is called again, the same case is attempted again, and

if the appropriate resources are provided, the machine proceeds to the

next state. The NEEDBITS() macro is usually the way the state evaluates

whether it can proceed or should return. NEEDBITS() does the return if

the requested bits are not available. The typical use of the BITS macros

is:

NEEDBITS(n);

... do something with BITS(n) ...

DROPBITS(n);

where NEEDBITS(n) either returns from inflate() if there isn't enough

input left to load n bits into the accumulator, or it continues. BITS(n)

gives the low n bits in the accumulator. When done, DROPBITS(n) drops

the low n bits off the accumulator. INITBITS() clears the accumulator

and sets the number of available bits to zero. BYTEBITS() discards just

enough bits to put the accumulator on a byte boundary. After BYTEBITS()

and a NEEDBITS(8), then BITS(8) would return the next byte in the stream.

NEEDBITS(n) uses PULLBYTE() to get an available byte of input, or to return

if there is no input available. The decoding of variable length codes uses

PULLBYTE() directly in order to pull just enough bytes to decode the next

code, and no more.

Some states loop until they get enough input, making sure that enough

state information is maintained to continue the loop where it left off

if NEEDBITS() returns in the loop. For example, want, need, and keep

would all have to actually be part of the saved state in case NEEDBITS()

returns:

case STATEw:

while (want < need) {

NEEDBITS(n);

keep[want++] = BITS(n);

DROPBITS(n);

}

state = STATEx;

case STATEx:

As shown above, if the next state is also the next case, then the break

is omitted.

A state may also return if there is not enough output space available to

complete that state. Those states are copying stored data, writing a

literal byte, and copying a matching string.

When returning, a "goto inf_leave" is used to update the total counters,

update the check value, and determine whether any progress has been made

during that inflate() call in order to return the proper return code.

Progress is defined as a change in either strm->avail_in or strm->avail_out.

When there is a window, goto inf_leave will update the window with the last

output written. If a goto inf_leave occurs in the middle of decompression

and there is no window currently, goto inf_leave will create one and copy

output to the window for the next call of inflate().

In this implementation, the flush parameter of inflate() only affects the

return code (per zlib.h). inflate() always writes as much as possible to

strm->next_out, given the space available and the provided input--the effect

documented in zlib.h of Z_SYNC_FLUSH. Furthermore, inflate() always defers

the allocation of and copying into a sliding window until necessary, which

provides the effect documented in zlib.h for Z_FINISH when the entire input

stream available. So the only thing the flush parameter actually does is:

when flush is set to Z_FINISH, inflate() cannot return Z_OK. Instead it

will return Z_BUF_ERROR if it has not reached the end of the stream.

*/

int ZEXPORT inflate(z_streamp strm, int flush) {

struct inflate_state FAR *state;

z_const unsigned char FAR *next; /* next input */

unsigned char FAR *put; /* next output */

unsigned have, left; /* available input and output */

unsigned long hold; /* bit buffer */

unsigned bits; /* bits in bit buffer */

unsigned in, out; /* save starting available input and output */

unsigned copy; /* number of stored or match bytes to copy */

unsigned char FAR *from; /* where to copy match bytes from */

code here; /* current decoding table entry */

code last; /* parent table entry */

unsigned len; /* length to copy for repeats, bits to drop */

int ret; /* return code */

#ifdef GUNZIP

unsigned char hbuf[4]; /* buffer for gzip header crc calculation */

#endif

static const unsigned short order[19] = /* permutation of code lengths */

{16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};

if (inflateStateCheck(strm) || strm->next_out == Z_NULL ||

(strm->next_in == Z_NULL && strm->avail_in != 0))

return Z_STREAM_ERROR;

state = (struct inflate_state FAR *)strm->state;

if (state->mode == TYPE) state->mode = TYPEDO; /* skip check */

LOAD();

in = have;

out = left;

ret = Z_OK;

for (;;)

switch (state->mode) {

case HEAD:

if (state->wrap == 0) {

state->mode = TYPEDO;

break;

}

NEEDBITS(16);

#ifdef GUNZIP

if ((state->wrap & 2) && hold == 0x8b1f) { /* gzip header */

if (state->wbits == 0)

state->wbits = 15;

state->check = crc32(0L, Z_NULL, 0);

CRC2(state->check, hold);

INITBITS();

state->mode = FLAGS;

break;

}

if (state->head != Z_NULL)

state->head->done = -1;

if (!(state->wrap & 1) || /* check if zlib header allowed */

#else

if (

#endif

((BITS(8) << 8) + (hold >> 8)) % 31) {

strm->msg = (char *)"incorrect header check";

state->mode = BAD;

break;

}

if (BITS(4) != Z_DEFLATED) {

strm->msg = (char *)"unknown compression method";

state->mode = BAD;

break;

}

DROPBITS(4);

len = BITS(4) + 8;

if (state->wbits == 0)

state->wbits = len;

if (len > 15 || len > state->wbits) {

strm->msg = (char *)"invalid window size";

state->mode = BAD;

break;

}

state->dmax = 1U << len;

state->flags = 0; /* indicate zlib header */

Tracev((stderr, "inflate: zlib header ok\n"));

strm->adler = state->check = adler32(0L, Z_NULL, 0);

state->mode = hold & 0x200 ? DICTID : TYPE;

INITBITS();

break;

#ifdef GUNZIP

case FLAGS:

NEEDBITS(16);

state->flags = (int)(hold);

if ((state->flags & 0xff) != Z_DEFLATED) {

strm->msg = (char *)"unknown compression method";

state->mode = BAD;

break;

}

if (state->flags & 0xe000) {

strm->msg = (char *)"unknown header flags set";

state->mode = BAD;

break;

}

if (state->head != Z_NULL)

state->head->text = (int)((hold >> 8) & 1);

if ((state->flags & 0x0200) && (state->wrap & 4))

CRC2(state->check, hold);

INITBITS();

state->mode = TIME;

/* fallthrough */

case TIME:

NEEDBITS(32);

if (state->head != Z_NULL)

state->head->time = hold;

if ((state->flags & 0x0200) && (state->wrap & 4))

CRC4(state->check, hold);

INITBITS();

state->mode = OS;

/* fallthrough */

case OS:

NEEDBITS(16);

if (state->head != Z_NULL) {

state->head->xflags = (int)(hold & 0xff);

state->head->os = (int)(hold >> 8);

}

if ((state->flags & 0x0200) && (state->wrap & 4))

CRC2(state->check, hold);

INITBITS();

state->mode = EXLEN;

/* fallthrough */

case EXLEN:

if (state->flags & 0x0400) {

NEEDBITS(16);

state->length = (unsigned)(hold);

if (state->head != Z_NULL)

state->head->extra_len = (unsigned)hold;

if ((state->flags & 0x0200) && (state->wrap & 4))

CRC2(state->check, hold);

INITBITS();

}

else if (state->head != Z_NULL)

state->head->extra = Z_NULL;

state->mode = EXTRA;

/* fallthrough */

case EXTRA:

if (state->flags & 0x0400) {

copy = state->length;

if (copy > have) copy = have;

if (copy) {

if (state->head != Z_NULL &&

state->head->extra != Z_NULL &&

(len = state->head->extra_len - state->length) <

state->head->extra_max) {

zmemcpy(state->head->extra + len, next,

len + copy > state->head->extra_max ?

state->head->extra_max - len : copy);

}

if ((state->flags & 0x0200) && (state->wrap & 4))

state->check = crc32(state->check, next, copy);

have -= copy;

next += copy;

state->length -= copy;

}

if (state->length) goto inf_leave;

}

state->length = 0;

state->mode = NAME;

/* fallthrough */

case NAME:

if (state->flags & 0x0800) {

if (have == 0) goto inf_leave;

copy = 0;

do {

len = (unsigned)(next[copy++]);

if (state->head != Z_NULL &&

state->head->name != Z_NULL &&

state->length < state->head->name_max)

state->head->name[state->length++] = (Bytef)len;

} while (len && copy < have);

if ((state->flags & 0x0200) && (state->wrap & 4))

state->check = crc32(state->check, next, copy);

have -= copy;

next += copy;

if (len) goto inf_leave;

}

else if (state->head != Z_NULL)

state->head->name = Z_NULL;

state->length = 0;

state->mode = COMMENT;

/* fallthrough */

case COMMENT:

if (state->flags & 0x1000) {

if (have == 0) goto inf_leave;

copy = 0;

do {

len = (unsigned)(next[copy++]);

if (state->head != Z_NULL &&

state->head->comment != Z_NULL &&

state->length < state->head->comm_max)

state->head->comment[state->length++] = (Bytef)len;

} while (len && copy < have);

if ((state->flags & 0x0200) && (state->wrap & 4))

state->check = crc32(state->check, next, copy);

have -= copy;

next += copy;

if (len) goto inf_leave;

}

else if (state->head != Z_NULL)

state->head->comment = Z_NULL;

state->mode = HCRC;

/* fallthrough */

case HCRC:

if (state->flags & 0x0200) {

NEEDBITS(16);

if ((state->wrap & 4) && hold != (state->check & 0xffff)) {

strm->msg = (char *)"header crc mismatch";

state->mode = BAD;

break;

}

INITBITS();

}

if (state->head != Z_NULL) {

state->head->hcrc = (int)((state->flags >> 9) & 1);

state->head->done = 1;

}

strm->adler = state->check = crc32(0L, Z_NULL, 0);

state->mode = TYPE;

break;

#endif

case DICTID:

NEEDBITS(32);

strm->adler = state->check = ZSWAP32(hold);

INITBITS();

state->mode = DICT;

/* fallthrough */

case DICT:

if (state->havedict == 0) {

RESTORE();

return Z_NEED_DICT;

}

strm->adler = state->check = adler32(0L, Z_NULL, 0);

state->mode = TYPE;

/* fallthrough */

case TYPE:

if (flush == Z_BLOCK || flush == Z_TREES) goto inf_leave;

/* fallthrough */

case TYPEDO:

if (state->last) {

BYTEBITS();

state->mode = CHECK;

break;

}

NEEDBITS(3);

state->last = BITS(1);

DROPBITS(1);

switch (BITS(2)) {

case 0: /* stored block */

Tracev((stderr, "inflate: stored block%s\n",

state->last ? " (last)" : ""));

state->mode = STORED;

break;

case 1: /* fixed block */

fixedtables(state);

Tracev((stderr, "inflate: fixed codes block%s\n",

state->last ? " (last)" : ""));

state->mode = LEN_; /* decode codes */

if (flush == Z_TREES) {

DROPBITS(2);

goto inf_leave;

}

break;

case 2: /* dynamic block */

Tracev((stderr, "inflate: dynamic codes block%s\n",

state->last ? " (last)" : ""));

state->mode = TABLE;

break;

case 3:

strm->msg = (char *)"invalid block type";

state->mode = BAD;

}

DROPBITS(2);

break;

case STORED:

BYTEBITS(); /* go to byte boundary */

NEEDBITS(32);

if ((hold & 0xffff) != ((hold >> 16) ^ 0xffff)) {

strm->msg = (char *)"invalid stored block lengths";

state->mode = BAD;

break;

}

state->length = (unsigned)hold & 0xffff;

Tracev((stderr, "inflate: stored length %u\n",

state->length));

INITBITS();

state->mode = COPY_;

if (flush == Z_TREES) goto inf_leave;

/* fallthrough */

case COPY_:

state->mode = COPY;

/* fallthrough */

case COPY:

copy = state->length;

if (copy) {

if (copy > have) copy = have;

if (copy > left) copy = left;

if (copy == 0) goto inf_leave;

zmemcpy(put, next, copy);

have -= copy;

next += copy;

left -= copy;

put += copy;

state->length -= copy;

break;

}

Tracev((stderr, "inflate: stored end\n"));

state->mode = TYPE;

break;

case TABLE:

NEEDBITS(14);

state->nlen = BITS(5) + 257;

DROPBITS(5);

state->ndist = BITS(5) + 1;

DROPBITS(5);

state->ncode = BITS(4) + 4;

DROPBITS(4);

#ifndef PKZIP_BUG_WORKAROUND

if (state->nlen > 286 || state->ndist > 30) {

strm->msg = (char *)"too many length or distance symbols";

state->mode = BAD;

break;

}

#endif

Tracev((stderr, "inflate: table sizes ok\n"));

state->have = 0;

state->mode = LENLENS;

/* fallthrough */

case LENLENS:

while (state->have < state->ncode) {

NEEDBITS(3);

state->lens[order[state->have++]] = (unsigned short)BITS(3);

DROPBITS(3);

}

while (state->have < 19)

state->lens[order[state->have++]] = 0;

state->next = state->codes;

state->lencode = (const code FAR *)(state->next);

state->lenbits = 7;

ret = inflate_table(CODES, state->lens, 19, &(state->next),

&(state->lenbits), state->work);

if (ret) {

strm->msg = (char *)"invalid code lengths set";

state->mode = BAD;

break;

}

Tracev((stderr, "inflate: code lengths ok\n"));

state->have = 0;

state->mode = CODELENS;

/* fallthrough */

case CODELENS:

while (state->have < state->nlen + state->ndist) {

for (;;) {

here = state->lencode[BITS(state->lenbits)];

if ((unsigned)(here.bits) <= bits) break;

PULLBYTE();

}

if (here.val < 16) {

DROPBITS(here.bits);

state->lens[state->have++] = here.val;

}

else {

if (here.val == 16) {

NEEDBITS(here.bits + 2);

DROPBITS(here.bits);

if (state->have == 0) {

strm->msg = (char *)"invalid bit length repeat";

state->mode = BAD;

break;

}

len = state->lens[state->have - 1];

copy = 3 + BITS(2);

DROPBITS(2);

}

else if (here.val == 17) {

NEEDBITS(here.bits + 3);

DROPBITS(here.bits);

len = 0;

copy = 3 + BITS(3);

DROPBITS(3);

}

else {

NEEDBITS(here.bits + 7);

DROPBITS(here.bits);

len = 0;

copy = 11 + BITS(7);

DROPBITS(7);

}

if (state->have + copy > state->nlen + state->ndist) {

strm->msg = (char *)"invalid bit length repeat";

state->mode = BAD;

break;

}

while (copy--)

state->lens[state->have++] = (unsigned short)len;

}

}

/* handle error breaks in while */

if (state->mode == BAD) break;

/* check for end-of-block code (better have one) */

if (state->lens[256] == 0) {

strm->msg = (char *)"invalid code -- missing end-of-block";

state->mode = BAD;

break;

}

/* build code tables -- note: do not change the lenbits or distbits

values here (10 and 9) without reading the comments in inftrees.h

concerning the ENOUGH constants, which depend on those values */