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 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(inflate_blocks_statef *s, z_streamp z, int r)

    24 {

    25   uInt n;

    26   Bytef *p;

    27   Bytef *q;

    28 

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

    30   p = z->next_out;

    31   q = s->read;

    32 

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

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

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

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

    37 

    38   /* update counters */

    39   z->avail_out -= n;

    40   z->total_out += n;

    41 

    42   /* update check information */

    43   if (s->checkfn != Z_NULL)

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

    45 

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

    47   zmemcpy(p, q, n);

    48   p += n;

    49   q += n;

    50 

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

    52   if (q == s->end)

    53   {

    54     /* wrap pointers */

    55     q = s->window;

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

    57       s->write = s->window;

    58 

    59     /* compute bytes to copy */

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

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

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

    63 

    64     /* update counters */

    65     z->avail_out -= n;

    66     z->total_out += n;

    67 

    68     /* update check information */

    69     if (s->checkfn != Z_NULL)

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

    71 

    72     /* copy */

    73     zmemcpy(p, q, n);

    74     p += n;

    75     q += n;

    76   }

    77 

    78   /* update pointers */

    79   z->next_out = p;

    80   s->read = q;

    81 

    82   /* done */

    83   return r;

    84 }