1 | /* inflate_util.c -- data and routines common to blocks and codes |
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2 | * Copyright (C) 1995-1998 Mark Adler |
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3 | * For conditions of distribution and use, see copyright notice in zlib.h |
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4 | */ |
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5 | |
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6 | #include "zutil.h" |
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7 | #include "infblock.h" |
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8 | #include "inftrees.h" |
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9 | #include "infcodes.h" |
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10 | #include "infutil.h" |
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11 | |
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12 | extern int memcpy(char *,char *, int); |
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13 | struct inflate_codes_state {int dummy;}; /* for buggy compilers */ |
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14 | |
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15 | /* And'ing with mask[n] masks the lower n bits */ |
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16 | uInt inflate_mask[17] = { |
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17 | 0x0000, |
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18 | 0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff, |
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19 | 0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff |
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20 | }; |
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21 | |
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22 | |
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23 | /* copy as much as possible from the sliding window to the output area */ |
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24 | int inflate_flush(s, z, r) |
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25 | inflate_blocks_statef *s; |
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26 | z_streamp z; |
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27 | int r; |
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28 | { |
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29 | uInt n; |
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30 | Bytef *p; |
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31 | Bytef *q; |
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32 | |
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33 | /* local copies of source and destination pointers */ |
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34 | p = z->next_out; |
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35 | q = s->read; |
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36 | |
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37 | /* compute number of bytes to copy as far as end of window */ |
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38 | n = (uInt)((q <= s->write ? s->write : s->end) - q); |
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39 | if (n > z->avail_out) n = z->avail_out; |
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40 | if (n && r == Z_BUF_ERROR) r = Z_OK; |
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41 | |
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42 | /* update counters */ |
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43 | z->avail_out -= n; |
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44 | z->total_out += n; |
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45 | |
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46 | /* update check information */ |
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47 | if (s->checkfn != Z_NULL) |
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48 | z->adler = s->check = (*s->checkfn)(s->check, q, n); |
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49 | |
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50 | /* copy as far as end of window */ |
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51 | zmemcpy((char *)p, (char *)q, n); |
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52 | p += n; |
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53 | q += n; |
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54 | |
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55 | /* see if more to copy at beginning of window */ |
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56 | if (q == s->end) |
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57 | { |
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58 | /* wrap pointers */ |
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59 | q = s->window; |
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60 | if (s->write == s->end) |
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61 | s->write = s->window; |
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62 | |
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63 | /* compute bytes to copy */ |
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64 | n = (uInt)(s->write - q); |
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65 | if (n > z->avail_out) n = z->avail_out; |
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66 | if (n && r == Z_BUF_ERROR) r = Z_OK; |
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67 | |
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68 | /* update counters */ |
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69 | z->avail_out -= n; |
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70 | z->total_out += n; |
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71 | |
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72 | /* update check information */ |
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73 | if (s->checkfn != Z_NULL) |
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74 | z->adler = s->check = (*s->checkfn)(s->check, q, n); |
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75 | |
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76 | /* copy */ |
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77 | zmemcpy((char *)p, (char *)q, n); |
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78 | p += n; |
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79 | q += n; |
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80 | } |
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81 | |
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82 | /* update pointers */ |
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83 | z->next_out = p; |
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84 | s->read = q; |
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85 | |
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86 | /* done */ |
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87 | return r; |
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88 | } |
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