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## src/java.desktop/share/native/libjavajpeg/jdphuff.c

 ``` `````` 198 199 200 /* 201 * Figure F.12: extend sign bit. 202 * On some machines, a shift and add will be faster than a table lookup. 203 */ 204 205 #ifdef AVOID_TABLES 206 207 #define HUFF_EXTEND(x,s) ((x) < (1<<((s)-1)) ? (x) + (((-1)<<(s)) + 1) : (x)) 208 209 #else 210 211 #define HUFF_EXTEND(x,s) ((x) < extend_test[s] ? (x) + extend_offset[s] : (x)) 212 213 static const int extend_test[16] = /* entry n is 2**(n-1) */ 214 { 0, 0x0001, 0x0002, 0x0004, 0x0008, 0x0010, 0x0020, 0x0040, 0x0080, 215 0x0100, 0x0200, 0x0400, 0x0800, 0x1000, 0x2000, 0x4000 }; 216 217 static const int extend_offset[16] = /* entry n is (-1 << n) + 1 */ 218 { 0, ((-1)<<1) + 1, ((-1)<<2) + 1, ((-1)<<3) + 1, ((-1)<<4) + 1, 219 ((-1)<<5) + 1, ((-1)<<6) + 1, ((-1)<<7) + 1, ((-1)<<8) + 1, 220 ((-1)<<9) + 1, ((-1)<<10) + 1, ((-1)<<11) + 1, ((-1)<<12) + 1, 221 ((-1)<<13) + 1, ((-1)<<14) + 1, ((-1)<<15) + 1 }; 222 223 #endif /* AVOID_TABLES */ 224 225 226 /* 227 * Check for a restart marker & resynchronize decoder. 228 * Returns FALSE if must suspend. 229 */ 230 231 LOCAL(boolean) 232 process_restart (j_decompress_ptr cinfo) 233 { 234 phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy; 235 int ci; 236 237 /* Throw away any unused bits remaining in bit buffer; */ 238 /* include any full bytes in next_marker's count of discarded bytes */ 239 cinfo->marker->discarded_bytes += entropy->bitstate.bits_left / 8; 240 entropy->bitstate.bits_left = 0; 241 ``` ``` `````` 198 199 200 /* 201 * Figure F.12: extend sign bit. 202 * On some machines, a shift and add will be faster than a table lookup. 203 */ 204 205 #ifdef AVOID_TABLES 206 207 #define HUFF_EXTEND(x,s) ((x) < (1<<((s)-1)) ? (x) + (((-1)<<(s)) + 1) : (x)) 208 209 #else 210 211 #define HUFF_EXTEND(x,s) ((x) < extend_test[s] ? (x) + extend_offset[s] : (x)) 212 213 static const int extend_test[16] = /* entry n is 2**(n-1) */ 214 { 0, 0x0001, 0x0002, 0x0004, 0x0008, 0x0010, 0x0020, 0x0040, 0x0080, 215 0x0100, 0x0200, 0x0400, 0x0800, 0x1000, 0x2000, 0x4000 }; 216 217 static const int extend_offset[16] = /* entry n is (-1 << n) + 1 */ 218 { 0, 219 (int)(((unsigned)(~0)<<1) + 1), (int)(((unsigned)(~0)<<2) + 1), 220 (int)(((unsigned)(~0)<<3) + 1), (int)(((unsigned)(~0)<<4) + 1), 221 (int)(((unsigned)(~0)<<5) + 1), (int)(((unsigned)(~0)<<6) + 1), 222 (int)(((unsigned)(~0)<<7) + 1), (int)(((unsigned)(~0)<<8) + 1), 223 (int)(((unsigned)(~0)<<9) + 1), (int)(((unsigned)(~0)<<10) + 1), 224 (int)(((unsigned)(~0)<<11) + 1), (int)(((unsigned)(~0)<<12) + 1), 225 (int)(((unsigned)(~0)<<13) + 1), (int)(((unsigned)(~0)<<14) + 1), 226 (int)(((unsigned)(~0)<<15) + 1) }; 227 228 #endif /* AVOID_TABLES */ 229 230 231 /* 232 * Check for a restart marker & resynchronize decoder. 233 * Returns FALSE if must suspend. 234 */ 235 236 LOCAL(boolean) 237 process_restart (j_decompress_ptr cinfo) 238 { 239 phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy; 240 int ci; 241 242 /* Throw away any unused bits remaining in bit buffer; */ 243 /* include any full bytes in next_marker's count of discarded bytes */ 244 cinfo->marker->discarded_bytes += entropy->bitstate.bits_left / 8; 245 entropy->bitstate.bits_left = 0; 246 ```