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annotate zlib/inffast.c @ 1971:80920c21bb52

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Add an event log soft flush and call it twice per frame in between hard flushes to netplay latency when there are insufficient hardware updates to flush packets in the middle of a frame
author Michael Pavone <pavone@retrodev.com>
date Fri, 08 May 2020 11:40:30 -0700
parents 00d788dac91a
children
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1 /* inffast.c -- fast decoding
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2 * Copyright (C) 1995-2017 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 "inftrees.h"
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8 #include "inflate.h"
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9 #include "inffast.h"
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10
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11 #ifdef ASMINF
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12 # pragma message("Assembler code may have bugs -- use at your own risk")
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13 #else
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14
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15 /*
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16 Decode literal, length, and distance codes and write out the resulting
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17 literal and match bytes until either not enough input or output is
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18 available, an end-of-block is encountered, or a data error is encountered.
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19 When large enough input and output buffers are supplied to inflate(), for
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20 example, a 16K input buffer and a 64K output buffer, more than 95% of the
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21 inflate execution time is spent in this routine.
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22
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23 Entry assumptions:
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24
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25 state->mode == LEN
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26 strm->avail_in >= 6
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27 strm->avail_out >= 258
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28 start >= strm->avail_out
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29 state->bits < 8
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30
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31 On return, state->mode is one of:
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32
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33 LEN -- ran out of enough output space or enough available input
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34 TYPE -- reached end of block code, inflate() to interpret next block
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35 BAD -- error in block data
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36
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37 Notes:
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38
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39 - The maximum input bits used by a length/distance pair is 15 bits for the
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40 length code, 5 bits for the length extra, 15 bits for the distance code,
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41 and 13 bits for the distance extra. This totals 48 bits, or six bytes.
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42 Therefore if strm->avail_in >= 6, then there is enough input to avoid
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43 checking for available input while decoding.
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44
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45 - The maximum bytes that a single length/distance pair can output is 258
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46 bytes, which is the maximum length that can be coded. inflate_fast()
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47 requires strm->avail_out >= 258 for each loop to avoid checking for
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48 output space.
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49 */
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50 void ZLIB_INTERNAL inflate_fast(strm, start)
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51 z_streamp strm;
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52 unsigned start; /* inflate()'s starting value for strm->avail_out */
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53 {
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54 struct inflate_state FAR *state;
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55 z_const unsigned char FAR *in; /* local strm->next_in */
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56 z_const unsigned char FAR *last; /* have enough input while in < last */
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57 unsigned char FAR *out; /* local strm->next_out */
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58 unsigned char FAR *beg; /* inflate()'s initial strm->next_out */
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59 unsigned char FAR *end; /* while out < end, enough space available */
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60 #ifdef INFLATE_STRICT
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61 unsigned dmax; /* maximum distance from zlib header */
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62 #endif
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63 unsigned wsize; /* window size or zero if not using window */
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64 unsigned whave; /* valid bytes in the window */
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65 unsigned wnext; /* window write index */
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66 unsigned char FAR *window; /* allocated sliding window, if wsize != 0 */
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67 unsigned long hold; /* local strm->hold */
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68 unsigned bits; /* local strm->bits */
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69 code const FAR *lcode; /* local strm->lencode */
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70 code const FAR *dcode; /* local strm->distcode */
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71 unsigned lmask; /* mask for first level of length codes */
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72 unsigned dmask; /* mask for first level of distance codes */
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73 code here; /* retrieved table entry */
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74 unsigned op; /* code bits, operation, extra bits, or */
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75 /* window position, window bytes to copy */
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76 unsigned len; /* match length, unused bytes */
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77 unsigned dist; /* match distance */
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78 unsigned char FAR *from; /* where to copy match from */
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79
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80 /* copy state to local variables */
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81 state = (struct inflate_state FAR *)strm->state;
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82 in = strm->next_in;
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83 last = in + (strm->avail_in - 5);
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84 out = strm->next_out;
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85 beg = out - (start - strm->avail_out);
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86 end = out + (strm->avail_out - 257);
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87 #ifdef INFLATE_STRICT
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88 dmax = state->dmax;
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89 #endif
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90 wsize = state->wsize;
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91 whave = state->whave;
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92 wnext = state->wnext;
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93 window = state->window;
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94 hold = state->hold;
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95 bits = state->bits;
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96 lcode = state->lencode;
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97 dcode = state->distcode;
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98 lmask = (1U << state->lenbits) - 1;
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99 dmask = (1U << state->distbits) - 1;
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100
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101 /* decode literals and length/distances until end-of-block or not enough
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102 input data or output space */
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103 do {
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104 if (bits < 15) {
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105 hold += (unsigned long)(*in++) << bits;
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106 bits += 8;
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107 hold += (unsigned long)(*in++) << bits;
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108 bits += 8;
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109 }
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110 here = lcode[hold & lmask];
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111 dolen:
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112 op = (unsigned)(here.bits);
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113 hold >>= op;
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114 bits -= op;
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115 op = (unsigned)(here.op);
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116 if (op == 0) { /* literal */
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117 Tracevv((stderr, here.val >= 0x20 && here.val < 0x7f ?
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118 "inflate: literal '%c'\n" :
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119 "inflate: literal 0x%02x\n", here.val));
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120 *out++ = (unsigned char)(here.val);
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121 }
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122 else if (op & 16) { /* length base */
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123 len = (unsigned)(here.val);
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124 op &= 15; /* number of extra bits */
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125 if (op) {
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126 if (bits < op) {
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127 hold += (unsigned long)(*in++) << bits;
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128 bits += 8;
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129 }
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130 len += (unsigned)hold & ((1U << op) - 1);
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131 hold >>= op;
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132 bits -= op;
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133 }
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134 Tracevv((stderr, "inflate: length %u\n", len));
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135 if (bits < 15) {
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136 hold += (unsigned long)(*in++) << bits;
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137 bits += 8;
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138 hold += (unsigned long)(*in++) << bits;
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139 bits += 8;
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140 }
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141 here = dcode[hold & dmask];
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142 dodist:
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diff changeset
143 op = (unsigned)(here.bits);
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
144 hold >>= op;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
145 bits -= op;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
146 op = (unsigned)(here.op);
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
147 if (op & 16) { /* distance base */
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
148 dist = (unsigned)(here.val);
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
149 op &= 15; /* number of extra bits */
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
150 if (bits < op) {
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
151 hold += (unsigned long)(*in++) << bits;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
152 bits += 8;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
153 if (bits < op) {
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
154 hold += (unsigned long)(*in++) << bits;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
155 bits += 8;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
156 }
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
157 }
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
158 dist += (unsigned)hold & ((1U << op) - 1);
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
159 #ifdef INFLATE_STRICT
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
160 if (dist > dmax) {
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
161 strm->msg = (char *)"invalid distance too far back";
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
162 state->mode = BAD;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
163 break;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
164 }
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
165 #endif
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
166 hold >>= op;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
167 bits -= op;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
168 Tracevv((stderr, "inflate: distance %u\n", dist));
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
169 op = (unsigned)(out - beg); /* max distance in output */
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
170 if (dist > op) { /* see if copy from window */
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
171 op = dist - op; /* distance back in window */
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
172 if (op > whave) {
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
173 if (state->sane) {
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
174 strm->msg =
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
175 (char *)"invalid distance too far back";
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
176 state->mode = BAD;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
177 break;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
178 }
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
179 #ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
180 if (len <= op - whave) {
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
181 do {
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
182 *out++ = 0;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
183 } while (--len);
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
184 continue;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
185 }
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
186 len -= op - whave;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
187 do {
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
188 *out++ = 0;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
189 } while (--op > whave);
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
190 if (op == 0) {
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
191 from = out - dist;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
192 do {
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
193 *out++ = *from++;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
194 } while (--len);
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
195 continue;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
196 }
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
197 #endif
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
198 }
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
199 from = window;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
200 if (wnext == 0) { /* very common case */
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
201 from += wsize - op;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
202 if (op < len) { /* some from window */
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
203 len -= op;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
204 do {
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
205 *out++ = *from++;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
206 } while (--op);
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
207 from = out - dist; /* rest from output */
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
208 }
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
209 }
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
210 else if (wnext < op) { /* wrap around window */
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
211 from += wsize + wnext - op;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
212 op -= wnext;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
213 if (op < len) { /* some from end of window */
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
214 len -= op;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
215 do {
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
216 *out++ = *from++;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
217 } while (--op);
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
218 from = window;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
219 if (wnext < len) { /* some from start of window */
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
220 op = wnext;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
221 len -= op;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
222 do {
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
223 *out++ = *from++;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
224 } while (--op);
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
225 from = out - dist; /* rest from output */
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
226 }
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
227 }
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
228 }
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
229 else { /* contiguous in window */
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
230 from += wnext - op;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
231 if (op < len) { /* some from window */
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
232 len -= op;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
233 do {
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
234 *out++ = *from++;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
235 } while (--op);
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
236 from = out - dist; /* rest from output */
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
237 }
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
238 }
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
239 while (len > 2) {
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
240 *out++ = *from++;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
241 *out++ = *from++;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
242 *out++ = *from++;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
243 len -= 3;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
244 }
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
245 if (len) {
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
246 *out++ = *from++;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
247 if (len > 1)
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
248 *out++ = *from++;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
249 }
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
250 }
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
251 else {
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
252 from = out - dist; /* copy direct from output */
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
253 do { /* minimum length is three */
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
254 *out++ = *from++;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
255 *out++ = *from++;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
256 *out++ = *from++;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
257 len -= 3;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
258 } while (len > 2);
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
259 if (len) {
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
260 *out++ = *from++;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
261 if (len > 1)
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
262 *out++ = *from++;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
263 }
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
264 }
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
265 }
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
266 else if ((op & 64) == 0) { /* 2nd level distance code */
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
267 here = dcode[here.val + (hold & ((1U << op) - 1))];
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
268 goto dodist;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
269 }
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
270 else {
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
271 strm->msg = (char *)"invalid distance code";
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
272 state->mode = BAD;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
273 break;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
274 }
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
275 }
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
276 else if ((op & 64) == 0) { /* 2nd level length code */
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
277 here = lcode[here.val + (hold & ((1U << op) - 1))];
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
278 goto dolen;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
279 }
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
280 else if (op & 32) { /* end-of-block */
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
281 Tracevv((stderr, "inflate: end of block\n"));
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
282 state->mode = TYPE;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
283 break;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
284 }
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
285 else {
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
286 strm->msg = (char *)"invalid literal/length code";
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
287 state->mode = BAD;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
288 break;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
289 }
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
290 } while (in < last && out < end);
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
291
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
292 /* return unused bytes (on entry, bits < 8, so in won't go too far back) */
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
293 len = bits >> 3;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
294 in -= len;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
295 bits -= len << 3;
00d788dac91a Added support for reading gzipped ROMs
Michael Pavone <pavone@retrodev.com>
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296 hold &= (1U << bits) - 1;
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297
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298 /* update state and return */
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299 strm->next_in = in;
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300 strm->next_out = out;
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301 strm->avail_in = (unsigned)(in < last ? 5 + (last - in) : 5 - (in - last));
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302 strm->avail_out = (unsigned)(out < end ?
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303 257 + (end - out) : 257 - (out - end));
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304 state->hold = hold;
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305 state->bits = bits;
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306 return;
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307 }
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308
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309 /*
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310 inflate_fast() speedups that turned out slower (on a PowerPC G3 750CXe):
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311 - Using bit fields for code structure
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312 - Different op definition to avoid & for extra bits (do & for table bits)
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313 - Three separate decoding do-loops for direct, window, and wnext == 0
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314 - Special case for distance > 1 copies to do overlapped load and store copy
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315 - Explicit branch predictions (based on measured branch probabilities)
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316 - Deferring match copy and interspersed it with decoding subsequent codes
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317 - Swapping literal/length else
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318 - Swapping window/direct else
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319 - Larger unrolled copy loops (three is about right)
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320 - Moving len -= 3 statement into middle of loop
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321 */
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322
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323 #endif /* !ASMINF */