reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame^] | 1 | #include "SkPackBits.h" |
| 2 | |
| 3 | #define GATHER_STATSx |
| 4 | |
| 5 | static inline void small_memcpy(void* SK_RESTRICT dst, |
| 6 | const void* SK_RESTRICT src, int n) { |
| 7 | SkASSERT(n > 0 && n <= 15); |
| 8 | uint8_t* d = (uint8_t*)dst; |
| 9 | const uint8_t* s = (const uint8_t*)src; |
| 10 | switch (n) { |
| 11 | case 15: *d++ = *s++; |
| 12 | case 14: *d++ = *s++; |
| 13 | case 13: *d++ = *s++; |
| 14 | case 12: *d++ = *s++; |
| 15 | case 11: *d++ = *s++; |
| 16 | case 10: *d++ = *s++; |
| 17 | case 9: *d++ = *s++; |
| 18 | case 8: *d++ = *s++; |
| 19 | case 7: *d++ = *s++; |
| 20 | case 6: *d++ = *s++; |
| 21 | case 5: *d++ = *s++; |
| 22 | case 4: *d++ = *s++; |
| 23 | case 3: *d++ = *s++; |
| 24 | case 2: *d++ = *s++; |
| 25 | case 1: *d++ = *s++; |
| 26 | case 0: break; |
| 27 | } |
| 28 | } |
| 29 | |
| 30 | static inline void small_memset(void* dst, uint8_t value, int n) { |
| 31 | SkASSERT(n > 0 && n <= 15); |
| 32 | uint8_t* d = (uint8_t*)dst; |
| 33 | switch (n) { |
| 34 | case 15: *d++ = value; |
| 35 | case 14: *d++ = value; |
| 36 | case 13: *d++ = value; |
| 37 | case 12: *d++ = value; |
| 38 | case 11: *d++ = value; |
| 39 | case 10: *d++ = value; |
| 40 | case 9: *d++ = value; |
| 41 | case 8: *d++ = value; |
| 42 | case 7: *d++ = value; |
| 43 | case 6: *d++ = value; |
| 44 | case 5: *d++ = value; |
| 45 | case 4: *d++ = value; |
| 46 | case 3: *d++ = value; |
| 47 | case 2: *d++ = value; |
| 48 | case 1: *d++ = value; |
| 49 | case 0: break; |
| 50 | } |
| 51 | } |
| 52 | |
| 53 | // can we do better for small counts with our own inlined memcpy/memset? |
| 54 | |
| 55 | #define PB_MEMSET(addr, value, count) \ |
| 56 | do { \ |
| 57 | if ((count) > 15) { \ |
| 58 | memset(addr, value, count); \ |
| 59 | } else { \ |
| 60 | small_memset(addr, value, count); \ |
| 61 | } \ |
| 62 | } while (0) |
| 63 | |
| 64 | #define PB_MEMCPY(dst, src, count) \ |
| 65 | do { \ |
| 66 | if ((count) > 15) { \ |
| 67 | memcpy(dst, src, count); \ |
| 68 | } else { \ |
| 69 | small_memcpy(dst, src, count); \ |
| 70 | } \ |
| 71 | } while (0) |
| 72 | |
| 73 | /////////////////////////////////////////////////////////////////////////////// |
| 74 | |
| 75 | #ifdef GATHER_STATS |
| 76 | static int gMemSetBuckets[129]; |
| 77 | static int gMemCpyBuckets[129]; |
| 78 | static int gCounter; |
| 79 | |
| 80 | static void register_memset_count(int n) { |
| 81 | SkASSERT((unsigned)n <= 128); |
| 82 | gMemSetBuckets[n] += 1; |
| 83 | gCounter += 1; |
| 84 | |
| 85 | if ((gCounter & 0xFF) == 0) { |
| 86 | SkDebugf("----- packbits memset stats: "); |
| 87 | for (size_t i = 0; i < SK_ARRAY_COUNT(gMemSetBuckets); i++) { |
| 88 | if (gMemSetBuckets[i]) { |
| 89 | SkDebugf(" %d:%d", i, gMemSetBuckets[i]); |
| 90 | } |
| 91 | } |
| 92 | } |
| 93 | } |
| 94 | static void register_memcpy_count(int n) { |
| 95 | SkASSERT((unsigned)n <= 128); |
| 96 | gMemCpyBuckets[n] += 1; |
| 97 | gCounter += 1; |
| 98 | |
| 99 | if ((gCounter & 0x1FF) == 0) { |
| 100 | SkDebugf("----- packbits memcpy stats: "); |
| 101 | for (size_t i = 0; i < SK_ARRAY_COUNT(gMemCpyBuckets); i++) { |
| 102 | if (gMemCpyBuckets[i]) { |
| 103 | SkDebugf(" %d:%d", i, gMemCpyBuckets[i]); |
| 104 | } |
| 105 | } |
| 106 | } |
| 107 | } |
| 108 | #else |
| 109 | #define register_memset_count(n) |
| 110 | #define register_memcpy_count(n) |
| 111 | #endif |
| 112 | |
| 113 | |
| 114 | /////////////////////////////////////////////////////////////////////////////// |
| 115 | |
| 116 | size_t SkPackBits::ComputeMaxSize16(int count) { |
| 117 | // worst case is the number of 16bit values (times 2) + |
| 118 | // 1 byte per (up to) 128 entries. |
| 119 | return ((count + 127) >> 7) + (count << 1); |
| 120 | } |
| 121 | |
| 122 | size_t SkPackBits::ComputeMaxSize8(int count) { |
| 123 | // worst case is the number of 8bit values + 1 byte per (up to) 128 entries. |
| 124 | return ((count + 127) >> 7) + count; |
| 125 | } |
| 126 | |
| 127 | static uint8_t* flush_same16(uint8_t dst[], uint16_t value, int count) { |
| 128 | while (count > 0) { |
| 129 | int n = count; |
| 130 | if (n > 128) { |
| 131 | n = 128; |
| 132 | } |
| 133 | *dst++ = (uint8_t)(n - 1); |
| 134 | *dst++ = (uint8_t)(value >> 8); |
| 135 | *dst++ = (uint8_t)value; |
| 136 | count -= n; |
| 137 | } |
| 138 | return dst; |
| 139 | } |
| 140 | |
| 141 | static uint8_t* flush_same8(uint8_t dst[], uint8_t value, int count) { |
| 142 | while (count > 0) { |
| 143 | int n = count; |
| 144 | if (n > 128) { |
| 145 | n = 128; |
| 146 | } |
| 147 | *dst++ = (uint8_t)(n - 1); |
| 148 | *dst++ = (uint8_t)value; |
| 149 | count -= n; |
| 150 | } |
| 151 | return dst; |
| 152 | } |
| 153 | |
| 154 | static uint8_t* flush_diff16(uint8_t SK_RESTRICT dst[], |
| 155 | const uint16_t SK_RESTRICT src[], int count) { |
| 156 | while (count > 0) { |
| 157 | int n = count; |
| 158 | if (n > 128) { |
| 159 | n = 128; |
| 160 | } |
| 161 | *dst++ = (uint8_t)(n + 127); |
| 162 | PB_MEMCPY(dst, src, n * sizeof(uint16_t)); |
| 163 | src += n; |
| 164 | dst += n * sizeof(uint16_t); |
| 165 | count -= n; |
| 166 | } |
| 167 | return dst; |
| 168 | } |
| 169 | |
| 170 | static uint8_t* flush_diff8(uint8_t SK_RESTRICT dst[], |
| 171 | const uint8_t SK_RESTRICT src[], int count) { |
| 172 | while (count > 0) { |
| 173 | int n = count; |
| 174 | if (n > 128) { |
| 175 | n = 128; |
| 176 | } |
| 177 | *dst++ = (uint8_t)(n + 127); |
| 178 | PB_MEMCPY(dst, src, n); |
| 179 | src += n; |
| 180 | dst += n; |
| 181 | count -= n; |
| 182 | } |
| 183 | return dst; |
| 184 | } |
| 185 | |
| 186 | size_t SkPackBits::Pack16(const uint16_t SK_RESTRICT src[], int count, |
| 187 | uint8_t SK_RESTRICT dst[]) { |
| 188 | uint8_t* origDst = dst; |
| 189 | const uint16_t* stop = src + count; |
| 190 | |
| 191 | for (;;) { |
| 192 | count = stop - src; |
| 193 | SkASSERT(count >= 0); |
| 194 | if (count == 0) { |
| 195 | return dst - origDst; |
| 196 | } |
| 197 | if (1 == count) { |
| 198 | *dst++ = 0; |
| 199 | *dst++ = (uint8_t)(*src >> 8); |
| 200 | *dst++ = (uint8_t)*src; |
| 201 | return dst - origDst; |
| 202 | } |
| 203 | |
| 204 | unsigned value = *src; |
| 205 | const uint16_t* s = src + 1; |
| 206 | |
| 207 | if (*s == value) { // accumulate same values... |
| 208 | do { |
| 209 | s++; |
| 210 | if (s == stop) { |
| 211 | break; |
| 212 | } |
| 213 | } while (*s == value); |
| 214 | dst = flush_same16(dst, value, s - src); |
| 215 | } else { // accumulate diff values... |
| 216 | do { |
| 217 | if (++s == stop) { |
| 218 | goto FLUSH_DIFF; |
| 219 | } |
| 220 | } while (*s != s[-1]); |
| 221 | s -= 1; // back up so we don't grab one of the "same" values that follow |
| 222 | FLUSH_DIFF: |
| 223 | dst = flush_diff16(dst, src, s - src); |
| 224 | } |
| 225 | src = s; |
| 226 | } |
| 227 | } |
| 228 | |
| 229 | size_t SkPackBits::Pack8(const uint8_t SK_RESTRICT src[], int count, |
| 230 | uint8_t SK_RESTRICT dst[]) { |
| 231 | uint8_t* origDst = dst; |
| 232 | const uint8_t* stop = src + count; |
| 233 | |
| 234 | for (;;) { |
| 235 | count = stop - src; |
| 236 | SkASSERT(count >= 0); |
| 237 | if (count == 0) { |
| 238 | return dst - origDst; |
| 239 | } |
| 240 | if (1 == count) { |
| 241 | *dst++ = 0; |
| 242 | *dst++ = *src; |
| 243 | return dst - origDst; |
| 244 | } |
| 245 | |
| 246 | unsigned value = *src; |
| 247 | const uint8_t* s = src + 1; |
| 248 | |
| 249 | if (*s == value) { // accumulate same values... |
| 250 | do { |
| 251 | s++; |
| 252 | if (s == stop) { |
| 253 | break; |
| 254 | } |
| 255 | } while (*s == value); |
| 256 | dst = flush_same8(dst, value, s - src); |
| 257 | } else { // accumulate diff values... |
| 258 | do { |
| 259 | if (++s == stop) { |
| 260 | goto FLUSH_DIFF; |
| 261 | } |
| 262 | // only stop if we hit 3 in a row, |
| 263 | // otherwise we get bigger than compuatemax |
| 264 | } while (*s != s[-1] || s[-1] != s[-2]); |
| 265 | s -= 2; // back up so we don't grab the "same" values that follow |
| 266 | FLUSH_DIFF: |
| 267 | dst = flush_diff8(dst, src, s - src); |
| 268 | } |
| 269 | src = s; |
| 270 | } |
| 271 | } |
| 272 | |
| 273 | #include "SkUtils.h" |
| 274 | |
| 275 | int SkPackBits::Unpack16(const uint8_t SK_RESTRICT src[], size_t srcSize, |
| 276 | uint16_t SK_RESTRICT dst[]) { |
| 277 | uint16_t* origDst = dst; |
| 278 | const uint8_t* stop = src + srcSize; |
| 279 | |
| 280 | while (src < stop) { |
| 281 | unsigned n = *src++; |
| 282 | if (n <= 127) { // repeat count (n + 1) |
| 283 | n += 1; |
| 284 | sk_memset16(dst, (src[0] << 8) | src[1], n); |
| 285 | src += 2; |
| 286 | } else { // same count (n - 127) |
| 287 | n -= 127; |
| 288 | PB_MEMCPY(dst, src, n * sizeof(uint16_t)); |
| 289 | src += n * sizeof(uint16_t); |
| 290 | } |
| 291 | dst += n; |
| 292 | } |
| 293 | SkASSERT(src == stop); |
| 294 | return dst - origDst; |
| 295 | } |
| 296 | |
| 297 | int SkPackBits::Unpack8(const uint8_t SK_RESTRICT src[], size_t srcSize, |
| 298 | uint8_t SK_RESTRICT dst[]) { |
| 299 | uint8_t* origDst = dst; |
| 300 | const uint8_t* stop = src + srcSize; |
| 301 | |
| 302 | while (src < stop) { |
| 303 | unsigned n = *src++; |
| 304 | if (n <= 127) { // repeat count (n + 1) |
| 305 | n += 1; |
| 306 | PB_MEMSET(dst, *src++, n); |
| 307 | } else { // same count (n - 127) |
| 308 | n -= 127; |
| 309 | PB_MEMCPY(dst, src, n); |
| 310 | src += n; |
| 311 | } |
| 312 | dst += n; |
| 313 | } |
| 314 | SkASSERT(src == stop); |
| 315 | return dst - origDst; |
| 316 | } |
| 317 | |
| 318 | enum UnpackState { |
| 319 | CLEAN_STATE, |
| 320 | REPEAT_BYTE_STATE, |
| 321 | COPY_SRC_STATE |
| 322 | }; |
| 323 | |
| 324 | void SkPackBits::Unpack8(uint8_t SK_RESTRICT dst[], size_t dstSkip, |
| 325 | size_t dstWrite, const uint8_t SK_RESTRICT src[]) { |
| 326 | if (dstWrite == 0) { |
| 327 | return; |
| 328 | } |
| 329 | |
| 330 | UnpackState state = CLEAN_STATE; |
| 331 | size_t stateCount = 0; |
| 332 | |
| 333 | // state 1: do the skip-loop |
| 334 | while (dstSkip > 0) { |
| 335 | unsigned n = *src++; |
| 336 | if (n <= 127) { // repeat count (n + 1) |
| 337 | n += 1; |
| 338 | if (n > dstSkip) { |
| 339 | state = REPEAT_BYTE_STATE; |
| 340 | stateCount = n - dstSkip; |
| 341 | n = dstSkip; |
| 342 | // we don't increment src here, since its needed in stage 2 |
| 343 | } else { |
| 344 | src++; // skip the src byte |
| 345 | } |
| 346 | } else { // same count (n - 127) |
| 347 | n -= 127; |
| 348 | if (n > dstSkip) { |
| 349 | state = COPY_SRC_STATE; |
| 350 | stateCount = n - dstSkip; |
| 351 | n = dstSkip; |
| 352 | } |
| 353 | src += n; |
| 354 | } |
| 355 | dstSkip -= n; |
| 356 | } |
| 357 | |
| 358 | // stage 2: perform any catchup from the skip-stage |
| 359 | if (stateCount > dstWrite) { |
| 360 | stateCount = dstWrite; |
| 361 | } |
| 362 | switch (state) { |
| 363 | case REPEAT_BYTE_STATE: |
| 364 | SkASSERT(stateCount > 0); |
| 365 | register_memset_count(stateCount); |
| 366 | PB_MEMSET(dst, *src++, stateCount); |
| 367 | break; |
| 368 | case COPY_SRC_STATE: |
| 369 | SkASSERT(stateCount > 0); |
| 370 | register_memcpy_count(stateCount); |
| 371 | PB_MEMCPY(dst, src, stateCount); |
| 372 | src += stateCount; |
| 373 | break; |
| 374 | default: |
| 375 | SkASSERT(stateCount == 0); |
| 376 | break; |
| 377 | } |
| 378 | dst += stateCount; |
| 379 | dstWrite -= stateCount; |
| 380 | |
| 381 | // copy at most dstWrite bytes into dst[] |
| 382 | while (dstWrite > 0) { |
| 383 | unsigned n = *src++; |
| 384 | if (n <= 127) { // repeat count (n + 1) |
| 385 | n += 1; |
| 386 | if (n > dstWrite) { |
| 387 | n = dstWrite; |
| 388 | } |
| 389 | register_memset_count(n); |
| 390 | PB_MEMSET(dst, *src++, n); |
| 391 | } else { // same count (n - 127) |
| 392 | n -= 127; |
| 393 | if (n > dstWrite) { |
| 394 | n = dstWrite; |
| 395 | } |
| 396 | register_memcpy_count(n); |
| 397 | PB_MEMCPY(dst, src, n); |
| 398 | src += n; |
| 399 | } |
| 400 | dst += n; |
| 401 | dstWrite -= n; |
| 402 | } |
| 403 | SkASSERT(0 == dstWrite); |
| 404 | } |
| 405 | |
| 406 | |
| 407 | |