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inflate.c
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/* inflate.c -- zlib decompression
* Copyright (C) 1995-2016 Mark Adler
* For conditions of distribution and use, see copyright notice in zlib.h
*/
#include "zbuild.h"
#include "zutil.h"
#include "inftrees.h"
#include "inflate.h"
#include "inffast.h"
#include "inflate_p.h"
#include "inffixed_tbl.h"
#include "functable.h"
/* function prototypes */
static int inflateStateCheck(PREFIX3(stream) *strm);
static uint32_t syncsearch(uint32_t *have, const unsigned char *buf, uint32_t len);
static int inflateStateCheck(PREFIX3(stream) *strm) {
struct inflate_state *state;
if (strm == NULL || strm->zalloc == NULL || strm->zfree == NULL)
return 1;
state = (struct inflate_state *)strm->state;
if (state == NULL || state->strm != strm || state->mode < HEAD || state->mode > SYNC)
return 1;
return 0;
}
int32_t Z_EXPORT PREFIX(inflateResetKeep)(PREFIX3(stream) *strm) {
struct inflate_state *state;
if (inflateStateCheck(strm))
return Z_STREAM_ERROR;
state = (struct inflate_state *)strm->state;
strm->total_in = strm->total_out = state->total = 0;
strm->msg = NULL;
if (state->wrap) /* to support ill-conceived Java test suite */
strm->adler = state->wrap & 1;
state->mode = HEAD;
state->check = ADLER32_INITIAL_VALUE;
state->last = 0;
state->havedict = 0;
state->flags = -1;
state->dmax = 32768U;
state->head = NULL;
state->hold = 0;
state->bits = 0;
state->lencode = state->distcode = state->next = state->codes;
state->sane = 1;
state->back = -1;
INFLATE_RESET_KEEP_HOOK(strm); /* hook for IBM Z DFLTCC */
Tracev((stderr, "inflate: reset\n"));
return Z_OK;
}
int32_t Z_EXPORT PREFIX(inflateReset)(PREFIX3(stream) *strm) {
struct inflate_state *state;
if (inflateStateCheck(strm))
return Z_STREAM_ERROR;
state = (struct inflate_state *)strm->state;
state->whave = 0;
state->wnext = 0;
return PREFIX(inflateResetKeep)(strm);
}
int32_t Z_EXPORT PREFIX(inflateReset2)(PREFIX3(stream) *strm, int32_t windowBits) {
int wrap;
struct inflate_state *state;
/* get the state */
if (inflateStateCheck(strm))
return Z_STREAM_ERROR;
state = (struct inflate_state *)strm->state;
/* extract wrap request from windowBits parameter */
if (windowBits < 0) {
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 != NULL && state->wbits != (unsigned)windowBits) {
ZFREE_WINDOW(strm, state->window);
state->window = NULL;
state->wsize = 0;
}
/* update state and reset the rest of it */
state->wrap = wrap;
state->wbits = (unsigned)windowBits;
return PREFIX(inflateReset)(strm);
}
int32_t Z_EXPORT PREFIX(inflateInit2_)(PREFIX3(stream) *strm, int32_t windowBits, const char *version, int32_t stream_size) {
int32_t ret;
struct inflate_state *state;
#if defined(X86_FEATURES)
x86_check_features();
#elif defined(ARM_FEATURES)
arm_check_features();
#endif
if (version == NULL || version[0] != PREFIX2(VERSION)[0] || stream_size != (int)(sizeof(PREFIX3(stream))))
return Z_VERSION_ERROR;
if (strm == NULL)
return Z_STREAM_ERROR;
strm->msg = NULL; /* in case we return an error */
if (strm->zalloc == NULL) {
strm->zalloc = zng_calloc;
strm->opaque = NULL;
}
if (strm->zfree == NULL)
strm->zfree = zng_cfree;
state = (struct inflate_state *) ZALLOC_STATE(strm, 1, sizeof(struct inflate_state));
if (state == NULL)
return Z_MEM_ERROR;
Tracev((stderr, "inflate: allocated\n"));
strm->state = (struct internal_state *)state;
state->strm = strm;
state->window = NULL;
state->wsize = 0;
state->mode = HEAD; /* to pass state test in inflateReset2() */
state->chunksize = functable.chunksize();
ret = PREFIX(inflateReset2)(strm, windowBits);
if (ret != Z_OK) {
ZFREE_STATE(strm, state);
strm->state = NULL;
return ret;
}
return ret;
}
int32_t Z_EXPORT PREFIX(inflateInit_)(PREFIX3(stream) *strm, const char *version, int32_t stream_size) {
return PREFIX(inflateInit2_)(strm, DEF_WBITS, version, stream_size);
}
int32_t Z_EXPORT PREFIX(inflatePrime)(PREFIX3(stream) *strm, int32_t bits, int32_t value) {
struct inflate_state *state;
if (inflateStateCheck(strm))
return Z_STREAM_ERROR;
INFLATE_PRIME_HOOK(strm, bits, value); /* hook for IBM Z DFLTCC */
state = (struct inflate_state *)strm->state;
if (bits < 0) {
state->hold = 0;
state->bits = 0;
return Z_OK;
}
if (bits > 16 || state->bits + (unsigned int)bits > 32)
return Z_STREAM_ERROR;
value &= (1L << bits) - 1;
state->hold += (unsigned)value << state->bits;
state->bits += (unsigned int)bits;
return Z_OK;
}
/*
Return state with length and distance decoding tables and index sizes set to
fixed code decoding. This returns fixed tables from inffixed_tbl.h.
*/
void Z_INTERNAL fixedtables(struct inflate_state *state) {
state->lencode = lenfix;
state->lenbits = 9;
state->distcode = distfix;
state->distbits = 5;
}
int Z_INTERNAL inflate_ensure_window(struct inflate_state *state) {
/* if it hasn't been done already, allocate space for the window */
if (state->window == NULL) {
unsigned wsize = 1U << state->wbits;
state->window = (unsigned char *)ZALLOC_WINDOW(state->strm, (wsize * 2) + state->chunksize, sizeof(unsigned char));
if (state->window == NULL)
return Z_MEM_ERROR;
memset(state->window + wsize, 0, state->chunksize);
}
/* if window not in use yet, initialize */
if (state->wsize == 0) {
state->wsize = 1U << state->wbits;
state->wnext = 0;
state->whave = 0;
}
return Z_OK;
}
/*
Private macros for inflate()
Look in inflate_p.h for macros shared with inflateBack()
*/
/* 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)(*next++) << bits); \
bits += 8; \
} 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.
*/
int32_t Z_EXPORT PREFIX(inflate)(PREFIX3(stream) *strm, int32_t flush) {
struct inflate_state *state;
const unsigned char *next; /* next input */
unsigned char *put; /* next output */
unsigned have, left; /* available input and output */
uint32_t hold; /* bit buffer */
unsigned bits; /* bits in bit buffer */
uint32_t in, out; /* save starting available input and output */
unsigned copy; /* number of stored or match bytes to copy */
code here; /* current decoding table entry */
code last; /* parent table entry */
unsigned len; /* length to copy for repeats, bits to drop */
int32_t ret; /* return code */
#ifdef GUNZIP
unsigned char hbuf[4]; /* buffer for gzip header crc calculation */
#endif
static const uint16_t 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 == NULL ||
(strm->next_in == NULL && strm->avail_in != 0))
return Z_STREAM_ERROR;
state = (struct inflate_state *)strm->state;
if (state->mode == TYPE) /* skip check */
state->mode = TYPEDO;
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_INITIAL_VALUE;
CRC2(state->check, hold);
INITBITS();
state->mode = FLAGS;
break;
}
if (state->head != NULL)
state->head->done = -1;
if (!(state->wrap & 1) || /* check if zlib header allowed */
#else
if (
#endif
((BITS(8) << 8) + (hold >> 8)) % 31) {
SET_BAD("incorrect header check");
break;
}
if (BITS(4) != Z_DEFLATED) {
SET_BAD("unknown compression method");
break;
}
DROPBITS(4);
len = BITS(4) + 8;
if (state->wbits == 0)
state->wbits = len;
if (len > 15 || len > state->wbits) {
SET_BAD("invalid window size");
break;
}
state->dmax = 1U << len;
state->flags = 0; /* indicate zlib header */
Tracev((stderr, "inflate: zlib header ok\n"));
strm->adler = state->check = ADLER32_INITIAL_VALUE;
state->mode = hold & 0x200 ? DICTID : TYPE;
INITBITS();
break;
#ifdef GUNZIP
case FLAGS:
NEEDBITS(16);
state->flags = (int)(hold);
if ((state->flags & 0xff) != Z_DEFLATED) {
SET_BAD("unknown compression method");
break;
}
if (state->flags & 0xe000) {
SET_BAD("unknown header flags set");
break;
}
if (state->head != NULL)
state->head->text = (int)((hold >> 8) & 1);
if ((state->flags & 0x0200) && (state->wrap & 4))
CRC2(state->check, hold);
INITBITS();
state->mode = TIME;
case TIME:
NEEDBITS(32);
if (state->head != NULL)
state->head->time = hold;
if ((state->flags & 0x0200) && (state->wrap & 4))
CRC4(state->check, hold);
INITBITS();
state->mode = OS;
case OS:
NEEDBITS(16);
if (state->head != 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;
case EXLEN:
if (state->flags & 0x0400) {
NEEDBITS(16);
state->length = (uint16_t)hold;
if (state->head != NULL)
state->head->extra_len = (uint16_t)hold;
if ((state->flags & 0x0200) && (state->wrap & 4))
CRC2(state->check, hold);
INITBITS();
} else if (state->head != NULL) {
state->head->extra = NULL;
}
state->mode = EXTRA;
case EXTRA:
if (state->flags & 0x0400) {
copy = state->length;
if (copy > have)
copy = have;
if (copy) {
if (state->head != NULL && state->head->extra != NULL) {
len = state->head->extra_len - state->length;
memcpy(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 = PREFIX(crc32)(state->check, next, copy);
have -= copy;
next += copy;
state->length -= copy;
}
if (state->length)
goto inf_leave;
}
state->length = 0;
state->mode = NAME;
case NAME:
if (state->flags & 0x0800) {
if (have == 0) goto inf_leave;
copy = 0;
do {
len = (unsigned)(next[copy++]);
if (state->head != NULL && state->head->name != NULL && state->length < state->head->name_max)
state->head->name[state->length++] = (unsigned char)len;
} while (len && copy < have);
if ((state->flags & 0x0200) && (state->wrap & 4))
state->check = PREFIX(crc32)(state->check, next, copy);
have -= copy;
next += copy;
if (len)
goto inf_leave;
} else if (state->head != NULL) {
state->head->name = NULL;
}
state->length = 0;
state->mode = COMMENT;
case COMMENT:
if (state->flags & 0x1000) {
if (have == 0) goto inf_leave;
copy = 0;
do {
len = (unsigned)(next[copy++]);
if (state->head != NULL && state->head->comment != NULL
&& state->length < state->head->comm_max)
state->head->comment[state->length++] = (unsigned char)len;
} while (len && copy < have);
if ((state->flags & 0x0200) && (state->wrap & 4))
state->check = PREFIX(crc32)(state->check, next, copy);
have -= copy;
next += copy;
if (len)
goto inf_leave;
} else if (state->head != NULL) {
state->head->comment = NULL;
}
state->mode = HCRC;
case HCRC:
if (state->flags & 0x0200) {
NEEDBITS(16);
if ((state->wrap & 4) && hold != (state->check & 0xffff)) {
SET_BAD("header crc mismatch");
break;
}
INITBITS();
}
if (state->head != NULL) {
state->head->hcrc = (int)((state->flags >> 9) & 1);
state->head->done = 1;
}
strm->adler = state->check = functable.crc32_fold_reset(&state->crc_fold);
state->mode = TYPE;
break;
#endif
case DICTID:
NEEDBITS(32);
strm->adler = state->check = ZSWAP32(hold);
INITBITS();
state->mode = DICT;
case DICT:
if (state->havedict == 0) {
RESTORE();
return Z_NEED_DICT;
}
strm->adler = state->check = ADLER32_INITIAL_VALUE;
state->mode = TYPE;
case TYPE:
if (flush == Z_BLOCK || flush == Z_TREES)
goto inf_leave;
case TYPEDO:
/* create window if it doesn't exist */
if (state->window == NULL) {
RESTORE();
ret = inflate_ensure_window(state);
if (ret != Z_OK) {
ZFREE_STATE(strm, state);
strm->state = NULL;
return ret;
}
LOAD();
}
/* determine and dispatch block type */
INFLATE_TYPEDO_HOOK(strm, flush); /* hook for IBM Z DFLTCC */
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:
SET_BAD("invalid block type");
}
DROPBITS(2);
break;
case STORED:
/* get and verify stored block length */
BYTEBITS(); /* go to byte boundary */
NEEDBITS(32);
if ((hold & 0xffff) != ((hold >> 16) ^ 0xffff)) {
SET_BAD("invalid stored block lengths");
break;
}
state->length = (uint16_t)hold;
Tracev((stderr, "inflate: stored length %u\n", state->length));
INITBITS();
state->mode = COPY_;
if (flush == Z_TREES)
goto inf_leave;
case COPY_:
state->mode = COPY;
case COPY:
/* copy stored block from input to output */
copy = state->length;
if (copy) {
unsigned char *end = state->window + (state->wsize * 2);
int64_t diff = end - put;
copy = MIN(copy, have);
if (copy > diff) {
if (left > 0) {
RESTORE();
window_output_flush(strm);
LOAD();
diff = end - put;
}
copy = MIN(copy, (uint32_t)diff);
}
if (copy == 0)
goto inf_leave;
memcpy(put, next, copy);
have -= copy;
next += copy;
put += copy;
state->length -= copy;
break;
}
Tracev((stderr, "inflate: stored end\n"));
state->mode = TYPE;
break;
case TABLE:
/* get dynamic table entries descriptor */
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) {
SET_BAD("too many length or distance symbols");
break;
}
#endif
Tracev((stderr, "inflate: table sizes ok\n"));
state->have = 0;
state->mode = LENLENS;
case LENLENS:
/* get code length code lengths (not a typo) */
while (state->have < state->ncode) {
NEEDBITS(3);
state->lens[order[state->have++]] = (uint16_t)BITS(3);
DROPBITS(3);
}
while (state->have < 19)
state->lens[order[state->have++]] = 0;
state->next = state->codes;
state->lencode = (const code *)(state->next);
state->lenbits = 7;
ret = zng_inflate_table(CODES, state->lens, 19, &(state->next), &(state->lenbits), state->work);
if (ret) {
SET_BAD("invalid code lengths set");
break;
}
Tracev((stderr, "inflate: code lengths ok\n"));
state->have = 0;
state->mode = CODELENS;
case CODELENS:
/* get length and distance code code lengths */
while (state->have < state->nlen + state->ndist) {
for (;;) {
here = state->lencode[BITS(state->lenbits)];
if (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) {
SET_BAD("invalid bit length repeat");
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) {
SET_BAD("invalid bit length repeat");
break;
}
while (copy) {
--copy;
state->lens[state->have++] = (uint16_t)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) {
SET_BAD("invalid code -- missing end-of-block");
break;
}
/* build code tables -- note: do not change the lenbits or distbits
values here (9 and 6) without reading the comments in inftrees.h
concerning the ENOUGH constants, which depend on those values */
state->next = state->codes;
state->lencode = (const code *)(state->next);
state->lenbits = 9;
ret = zng_inflate_table(LENS, state->lens, state->nlen, &(state->next), &(state->lenbits), state->work);
if (ret) {
SET_BAD("invalid literal/lengths set");
break;
}
state->distcode = (const code *)(state->next);
state->distbits = 6;
ret = zng_inflate_table(DISTS, state->lens + state->nlen, state->ndist,
&(state->next), &(state->distbits), state->work);
if (ret) {
SET_BAD("invalid distances set");
break;
}
Tracev((stderr, "inflate: codes ok\n"));
state->mode = LEN_;
if (flush == Z_TREES)
goto inf_leave;
case LEN_:
state->mode = LEN;
case LEN:
/* use inflate_fast() if we have enough input and output */
if (have >= INFLATE_FAST_MIN_HAVE && left >= INFLATE_FAST_MIN_LEFT) {
RESTORE();
zng_inflate_fast(strm);
LOAD();
if (state->mode == TYPE)
state->back = -1;
break;
}
state->back = 0;
/* get a literal, length, or end-of-block code */
for (;;) {
here = state->lencode[BITS(state->lenbits)];
if (here.bits <= bits)
break;
PULLBYTE();
}
if (here.op && (here.op & 0xf0) == 0) {
last = here;
for (;;) {
here = state->lencode[last.val + (BITS(last.bits + last.op) >> last.bits)];
if ((unsigned)last.bits + (unsigned)here.bits <= bits)
break;
PULLBYTE();
}
DROPBITS(last.bits);
state->back += last.bits;
}
DROPBITS(here.bits);
state->back += here.bits;
state->length = here.val;
/* process literal */
if ((int)(here.op) == 0) {
Tracevv((stderr, here.val >= 0x20 && here.val < 0x7f ?
"inflate: literal '%c'\n" :
"inflate: literal 0x%02x\n", here.val));
state->mode = LIT;
break;
}
/* process end of block */
if (here.op & 32) {
Tracevv((stderr, "inflate: end of block\n"));
state->back = -1;
state->mode = TYPE;
break;
}
/* invalid code */
if (here.op & 64) {
SET_BAD("invalid literal/length code");
break;
}
/* length code */
state->extra = (here.op & 15);
state->mode = LENEXT;
case LENEXT:
/* get extra bits, if any */
if (state->extra) {
NEEDBITS(state->extra);
state->length += BITS(state->extra);
DROPBITS(state->extra);
state->back += state->extra;
}
Tracevv((stderr, "inflate: length %u\n", state->length));
state->was = state->length;
state->mode = DIST;
case DIST:
/* get distance code */
for (;;) {
here = state->distcode[BITS(state->distbits)];
if (here.bits <= bits)
break;
PULLBYTE();
}
if ((here.op & 0xf0) == 0) {
last = here;
for (;;) {
here = state->distcode[last.val + (BITS(last.bits + last.op) >> last.bits)];
if ((unsigned)last.bits + (unsigned)here.bits <= bits)
break;
PULLBYTE();
}
DROPBITS(last.bits);
state->back += last.bits;
}
DROPBITS(here.bits);
state->back += here.bits;
if (here.op & 64) {
SET_BAD("invalid distance code");
break;
}
state->offset = here.val;
state->extra = (here.op & 15);
state->mode = DISTEXT;
case DISTEXT:
/* get distance extra bits, if any */
if (state->extra) {
NEEDBITS(state->extra);
state->offset += BITS(state->extra);
DROPBITS(state->extra);
state->back += state->extra;
}
#ifdef INFLATE_STRICT
if (state->offset > state->dmax) {
SET_BAD("invalid distance too far back");
break;
}
#endif
Tracevv((stderr, "inflate: distance %u\n", state->offset));
state->mode = MATCH;
case MATCH: {
/* copy match from window to output */
if (left == 0)
goto inf_leave;
unsigned char *end = state->window + (state->wsize * 2);
int64_t buf_left = end - put;
copy = state->length;
RESTORE();
if (copy > buf_left) {
if (strm->avail_out > 0) {
/* relies on RESTORE() above with no changes to those vars */
window_output_flush(strm);
LOAD();
buf_left = end - put;
}
copy = MIN(copy, (uint32_t)buf_left);
}
if (copy == 0)
goto inf_leave;
if (state->offset > state->wnext + state->whave) {
if (state->sane) {
SET_BAD("invalid distance too far back");
break;
}
}
unsigned char *next_out = state->window + state->wsize + state->wnext;
if (copy <= state->offset) {
functable.chunkcopy_safe(next_out, next_out - state->offset, copy, put + buf_left);
} else { /* copy from output */
functable.chunkmemset_safe(next_out, state->offset, copy, (uint32_t)buf_left);
}
state->wnext += copy;
state->length -= copy;
LOAD();
if (state->length == 0)
state->mode = LEN;
break;
}
case LIT:
if (put >= state->window + (state->wsize * 2)) {
RESTORE();
window_output_flush(strm);
LOAD();
}
if (left == 0)
goto inf_leave;
*put++ = (unsigned char)(state->length);
state->mode = LEN;
break;
case CHECK:
if (INFLATE_NEED_WINDOW_OUTPUT_FLUSH(strm)) {
RESTORE();
window_output_flush(strm);
LOAD();
if (strm->avail_out == 0 && state->wnext)
goto inf_leave;
}
if (state->wrap) {
NEEDBITS(32);
out -= left;
strm->total_out += out;
state->total += out;
if (INFLATE_NEED_CHECKSUM(strm) && strm->total_out) {
if (state->wrap & 2)
strm->adler = state->check = functable.crc32_fold_final(&state->crc_fold);
}
out = left;
if ((state->wrap & 4) && (
#ifdef GUNZIP
state->flags ? hold :
#endif
ZSWAP32(hold)) != state->check) {
SET_BAD("incorrect data check");
break;
}
INITBITS();
Tracev((stderr, "inflate: check matches trailer\n"));
}
#ifdef GUNZIP
state->mode = LENGTH;
case LENGTH:
if (state->wrap && state->flags) {
NEEDBITS(32);
if ((state->wrap & 4) && hold != (state->total & 0xffffffff)) {
SET_BAD("incorrect length check");
break;
}
INITBITS();
Tracev((stderr, "inflate: length matches trailer\n"));
}
#endif
state->mode = DONE;
case DONE:
/* inflate stream terminated properly */
ret = Z_STREAM_END;
goto inf_leave;
case BAD:
ret = Z_DATA_ERROR;
goto inf_leave;
case MEM:
return Z_MEM_ERROR;
case SYNC:
default: /* can't happen, but makes compilers happy */
return Z_STREAM_ERROR;
}
/*
Return from inflate(), updating the total counts and the check value.
If there was no progress during the inflate() call, return a buffer
error.
Note: a memory error from inflate() is non-recoverable.
*/
inf_leave:
RESTORE();
if (INFLATE_NEED_WINDOW_OUTPUT_FLUSH(strm) && strm->avail_out && state->wnext)
window_output_flush(strm);
in -= strm->avail_in;
out -= strm->avail_out;
strm->total_in += in;
strm->total_out += out;
state->total += out;
strm->data_type = (int)state->bits + (state->last ? 64 : 0) +
(state->mode == TYPE ? 128 : 0) + (state->mode == LEN_ || state->mode == COPY_ ? 256 : 0);
if (((in == 0 && out == 0) || flush == Z_FINISH) && ret == Z_OK)
ret = Z_BUF_ERROR;
return ret;