Chris@4: /* inflate.c -- zlib decompression
Chris@4:  * Copyright (C) 1995-2012 Mark Adler
Chris@4:  * For conditions of distribution and use, see copyright notice in zlib.h
Chris@4:  */
Chris@4: 
Chris@4: /*
Chris@4:  * Change history:
Chris@4:  *
Chris@4:  * 1.2.beta0    24 Nov 2002
Chris@4:  * - First version -- complete rewrite of inflate to simplify code, avoid
Chris@4:  *   creation of window when not needed, minimize use of window when it is
Chris@4:  *   needed, make inffast.c even faster, implement gzip decoding, and to
Chris@4:  *   improve code readability and style over the previous zlib inflate code
Chris@4:  *
Chris@4:  * 1.2.beta1    25 Nov 2002
Chris@4:  * - Use pointers for available input and output checking in inffast.c
Chris@4:  * - Remove input and output counters in inffast.c
Chris@4:  * - Change inffast.c entry and loop from avail_in >= 7 to >= 6
Chris@4:  * - Remove unnecessary second byte pull from length extra in inffast.c
Chris@4:  * - Unroll direct copy to three copies per loop in inffast.c
Chris@4:  *
Chris@4:  * 1.2.beta2    4 Dec 2002
Chris@4:  * - Change external routine names to reduce potential conflicts
Chris@4:  * - Correct filename to inffixed.h for fixed tables in inflate.c
Chris@4:  * - Make hbuf[] unsigned char to match parameter type in inflate.c
Chris@4:  * - Change strm->next_out[-state->offset] to *(strm->next_out - state->offset)
Chris@4:  *   to avoid negation problem on Alphas (64 bit) in inflate.c
Chris@4:  *
Chris@4:  * 1.2.beta3    22 Dec 2002
Chris@4:  * - Add comments on state->bits assertion in inffast.c
Chris@4:  * - Add comments on op field in inftrees.h
Chris@4:  * - Fix bug in reuse of allocated window after inflateReset()
Chris@4:  * - Remove bit fields--back to byte structure for speed
Chris@4:  * - Remove distance extra == 0 check in inflate_fast()--only helps for lengths
Chris@4:  * - Change post-increments to pre-increments in inflate_fast(), PPC biased?
Chris@4:  * - Add compile time option, POSTINC, to use post-increments instead (Intel?)
Chris@4:  * - Make MATCH copy in inflate() much faster for when inflate_fast() not used
Chris@4:  * - Use local copies of stream next and avail values, as well as local bit
Chris@4:  *   buffer and bit count in inflate()--for speed when inflate_fast() not used
Chris@4:  *
Chris@4:  * 1.2.beta4    1 Jan 2003
Chris@4:  * - Split ptr - 257 statements in inflate_table() to avoid compiler warnings
Chris@4:  * - Move a comment on output buffer sizes from inffast.c to inflate.c
Chris@4:  * - Add comments in inffast.c to introduce the inflate_fast() routine
Chris@4:  * - Rearrange window copies in inflate_fast() for speed and simplification
Chris@4:  * - Unroll last copy for window match in inflate_fast()
Chris@4:  * - Use local copies of window variables in inflate_fast() for speed
Chris@4:  * - Pull out common wnext == 0 case for speed in inflate_fast()
Chris@4:  * - Make op and len in inflate_fast() unsigned for consistency
Chris@4:  * - Add FAR to lcode and dcode declarations in inflate_fast()
Chris@4:  * - Simplified bad distance check in inflate_fast()
Chris@4:  * - Added inflateBackInit(), inflateBack(), and inflateBackEnd() in new
Chris@4:  *   source file infback.c to provide a call-back interface to inflate for
Chris@4:  *   programs like gzip and unzip -- uses window as output buffer to avoid
Chris@4:  *   window copying
Chris@4:  *
Chris@4:  * 1.2.beta5    1 Jan 2003
Chris@4:  * - Improved inflateBack() interface to allow the caller to provide initial
Chris@4:  *   input in strm.
Chris@4:  * - Fixed stored blocks bug in inflateBack()
Chris@4:  *
Chris@4:  * 1.2.beta6    4 Jan 2003
Chris@4:  * - Added comments in inffast.c on effectiveness of POSTINC
Chris@4:  * - Typecasting all around to reduce compiler warnings
Chris@4:  * - Changed loops from while (1) or do {} while (1) to for (;;), again to
Chris@4:  *   make compilers happy
Chris@4:  * - Changed type of window in inflateBackInit() to unsigned char *
Chris@4:  *
Chris@4:  * 1.2.beta7    27 Jan 2003
Chris@4:  * - Changed many types to unsigned or unsigned short to avoid warnings
Chris@4:  * - Added inflateCopy() function
Chris@4:  *
Chris@4:  * 1.2.0        9 Mar 2003
Chris@4:  * - Changed inflateBack() interface to provide separate opaque descriptors
Chris@4:  *   for the in() and out() functions
Chris@4:  * - Changed inflateBack() argument and in_func typedef to swap the length
Chris@4:  *   and buffer address return values for the input function
Chris@4:  * - Check next_in and next_out for Z_NULL on entry to inflate()
Chris@4:  *
Chris@4:  * The history for versions after 1.2.0 are in ChangeLog in zlib distribution.
Chris@4:  */
Chris@4: 
Chris@4: #include "zutil.h"
Chris@4: #include "inftrees.h"
Chris@4: #include "inflate.h"
Chris@4: #include "inffast.h"
Chris@4: 
Chris@4: #ifdef MAKEFIXED
Chris@4: #  ifndef BUILDFIXED
Chris@4: #    define BUILDFIXED
Chris@4: #  endif
Chris@4: #endif
Chris@4: 
Chris@4: /* function prototypes */
Chris@4: local void fixedtables OF((struct inflate_state FAR *state));
Chris@4: local int updatewindow OF((z_streamp strm, unsigned out));
Chris@4: #ifdef BUILDFIXED
Chris@4:    void makefixed OF((void));
Chris@4: #endif
Chris@4: local unsigned syncsearch OF((unsigned FAR *have, unsigned char FAR *buf,
Chris@4:                               unsigned len));
Chris@4: 
Chris@4: int ZEXPORT inflateResetKeep(strm)
Chris@4: z_streamp strm;
Chris@4: {
Chris@4:     struct inflate_state FAR *state;
Chris@4: 
Chris@4:     if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
Chris@4:     state = (struct inflate_state FAR *)strm->state;
Chris@4:     strm->total_in = strm->total_out = state->total = 0;
Chris@4:     strm->msg = Z_NULL;
Chris@4:     if (state->wrap)        /* to support ill-conceived Java test suite */
Chris@4:         strm->adler = state->wrap & 1;
Chris@4:     state->mode = HEAD;
Chris@4:     state->last = 0;
Chris@4:     state->havedict = 0;
Chris@4:     state->dmax = 32768U;
Chris@4:     state->head = Z_NULL;
Chris@4:     state->hold = 0;
Chris@4:     state->bits = 0;
Chris@4:     state->lencode = state->distcode = state->next = state->codes;
Chris@4:     state->sane = 1;
Chris@4:     state->back = -1;
Chris@4:     Tracev((stderr, "inflate: reset\n"));
Chris@4:     return Z_OK;
Chris@4: }
Chris@4: 
Chris@4: int ZEXPORT inflateReset(strm)
Chris@4: z_streamp strm;
Chris@4: {
Chris@4:     struct inflate_state FAR *state;
Chris@4: 
Chris@4:     if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
Chris@4:     state = (struct inflate_state FAR *)strm->state;
Chris@4:     state->wsize = 0;
Chris@4:     state->whave = 0;
Chris@4:     state->wnext = 0;
Chris@4:     return inflateResetKeep(strm);
Chris@4: }
Chris@4: 
Chris@4: int ZEXPORT inflateReset2(strm, windowBits)
Chris@4: z_streamp strm;
Chris@4: int windowBits;
Chris@4: {
Chris@4:     int wrap;
Chris@4:     struct inflate_state FAR *state;
Chris@4: 
Chris@4:     /* get the state */
Chris@4:     if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
Chris@4:     state = (struct inflate_state FAR *)strm->state;
Chris@4: 
Chris@4:     /* extract wrap request from windowBits parameter */
Chris@4:     if (windowBits < 0) {
Chris@4:         wrap = 0;
Chris@4:         windowBits = -windowBits;
Chris@4:     }
Chris@4:     else {
Chris@4:         wrap = (windowBits >> 4) + 1;
Chris@4: #ifdef GUNZIP
Chris@4:         if (windowBits < 48)
Chris@4:             windowBits &= 15;
Chris@4: #endif
Chris@4:     }
Chris@4: 
Chris@4:     /* set number of window bits, free window if different */
Chris@4:     if (windowBits && (windowBits < 8 || windowBits > 15))
Chris@4:         return Z_STREAM_ERROR;
Chris@4:     if (state->window != Z_NULL && state->wbits != (unsigned)windowBits) {
Chris@4:         ZFREE(strm, state->window);
Chris@4:         state->window = Z_NULL;
Chris@4:     }
Chris@4: 
Chris@4:     /* update state and reset the rest of it */
Chris@4:     state->wrap = wrap;
Chris@4:     state->wbits = (unsigned)windowBits;
Chris@4:     return inflateReset(strm);
Chris@4: }
Chris@4: 
Chris@4: int ZEXPORT inflateInit2_(strm, windowBits, version, stream_size)
Chris@4: z_streamp strm;
Chris@4: int windowBits;
Chris@4: const char *version;
Chris@4: int stream_size;
Chris@4: {
Chris@4:     int ret;
Chris@4:     struct inflate_state FAR *state;
Chris@4: 
Chris@4:     if (version == Z_NULL || version[0] != ZLIB_VERSION[0] ||
Chris@4:         stream_size != (int)(sizeof(z_stream)))
Chris@4:         return Z_VERSION_ERROR;
Chris@4:     if (strm == Z_NULL) return Z_STREAM_ERROR;
Chris@4:     strm->msg = Z_NULL;                 /* in case we return an error */
Chris@4:     if (strm->zalloc == (alloc_func)0) {
Chris@4: #ifdef Z_SOLO
Chris@4:         return Z_STREAM_ERROR;
Chris@4: #else
Chris@4:         strm->zalloc = zcalloc;
Chris@4:         strm->opaque = (voidpf)0;
Chris@4: #endif
Chris@4:     }
Chris@4:     if (strm->zfree == (free_func)0)
Chris@4: #ifdef Z_SOLO
Chris@4:         return Z_STREAM_ERROR;
Chris@4: #else
Chris@4:         strm->zfree = zcfree;
Chris@4: #endif
Chris@4:     state = (struct inflate_state FAR *)
Chris@4:             ZALLOC(strm, 1, sizeof(struct inflate_state));
Chris@4:     if (state == Z_NULL) return Z_MEM_ERROR;
Chris@4:     Tracev((stderr, "inflate: allocated\n"));
Chris@4:     strm->state = (struct internal_state FAR *)state;
Chris@4:     state->window = Z_NULL;
Chris@4:     ret = inflateReset2(strm, windowBits);
Chris@4:     if (ret != Z_OK) {
Chris@4:         ZFREE(strm, state);
Chris@4:         strm->state = Z_NULL;
Chris@4:     }
Chris@4:     return ret;
Chris@4: }
Chris@4: 
Chris@4: int ZEXPORT inflateInit_(strm, version, stream_size)
Chris@4: z_streamp strm;
Chris@4: const char *version;
Chris@4: int stream_size;
Chris@4: {
Chris@4:     return inflateInit2_(strm, DEF_WBITS, version, stream_size);
Chris@4: }
Chris@4: 
Chris@4: int ZEXPORT inflatePrime(strm, bits, value)
Chris@4: z_streamp strm;
Chris@4: int bits;
Chris@4: int value;
Chris@4: {
Chris@4:     struct inflate_state FAR *state;
Chris@4: 
Chris@4:     if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
Chris@4:     state = (struct inflate_state FAR *)strm->state;
Chris@4:     if (bits < 0) {
Chris@4:         state->hold = 0;
Chris@4:         state->bits = 0;
Chris@4:         return Z_OK;
Chris@4:     }
Chris@4:     if (bits > 16 || state->bits + bits > 32) return Z_STREAM_ERROR;
Chris@4:     value &= (1L << bits) - 1;
Chris@4:     state->hold += value << state->bits;
Chris@4:     state->bits += bits;
Chris@4:     return Z_OK;
Chris@4: }
Chris@4: 
Chris@4: /*
Chris@4:    Return state with length and distance decoding tables and index sizes set to
Chris@4:    fixed code decoding.  Normally this returns fixed tables from inffixed.h.
Chris@4:    If BUILDFIXED is defined, then instead this routine builds the tables the
Chris@4:    first time it's called, and returns those tables the first time and
Chris@4:    thereafter.  This reduces the size of the code by about 2K bytes, in
Chris@4:    exchange for a little execution time.  However, BUILDFIXED should not be
Chris@4:    used for threaded applications, since the rewriting of the tables and virgin
Chris@4:    may not be thread-safe.
Chris@4:  */
Chris@4: local void fixedtables(state)
Chris@4: struct inflate_state FAR *state;
Chris@4: {
Chris@4: #ifdef BUILDFIXED
Chris@4:     static int virgin = 1;
Chris@4:     static code *lenfix, *distfix;
Chris@4:     static code fixed[544];
Chris@4: 
Chris@4:     /* build fixed huffman tables if first call (may not be thread safe) */
Chris@4:     if (virgin) {
Chris@4:         unsigned sym, bits;
Chris@4:         static code *next;
Chris@4: 
Chris@4:         /* literal/length table */
Chris@4:         sym = 0;
Chris@4:         while (sym < 144) state->lens[sym++] = 8;
Chris@4:         while (sym < 256) state->lens[sym++] = 9;
Chris@4:         while (sym < 280) state->lens[sym++] = 7;
Chris@4:         while (sym < 288) state->lens[sym++] = 8;
Chris@4:         next = fixed;
Chris@4:         lenfix = next;
Chris@4:         bits = 9;
Chris@4:         inflate_table(LENS, state->lens, 288, &(next), &(bits), state->work);
Chris@4: 
Chris@4:         /* distance table */
Chris@4:         sym = 0;
Chris@4:         while (sym < 32) state->lens[sym++] = 5;
Chris@4:         distfix = next;
Chris@4:         bits = 5;
Chris@4:         inflate_table(DISTS, state->lens, 32, &(next), &(bits), state->work);
Chris@4: 
Chris@4:         /* do this just once */
Chris@4:         virgin = 0;
Chris@4:     }
Chris@4: #else /* !BUILDFIXED */
Chris@4: #   include "inffixed.h"
Chris@4: #endif /* BUILDFIXED */
Chris@4:     state->lencode = lenfix;
Chris@4:     state->lenbits = 9;
Chris@4:     state->distcode = distfix;
Chris@4:     state->distbits = 5;
Chris@4: }
Chris@4: 
Chris@4: #ifdef MAKEFIXED
Chris@4: #include <stdio.h>
Chris@4: 
Chris@4: /*
Chris@4:    Write out the inffixed.h that is #include'd above.  Defining MAKEFIXED also
Chris@4:    defines BUILDFIXED, so the tables are built on the fly.  makefixed() writes
Chris@4:    those tables to stdout, which would be piped to inffixed.h.  A small program
Chris@4:    can simply call makefixed to do this:
Chris@4: 
Chris@4:     void makefixed(void);
Chris@4: 
Chris@4:     int main(void)
Chris@4:     {
Chris@4:         makefixed();
Chris@4:         return 0;
Chris@4:     }
Chris@4: 
Chris@4:    Then that can be linked with zlib built with MAKEFIXED defined and run:
Chris@4: 
Chris@4:     a.out > inffixed.h
Chris@4:  */
Chris@4: void makefixed()
Chris@4: {
Chris@4:     unsigned low, size;
Chris@4:     struct inflate_state state;
Chris@4: 
Chris@4:     fixedtables(&state);
Chris@4:     puts("    /* inffixed.h -- table for decoding fixed codes");
Chris@4:     puts("     * Generated automatically by makefixed().");
Chris@4:     puts("     */");
Chris@4:     puts("");
Chris@4:     puts("    /* WARNING: this file should *not* be used by applications.");
Chris@4:     puts("       It is part of the implementation of this library and is");
Chris@4:     puts("       subject to change. Applications should only use zlib.h.");
Chris@4:     puts("     */");
Chris@4:     puts("");
Chris@4:     size = 1U << 9;
Chris@4:     printf("    static const code lenfix[%u] = {", size);
Chris@4:     low = 0;
Chris@4:     for (;;) {
Chris@4:         if ((low % 7) == 0) printf("\n        ");
Chris@4:         printf("{%u,%u,%d}", (low & 127) == 99 ? 64 : state.lencode[low].op,
Chris@4:                state.lencode[low].bits, state.lencode[low].val);
Chris@4:         if (++low == size) break;
Chris@4:         putchar(',');
Chris@4:     }
Chris@4:     puts("\n    };");
Chris@4:     size = 1U << 5;
Chris@4:     printf("\n    static const code distfix[%u] = {", size);
Chris@4:     low = 0;
Chris@4:     for (;;) {
Chris@4:         if ((low % 6) == 0) printf("\n        ");
Chris@4:         printf("{%u,%u,%d}", state.distcode[low].op, state.distcode[low].bits,
Chris@4:                state.distcode[low].val);
Chris@4:         if (++low == size) break;
Chris@4:         putchar(',');
Chris@4:     }
Chris@4:     puts("\n    };");
Chris@4: }
Chris@4: #endif /* MAKEFIXED */
Chris@4: 
Chris@4: /*
Chris@4:    Update the window with the last wsize (normally 32K) bytes written before
Chris@4:    returning.  If window does not exist yet, create it.  This is only called
Chris@4:    when a window is already in use, or when output has been written during this
Chris@4:    inflate call, but the end of the deflate stream has not been reached yet.
Chris@4:    It is also called to create a window for dictionary data when a dictionary
Chris@4:    is loaded.
Chris@4: 
Chris@4:    Providing output buffers larger than 32K to inflate() should provide a speed
Chris@4:    advantage, since only the last 32K of output is copied to the sliding window
Chris@4:    upon return from inflate(), and since all distances after the first 32K of
Chris@4:    output will fall in the output data, making match copies simpler and faster.
Chris@4:    The advantage may be dependent on the size of the processor's data caches.
Chris@4:  */
Chris@4: local int updatewindow(strm, out)
Chris@4: z_streamp strm;
Chris@4: unsigned out;
Chris@4: {
Chris@4:     struct inflate_state FAR *state;
Chris@4:     unsigned copy, dist;
Chris@4: 
Chris@4:     state = (struct inflate_state FAR *)strm->state;
Chris@4: 
Chris@4:     /* if it hasn't been done already, allocate space for the window */
Chris@4:     if (state->window == Z_NULL) {
Chris@4:         state->window = (unsigned char FAR *)
Chris@4:                         ZALLOC(strm, 1U << state->wbits,
Chris@4:                                sizeof(unsigned char));
Chris@4:         if (state->window == Z_NULL) return 1;
Chris@4:     }
Chris@4: 
Chris@4:     /* if window not in use yet, initialize */
Chris@4:     if (state->wsize == 0) {
Chris@4:         state->wsize = 1U << state->wbits;
Chris@4:         state->wnext = 0;
Chris@4:         state->whave = 0;
Chris@4:     }
Chris@4: 
Chris@4:     /* copy state->wsize or less output bytes into the circular window */
Chris@4:     copy = out - strm->avail_out;
Chris@4:     if (copy >= state->wsize) {
Chris@4:         zmemcpy(state->window, strm->next_out - state->wsize, state->wsize);
Chris@4:         state->wnext = 0;
Chris@4:         state->whave = state->wsize;
Chris@4:     }
Chris@4:     else {
Chris@4:         dist = state->wsize - state->wnext;
Chris@4:         if (dist > copy) dist = copy;
Chris@4:         zmemcpy(state->window + state->wnext, strm->next_out - copy, dist);
Chris@4:         copy -= dist;
Chris@4:         if (copy) {
Chris@4:             zmemcpy(state->window, strm->next_out - copy, copy);
Chris@4:             state->wnext = copy;
Chris@4:             state->whave = state->wsize;
Chris@4:         }
Chris@4:         else {
Chris@4:             state->wnext += dist;
Chris@4:             if (state->wnext == state->wsize) state->wnext = 0;
Chris@4:             if (state->whave < state->wsize) state->whave += dist;
Chris@4:         }
Chris@4:     }
Chris@4:     return 0;
Chris@4: }
Chris@4: 
Chris@4: /* Macros for inflate(): */
Chris@4: 
Chris@4: /* check function to use adler32() for zlib or crc32() for gzip */
Chris@4: #ifdef GUNZIP
Chris@4: #  define UPDATE(check, buf, len) \
Chris@4:     (state->flags ? crc32(check, buf, len) : adler32(check, buf, len))
Chris@4: #else
Chris@4: #  define UPDATE(check, buf, len) adler32(check, buf, len)
Chris@4: #endif
Chris@4: 
Chris@4: /* check macros for header crc */
Chris@4: #ifdef GUNZIP
Chris@4: #  define CRC2(check, word) \
Chris@4:     do { \
Chris@4:         hbuf[0] = (unsigned char)(word); \
Chris@4:         hbuf[1] = (unsigned char)((word) >> 8); \
Chris@4:         check = crc32(check, hbuf, 2); \
Chris@4:     } while (0)
Chris@4: 
Chris@4: #  define CRC4(check, word) \
Chris@4:     do { \
Chris@4:         hbuf[0] = (unsigned char)(word); \
Chris@4:         hbuf[1] = (unsigned char)((word) >> 8); \
Chris@4:         hbuf[2] = (unsigned char)((word) >> 16); \
Chris@4:         hbuf[3] = (unsigned char)((word) >> 24); \
Chris@4:         check = crc32(check, hbuf, 4); \
Chris@4:     } while (0)
Chris@4: #endif
Chris@4: 
Chris@4: /* Load registers with state in inflate() for speed */
Chris@4: #define LOAD() \
Chris@4:     do { \
Chris@4:         put = strm->next_out; \
Chris@4:         left = strm->avail_out; \
Chris@4:         next = strm->next_in; \
Chris@4:         have = strm->avail_in; \
Chris@4:         hold = state->hold; \
Chris@4:         bits = state->bits; \
Chris@4:     } while (0)
Chris@4: 
Chris@4: /* Restore state from registers in inflate() */
Chris@4: #define RESTORE() \
Chris@4:     do { \
Chris@4:         strm->next_out = put; \
Chris@4:         strm->avail_out = left; \
Chris@4:         strm->next_in = next; \
Chris@4:         strm->avail_in = have; \
Chris@4:         state->hold = hold; \
Chris@4:         state->bits = bits; \
Chris@4:     } while (0)
Chris@4: 
Chris@4: /* Clear the input bit accumulator */
Chris@4: #define INITBITS() \
Chris@4:     do { \
Chris@4:         hold = 0; \
Chris@4:         bits = 0; \
Chris@4:     } while (0)
Chris@4: 
Chris@4: /* Get a byte of input into the bit accumulator, or return from inflate()
Chris@4:    if there is no input available. */
Chris@4: #define PULLBYTE() \
Chris@4:     do { \
Chris@4:         if (have == 0) goto inf_leave; \
Chris@4:         have--; \
Chris@4:         hold += (unsigned long)(*next++) << bits; \
Chris@4:         bits += 8; \
Chris@4:     } while (0)
Chris@4: 
Chris@4: /* Assure that there are at least n bits in the bit accumulator.  If there is
Chris@4:    not enough available input to do that, then return from inflate(). */
Chris@4: #define NEEDBITS(n) \
Chris@4:     do { \
Chris@4:         while (bits < (unsigned)(n)) \
Chris@4:             PULLBYTE(); \
Chris@4:     } while (0)
Chris@4: 
Chris@4: /* Return the low n bits of the bit accumulator (n < 16) */
Chris@4: #define BITS(n) \
Chris@4:     ((unsigned)hold & ((1U << (n)) - 1))
Chris@4: 
Chris@4: /* Remove n bits from the bit accumulator */
Chris@4: #define DROPBITS(n) \
Chris@4:     do { \
Chris@4:         hold >>= (n); \
Chris@4:         bits -= (unsigned)(n); \
Chris@4:     } while (0)
Chris@4: 
Chris@4: /* Remove zero to seven bits as needed to go to a byte boundary */
Chris@4: #define BYTEBITS() \
Chris@4:     do { \
Chris@4:         hold >>= bits & 7; \
Chris@4:         bits -= bits & 7; \
Chris@4:     } while (0)
Chris@4: 
Chris@4: /*
Chris@4:    inflate() uses a state machine to process as much input data and generate as
Chris@4:    much output data as possible before returning.  The state machine is
Chris@4:    structured roughly as follows:
Chris@4: 
Chris@4:     for (;;) switch (state) {
Chris@4:     ...
Chris@4:     case STATEn:
Chris@4:         if (not enough input data or output space to make progress)
Chris@4:             return;
Chris@4:         ... make progress ...
Chris@4:         state = STATEm;
Chris@4:         break;
Chris@4:     ...
Chris@4:     }
Chris@4: 
Chris@4:    so when inflate() is called again, the same case is attempted again, and
Chris@4:    if the appropriate resources are provided, the machine proceeds to the
Chris@4:    next state.  The NEEDBITS() macro is usually the way the state evaluates
Chris@4:    whether it can proceed or should return.  NEEDBITS() does the return if
Chris@4:    the requested bits are not available.  The typical use of the BITS macros
Chris@4:    is:
Chris@4: 
Chris@4:         NEEDBITS(n);
Chris@4:         ... do something with BITS(n) ...
Chris@4:         DROPBITS(n);
Chris@4: 
Chris@4:    where NEEDBITS(n) either returns from inflate() if there isn't enough
Chris@4:    input left to load n bits into the accumulator, or it continues.  BITS(n)
Chris@4:    gives the low n bits in the accumulator.  When done, DROPBITS(n) drops
Chris@4:    the low n bits off the accumulator.  INITBITS() clears the accumulator
Chris@4:    and sets the number of available bits to zero.  BYTEBITS() discards just
Chris@4:    enough bits to put the accumulator on a byte boundary.  After BYTEBITS()
Chris@4:    and a NEEDBITS(8), then BITS(8) would return the next byte in the stream.
Chris@4: 
Chris@4:    NEEDBITS(n) uses PULLBYTE() to get an available byte of input, or to return
Chris@4:    if there is no input available.  The decoding of variable length codes uses
Chris@4:    PULLBYTE() directly in order to pull just enough bytes to decode the next
Chris@4:    code, and no more.
Chris@4: 
Chris@4:    Some states loop until they get enough input, making sure that enough
Chris@4:    state information is maintained to continue the loop where it left off
Chris@4:    if NEEDBITS() returns in the loop.  For example, want, need, and keep
Chris@4:    would all have to actually be part of the saved state in case NEEDBITS()
Chris@4:    returns:
Chris@4: 
Chris@4:     case STATEw:
Chris@4:         while (want < need) {
Chris@4:             NEEDBITS(n);
Chris@4:             keep[want++] = BITS(n);
Chris@4:             DROPBITS(n);
Chris@4:         }
Chris@4:         state = STATEx;
Chris@4:     case STATEx:
Chris@4: 
Chris@4:    As shown above, if the next state is also the next case, then the break
Chris@4:    is omitted.
Chris@4: 
Chris@4:    A state may also return if there is not enough output space available to
Chris@4:    complete that state.  Those states are copying stored data, writing a
Chris@4:    literal byte, and copying a matching string.
Chris@4: 
Chris@4:    When returning, a "goto inf_leave" is used to update the total counters,
Chris@4:    update the check value, and determine whether any progress has been made
Chris@4:    during that inflate() call in order to return the proper return code.
Chris@4:    Progress is defined as a change in either strm->avail_in or strm->avail_out.
Chris@4:    When there is a window, goto inf_leave will update the window with the last
Chris@4:    output written.  If a goto inf_leave occurs in the middle of decompression
Chris@4:    and there is no window currently, goto inf_leave will create one and copy
Chris@4:    output to the window for the next call of inflate().
Chris@4: 
Chris@4:    In this implementation, the flush parameter of inflate() only affects the
Chris@4:    return code (per zlib.h).  inflate() always writes as much as possible to
Chris@4:    strm->next_out, given the space available and the provided input--the effect
Chris@4:    documented in zlib.h of Z_SYNC_FLUSH.  Furthermore, inflate() always defers
Chris@4:    the allocation of and copying into a sliding window until necessary, which
Chris@4:    provides the effect documented in zlib.h for Z_FINISH when the entire input
Chris@4:    stream available.  So the only thing the flush parameter actually does is:
Chris@4:    when flush is set to Z_FINISH, inflate() cannot return Z_OK.  Instead it
Chris@4:    will return Z_BUF_ERROR if it has not reached the end of the stream.
Chris@4:  */
Chris@4: 
Chris@4: int ZEXPORT inflate(strm, flush)
Chris@4: z_streamp strm;
Chris@4: int flush;
Chris@4: {
Chris@4:     struct inflate_state FAR *state;
Chris@4:     unsigned char FAR *next;    /* next input */
Chris@4:     unsigned char FAR *put;     /* next output */
Chris@4:     unsigned have, left;        /* available input and output */
Chris@4:     unsigned long hold;         /* bit buffer */
Chris@4:     unsigned bits;              /* bits in bit buffer */
Chris@4:     unsigned in, out;           /* save starting available input and output */
Chris@4:     unsigned copy;              /* number of stored or match bytes to copy */
Chris@4:     unsigned char FAR *from;    /* where to copy match bytes from */
Chris@4:     code here;                  /* current decoding table entry */
Chris@4:     code last;                  /* parent table entry */
Chris@4:     unsigned len;               /* length to copy for repeats, bits to drop */
Chris@4:     int ret;                    /* return code */
Chris@4: #ifdef GUNZIP
Chris@4:     unsigned char hbuf[4];      /* buffer for gzip header crc calculation */
Chris@4: #endif
Chris@4:     static const unsigned short order[19] = /* permutation of code lengths */
Chris@4:         {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
Chris@4: 
Chris@4:     if (strm == Z_NULL || strm->state == Z_NULL || strm->next_out == Z_NULL ||
Chris@4:         (strm->next_in == Z_NULL && strm->avail_in != 0))
Chris@4:         return Z_STREAM_ERROR;
Chris@4: 
Chris@4:     state = (struct inflate_state FAR *)strm->state;
Chris@4:     if (state->mode == TYPE) state->mode = TYPEDO;      /* skip check */
Chris@4:     LOAD();
Chris@4:     in = have;
Chris@4:     out = left;
Chris@4:     ret = Z_OK;
Chris@4:     for (;;)
Chris@4:         switch (state->mode) {
Chris@4:         case HEAD:
Chris@4:             if (state->wrap == 0) {
Chris@4:                 state->mode = TYPEDO;
Chris@4:                 break;
Chris@4:             }
Chris@4:             NEEDBITS(16);
Chris@4: #ifdef GUNZIP
Chris@4:             if ((state->wrap & 2) && hold == 0x8b1f) {  /* gzip header */
Chris@4:                 state->check = crc32(0L, Z_NULL, 0);
Chris@4:                 CRC2(state->check, hold);
Chris@4:                 INITBITS();
Chris@4:                 state->mode = FLAGS;
Chris@4:                 break;
Chris@4:             }
Chris@4:             state->flags = 0;           /* expect zlib header */
Chris@4:             if (state->head != Z_NULL)
Chris@4:                 state->head->done = -1;
Chris@4:             if (!(state->wrap & 1) ||   /* check if zlib header allowed */
Chris@4: #else
Chris@4:             if (
Chris@4: #endif
Chris@4:                 ((BITS(8) << 8) + (hold >> 8)) % 31) {
Chris@4:                 strm->msg = (char *)"incorrect header check";
Chris@4:                 state->mode = BAD;
Chris@4:                 break;
Chris@4:             }
Chris@4:             if (BITS(4) != Z_DEFLATED) {
Chris@4:                 strm->msg = (char *)"unknown compression method";
Chris@4:                 state->mode = BAD;
Chris@4:                 break;
Chris@4:             }
Chris@4:             DROPBITS(4);
Chris@4:             len = BITS(4) + 8;
Chris@4:             if (state->wbits == 0)
Chris@4:                 state->wbits = len;
Chris@4:             else if (len > state->wbits) {
Chris@4:                 strm->msg = (char *)"invalid window size";
Chris@4:                 state->mode = BAD;
Chris@4:                 break;
Chris@4:             }
Chris@4:             state->dmax = 1U << len;
Chris@4:             Tracev((stderr, "inflate:   zlib header ok\n"));
Chris@4:             strm->adler = state->check = adler32(0L, Z_NULL, 0);
Chris@4:             state->mode = hold & 0x200 ? DICTID : TYPE;
Chris@4:             INITBITS();
Chris@4:             break;
Chris@4: #ifdef GUNZIP
Chris@4:         case FLAGS:
Chris@4:             NEEDBITS(16);
Chris@4:             state->flags = (int)(hold);
Chris@4:             if ((state->flags & 0xff) != Z_DEFLATED) {
Chris@4:                 strm->msg = (char *)"unknown compression method";
Chris@4:                 state->mode = BAD;
Chris@4:                 break;
Chris@4:             }
Chris@4:             if (state->flags & 0xe000) {
Chris@4:                 strm->msg = (char *)"unknown header flags set";
Chris@4:                 state->mode = BAD;
Chris@4:                 break;
Chris@4:             }
Chris@4:             if (state->head != Z_NULL)
Chris@4:                 state->head->text = (int)((hold >> 8) & 1);
Chris@4:             if (state->flags & 0x0200) CRC2(state->check, hold);
Chris@4:             INITBITS();
Chris@4:             state->mode = TIME;
Chris@4:         case TIME:
Chris@4:             NEEDBITS(32);
Chris@4:             if (state->head != Z_NULL)
Chris@4:                 state->head->time = hold;
Chris@4:             if (state->flags & 0x0200) CRC4(state->check, hold);
Chris@4:             INITBITS();
Chris@4:             state->mode = OS;
Chris@4:         case OS:
Chris@4:             NEEDBITS(16);
Chris@4:             if (state->head != Z_NULL) {
Chris@4:                 state->head->xflags = (int)(hold & 0xff);
Chris@4:                 state->head->os = (int)(hold >> 8);
Chris@4:             }
Chris@4:             if (state->flags & 0x0200) CRC2(state->check, hold);
Chris@4:             INITBITS();
Chris@4:             state->mode = EXLEN;
Chris@4:         case EXLEN:
Chris@4:             if (state->flags & 0x0400) {
Chris@4:                 NEEDBITS(16);
Chris@4:                 state->length = (unsigned)(hold);
Chris@4:                 if (state->head != Z_NULL)
Chris@4:                     state->head->extra_len = (unsigned)hold;
Chris@4:                 if (state->flags & 0x0200) CRC2(state->check, hold);
Chris@4:                 INITBITS();
Chris@4:             }
Chris@4:             else if (state->head != Z_NULL)
Chris@4:                 state->head->extra = Z_NULL;
Chris@4:             state->mode = EXTRA;
Chris@4:         case EXTRA:
Chris@4:             if (state->flags & 0x0400) {
Chris@4:                 copy = state->length;
Chris@4:                 if (copy > have) copy = have;
Chris@4:                 if (copy) {
Chris@4:                     if (state->head != Z_NULL &&
Chris@4:                         state->head->extra != Z_NULL) {
Chris@4:                         len = state->head->extra_len - state->length;
Chris@4:                         zmemcpy(state->head->extra + len, next,
Chris@4:                                 len + copy > state->head->extra_max ?
Chris@4:                                 state->head->extra_max - len : copy);
Chris@4:                     }
Chris@4:                     if (state->flags & 0x0200)
Chris@4:                         state->check = crc32(state->check, next, copy);
Chris@4:                     have -= copy;
Chris@4:                     next += copy;
Chris@4:                     state->length -= copy;
Chris@4:                 }
Chris@4:                 if (state->length) goto inf_leave;
Chris@4:             }
Chris@4:             state->length = 0;
Chris@4:             state->mode = NAME;
Chris@4:         case NAME:
Chris@4:             if (state->flags & 0x0800) {
Chris@4:                 if (have == 0) goto inf_leave;
Chris@4:                 copy = 0;
Chris@4:                 do {
Chris@4:                     len = (unsigned)(next[copy++]);
Chris@4:                     if (state->head != Z_NULL &&
Chris@4:                             state->head->name != Z_NULL &&
Chris@4:                             state->length < state->head->name_max)
Chris@4:                         state->head->name[state->length++] = len;
Chris@4:                 } while (len && copy < have);
Chris@4:                 if (state->flags & 0x0200)
Chris@4:                     state->check = crc32(state->check, next, copy);
Chris@4:                 have -= copy;
Chris@4:                 next += copy;
Chris@4:                 if (len) goto inf_leave;
Chris@4:             }
Chris@4:             else if (state->head != Z_NULL)
Chris@4:                 state->head->name = Z_NULL;
Chris@4:             state->length = 0;
Chris@4:             state->mode = COMMENT;
Chris@4:         case COMMENT:
Chris@4:             if (state->flags & 0x1000) {
Chris@4:                 if (have == 0) goto inf_leave;
Chris@4:                 copy = 0;
Chris@4:                 do {
Chris@4:                     len = (unsigned)(next[copy++]);
Chris@4:                     if (state->head != Z_NULL &&
Chris@4:                             state->head->comment != Z_NULL &&
Chris@4:                             state->length < state->head->comm_max)
Chris@4:                         state->head->comment[state->length++] = len;
Chris@4:                 } while (len && copy < have);
Chris@4:                 if (state->flags & 0x0200)
Chris@4:                     state->check = crc32(state->check, next, copy);
Chris@4:                 have -= copy;
Chris@4:                 next += copy;
Chris@4:                 if (len) goto inf_leave;
Chris@4:             }
Chris@4:             else if (state->head != Z_NULL)
Chris@4:                 state->head->comment = Z_NULL;
Chris@4:             state->mode = HCRC;
Chris@4:         case HCRC:
Chris@4:             if (state->flags & 0x0200) {
Chris@4:                 NEEDBITS(16);
Chris@4:                 if (hold != (state->check & 0xffff)) {
Chris@4:                     strm->msg = (char *)"header crc mismatch";
Chris@4:                     state->mode = BAD;
Chris@4:                     break;
Chris@4:                 }
Chris@4:                 INITBITS();
Chris@4:             }
Chris@4:             if (state->head != Z_NULL) {
Chris@4:                 state->head->hcrc = (int)((state->flags >> 9) & 1);
Chris@4:                 state->head->done = 1;
Chris@4:             }
Chris@4:             strm->adler = state->check = crc32(0L, Z_NULL, 0);
Chris@4:             state->mode = TYPE;
Chris@4:             break;
Chris@4: #endif
Chris@4:         case DICTID:
Chris@4:             NEEDBITS(32);
Chris@4:             strm->adler = state->check = ZSWAP32(hold);
Chris@4:             INITBITS();
Chris@4:             state->mode = DICT;
Chris@4:         case DICT:
Chris@4:             if (state->havedict == 0) {
Chris@4:                 RESTORE();
Chris@4:                 return Z_NEED_DICT;
Chris@4:             }
Chris@4:             strm->adler = state->check = adler32(0L, Z_NULL, 0);
Chris@4:             state->mode = TYPE;
Chris@4:         case TYPE:
Chris@4:             if (flush == Z_BLOCK || flush == Z_TREES) goto inf_leave;
Chris@4:         case TYPEDO:
Chris@4:             if (state->last) {
Chris@4:                 BYTEBITS();
Chris@4:                 state->mode = CHECK;
Chris@4:                 break;
Chris@4:             }
Chris@4:             NEEDBITS(3);
Chris@4:             state->last = BITS(1);
Chris@4:             DROPBITS(1);
Chris@4:             switch (BITS(2)) {
Chris@4:             case 0:                             /* stored block */
Chris@4:                 Tracev((stderr, "inflate:     stored block%s\n",
Chris@4:                         state->last ? " (last)" : ""));
Chris@4:                 state->mode = STORED;
Chris@4:                 break;
Chris@4:             case 1:                             /* fixed block */
Chris@4:                 fixedtables(state);
Chris@4:                 Tracev((stderr, "inflate:     fixed codes block%s\n",
Chris@4:                         state->last ? " (last)" : ""));
Chris@4:                 state->mode = LEN_;             /* decode codes */
Chris@4:                 if (flush == Z_TREES) {
Chris@4:                     DROPBITS(2);
Chris@4:                     goto inf_leave;
Chris@4:                 }
Chris@4:                 break;
Chris@4:             case 2:                             /* dynamic block */
Chris@4:                 Tracev((stderr, "inflate:     dynamic codes block%s\n",
Chris@4:                         state->last ? " (last)" : ""));
Chris@4:                 state->mode = TABLE;
Chris@4:                 break;
Chris@4:             case 3:
Chris@4:                 strm->msg = (char *)"invalid block type";
Chris@4:                 state->mode = BAD;
Chris@4:             }
Chris@4:             DROPBITS(2);
Chris@4:             break;
Chris@4:         case STORED:
Chris@4:             BYTEBITS();                         /* go to byte boundary */
Chris@4:             NEEDBITS(32);
Chris@4:             if ((hold & 0xffff) != ((hold >> 16) ^ 0xffff)) {
Chris@4:                 strm->msg = (char *)"invalid stored block lengths";
Chris@4:                 state->mode = BAD;
Chris@4:                 break;
Chris@4:             }
Chris@4:             state->length = (unsigned)hold & 0xffff;
Chris@4:             Tracev((stderr, "inflate:       stored length %u\n",
Chris@4:                     state->length));
Chris@4:             INITBITS();
Chris@4:             state->mode = COPY_;
Chris@4:             if (flush == Z_TREES) goto inf_leave;
Chris@4:         case COPY_:
Chris@4:             state->mode = COPY;
Chris@4:         case COPY:
Chris@4:             copy = state->length;
Chris@4:             if (copy) {
Chris@4:                 if (copy > have) copy = have;
Chris@4:                 if (copy > left) copy = left;
Chris@4:                 if (copy == 0) goto inf_leave;
Chris@4:                 zmemcpy(put, next, copy);
Chris@4:                 have -= copy;
Chris@4:                 next += copy;
Chris@4:                 left -= copy;
Chris@4:                 put += copy;
Chris@4:                 state->length -= copy;
Chris@4:                 break;
Chris@4:             }
Chris@4:             Tracev((stderr, "inflate:       stored end\n"));
Chris@4:             state->mode = TYPE;
Chris@4:             break;
Chris@4:         case TABLE:
Chris@4:             NEEDBITS(14);
Chris@4:             state->nlen = BITS(5) + 257;
Chris@4:             DROPBITS(5);
Chris@4:             state->ndist = BITS(5) + 1;
Chris@4:             DROPBITS(5);
Chris@4:             state->ncode = BITS(4) + 4;
Chris@4:             DROPBITS(4);
Chris@4: #ifndef PKZIP_BUG_WORKAROUND
Chris@4:             if (state->nlen > 286 || state->ndist > 30) {
Chris@4:                 strm->msg = (char *)"too many length or distance symbols";
Chris@4:                 state->mode = BAD;
Chris@4:                 break;
Chris@4:             }
Chris@4: #endif
Chris@4:             Tracev((stderr, "inflate:       table sizes ok\n"));
Chris@4:             state->have = 0;
Chris@4:             state->mode = LENLENS;
Chris@4:         case LENLENS:
Chris@4:             while (state->have < state->ncode) {
Chris@4:                 NEEDBITS(3);
Chris@4:                 state->lens[order[state->have++]] = (unsigned short)BITS(3);
Chris@4:                 DROPBITS(3);
Chris@4:             }
Chris@4:             while (state->have < 19)
Chris@4:                 state->lens[order[state->have++]] = 0;
Chris@4:             state->next = state->codes;
Chris@4:             state->lencode = (code const FAR *)(state->next);
Chris@4:             state->lenbits = 7;
Chris@4:             ret = inflate_table(CODES, state->lens, 19, &(state->next),
Chris@4:                                 &(state->lenbits), state->work);
Chris@4:             if (ret) {
Chris@4:                 strm->msg = (char *)"invalid code lengths set";
Chris@4:                 state->mode = BAD;
Chris@4:                 break;
Chris@4:             }
Chris@4:             Tracev((stderr, "inflate:       code lengths ok\n"));
Chris@4:             state->have = 0;
Chris@4:             state->mode = CODELENS;
Chris@4:         case CODELENS:
Chris@4:             while (state->have < state->nlen + state->ndist) {
Chris@4:                 for (;;) {
Chris@4:                     here = state->lencode[BITS(state->lenbits)];
Chris@4:                     if ((unsigned)(here.bits) <= bits) break;
Chris@4:                     PULLBYTE();
Chris@4:                 }
Chris@4:                 if (here.val < 16) {
Chris@4:                     DROPBITS(here.bits);
Chris@4:                     state->lens[state->have++] = here.val;
Chris@4:                 }
Chris@4:                 else {
Chris@4:                     if (here.val == 16) {
Chris@4:                         NEEDBITS(here.bits + 2);
Chris@4:                         DROPBITS(here.bits);
Chris@4:                         if (state->have == 0) {
Chris@4:                             strm->msg = (char *)"invalid bit length repeat";
Chris@4:                             state->mode = BAD;
Chris@4:                             break;
Chris@4:                         }
Chris@4:                         len = state->lens[state->have - 1];
Chris@4:                         copy = 3 + BITS(2);
Chris@4:                         DROPBITS(2);
Chris@4:                     }
Chris@4:                     else if (here.val == 17) {
Chris@4:                         NEEDBITS(here.bits + 3);
Chris@4:                         DROPBITS(here.bits);
Chris@4:                         len = 0;
Chris@4:                         copy = 3 + BITS(3);
Chris@4:                         DROPBITS(3);
Chris@4:                     }
Chris@4:                     else {
Chris@4:                         NEEDBITS(here.bits + 7);
Chris@4:                         DROPBITS(here.bits);
Chris@4:                         len = 0;
Chris@4:                         copy = 11 + BITS(7);
Chris@4:                         DROPBITS(7);
Chris@4:                     }
Chris@4:                     if (state->have + copy > state->nlen + state->ndist) {
Chris@4:                         strm->msg = (char *)"invalid bit length repeat";
Chris@4:                         state->mode = BAD;
Chris@4:                         break;
Chris@4:                     }
Chris@4:                     while (copy--)
Chris@4:                         state->lens[state->have++] = (unsigned short)len;
Chris@4:                 }
Chris@4:             }
Chris@4: 
Chris@4:             /* handle error breaks in while */
Chris@4:             if (state->mode == BAD) break;
Chris@4: 
Chris@4:             /* check for end-of-block code (better have one) */
Chris@4:             if (state->lens[256] == 0) {
Chris@4:                 strm->msg = (char *)"invalid code -- missing end-of-block";
Chris@4:                 state->mode = BAD;
Chris@4:                 break;
Chris@4:             }
Chris@4: 
Chris@4:             /* build code tables -- note: do not change the lenbits or distbits
Chris@4:                values here (9 and 6) without reading the comments in inftrees.h
Chris@4:                concerning the ENOUGH constants, which depend on those values */
Chris@4:             state->next = state->codes;
Chris@4:             state->lencode = (code const FAR *)(state->next);
Chris@4:             state->lenbits = 9;
Chris@4:             ret = inflate_table(LENS, state->lens, state->nlen, &(state->next),
Chris@4:                                 &(state->lenbits), state->work);
Chris@4:             if (ret) {
Chris@4:                 strm->msg = (char *)"invalid literal/lengths set";
Chris@4:                 state->mode = BAD;
Chris@4:                 break;
Chris@4:             }
Chris@4:             state->distcode = (code const FAR *)(state->next);
Chris@4:             state->distbits = 6;
Chris@4:             ret = inflate_table(DISTS, state->lens + state->nlen, state->ndist,
Chris@4:                             &(state->next), &(state->distbits), state->work);
Chris@4:             if (ret) {
Chris@4:                 strm->msg = (char *)"invalid distances set";
Chris@4:                 state->mode = BAD;
Chris@4:                 break;
Chris@4:             }
Chris@4:             Tracev((stderr, "inflate:       codes ok\n"));
Chris@4:             state->mode = LEN_;
Chris@4:             if (flush == Z_TREES) goto inf_leave;
Chris@4:         case LEN_:
Chris@4:             state->mode = LEN;
Chris@4:         case LEN:
Chris@4:             if (have >= 6 && left >= 258) {
Chris@4:                 RESTORE();
Chris@4:                 inflate_fast(strm, out);
Chris@4:                 LOAD();
Chris@4:                 if (state->mode == TYPE)
Chris@4:                     state->back = -1;
Chris@4:                 break;
Chris@4:             }
Chris@4:             state->back = 0;
Chris@4:             for (;;) {
Chris@4:                 here = state->lencode[BITS(state->lenbits)];
Chris@4:                 if ((unsigned)(here.bits) <= bits) break;
Chris@4:                 PULLBYTE();
Chris@4:             }
Chris@4:             if (here.op && (here.op & 0xf0) == 0) {
Chris@4:                 last = here;
Chris@4:                 for (;;) {
Chris@4:                     here = state->lencode[last.val +
Chris@4:                             (BITS(last.bits + last.op) >> last.bits)];
Chris@4:                     if ((unsigned)(last.bits + here.bits) <= bits) break;
Chris@4:                     PULLBYTE();
Chris@4:                 }
Chris@4:                 DROPBITS(last.bits);
Chris@4:                 state->back += last.bits;
Chris@4:             }
Chris@4:             DROPBITS(here.bits);
Chris@4:             state->back += here.bits;
Chris@4:             state->length = (unsigned)here.val;
Chris@4:             if ((int)(here.op) == 0) {
Chris@4:                 Tracevv((stderr, here.val >= 0x20 && here.val < 0x7f ?
Chris@4:                         "inflate:         literal '%c'\n" :
Chris@4:                         "inflate:         literal 0x%02x\n", here.val));
Chris@4:                 state->mode = LIT;
Chris@4:                 break;
Chris@4:             }
Chris@4:             if (here.op & 32) {
Chris@4:                 Tracevv((stderr, "inflate:         end of block\n"));
Chris@4:                 state->back = -1;
Chris@4:                 state->mode = TYPE;
Chris@4:                 break;
Chris@4:             }
Chris@4:             if (here.op & 64) {
Chris@4:                 strm->msg = (char *)"invalid literal/length code";
Chris@4:                 state->mode = BAD;
Chris@4:                 break;
Chris@4:             }
Chris@4:             state->extra = (unsigned)(here.op) & 15;
Chris@4:             state->mode = LENEXT;
Chris@4:         case LENEXT:
Chris@4:             if (state->extra) {
Chris@4:                 NEEDBITS(state->extra);
Chris@4:                 state->length += BITS(state->extra);
Chris@4:                 DROPBITS(state->extra);
Chris@4:                 state->back += state->extra;
Chris@4:             }
Chris@4:             Tracevv((stderr, "inflate:         length %u\n", state->length));
Chris@4:             state->was = state->length;
Chris@4:             state->mode = DIST;
Chris@4:         case DIST:
Chris@4:             for (;;) {
Chris@4:                 here = state->distcode[BITS(state->distbits)];
Chris@4:                 if ((unsigned)(here.bits) <= bits) break;
Chris@4:                 PULLBYTE();
Chris@4:             }
Chris@4:             if ((here.op & 0xf0) == 0) {
Chris@4:                 last = here;
Chris@4:                 for (;;) {
Chris@4:                     here = state->distcode[last.val +
Chris@4:                             (BITS(last.bits + last.op) >> last.bits)];
Chris@4:                     if ((unsigned)(last.bits + here.bits) <= bits) break;
Chris@4:                     PULLBYTE();
Chris@4:                 }
Chris@4:                 DROPBITS(last.bits);
Chris@4:                 state->back += last.bits;
Chris@4:             }
Chris@4:             DROPBITS(here.bits);
Chris@4:             state->back += here.bits;
Chris@4:             if (here.op & 64) {
Chris@4:                 strm->msg = (char *)"invalid distance code";
Chris@4:                 state->mode = BAD;
Chris@4:                 break;
Chris@4:             }
Chris@4:             state->offset = (unsigned)here.val;
Chris@4:             state->extra = (unsigned)(here.op) & 15;
Chris@4:             state->mode = DISTEXT;
Chris@4:         case DISTEXT:
Chris@4:             if (state->extra) {
Chris@4:                 NEEDBITS(state->extra);
Chris@4:                 state->offset += BITS(state->extra);
Chris@4:                 DROPBITS(state->extra);
Chris@4:                 state->back += state->extra;
Chris@4:             }
Chris@4: #ifdef INFLATE_STRICT
Chris@4:             if (state->offset > state->dmax) {
Chris@4:                 strm->msg = (char *)"invalid distance too far back";
Chris@4:                 state->mode = BAD;
Chris@4:                 break;
Chris@4:             }
Chris@4: #endif
Chris@4:             Tracevv((stderr, "inflate:         distance %u\n", state->offset));
Chris@4:             state->mode = MATCH;
Chris@4:         case MATCH:
Chris@4:             if (left == 0) goto inf_leave;
Chris@4:             copy = out - left;
Chris@4:             if (state->offset > copy) {         /* copy from window */
Chris@4:                 copy = state->offset - copy;
Chris@4:                 if (copy > state->whave) {
Chris@4:                     if (state->sane) {
Chris@4:                         strm->msg = (char *)"invalid distance too far back";
Chris@4:                         state->mode = BAD;
Chris@4:                         break;
Chris@4:                     }
Chris@4: #ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR
Chris@4:                     Trace((stderr, "inflate.c too far\n"));
Chris@4:                     copy -= state->whave;
Chris@4:                     if (copy > state->length) copy = state->length;
Chris@4:                     if (copy > left) copy = left;
Chris@4:                     left -= copy;
Chris@4:                     state->length -= copy;
Chris@4:                     do {
Chris@4:                         *put++ = 0;
Chris@4:                     } while (--copy);
Chris@4:                     if (state->length == 0) state->mode = LEN;
Chris@4:                     break;
Chris@4: #endif
Chris@4:                 }
Chris@4:                 if (copy > state->wnext) {
Chris@4:                     copy -= state->wnext;
Chris@4:                     from = state->window + (state->wsize - copy);
Chris@4:                 }
Chris@4:                 else
Chris@4:                     from = state->window + (state->wnext - copy);
Chris@4:                 if (copy > state->length) copy = state->length;
Chris@4:             }
Chris@4:             else {                              /* copy from output */
Chris@4:                 from = put - state->offset;
Chris@4:                 copy = state->length;
Chris@4:             }
Chris@4:             if (copy > left) copy = left;
Chris@4:             left -= copy;
Chris@4:             state->length -= copy;
Chris@4:             do {
Chris@4:                 *put++ = *from++;
Chris@4:             } while (--copy);
Chris@4:             if (state->length == 0) state->mode = LEN;
Chris@4:             break;
Chris@4:         case LIT:
Chris@4:             if (left == 0) goto inf_leave;
Chris@4:             *put++ = (unsigned char)(state->length);
Chris@4:             left--;
Chris@4:             state->mode = LEN;
Chris@4:             break;
Chris@4:         case CHECK:
Chris@4:             if (state->wrap) {
Chris@4:                 NEEDBITS(32);
Chris@4:                 out -= left;
Chris@4:                 strm->total_out += out;
Chris@4:                 state->total += out;
Chris@4:                 if (out)
Chris@4:                     strm->adler = state->check =
Chris@4:                         UPDATE(state->check, put - out, out);
Chris@4:                 out = left;
Chris@4:                 if ((
Chris@4: #ifdef GUNZIP
Chris@4:                      state->flags ? hold :
Chris@4: #endif
Chris@4:                      ZSWAP32(hold)) != state->check) {
Chris@4:                     strm->msg = (char *)"incorrect data check";
Chris@4:                     state->mode = BAD;
Chris@4:                     break;
Chris@4:                 }
Chris@4:                 INITBITS();
Chris@4:                 Tracev((stderr, "inflate:   check matches trailer\n"));
Chris@4:             }
Chris@4: #ifdef GUNZIP
Chris@4:             state->mode = LENGTH;
Chris@4:         case LENGTH:
Chris@4:             if (state->wrap && state->flags) {
Chris@4:                 NEEDBITS(32);
Chris@4:                 if (hold != (state->total & 0xffffffffUL)) {
Chris@4:                     strm->msg = (char *)"incorrect length check";
Chris@4:                     state->mode = BAD;
Chris@4:                     break;
Chris@4:                 }
Chris@4:                 INITBITS();
Chris@4:                 Tracev((stderr, "inflate:   length matches trailer\n"));
Chris@4:             }
Chris@4: #endif
Chris@4:             state->mode = DONE;
Chris@4:         case DONE:
Chris@4:             ret = Z_STREAM_END;
Chris@4:             goto inf_leave;
Chris@4:         case BAD:
Chris@4:             ret = Z_DATA_ERROR;
Chris@4:             goto inf_leave;
Chris@4:         case MEM:
Chris@4:             return Z_MEM_ERROR;
Chris@4:         case SYNC:
Chris@4:         default:
Chris@4:             return Z_STREAM_ERROR;
Chris@4:         }
Chris@4: 
Chris@4:     /*
Chris@4:        Return from inflate(), updating the total counts and the check value.
Chris@4:        If there was no progress during the inflate() call, return a buffer
Chris@4:        error.  Call updatewindow() to create and/or update the window state.
Chris@4:        Note: a memory error from inflate() is non-recoverable.
Chris@4:      */
Chris@4:   inf_leave:
Chris@4:     RESTORE();
Chris@4:     if (state->wsize || (out != strm->avail_out && state->mode < BAD &&
Chris@4:             (state->mode < CHECK || flush != Z_FINISH)))
Chris@4:         if (updatewindow(strm, out)) {
Chris@4:             state->mode = MEM;
Chris@4:             return Z_MEM_ERROR;
Chris@4:         }
Chris@4:     in -= strm->avail_in;
Chris@4:     out -= strm->avail_out;
Chris@4:     strm->total_in += in;
Chris@4:     strm->total_out += out;
Chris@4:     state->total += out;
Chris@4:     if (state->wrap && out)
Chris@4:         strm->adler = state->check =
Chris@4:             UPDATE(state->check, strm->next_out - out, out);
Chris@4:     strm->data_type = state->bits + (state->last ? 64 : 0) +
Chris@4:                       (state->mode == TYPE ? 128 : 0) +
Chris@4:                       (state->mode == LEN_ || state->mode == COPY_ ? 256 : 0);
Chris@4:     if (((in == 0 && out == 0) || flush == Z_FINISH) && ret == Z_OK)
Chris@4:         ret = Z_BUF_ERROR;
Chris@4:     return ret;
Chris@4: }
Chris@4: 
Chris@4: int ZEXPORT inflateEnd(strm)
Chris@4: z_streamp strm;
Chris@4: {
Chris@4:     struct inflate_state FAR *state;
Chris@4:     if (strm == Z_NULL || strm->state == Z_NULL || strm->zfree == (free_func)0)
Chris@4:         return Z_STREAM_ERROR;
Chris@4:     state = (struct inflate_state FAR *)strm->state;
Chris@4:     if (state->window != Z_NULL) ZFREE(strm, state->window);
Chris@4:     ZFREE(strm, strm->state);
Chris@4:     strm->state = Z_NULL;
Chris@4:     Tracev((stderr, "inflate: end\n"));
Chris@4:     return Z_OK;
Chris@4: }
Chris@4: 
Chris@4: int ZEXPORT inflateSetDictionary(strm, dictionary, dictLength)
Chris@4: z_streamp strm;
Chris@4: const Bytef *dictionary;
Chris@4: uInt dictLength;
Chris@4: {
Chris@4:     struct inflate_state FAR *state;
Chris@4:     unsigned long dictid;
Chris@4:     unsigned char *next;
Chris@4:     unsigned avail;
Chris@4:     int ret;
Chris@4: 
Chris@4:     /* check state */
Chris@4:     if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
Chris@4:     state = (struct inflate_state FAR *)strm->state;
Chris@4:     if (state->wrap != 0 && state->mode != DICT)
Chris@4:         return Z_STREAM_ERROR;
Chris@4: 
Chris@4:     /* check for correct dictionary identifier */
Chris@4:     if (state->mode == DICT) {
Chris@4:         dictid = adler32(0L, Z_NULL, 0);
Chris@4:         dictid = adler32(dictid, dictionary, dictLength);
Chris@4:         if (dictid != state->check)
Chris@4:             return Z_DATA_ERROR;
Chris@4:     }
Chris@4: 
Chris@4:     /* copy dictionary to window using updatewindow(), which will amend the
Chris@4:        existing dictionary if appropriate */
Chris@4:     next = strm->next_out;
Chris@4:     avail = strm->avail_out;
Chris@4:     strm->next_out = (Bytef *)dictionary + dictLength;
Chris@4:     strm->avail_out = 0;
Chris@4:     ret = updatewindow(strm, dictLength);
Chris@4:     strm->avail_out = avail;
Chris@4:     strm->next_out = next;
Chris@4:     if (ret) {
Chris@4:         state->mode = MEM;
Chris@4:         return Z_MEM_ERROR;
Chris@4:     }
Chris@4:     state->havedict = 1;
Chris@4:     Tracev((stderr, "inflate:   dictionary set\n"));
Chris@4:     return Z_OK;
Chris@4: }
Chris@4: 
Chris@4: int ZEXPORT inflateGetHeader(strm, head)
Chris@4: z_streamp strm;
Chris@4: gz_headerp head;
Chris@4: {
Chris@4:     struct inflate_state FAR *state;
Chris@4: 
Chris@4:     /* check state */
Chris@4:     if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
Chris@4:     state = (struct inflate_state FAR *)strm->state;
Chris@4:     if ((state->wrap & 2) == 0) return Z_STREAM_ERROR;
Chris@4: 
Chris@4:     /* save header structure */
Chris@4:     state->head = head;
Chris@4:     head->done = 0;
Chris@4:     return Z_OK;
Chris@4: }
Chris@4: 
Chris@4: /*
Chris@4:    Search buf[0..len-1] for the pattern: 0, 0, 0xff, 0xff.  Return when found
Chris@4:    or when out of input.  When called, *have is the number of pattern bytes
Chris@4:    found in order so far, in 0..3.  On return *have is updated to the new
Chris@4:    state.  If on return *have equals four, then the pattern was found and the
Chris@4:    return value is how many bytes were read including the last byte of the
Chris@4:    pattern.  If *have is less than four, then the pattern has not been found
Chris@4:    yet and the return value is len.  In the latter case, syncsearch() can be
Chris@4:    called again with more data and the *have state.  *have is initialized to
Chris@4:    zero for the first call.
Chris@4:  */
Chris@4: local unsigned syncsearch(have, buf, len)
Chris@4: unsigned FAR *have;
Chris@4: unsigned char FAR *buf;
Chris@4: unsigned len;
Chris@4: {
Chris@4:     unsigned got;
Chris@4:     unsigned next;
Chris@4: 
Chris@4:     got = *have;
Chris@4:     next = 0;
Chris@4:     while (next < len && got < 4) {
Chris@4:         if ((int)(buf[next]) == (got < 2 ? 0 : 0xff))
Chris@4:             got++;
Chris@4:         else if (buf[next])
Chris@4:             got = 0;
Chris@4:         else
Chris@4:             got = 4 - got;
Chris@4:         next++;
Chris@4:     }
Chris@4:     *have = got;
Chris@4:     return next;
Chris@4: }
Chris@4: 
Chris@4: int ZEXPORT inflateSync(strm)
Chris@4: z_streamp strm;
Chris@4: {
Chris@4:     unsigned len;               /* number of bytes to look at or looked at */
Chris@4:     unsigned long in, out;      /* temporary to save total_in and total_out */
Chris@4:     unsigned char buf[4];       /* to restore bit buffer to byte string */
Chris@4:     struct inflate_state FAR *state;
Chris@4: 
Chris@4:     /* check parameters */
Chris@4:     if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
Chris@4:     state = (struct inflate_state FAR *)strm->state;
Chris@4:     if (strm->avail_in == 0 && state->bits < 8) return Z_BUF_ERROR;
Chris@4: 
Chris@4:     /* if first time, start search in bit buffer */
Chris@4:     if (state->mode != SYNC) {
Chris@4:         state->mode = SYNC;
Chris@4:         state->hold <<= state->bits & 7;
Chris@4:         state->bits -= state->bits & 7;
Chris@4:         len = 0;
Chris@4:         while (state->bits >= 8) {
Chris@4:             buf[len++] = (unsigned char)(state->hold);
Chris@4:             state->hold >>= 8;
Chris@4:             state->bits -= 8;
Chris@4:         }
Chris@4:         state->have = 0;
Chris@4:         syncsearch(&(state->have), buf, len);
Chris@4:     }
Chris@4: 
Chris@4:     /* search available input */
Chris@4:     len = syncsearch(&(state->have), strm->next_in, strm->avail_in);
Chris@4:     strm->avail_in -= len;
Chris@4:     strm->next_in += len;
Chris@4:     strm->total_in += len;
Chris@4: 
Chris@4:     /* return no joy or set up to restart inflate() on a new block */
Chris@4:     if (state->have != 4) return Z_DATA_ERROR;
Chris@4:     in = strm->total_in;  out = strm->total_out;
Chris@4:     inflateReset(strm);
Chris@4:     strm->total_in = in;  strm->total_out = out;
Chris@4:     state->mode = TYPE;
Chris@4:     return Z_OK;
Chris@4: }
Chris@4: 
Chris@4: /*
Chris@4:    Returns true if inflate is currently at the end of a block generated by
Chris@4:    Z_SYNC_FLUSH or Z_FULL_FLUSH. This function is used by one PPP
Chris@4:    implementation to provide an additional safety check. PPP uses
Chris@4:    Z_SYNC_FLUSH but removes the length bytes of the resulting empty stored
Chris@4:    block. When decompressing, PPP checks that at the end of input packet,
Chris@4:    inflate is waiting for these length bytes.
Chris@4:  */
Chris@4: int ZEXPORT inflateSyncPoint(strm)
Chris@4: z_streamp strm;
Chris@4: {
Chris@4:     struct inflate_state FAR *state;
Chris@4: 
Chris@4:     if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
Chris@4:     state = (struct inflate_state FAR *)strm->state;
Chris@4:     return state->mode == STORED && state->bits == 0;
Chris@4: }
Chris@4: 
Chris@4: int ZEXPORT inflateCopy(dest, source)
Chris@4: z_streamp dest;
Chris@4: z_streamp source;
Chris@4: {
Chris@4:     struct inflate_state FAR *state;
Chris@4:     struct inflate_state FAR *copy;
Chris@4:     unsigned char FAR *window;
Chris@4:     unsigned wsize;
Chris@4: 
Chris@4:     /* check input */
Chris@4:     if (dest == Z_NULL || source == Z_NULL || source->state == Z_NULL ||
Chris@4:         source->zalloc == (alloc_func)0 || source->zfree == (free_func)0)
Chris@4:         return Z_STREAM_ERROR;
Chris@4:     state = (struct inflate_state FAR *)source->state;
Chris@4: 
Chris@4:     /* allocate space */
Chris@4:     copy = (struct inflate_state FAR *)
Chris@4:            ZALLOC(source, 1, sizeof(struct inflate_state));
Chris@4:     if (copy == Z_NULL) return Z_MEM_ERROR;
Chris@4:     window = Z_NULL;
Chris@4:     if (state->window != Z_NULL) {
Chris@4:         window = (unsigned char FAR *)
Chris@4:                  ZALLOC(source, 1U << state->wbits, sizeof(unsigned char));
Chris@4:         if (window == Z_NULL) {
Chris@4:             ZFREE(source, copy);
Chris@4:             return Z_MEM_ERROR;
Chris@4:         }
Chris@4:     }
Chris@4: 
Chris@4:     /* copy state */
Chris@4:     zmemcpy((voidpf)dest, (voidpf)source, sizeof(z_stream));
Chris@4:     zmemcpy((voidpf)copy, (voidpf)state, sizeof(struct inflate_state));
Chris@4:     if (state->lencode >= state->codes &&
Chris@4:         state->lencode <= state->codes + ENOUGH - 1) {
Chris@4:         copy->lencode = copy->codes + (state->lencode - state->codes);
Chris@4:         copy->distcode = copy->codes + (state->distcode - state->codes);
Chris@4:     }
Chris@4:     copy->next = copy->codes + (state->next - state->codes);
Chris@4:     if (window != Z_NULL) {
Chris@4:         wsize = 1U << state->wbits;
Chris@4:         zmemcpy(window, state->window, wsize);
Chris@4:     }
Chris@4:     copy->window = window;
Chris@4:     dest->state = (struct internal_state FAR *)copy;
Chris@4:     return Z_OK;
Chris@4: }
Chris@4: 
Chris@4: int ZEXPORT inflateUndermine(strm, subvert)
Chris@4: z_streamp strm;
Chris@4: int subvert;
Chris@4: {
Chris@4:     struct inflate_state FAR *state;
Chris@4: 
Chris@4:     if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
Chris@4:     state = (struct inflate_state FAR *)strm->state;
Chris@4:     state->sane = !subvert;
Chris@4: #ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR
Chris@4:     return Z_OK;
Chris@4: #else
Chris@4:     state->sane = 1;
Chris@4:     return Z_DATA_ERROR;
Chris@4: #endif
Chris@4: }
Chris@4: 
Chris@4: long ZEXPORT inflateMark(strm)
Chris@4: z_streamp strm;
Chris@4: {
Chris@4:     struct inflate_state FAR *state;
Chris@4: 
Chris@4:     if (strm == Z_NULL || strm->state == Z_NULL) return -1L << 16;
Chris@4:     state = (struct inflate_state FAR *)strm->state;
Chris@4:     return ((long)(state->back) << 16) +
Chris@4:         (state->mode == COPY ? state->length :
Chris@4:             (state->mode == MATCH ? state->was - state->length : 0));
Chris@4: }