The Tor Browser: comparison modules/zlib/src/inflate.c

--1:000000000000
+:a5f7ab210012
+/* inflate.c -- zlib decompression
+* Copyright (C) 1995-2012 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
+/* function prototypes */
+local void fixedtables OF((struct inflate_state FAR *state));
+local int updatewindow OF((z_streamp strm, const unsigned char FAR *end,
+unsigned copy));
+#ifdef BUILDFIXED
+void makefixed OF((void));
+#endif
+local unsigned syncsearch OF((unsigned FAR *have, const unsigned char FAR *buf,
+unsigned len));
+int ZEXPORT inflateResetKeep(strm)
+z_streamp strm;
+{
+struct inflate_state FAR *state;
+if (strm == Z_NULL || strm->state == Z_NULL) 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->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(strm)
+z_streamp strm;
+{
+struct inflate_state FAR *state;
+if (strm == Z_NULL || strm->state == Z_NULL) 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(strm, windowBits)
+z_streamp strm;
+int windowBits;
+{
+int wrap;
+struct inflate_state FAR *state;
+/* get the state */
+if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
+state = (struct inflate_state FAR *)strm->state;
+/* extract wrap request from windowBits parameter */
+if (windowBits < 0) {
+wrap = 0;
+windowBits = -windowBits;
+}
+else {
+wrap = (windowBits >> 4) + 1;
+#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_(strm, windowBits, version, stream_size)
+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->window = Z_NULL;
+ret = inflateReset2(strm, windowBits);
+if (ret != Z_OK) {
+ZFREE(strm, state);
+strm->state = Z_NULL;
+}
+return ret;
+}
+int ZEXPORT inflateInit_(strm, version, stream_size)
+z_streamp strm;
+const char *version;
+int stream_size;
+{
+return inflateInit2_(strm, DEF_WBITS, version, stream_size);
+}
+int ZEXPORT inflatePrime(strm, bits, value)
+z_streamp strm;
+int bits;
+int value;
+{
+struct inflate_state FAR *state;
+if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
+state = (struct inflate_state FAR *)strm->state;
+if (bits < 0) {
+state->hold = 0;
+state->bits = 0;
+return Z_OK;
+}
+if (bits > 16 || state->bits + bits > 32) return Z_STREAM_ERROR;
+value &= (1L << bits) - 1;
+state->hold += value << state->bits;
+state->bits += 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(state)
+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()
+{
+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(strm, end, copy)
+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, buf, len) \
+(state->flags ? crc32(check, buf, len) : adler32(check, buf, len))
+#else
+#  define UPDATE(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(strm, flush)
+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 (strm == Z_NULL || strm->state == Z_NULL || 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 */
+state->check = crc32(0L, Z_NULL, 0);
+CRC2(state->check, hold);
+INITBITS();
+state->mode = FLAGS;
+break;
+}
+state->flags = 0;           /* expect zlib header */
+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;
+else if (len > state->wbits) {
+strm->msg = (char *)"invalid window size";
+state->mode = BAD;
+break;
+}
+state->dmax = 1U << len;
+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) CRC2(state->check, hold);
+INITBITS();
+state->mode = TIME;
+case TIME:
+NEEDBITS(32);
+if (state->head != Z_NULL)
+state->head->time = hold;
+if (state->flags & 0x0200) CRC4(state->check, hold);
+INITBITS();
+state->mode = OS;
+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) CRC2(state->check, hold);
+INITBITS();
+state->mode = EXLEN;
+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) CRC2(state->check, hold);
+INITBITS();
+}
+else if (state->head != Z_NULL)
+state->head->extra = Z_NULL;
+state->mode = EXTRA;
+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;
+zmemcpy(state->head->extra + len, next,
+len + copy > state->head->extra_max ?
+state->head->extra_max - len : copy);
+}
+if (state->flags & 0x0200)
+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;
+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++] = len;
+} while (len && copy < have);
+if (state->flags & 0x0200)
+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;
+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++] = len;
+} while (len && copy < have);
+if (state->flags & 0x0200)
+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;
+case HCRC:
+if (state->flags & 0x0200) {
+NEEDBITS(16);
+if (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;
+case DICT:
+if (state->havedict == 0) {
+RESTORE();
+return Z_NEED_DICT;
+}
+strm->adler = state->check = adler32(0L, Z_NULL, 0);
+state->mode = TYPE;
+case TYPE:
+if (flush == Z_BLOCK || flush == Z_TREES) goto inf_leave;
+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;
+case COPY_:
+state->mode = COPY;
+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;
+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;
+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 (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 FAR *)(state->next);
+state->lenbits = 9;
+ret = inflate_table(LENS, state->lens, state->nlen, &(state->next),
+&(state->lenbits), state->work);
+if (ret) {
+strm->msg = (char *)"invalid literal/lengths set";
+state->mode = BAD;
+break;
+}
+state->distcode = (const code FAR *)(state->next);
+state->distbits = 6;
+ret = inflate_table(DISTS, state->lens + state->nlen, state->ndist,
+&(state->next), &(state->distbits), state->work);
+if (ret) {
+strm->msg = (char *)"invalid distances set";
+state->mode = BAD;
+break;
+}
+Tracev((stderr, "inflate:       codes ok\n"));
+state->mode = LEN_;
+if (flush == Z_TREES) goto inf_leave;
+case LEN_:
+state->mode = LEN;
+case LEN:
+if (have >= 6 && left >= 258) {
+RESTORE();
+inflate_fast(strm, out);
+LOAD();
+if (state->mode == TYPE)
+state->back = -1;
+break;
+}
+state->back = 0;
+for (;;) {
+here = state->lencode[BITS(state->lenbits)];
+if ((unsigned)(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 + here.bits) <= bits) break;
+PULLBYTE();
+}
+DROPBITS(last.bits);
+state->back += last.bits;
+}
+DROPBITS(here.bits);
+state->back += here.bits;
+state->length = (unsigned)here.val;
+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;
+}
+if (here.op & 32) {
+Tracevv((stderr, "inflate:         end of block\n"));
+state->back = -1;
+state->mode = TYPE;
+break;
+}
+if (here.op & 64) {
+strm->msg = (char *)"invalid literal/length code";
+state->mode = BAD;
+break;
+}
+state->extra = (unsigned)(here.op) & 15;
+state->mode = LENEXT;
+case LENEXT:
+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:
+for (;;) {
+here = state->distcode[BITS(state->distbits)];
+if ((unsigned)(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 + here.bits) <= bits) break;
+PULLBYTE();
+}
+DROPBITS(last.bits);
+state->back += last.bits;
+}
+DROPBITS(here.bits);
+state->back += here.bits;
+if (here.op & 64) {
+strm->msg = (char *)"invalid distance code";
+state->mode = BAD;
+break;
+}
+state->offset = (unsigned)here.val;
+state->extra = (unsigned)(here.op) & 15;
+state->mode = DISTEXT;
+case DISTEXT:
+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) {
+strm->msg = (char *)"invalid distance too far back";
+state->mode = BAD;
+break;
+}
+#endif
+Tracevv((stderr, "inflate:         distance %u\n", state->offset));
+state->mode = MATCH;
+case MATCH:
+if (left == 0) goto inf_leave;
+copy = out - left;
+if (state->offset > copy) {         /* copy from window */
+copy = state->offset - copy;
+if (copy > state->whave) {
+if (state->sane) {
+strm->msg = (char *)"invalid distance too far back";
+state->mode = BAD;
+break;
+}
+#ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR
+Trace((stderr, "inflate.c too far\n"));
+copy -= state->whave;
+if (copy > state->length) copy = state->length;
+if (copy > left) copy = left;
+left -= copy;
+state->length -= copy;
+do {
+*put++ = 0;
+} while (--copy);
+if (state->length == 0) state->mode = LEN;
+break;
+#endif
+}
+if (copy > state->wnext) {
+copy -= state->wnext;
+from = state->window + (state->wsize - copy);
+}
+else
+from = state->window + (state->wnext - copy);
+if (copy > state->length) copy = state->length;
+}
+else {                              /* copy from output */
+from = put - state->offset;
+copy = state->length;
+}
+if (copy > left) copy = left;
+left -= copy;
+state->length -= copy;
+do {
+*put++ = *from++;
+} while (--copy);
+if (state->length == 0) state->mode = LEN;
+break;
+case LIT:
+if (left == 0) goto inf_leave;
+*put++ = (unsigned char)(state->length);
+left--;
+state->mode = LEN;
+break;
+case CHECK:
+if (state->wrap) {
+NEEDBITS(32);
+out -= left;
+strm->total_out += out;
+state->total += out;
+if (out)
+strm->adler = state->check =
+UPDATE(state->check, put - out, out);
+out = left;
+if ((
+#ifdef GUNZIP
+state->flags ? hold :
+#endif
+ZSWAP32(hold)) != state->check) {
+strm->msg = (char *)"incorrect data check";
+state->mode = BAD;
+break;
+}
+INITBITS();
+Tracev((stderr, "inflate:   check matches trailer\n"));
+}
+#ifdef GUNZIP
+state->mode = LENGTH;
+case LENGTH:
+if (state->wrap && state->flags) {
+NEEDBITS(32);
+if (hold != (state->total & 0xffffffffUL)) {
+strm->msg = (char *)"incorrect length check";
+state->mode = BAD;
+break;
+}
+INITBITS();
+Tracev((stderr, "inflate:   length matches trailer\n"));
+}
+#endif
+state->mode = DONE;
+case DONE:
+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:
+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.  Call updatewindow() to create and/or update the window state.
+Note: a memory error from inflate() is non-recoverable.
+*/
+inf_leave:
+RESTORE();
+if (state->wsize || (out != strm->avail_out && state->mode < BAD &&
+(state->mode < CHECK || flush != Z_FINISH)))
+if (updatewindow(strm, strm->next_out, out - strm->avail_out)) {
+state->mode = MEM;
+return Z_MEM_ERROR;
+}
+in -= strm->avail_in;
+out -= strm->avail_out;
+strm->total_in += in;
+strm->total_out += out;
+state->total += out;
+if (state->wrap && out)
+strm->adler = state->check =
+UPDATE(state->check, strm->next_out - out, out);
+strm->data_type = 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;
+}
+int ZEXPORT inflateEnd(strm)
+z_streamp strm;
+{
+struct inflate_state FAR *state;
+if (strm == Z_NULL || strm->state == Z_NULL || strm->zfree == (free_func)0)
+return Z_STREAM_ERROR;
+state = (struct inflate_state FAR *)strm->state;
+if (state->window != Z_NULL) ZFREE(strm, state->window);
+ZFREE(strm, strm->state);
+strm->state = Z_NULL;
+Tracev((stderr, "inflate: end\n"));
+return Z_OK;
+}
+int ZEXPORT inflateGetDictionary(strm, dictionary, dictLength)
+z_streamp strm;
+Bytef *dictionary;
+uInt *dictLength;
+{
+struct inflate_state FAR *state;
+/* check state */
+if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
+state = (struct inflate_state FAR *)strm->state;
+/* copy dictionary */
+if (state->whave && dictionary != Z_NULL) {
+zmemcpy(dictionary, state->window + state->wnext,
+state->whave - state->wnext);
+zmemcpy(dictionary + state->whave - state->wnext,
+state->window, state->wnext);
+}
+if (dictLength != Z_NULL)
+*dictLength = state->whave;
+return Z_OK;
+}
+int ZEXPORT inflateSetDictionary(strm, dictionary, dictLength)
+z_streamp strm;
+const Bytef *dictionary;
+uInt dictLength;
+{
+struct inflate_state FAR *state;
+unsigned long dictid;
+int ret;
+/* check state */
+if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
+state = (struct inflate_state FAR *)strm->state;
+if (state->wrap != 0 && state->mode != DICT)
+return Z_STREAM_ERROR;
+/* check for correct dictionary identifier */
+if (state->mode == DICT) {
+dictid = adler32(0L, Z_NULL, 0);
+dictid = adler32(dictid, dictionary, dictLength);
+if (dictid != state->check)
+return Z_DATA_ERROR;
+}
+/* copy dictionary to window using updatewindow(), which will amend the
+existing dictionary if appropriate */
+ret = updatewindow(strm, dictionary + dictLength, dictLength);
+if (ret) {
+state->mode = MEM;
+return Z_MEM_ERROR;
+}
+state->havedict = 1;
+Tracev((stderr, "inflate:   dictionary set\n"));
+return Z_OK;
+}
+int ZEXPORT inflateGetHeader(strm, head)
+z_streamp strm;
+gz_headerp head;
+{
+struct inflate_state FAR *state;
+/* check state */
+if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
+state = (struct inflate_state FAR *)strm->state;
+if ((state->wrap & 2) == 0) return Z_STREAM_ERROR;
+/* save header structure */
+state->head = head;
+head->done = 0;
+return Z_OK;
+}
+/*
+Search buf[0..len-1] for the pattern: 0, 0, 0xff, 0xff.  Return when found
+or when out of input.  When called, *have is the number of pattern bytes
+found in order so far, in 0..3.  On return *have is updated to the new
+state.  If on return *have equals four, then the pattern was found and the
+return value is how many bytes were read including the last byte of the
+pattern.  If *have is less than four, then the pattern has not been found
+yet and the return value is len.  In the latter case, syncsearch() can be
+called again with more data and the *have state.  *have is initialized to
+zero for the first call.
+*/
+local unsigned syncsearch(have, buf, len)
+unsigned FAR *have;
+const unsigned char FAR *buf;
+unsigned len;
+{
+unsigned got;
+unsigned next;
+got = *have;
+next = 0;
+while (next < len && got < 4) {
+if ((int)(buf[next]) == (got < 2 ? 0 : 0xff))
+got++;
+else if (buf[next])
+got = 0;
+else
+got = 4 - got;
+next++;
+}
+*have = got;
+return next;
+}
+int ZEXPORT inflateSync(strm)
+z_streamp strm;
+{
+unsigned len;               /* number of bytes to look at or looked at */
+unsigned long in, out;      /* temporary to save total_in and total_out */
+unsigned char buf[4];       /* to restore bit buffer to byte string */
+struct inflate_state FAR *state;
+/* check parameters */
+if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
+state = (struct inflate_state FAR *)strm->state;
+if (strm->avail_in == 0 && state->bits < 8) return Z_BUF_ERROR;
+/* if first time, start search in bit buffer */
+if (state->mode != SYNC) {
+state->mode = SYNC;
+state->hold <<= state->bits & 7;
+state->bits -= state->bits & 7;
+len = 0;
+while (state->bits >= 8) {
+buf[len++] = (unsigned char)(state->hold);
+state->hold >>= 8;
+state->bits -= 8;
+}
+state->have = 0;
+syncsearch(&(state->have), buf, len);
+}
+/* search available input */
+len = syncsearch(&(state->have), strm->next_in, strm->avail_in);
+strm->avail_in -= len;
+strm->next_in += len;
+strm->total_in += len;
+/* return no joy or set up to restart inflate() on a new block */
+if (state->have != 4) return Z_DATA_ERROR;
+in = strm->total_in;  out = strm->total_out;
+inflateReset(strm);
+strm->total_in = in;  strm->total_out = out;
+state->mode = TYPE;
+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(strm)
+z_streamp strm;
+{
+struct inflate_state FAR *state;
+if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
+state = (struct inflate_state FAR *)strm->state;
+return state->mode == STORED && state->bits == 0;
+}
+int ZEXPORT inflateCopy(dest, source)
+z_streamp dest;
+z_streamp source;
+{
+struct inflate_state FAR *state;
+struct inflate_state FAR *copy;
+unsigned char FAR *window;
+unsigned wsize;
+/* check input */
+if (dest == Z_NULL || source == Z_NULL || source->state == Z_NULL ||
+source->zalloc == (alloc_func)0 || source->zfree == (free_func)0)
+return Z_STREAM_ERROR;
+state = (struct inflate_state FAR *)source->state;
+/* allocate space */
+copy = (struct inflate_state FAR *)
+ZALLOC(source, 1, sizeof(struct inflate_state));
+if (copy == Z_NULL) return Z_MEM_ERROR;
+window = Z_NULL;
+if (state->window != Z_NULL) {
+window = (unsigned char FAR *)
+ZALLOC(source, 1U << state->wbits, sizeof(unsigned char));
+if (window == Z_NULL) {
+ZFREE(source, copy);
+return Z_MEM_ERROR;
+}
+}
+/* copy state */
+zmemcpy((voidpf)dest, (voidpf)source, sizeof(z_stream));
+zmemcpy((voidpf)copy, (voidpf)state, sizeof(struct inflate_state));
+if (state->lencode >= state->codes &&
+state->lencode <= state->codes + ENOUGH - 1) {
+copy->lencode = copy->codes + (state->lencode - state->codes);
+copy->distcode = copy->codes + (state->distcode - state->codes);
+}
+copy->next = copy->codes + (state->next - state->codes);
+if (window != Z_NULL) {
+wsize = 1U << state->wbits;
+zmemcpy(window, state->window, wsize);
+}
+copy->window = window;
+dest->state = (struct internal_state FAR *)copy;
+return Z_OK;
+}
+int ZEXPORT inflateUndermine(strm, subvert)
+z_streamp strm;
+int subvert;
+{
+struct inflate_state FAR *state;
+if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
+state = (struct inflate_state FAR *)strm->state;
+state->sane = !subvert;
+#ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR
+return Z_OK;
+#else
+state->sane = 1;
+return Z_DATA_ERROR;
+#endif
+}
+long ZEXPORT inflateMark(strm)
+z_streamp strm;
+{
+struct inflate_state FAR *state;
+if (strm == Z_NULL || strm->state == Z_NULL) return -1L << 16;
+state = (struct inflate_state FAR *)strm->state;
+return ((long)(state->back) << 16) +
+(state->mode == COPY ? state->length :
+(state->mode == MATCH ? state->was - state->length : 0));
+}

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modules/zlib/src/inflate.c