1 /* inflate_util.c -- data and routines common to blocks and codes

     2  * Copyright (C) 1995-1998 Mark Adler

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

     4  */

     5 

     6 #include "zutil.h"

     7 #include "infblock.h"

     8 #include "inftrees.h"

     9 #include "infcodes.h"

    10 #include "infutil.h"

    11 

    12 struct inflate_codes_state {int dummy;}; /* for buggy compilers */

    13 

    14 /* And'ing with mask[n] masks the lower n bits */

    15 const uInt inflate_mask[17] = {

    16     0x0000,

    17     0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,

    18     0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff

    19 };

    20 

    21 

    22 /* copy as much as possible from the sliding window to the output area */

    23 int inflate_flush(

    24 inflate_blocks_statef *s,

    25 z_streamp z,

    26 int r)

    27 {

    28   uInt n;

    29   Bytef *p;

    30   Bytef *q;

    31 

    32   /* local copies of source and destination pointers */

    33   p = z->next_out;

    34   q = s->read;

    35 

    36   /* compute number of bytes to copy as far as end of window */

    37   n = (uInt)((q <= s->write ? s->write : s->end) - q);

    38   if (n > z->avail_out) n = z->avail_out;

    39   if (n && r == Z_BUF_ERROR) r = Z_OK;

    40 

    41   /* update counters */

    42   z->avail_out -= n;

    43   z->total_out += n;

    44 

    45   /* update check information */

    46   if (s->checkfn != Z_NULL)

    47     z->adler = s->check = (*s->checkfn)(s->check, q, n);

    48 

    49   /* copy as far as end of window */

    50   zmemcpy(p, q, n);

    51   p += n;

    52   q += n;

    53 

    54   /* see if more to copy at beginning of window */

    55   if (q == s->end)

    56   {

    57     /* wrap pointers */

    58     q = s->window;

    59     if (s->write == s->end)

    60       s->write = s->window;

    61 

    62     /* compute bytes to copy */

    63     n = (uInt)(s->write - q);

    64     if (n > z->avail_out) n = z->avail_out;

    65     if (n && r == Z_BUF_ERROR) r = Z_OK;

    66 

    67     /* update counters */

    68     z->avail_out -= n;

    69     z->total_out += n;

    70 

    71     /* update check information */

    72     if (s->checkfn != Z_NULL)

    73       z->adler = s->check = (*s->checkfn)(s->check, q, n);

    74 

    75     /* copy */

    76     zmemcpy(p, q, n);

    77     p += n;

    78     q += n;

    79   }

    80 

    81   /* update pointers */

    82   z->next_out = p;

    83   s->read = q;

    84 

    85   /* done */

    86   return r;

    87 }