Chris@4: /* infback9.c -- inflate deflate64 data using a call-back interface
Chris@4:  * Copyright (C) 1995-2008 Mark Adler
Chris@4:  * For conditions of distribution and use, see copyright notice in zlib.h
Chris@4:  */
Chris@4: 
Chris@4: #include "zutil.h"
Chris@4: #include "infback9.h"
Chris@4: #include "inftree9.h"
Chris@4: #include "inflate9.h"
Chris@4: 
Chris@4: #define WSIZE 65536UL
Chris@4: 
Chris@4: /*
Chris@4:    strm provides memory allocation functions in zalloc and zfree, or
Chris@4:    Z_NULL to use the library memory allocation functions.
Chris@4: 
Chris@4:    window is a user-supplied window and output buffer that is 64K bytes.
Chris@4:  */
Chris@4: int ZEXPORT inflateBack9Init_(strm, window, version, stream_size)
Chris@4: z_stream FAR *strm;
Chris@4: unsigned char FAR *window;
Chris@4: const char *version;
Chris@4: int stream_size;
Chris@4: {
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 || window == Z_NULL)
Chris@4:         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:         strm->zalloc = zcalloc;
Chris@4:         strm->opaque = (voidpf)0;
Chris@4:     }
Chris@4:     if (strm->zfree == (free_func)0) strm->zfree = zcfree;
Chris@4:     state = (struct inflate_state FAR *)ZALLOC(strm, 1,
Chris@4:                                                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 = (voidpf)state;
Chris@4:     state->window = window;
Chris@4:     return Z_OK;
Chris@4: }
Chris@4: 
Chris@4: /*
Chris@4:    Build and output length and distance decoding tables for fixed code
Chris@4:    decoding.
Chris@4:  */
Chris@4: #ifdef MAKEFIXED
Chris@4: #include <stdio.h>
Chris@4: 
Chris@4: void makefixed9(void)
Chris@4: {
Chris@4:     unsigned sym, bits, low, size;
Chris@4:     code *next, *lenfix, *distfix;
Chris@4:     struct inflate_state state;
Chris@4:     code fixed[544];
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_table9(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_table9(DISTS, state.lens, 32, &(next), &(bits), state.work);
Chris@4: 
Chris@4:     /* write tables */
Chris@4:     puts("    /* inffix9.h -- table for decoding deflate64 fixed codes");
Chris@4:     puts("     * Generated automatically by makefixed9().");
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 % 6) == 0) printf("\n        ");
Chris@4:         printf("{%u,%u,%d}", lenfix[low].op, lenfix[low].bits,
Chris@4:                lenfix[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 % 5) == 0) printf("\n        ");
Chris@4:         printf("{%u,%u,%d}", distfix[low].op, distfix[low].bits,
Chris@4:                distfix[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: /* Macros for inflateBack(): */
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: /* Assure that some input is available.  If input is requested, but denied,
Chris@4:    then return a Z_BUF_ERROR from inflateBack(). */
Chris@4: #define PULL() \
Chris@4:     do { \
Chris@4:         if (have == 0) { \
Chris@4:             have = in(in_desc, &next); \
Chris@4:             if (have == 0) { \
Chris@4:                 next = Z_NULL; \
Chris@4:                 ret = Z_BUF_ERROR; \
Chris@4:                 goto inf_leave; \
Chris@4:             } \
Chris@4:         } \
Chris@4:     } while (0)
Chris@4: 
Chris@4: /* Get a byte of input into the bit accumulator, or return from inflateBack()
Chris@4:    with an error if there is no input available. */
Chris@4: #define PULLBYTE() \
Chris@4:     do { \
Chris@4:         PULL(); \
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 inflateBack() with
Chris@4:    an error. */
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: /* Assure that some output space is available, by writing out the window
Chris@4:    if it's full.  If the write fails, return from inflateBack() with a
Chris@4:    Z_BUF_ERROR. */
Chris@4: #define ROOM() \
Chris@4:     do { \
Chris@4:         if (left == 0) { \
Chris@4:             put = window; \
Chris@4:             left = WSIZE; \
Chris@4:             wrap = 1; \
Chris@4:             if (out(out_desc, put, (unsigned)left)) { \
Chris@4:                 ret = Z_BUF_ERROR; \
Chris@4:                 goto inf_leave; \
Chris@4:             } \
Chris@4:         } \
Chris@4:     } while (0)
Chris@4: 
Chris@4: /*
Chris@4:    strm provides the memory allocation functions and window buffer on input,
Chris@4:    and provides information on the unused input on return.  For Z_DATA_ERROR
Chris@4:    returns, strm will also provide an error message.
Chris@4: 
Chris@4:    in() and out() are the call-back input and output functions.  When
Chris@4:    inflateBack() needs more input, it calls in().  When inflateBack() has
Chris@4:    filled the window with output, or when it completes with data in the
Chris@4:    window, it calls out() to write out the data.  The application must not
Chris@4:    change the provided input until in() is called again or inflateBack()
Chris@4:    returns.  The application must not change the window/output buffer until
Chris@4:    inflateBack() returns.
Chris@4: 
Chris@4:    in() and out() are called with a descriptor parameter provided in the
Chris@4:    inflateBack() call.  This parameter can be a structure that provides the
Chris@4:    information required to do the read or write, as well as accumulated
Chris@4:    information on the input and output such as totals and check values.
Chris@4: 
Chris@4:    in() should return zero on failure.  out() should return non-zero on
Chris@4:    failure.  If either in() or out() fails, than inflateBack() returns a
Chris@4:    Z_BUF_ERROR.  strm->next_in can be checked for Z_NULL to see whether it
Chris@4:    was in() or out() that caused in the error.  Otherwise,  inflateBack()
Chris@4:    returns Z_STREAM_END on success, Z_DATA_ERROR for an deflate format
Chris@4:    error, or Z_MEM_ERROR if it could not allocate memory for the state.
Chris@4:    inflateBack() can also return Z_STREAM_ERROR if the input parameters
Chris@4:    are not correct, i.e. strm is Z_NULL or the state was not initialized.
Chris@4:  */
Chris@4: int ZEXPORT inflateBack9(strm, in, in_desc, out, out_desc)
Chris@4: z_stream FAR *strm;
Chris@4: in_func in;
Chris@4: void FAR *in_desc;
Chris@4: out_func out;
Chris@4: void FAR *out_desc;
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;              /* available input */
Chris@4:     unsigned long left;         /* available output */
Chris@4:     inflate_mode mode;          /* current inflate mode */
Chris@4:     int lastblock;              /* true if processing last block */
Chris@4:     int wrap;                   /* true if the window has wrapped */
Chris@4:     unsigned long write;        /* window write index */
Chris@4:     unsigned char FAR *window;  /* allocated sliding window, if needed */
Chris@4:     unsigned long hold;         /* bit buffer */
Chris@4:     unsigned bits;              /* bits in bit buffer */
Chris@4:     unsigned extra;             /* extra bits needed */
Chris@4:     unsigned long length;       /* literal or length of data to copy */
Chris@4:     unsigned long offset;       /* distance back to copy string from */
Chris@4:     unsigned long copy;         /* number of stored or match bytes to copy */
Chris@4:     unsigned char FAR *from;    /* where to copy match bytes from */
Chris@4:     code const FAR *lencode;    /* starting table for length/literal codes */
Chris@4:     code const FAR *distcode;   /* starting table for distance codes */
Chris@4:     unsigned lenbits;           /* index bits for lencode */
Chris@4:     unsigned distbits;          /* index bits for distcode */
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:     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: #include "inffix9.h"
Chris@4: 
Chris@4:     /* Check that the strm exists and that the state was initialized */
Chris@4:     if (strm == Z_NULL || strm->state == Z_NULL)
Chris@4:         return Z_STREAM_ERROR;
Chris@4:     state = (struct inflate_state FAR *)strm->state;
Chris@4: 
Chris@4:     /* Reset the state */
Chris@4:     strm->msg = Z_NULL;
Chris@4:     mode = TYPE;
Chris@4:     lastblock = 0;
Chris@4:     write = 0;
Chris@4:     wrap = 0;
Chris@4:     window = state->window;
Chris@4:     next = strm->next_in;
Chris@4:     have = next != Z_NULL ? strm->avail_in : 0;
Chris@4:     hold = 0;
Chris@4:     bits = 0;
Chris@4:     put = window;
Chris@4:     left = WSIZE;
Chris@4:     lencode = Z_NULL;
Chris@4:     distcode = Z_NULL;
Chris@4: 
Chris@4:     /* Inflate until end of block marked as last */
Chris@4:     for (;;)
Chris@4:         switch (mode) {
Chris@4:         case TYPE:
Chris@4:             /* determine and dispatch block type */
Chris@4:             if (lastblock) {
Chris@4:                 BYTEBITS();
Chris@4:                 mode = DONE;
Chris@4:                 break;
Chris@4:             }
Chris@4:             NEEDBITS(3);
Chris@4:             lastblock = 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:                         lastblock ? " (last)" : ""));
Chris@4:                 mode = STORED;
Chris@4:                 break;
Chris@4:             case 1:                             /* fixed block */
Chris@4:                 lencode = lenfix;
Chris@4:                 lenbits = 9;
Chris@4:                 distcode = distfix;
Chris@4:                 distbits = 5;
Chris@4:                 Tracev((stderr, "inflate:     fixed codes block%s\n",
Chris@4:                         lastblock ? " (last)" : ""));
Chris@4:                 mode = LEN;                     /* decode codes */
Chris@4:                 break;
Chris@4:             case 2:                             /* dynamic block */
Chris@4:                 Tracev((stderr, "inflate:     dynamic codes block%s\n",
Chris@4:                         lastblock ? " (last)" : ""));
Chris@4:                 mode = TABLE;
Chris@4:                 break;
Chris@4:             case 3:
Chris@4:                 strm->msg = (char *)"invalid block type";
Chris@4:                 mode = BAD;
Chris@4:             }
Chris@4:             DROPBITS(2);
Chris@4:             break;
Chris@4: 
Chris@4:         case STORED:
Chris@4:             /* get and verify stored block length */
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:                 mode = BAD;
Chris@4:                 break;
Chris@4:             }
Chris@4:             length = (unsigned)hold & 0xffff;
Chris@4:             Tracev((stderr, "inflate:       stored length %lu\n",
Chris@4:                     length));
Chris@4:             INITBITS();
Chris@4: 
Chris@4:             /* copy stored block from input to output */
Chris@4:             while (length != 0) {
Chris@4:                 copy = length;
Chris@4:                 PULL();
Chris@4:                 ROOM();
Chris@4:                 if (copy > have) copy = have;
Chris@4:                 if (copy > left) copy = left;
Chris@4:                 zmemcpy(put, next, copy);
Chris@4:                 have -= copy;
Chris@4:                 next += copy;
Chris@4:                 left -= copy;
Chris@4:                 put += copy;
Chris@4:                 length -= copy;
Chris@4:             }
Chris@4:             Tracev((stderr, "inflate:       stored end\n"));
Chris@4:             mode = TYPE;
Chris@4:             break;
Chris@4: 
Chris@4:         case TABLE:
Chris@4:             /* get dynamic table entries descriptor */
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:             if (state->nlen > 286) {
Chris@4:                 strm->msg = (char *)"too many length symbols";
Chris@4:                 mode = BAD;
Chris@4:                 break;
Chris@4:             }
Chris@4:             Tracev((stderr, "inflate:       table sizes ok\n"));
Chris@4: 
Chris@4:             /* get code length code lengths (not a typo) */
Chris@4:             state->have = 0;
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:             lencode = (code const FAR *)(state->next);
Chris@4:             lenbits = 7;
Chris@4:             ret = inflate_table9(CODES, state->lens, 19, &(state->next),
Chris@4:                                 &(lenbits), state->work);
Chris@4:             if (ret) {
Chris@4:                 strm->msg = (char *)"invalid code lengths set";
Chris@4:                 mode = BAD;
Chris@4:                 break;
Chris@4:             }
Chris@4:             Tracev((stderr, "inflate:       code lengths ok\n"));
Chris@4: 
Chris@4:             /* get length and distance code code lengths */
Chris@4:             state->have = 0;
Chris@4:             while (state->have < state->nlen + state->ndist) {
Chris@4:                 for (;;) {
Chris@4:                     here = lencode[BITS(lenbits)];
Chris@4:                     if ((unsigned)(here.bits) <= bits) break;
Chris@4:                     PULLBYTE();
Chris@4:                 }
Chris@4:                 if (here.val < 16) {
Chris@4:                     NEEDBITS(here.bits);
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:                             mode = BAD;
Chris@4:                             break;
Chris@4:                         }
Chris@4:                         len = (unsigned)(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:                         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 (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:                 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 inftree9.h
Chris@4:                concerning the ENOUGH constants, which depend on those values */
Chris@4:             state->next = state->codes;
Chris@4:             lencode = (code const FAR *)(state->next);
Chris@4:             lenbits = 9;
Chris@4:             ret = inflate_table9(LENS, state->lens, state->nlen,
Chris@4:                             &(state->next), &(lenbits), state->work);
Chris@4:             if (ret) {
Chris@4:                 strm->msg = (char *)"invalid literal/lengths set";
Chris@4:                 mode = BAD;
Chris@4:                 break;
Chris@4:             }
Chris@4:             distcode = (code const FAR *)(state->next);
Chris@4:             distbits = 6;
Chris@4:             ret = inflate_table9(DISTS, state->lens + state->nlen,
Chris@4:                             state->ndist, &(state->next), &(distbits),
Chris@4:                             state->work);
Chris@4:             if (ret) {
Chris@4:                 strm->msg = (char *)"invalid distances set";
Chris@4:                 mode = BAD;
Chris@4:                 break;
Chris@4:             }
Chris@4:             Tracev((stderr, "inflate:       codes ok\n"));
Chris@4:             mode = LEN;
Chris@4: 
Chris@4:         case LEN:
Chris@4:             /* get a literal, length, or end-of-block code */
Chris@4:             for (;;) {
Chris@4:                 here = lencode[BITS(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 = 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:             }
Chris@4:             DROPBITS(here.bits);
Chris@4:             length = (unsigned)here.val;
Chris@4: 
Chris@4:             /* process literal */
Chris@4:             if (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:                 ROOM();
Chris@4:                 *put++ = (unsigned char)(length);
Chris@4:                 left--;
Chris@4:                 mode = LEN;
Chris@4:                 break;
Chris@4:             }
Chris@4: 
Chris@4:             /* process end of block */
Chris@4:             if (here.op & 32) {
Chris@4:                 Tracevv((stderr, "inflate:         end of block\n"));
Chris@4:                 mode = TYPE;
Chris@4:                 break;
Chris@4:             }
Chris@4: 
Chris@4:             /* invalid code */
Chris@4:             if (here.op & 64) {
Chris@4:                 strm->msg = (char *)"invalid literal/length code";
Chris@4:                 mode = BAD;
Chris@4:                 break;
Chris@4:             }
Chris@4: 
Chris@4:             /* length code -- get extra bits, if any */
Chris@4:             extra = (unsigned)(here.op) & 31;
Chris@4:             if (extra != 0) {
Chris@4:                 NEEDBITS(extra);
Chris@4:                 length += BITS(extra);
Chris@4:                 DROPBITS(extra);
Chris@4:             }
Chris@4:             Tracevv((stderr, "inflate:         length %lu\n", length));
Chris@4: 
Chris@4:             /* get distance code */
Chris@4:             for (;;) {
Chris@4:                 here = distcode[BITS(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 = 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:             }
Chris@4:             DROPBITS(here.bits);
Chris@4:             if (here.op & 64) {
Chris@4:                 strm->msg = (char *)"invalid distance code";
Chris@4:                 mode = BAD;
Chris@4:                 break;
Chris@4:             }
Chris@4:             offset = (unsigned)here.val;
Chris@4: 
Chris@4:             /* get distance extra bits, if any */
Chris@4:             extra = (unsigned)(here.op) & 15;
Chris@4:             if (extra != 0) {
Chris@4:                 NEEDBITS(extra);
Chris@4:                 offset += BITS(extra);
Chris@4:                 DROPBITS(extra);
Chris@4:             }
Chris@4:             if (offset > WSIZE - (wrap ? 0: left)) {
Chris@4:                 strm->msg = (char *)"invalid distance too far back";
Chris@4:                 mode = BAD;
Chris@4:                 break;
Chris@4:             }
Chris@4:             Tracevv((stderr, "inflate:         distance %lu\n", offset));
Chris@4: 
Chris@4:             /* copy match from window to output */
Chris@4:             do {
Chris@4:                 ROOM();
Chris@4:                 copy = WSIZE - offset;
Chris@4:                 if (copy < left) {
Chris@4:                     from = put + copy;
Chris@4:                     copy = left - copy;
Chris@4:                 }
Chris@4:                 else {
Chris@4:                     from = put - offset;
Chris@4:                     copy = left;
Chris@4:                 }
Chris@4:                 if (copy > length) copy = length;
Chris@4:                 length -= copy;
Chris@4:                 left -= copy;
Chris@4:                 do {
Chris@4:                     *put++ = *from++;
Chris@4:                 } while (--copy);
Chris@4:             } while (length != 0);
Chris@4:             break;
Chris@4: 
Chris@4:         case DONE:
Chris@4:             /* inflate stream terminated properly -- write leftover output */
Chris@4:             ret = Z_STREAM_END;
Chris@4:             if (left < WSIZE) {
Chris@4:                 if (out(out_desc, window, (unsigned)(WSIZE - left)))
Chris@4:                     ret = Z_BUF_ERROR;
Chris@4:             }
Chris@4:             goto inf_leave;
Chris@4: 
Chris@4:         case BAD:
Chris@4:             ret = Z_DATA_ERROR;
Chris@4:             goto inf_leave;
Chris@4: 
Chris@4:         default:                /* can't happen, but makes compilers happy */
Chris@4:             ret = Z_STREAM_ERROR;
Chris@4:             goto inf_leave;
Chris@4:         }
Chris@4: 
Chris@4:     /* Return unused input */
Chris@4:   inf_leave:
Chris@4:     strm->next_in = next;
Chris@4:     strm->avail_in = have;
Chris@4:     return ret;
Chris@4: }
Chris@4: 
Chris@4: int ZEXPORT inflateBack9End(strm)
Chris@4: z_stream FAR *strm;
Chris@4: {
Chris@4:     if (strm == Z_NULL || strm->state == Z_NULL || strm->zfree == (free_func)0)
Chris@4:         return Z_STREAM_ERROR;
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: }