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comparison zlib/inffast.c @ 2690:9ef72ee5c0b0

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Update vendored zlib to 1.3.1
author Michael Pavone <pavone@retrodev.com>
date Sun, 15 Jun 2025 15:39:33 -0700
parents 00d788dac91a
children
comparison
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2689:bd6e33de0972 2690:9ef72ee5c0b0
45 - The maximum bytes that a single length/distance pair can output is 258 45 - The maximum bytes that a single length/distance pair can output is 258
46 bytes, which is the maximum length that can be coded. inflate_fast() 46 bytes, which is the maximum length that can be coded. inflate_fast()
47 requires strm->avail_out >= 258 for each loop to avoid checking for 47 requires strm->avail_out >= 258 for each loop to avoid checking for
48 output space. 48 output space.
49 */ 49 */
50 void ZLIB_INTERNAL inflate_fast(strm, start) 50 void ZLIB_INTERNAL inflate_fast(z_streamp strm, unsigned start) {
51 z_streamp strm;
52 unsigned start; /* inflate()'s starting value for strm->avail_out */
53 {
54 struct inflate_state FAR *state; 51 struct inflate_state FAR *state;
55 z_const unsigned char FAR *in; /* local strm->next_in */ 52 z_const unsigned char FAR *in; /* local strm->next_in */
56 z_const unsigned char FAR *last; /* have enough input while in < last */ 53 z_const unsigned char FAR *last; /* have enough input while in < last */
57 unsigned char FAR *out; /* local strm->next_out */ 54 unsigned char FAR *out; /* local strm->next_out */
58 unsigned char FAR *beg; /* inflate()'s initial strm->next_out */ 55 unsigned char FAR *beg; /* inflate()'s initial strm->next_out */
68 unsigned bits; /* local strm->bits */ 65 unsigned bits; /* local strm->bits */
69 code const FAR *lcode; /* local strm->lencode */ 66 code const FAR *lcode; /* local strm->lencode */
70 code const FAR *dcode; /* local strm->distcode */ 67 code const FAR *dcode; /* local strm->distcode */
71 unsigned lmask; /* mask for first level of length codes */ 68 unsigned lmask; /* mask for first level of length codes */
72 unsigned dmask; /* mask for first level of distance codes */ 69 unsigned dmask; /* mask for first level of distance codes */
73 code here; /* retrieved table entry */ 70 code const *here; /* retrieved table entry */
74 unsigned op; /* code bits, operation, extra bits, or */ 71 unsigned op; /* code bits, operation, extra bits, or */
75 /* window position, window bytes to copy */ 72 /* window position, window bytes to copy */
76 unsigned len; /* match length, unused bytes */ 73 unsigned len; /* match length, unused bytes */
77 unsigned dist; /* match distance */ 74 unsigned dist; /* match distance */
78 unsigned char FAR *from; /* where to copy match from */ 75 unsigned char FAR *from; /* where to copy match from */
105 hold += (unsigned long)(*in++) << bits; 102 hold += (unsigned long)(*in++) << bits;
106 bits += 8; 103 bits += 8;
107 hold += (unsigned long)(*in++) << bits; 104 hold += (unsigned long)(*in++) << bits;
108 bits += 8; 105 bits += 8;
109 } 106 }
110 here = lcode[hold & lmask]; 107 here = lcode + (hold & lmask);
111 dolen: 108 dolen:
112 op = (unsigned)(here.bits); 109 op = (unsigned)(here->bits);
113 hold >>= op; 110 hold >>= op;
114 bits -= op; 111 bits -= op;
115 op = (unsigned)(here.op); 112 op = (unsigned)(here->op);
116 if (op == 0) { /* literal */ 113 if (op == 0) { /* literal */
117 Tracevv((stderr, here.val >= 0x20 && here.val < 0x7f ? 114 Tracevv((stderr, here->val >= 0x20 && here->val < 0x7f ?
118 "inflate: literal '%c'\n" : 115 "inflate: literal '%c'\n" :
119 "inflate: literal 0x%02x\n", here.val)); 116 "inflate: literal 0x%02x\n", here->val));
120 *out++ = (unsigned char)(here.val); 117 *out++ = (unsigned char)(here->val);
121 } 118 }
122 else if (op & 16) { /* length base */ 119 else if (op & 16) { /* length base */
123 len = (unsigned)(here.val); 120 len = (unsigned)(here->val);
124 op &= 15; /* number of extra bits */ 121 op &= 15; /* number of extra bits */
125 if (op) { 122 if (op) {
126 if (bits < op) { 123 if (bits < op) {
127 hold += (unsigned long)(*in++) << bits; 124 hold += (unsigned long)(*in++) << bits;
128 bits += 8; 125 bits += 8;
136 hold += (unsigned long)(*in++) << bits; 133 hold += (unsigned long)(*in++) << bits;
137 bits += 8; 134 bits += 8;
138 hold += (unsigned long)(*in++) << bits; 135 hold += (unsigned long)(*in++) << bits;
139 bits += 8; 136 bits += 8;
140 } 137 }
141 here = dcode[hold & dmask]; 138 here = dcode + (hold & dmask);
142 dodist: 139 dodist:
143 op = (unsigned)(here.bits); 140 op = (unsigned)(here->bits);
144 hold >>= op; 141 hold >>= op;
145 bits -= op; 142 bits -= op;
146 op = (unsigned)(here.op); 143 op = (unsigned)(here->op);
147 if (op & 16) { /* distance base */ 144 if (op & 16) { /* distance base */
148 dist = (unsigned)(here.val); 145 dist = (unsigned)(here->val);
149 op &= 15; /* number of extra bits */ 146 op &= 15; /* number of extra bits */
150 if (bits < op) { 147 if (bits < op) {
151 hold += (unsigned long)(*in++) << bits; 148 hold += (unsigned long)(*in++) << bits;
152 bits += 8; 149 bits += 8;
153 if (bits < op) { 150 if (bits < op) {
262 *out++ = *from++; 259 *out++ = *from++;
263 } 260 }
264 } 261 }
265 } 262 }
266 else if ((op & 64) == 0) { /* 2nd level distance code */ 263 else if ((op & 64) == 0) { /* 2nd level distance code */
267 here = dcode[here.val + (hold & ((1U << op) - 1))]; 264 here = dcode + here->val + (hold & ((1U << op) - 1));
268 goto dodist; 265 goto dodist;
269 } 266 }
270 else { 267 else {
271 strm->msg = (char *)"invalid distance code"; 268 strm->msg = (char *)"invalid distance code";
272 state->mode = BAD; 269 state->mode = BAD;
273 break; 270 break;
274 } 271 }
275 } 272 }
276 else if ((op & 64) == 0) { /* 2nd level length code */ 273 else if ((op & 64) == 0) { /* 2nd level length code */
277 here = lcode[here.val + (hold & ((1U << op) - 1))]; 274 here = lcode + here->val + (hold & ((1U << op) - 1));
278 goto dolen; 275 goto dolen;
279 } 276 }
280 else if (op & 32) { /* end-of-block */ 277 else if (op & 32) { /* end-of-block */
281 Tracevv((stderr, "inflate: end of block\n")); 278 Tracevv((stderr, "inflate: end of block\n"));
282 state->mode = TYPE; 279 state->mode = TYPE;