1 | /* |
1 | /* |
2 | * Copyright (c) 2000-2007 Marc Alexander Lehmann <schmorp@schmorp.de> |
2 | * Copyright (c) 2000-2008 Marc Alexander Lehmann <schmorp@schmorp.de> |
3 | * |
3 | * |
4 | * Redistribution and use in source and binary forms, with or without modifica- |
4 | * Redistribution and use in source and binary forms, with or without modifica- |
5 | * tion, are permitted provided that the following conditions are met: |
5 | * tion, are permitted provided that the following conditions are met: |
6 | * |
6 | * |
7 | * 1. Redistributions of source code must retain the above copyright notice, |
7 | * 1. Redistributions of source code must retain the above copyright notice, |
… | |
… | |
45 | * it works ;) |
45 | * it works ;) |
46 | */ |
46 | */ |
47 | #ifndef FRST |
47 | #ifndef FRST |
48 | # define FRST(p) (((p[0]) << 8) | p[1]) |
48 | # define FRST(p) (((p[0]) << 8) | p[1]) |
49 | # define NEXT(v,p) (((v) << 8) | p[2]) |
49 | # define NEXT(v,p) (((v) << 8) | p[2]) |
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50 | # if ULTRA_FAST |
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51 | # define IDX(h) ((( h >> (3*8 - HLOG)) - h ) & (HSIZE - 1)) |
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52 | # elif VERY_FAST |
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53 | # define IDX(h) ((( h >> (3*8 - HLOG)) - h*5) & (HSIZE - 1)) |
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54 | # else |
50 | # define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1)) |
55 | # define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1)) |
51 | /*# define IDX(h) ((ip[0] * 121 ^ ip[1] * 33 ^ ip[2] * 1) & (HSIZE-1))*/ |
56 | # endif |
52 | #endif |
57 | #endif |
53 | /* |
58 | /* |
54 | * IDX works because it is very similar to a multiplicative hash, e.g. |
59 | * IDX works because it is very similar to a multiplicative hash, e.g. |
55 | * ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1)) |
60 | * ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1)) |
56 | * the latter is also quite fast on newer CPUs, and compresses similarly. |
61 | * the latter is also quite fast on newer CPUs, and compresses similarly. |
… | |
… | |
67 | #endif |
72 | #endif |
68 | |
73 | |
69 | #define MAX_LIT (1 << 5) |
74 | #define MAX_LIT (1 << 5) |
70 | #define MAX_OFF (1 << 13) |
75 | #define MAX_OFF (1 << 13) |
71 | #define MAX_REF ((1 << 8) + (1 << 3)) |
76 | #define MAX_REF ((1 << 8) + (1 << 3)) |
72 | |
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73 | #if (__i386 || __amd64) && __GNUC__ >= 3 |
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74 | # define lzf_movsb(dst, src, len) \ |
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75 | asm ("rep movsb" \ |
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76 | : "=D" (dst), "=S" (src), "=c" (len) \ |
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77 | : "0" (dst), "1" (src), "2" (len)); |
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78 | #endif |
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79 | |
77 | |
80 | #if __GNUC__ >= 3 |
78 | #if __GNUC__ >= 3 |
81 | # define expect(expr,value) __builtin_expect ((expr),(value)) |
79 | # define expect(expr,value) __builtin_expect ((expr),(value)) |
82 | # define inline inline |
80 | # define inline inline |
83 | #else |
81 | #else |
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113 | u8 *op = (u8 *)out_data; |
111 | u8 *op = (u8 *)out_data; |
114 | const u8 *in_end = ip + in_len; |
112 | const u8 *in_end = ip + in_len; |
115 | u8 *out_end = op + out_len; |
113 | u8 *out_end = op + out_len; |
116 | const u8 *ref; |
114 | const u8 *ref; |
117 | |
115 | |
118 | unsigned int hval = FRST (ip); |
116 | /* off requires a type wide enough to hold a general pointer difference. |
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117 | * ISO C doesn't have that (size_t might not be enough and ptrdiff_t only |
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118 | * works for differences within a single object). We also assume that no |
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119 | * no bit pattern traps. Since the only platform that is both non-POSIX |
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120 | * and fails to support both assumptions is windows 64 bit, we make a |
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121 | * special workaround for it. |
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122 | */ |
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123 | #if defined (WIN32) && defined (_M_X64) |
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124 | unsigned _int64 off; /* workaround for missing POSIX compliance */ |
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125 | #else |
119 | unsigned long off; |
126 | unsigned long off; |
120 | int lit = 0; |
127 | #endif |
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128 | unsigned int hval; |
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129 | int lit; |
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130 | |
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131 | if (!in_len || !out_len) |
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132 | return 0; |
121 | |
133 | |
122 | #if INIT_HTAB |
134 | #if INIT_HTAB |
123 | memset (htab, 0, sizeof (htab)); |
135 | memset (htab, 0, sizeof (htab)); |
124 | # if 0 |
136 | # if 0 |
125 | for (hslot = htab; hslot < htab + HSIZE; hslot++) |
137 | for (hslot = htab; hslot < htab + HSIZE; hslot++) |
126 | *hslot++ = ip; |
138 | *hslot++ = ip; |
127 | # endif |
139 | # endif |
128 | #endif |
140 | #endif |
129 | |
141 | |
130 | for (;;) |
142 | lit = 0; op++; /* start run */ |
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143 | |
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144 | hval = FRST (ip); |
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145 | while (ip < in_end - 2) |
131 | { |
146 | { |
132 | if (expect_true (ip < in_end - 2)) |
147 | hval = NEXT (hval, ip); |
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148 | hslot = htab + IDX (hval); |
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149 | ref = *hslot; *hslot = ip; |
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150 | |
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151 | if (1 |
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152 | #if INIT_HTAB |
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153 | && ref < ip /* the next test will actually take care of this, but this is faster */ |
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154 | #endif |
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155 | && (off = ip - ref - 1) < MAX_OFF |
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156 | && ip + 4 < in_end |
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157 | && ref > (u8 *)in_data |
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158 | #if STRICT_ALIGN |
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159 | && ref[0] == ip[0] |
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160 | && ref[1] == ip[1] |
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161 | && ref[2] == ip[2] |
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162 | #else |
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163 | && *(u16 *)ref == *(u16 *)ip |
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164 | && ref[2] == ip[2] |
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165 | #endif |
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166 | ) |
133 | { |
167 | { |
134 | hval = NEXT (hval, ip); |
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135 | hslot = htab + IDX (hval); |
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136 | ref = *hslot; *hslot = ip; |
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137 | |
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138 | if (1 |
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139 | #if INIT_HTAB && !USE_MEMCPY |
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140 | && ref < ip /* the next test will actually take care of this, but this is faster */ |
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141 | #endif |
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142 | && (off = ip - ref - 1) < MAX_OFF |
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143 | && ip + 4 < in_end |
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144 | && ref > (u8 *)in_data |
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145 | #if STRICT_ALIGN |
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146 | x x x |
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147 | && ref[0] == ip[0] |
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148 | && ref[1] == ip[1] |
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149 | && ref[2] == ip[2] |
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150 | #else |
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151 | && *(u16 *)ref == *(u16 *)ip |
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152 | && ref[2] == ip[2] |
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153 | #endif |
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154 | ) |
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155 | { |
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156 | /* match found at *ref++ */ |
168 | /* match found at *ref++ */ |
157 | unsigned int len = 2; |
169 | unsigned int len = 2; |
158 | unsigned int maxlen = in_end - ip - len; |
170 | unsigned int maxlen = in_end - ip - len; |
159 | maxlen = maxlen > MAX_REF ? MAX_REF : maxlen; |
171 | maxlen = maxlen > MAX_REF ? MAX_REF : maxlen; |
160 | |
172 | |
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173 | op [- lit - 1] = lit - 1; /* stop run */ |
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174 | op -= !lit; /* undo run if length is zero */ |
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175 | |
161 | if (expect_false (op + lit + 1 + 3 >= out_end)) |
176 | if (expect_false (op + 3 + 1 >= out_end)) |
162 | return 0; |
177 | return 0; |
163 | |
178 | |
164 | if (expect_false (lit)) |
179 | for (;;) |
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180 | { |
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181 | if (expect_true (maxlen > 16)) |
165 | { |
182 | { |
166 | *op++ = lit - 1; |
183 | len++; if (ref [len] != ip [len]) break; |
167 | lit = -lit; |
184 | len++; if (ref [len] != ip [len]) break; |
168 | do |
185 | len++; if (ref [len] != ip [len]) break; |
169 | *op++ = ip[lit]; |
186 | len++; if (ref [len] != ip [len]) break; |
170 | while (expect_false (++lit)); |
187 | |
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188 | len++; if (ref [len] != ip [len]) break; |
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189 | len++; if (ref [len] != ip [len]) break; |
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190 | len++; if (ref [len] != ip [len]) break; |
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191 | len++; if (ref [len] != ip [len]) break; |
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192 | |
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193 | len++; if (ref [len] != ip [len]) break; |
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194 | len++; if (ref [len] != ip [len]) break; |
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195 | len++; if (ref [len] != ip [len]) break; |
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196 | len++; if (ref [len] != ip [len]) break; |
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197 | |
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198 | len++; if (ref [len] != ip [len]) break; |
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199 | len++; if (ref [len] != ip [len]) break; |
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200 | len++; if (ref [len] != ip [len]) break; |
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201 | len++; if (ref [len] != ip [len]) break; |
171 | } |
202 | } |
172 | |
203 | |
173 | for (;;) |
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174 | { |
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175 | if (expect_true (maxlen > 16)) |
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176 | { |
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177 | len++; if (ref [len] != ip [len]) break; |
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178 | len++; if (ref [len] != ip [len]) break; |
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179 | len++; if (ref [len] != ip [len]) break; |
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180 | len++; if (ref [len] != ip [len]) break; |
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181 | len++; if (ref [len] != ip [len]) break; |
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182 | len++; if (ref [len] != ip [len]) break; |
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183 | len++; if (ref [len] != ip [len]) break; |
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184 | len++; if (ref [len] != ip [len]) break; |
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185 | len++; if (ref [len] != ip [len]) break; |
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186 | len++; if (ref [len] != ip [len]) break; |
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187 | len++; if (ref [len] != ip [len]) break; |
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188 | len++; if (ref [len] != ip [len]) break; |
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189 | len++; if (ref [len] != ip [len]) break; |
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190 | len++; if (ref [len] != ip [len]) break; |
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191 | len++; if (ref [len] != ip [len]) break; |
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192 | len++; if (ref [len] != ip [len]) break; |
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193 | } |
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194 | |
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195 | do |
204 | do |
196 | len++; |
205 | len++; |
197 | while (len < maxlen && ref[len] == ip[len]); |
206 | while (len < maxlen && ref[len] == ip[len]); |
198 | |
207 | |
199 | break; |
208 | break; |
200 | } |
209 | } |
201 | |
210 | |
202 | len -= 2; |
211 | len -= 2; /* len is now #octets - 1 */ |
203 | ip++; |
212 | ip++; |
204 | |
213 | |
205 | if (len < 7) |
214 | if (len < 7) |
206 | { |
215 | { |
207 | *op++ = (off >> 8) + (len << 5); |
216 | *op++ = (off >> 8) + (len << 5); |
208 | } |
217 | } |
209 | else |
218 | else |
210 | { |
219 | { |
211 | *op++ = (off >> 8) + ( 7 << 5); |
220 | *op++ = (off >> 8) + ( 7 << 5); |
212 | *op++ = len - 7; |
221 | *op++ = len - 7; |
213 | } |
222 | } |
214 | |
223 | |
215 | *op++ = off; |
224 | *op++ = off; |
216 | |
225 | |
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226 | if (expect_true (ip + len < in_end - 2)) |
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227 | { |
217 | #if ULTRA_FAST || VERY_FAST |
228 | #if ULTRA_FAST || VERY_FAST |
218 | ip += len; |
229 | ip += len; |
219 | #if VERY_FAST && !ULTRA_FAST |
230 | # if VERY_FAST && !ULTRA_FAST |
220 | --ip; |
231 | --ip; |
221 | #endif |
232 | # endif |
222 | hval = FRST (ip); |
233 | hval = FRST (ip); |
223 | |
234 | |
224 | hval = NEXT (hval, ip); |
235 | hval = NEXT (hval, ip); |
225 | htab[IDX (hval)] = ip; |
236 | htab[IDX (hval)] = ip; |
226 | ip++; |
237 | ip++; |
227 | |
238 | |
228 | #if VERY_FAST && !ULTRA_FAST |
239 | # if VERY_FAST && !ULTRA_FAST |
229 | hval = NEXT (hval, ip); |
240 | hval = NEXT (hval, ip); |
230 | htab[IDX (hval)] = ip; |
241 | htab[IDX (hval)] = ip; |
231 | ip++; |
242 | ip++; |
232 | #endif |
243 | # endif |
233 | #else |
244 | #else |
234 | do |
245 | do |
235 | { |
246 | { |
236 | hval = NEXT (hval, ip); |
247 | hval = NEXT (hval, ip); |
237 | htab[IDX (hval)] = ip; |
248 | htab[IDX (hval)] = ip; |
238 | ip++; |
249 | ip++; |
239 | } |
250 | } |
240 | while (len--); |
251 | while (len--); |
241 | #endif |
252 | #endif |
242 | continue; |
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243 | } |
253 | } |
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254 | |
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255 | lit = 0; op++; /* start run */ |
244 | } |
256 | } |
245 | else if (expect_false (ip == in_end)) |
257 | else |
246 | break; |
258 | { |
247 | |
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248 | /* one more literal byte we must copy */ |
259 | /* one more literal byte we must copy */ |
249 | lit++; |
260 | if (expect_false (op >= out_end)) |
250 | ip++; |
261 | return 0; |
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262 | |
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263 | lit++; *op++ = *ip++; |
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264 | |
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265 | if (expect_false (lit == MAX_LIT)) |
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266 | { |
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267 | op [- lit - 1] = lit - 1; /* stop run */ |
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268 | lit = 0; op++; /* start run */ |
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269 | } |
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270 | } |
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271 | } |
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272 | |
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273 | if (op + 3 > out_end) /* at most 3 bytes can be missing here */ |
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274 | return 0; |
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275 | |
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276 | while (ip < in_end) |
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277 | { |
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278 | lit++; *op++ = *ip++; |
251 | |
279 | |
252 | if (expect_false (lit == MAX_LIT)) |
280 | if (expect_false (lit == MAX_LIT)) |
253 | { |
281 | { |
254 | if (op + 1 + MAX_LIT >= out_end) |
282 | op [- lit - 1] = lit - 1; /* stop run */ |
255 | return 0; |
283 | lit = 0; op++; /* start run */ |
256 | |
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257 | *op++ = MAX_LIT - 1; |
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258 | |
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259 | #ifdef lzf_movsb |
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260 | ip -= MAX_LIT; |
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261 | lzf_movsb (op, ip, lit); |
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262 | #else |
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263 | lit = -lit; |
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264 | do |
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265 | *op++ = ip[lit]; |
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266 | while (++lit); |
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267 | #endif |
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268 | } |
284 | } |
269 | } |
285 | } |
270 | |
286 | |
271 | if (lit) |
287 | op [- lit - 1] = lit - 1; /* end run */ |
272 | { |
288 | op -= !lit; /* undo run if length is zero */ |
273 | if (op + lit + 1 >= out_end) |
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274 | return 0; |
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275 | |
289 | |
276 | *op++ = lit - 1; |
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277 | #ifdef lzf_movsb |
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278 | ip -= lit; |
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279 | lzf_movsb (op, ip, lit); |
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280 | #else |
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281 | lit = -lit; |
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282 | do |
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283 | *op++ = ip[lit]; |
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284 | while (++lit); |
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285 | #endif |
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286 | } |
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287 | |
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288 | return op - (u8 *) out_data; |
290 | return op - (u8 *)out_data; |
289 | } |
291 | } |
290 | |
292 | |