The Tor Browser: gfx/skia/trunk/src/core/SkPackBits.cpp@129ffea94266 (annotated)

gfx/skia/trunk/src/core/SkPackBits.cpp@129ffea94266 (annotated)

gfx/skia/trunk/src/core/SkPackBits.cpp

Sat, 03 Jan 2015 20:18:00 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Sat, 03 Jan 2015 20:18:00 +0100
branch: TOR_BUG_3246
changeset 7: 129ffea94266
permissions: -rw-r--r--

Conditionally enable double key logic according to:
private browsing mode or privacy.thirdparty.isolate preference and
implement in GetCookieStringCommon and FindCookie where it counts...
With some reservations of how to convince FindCookie users to test
condition and pass a nullptr when disabling double key logic.

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include "SkPackBits.h"
 #define GATHER_STATSx
 static inline void small_memcpy(void* SK_RESTRICT dst,
                                 const void* SK_RESTRICT src, int n) {
     SkASSERT(n > 0 && n <= 15);
     uint8_t* d = (uint8_t*)dst;
     const uint8_t* s = (const uint8_t*)src;
     switch (n) {
         case 15: *d++ = *s++;
         case 14: *d++ = *s++;
         case 13: *d++ = *s++;
         case 12: *d++ = *s++;
         case 11: *d++ = *s++;
         case 10: *d++ = *s++;
         case  9: *d++ = *s++;
         case  8: *d++ = *s++;
         case  7: *d++ = *s++;
         case  6: *d++ = *s++;
         case  5: *d++ = *s++;
         case  4: *d++ = *s++;
         case  3: *d++ = *s++;
         case  2: *d++ = *s++;
         case  1: *d++ = *s++;
         case  0: break;
     }
 }
 static inline void small_memset(void* dst, uint8_t value, int n) {
     SkASSERT(n > 0 && n <= 15);
     uint8_t* d = (uint8_t*)dst;
     switch (n) {
         case 15: *d++ = value;
         case 14: *d++ = value;
         case 13: *d++ = value;
         case 12: *d++ = value;
         case 11: *d++ = value;
         case 10: *d++ = value;
         case  9: *d++ = value;
         case  8: *d++ = value;
         case  7: *d++ = value;
         case  6: *d++ = value;
         case  5: *d++ = value;
         case  4: *d++ = value;
         case  3: *d++ = value;
         case  2: *d++ = value;
         case  1: *d++ = value;
         case  0: break;
     }
 }
 // can we do better for small counts with our own inlined memcpy/memset?
 #define PB_MEMSET(addr, value, count)       \
 do {                                        \
 if ((count) > 15) {                     \
 memset(addr, value, count);         \
 } else {                                \
 small_memset(addr, value, count);   \
 }                                       \
 } while (0)
 #define PB_MEMCPY(dst, src, count)      \
 do {                                    \
     if ((count) > 15) {                 \
         memcpy(dst, src, count);        \
     } else {                            \
         small_memcpy(dst, src, count);  \
     }                                   \
 } while (0)
 ///////////////////////////////////////////////////////////////////////////////
 #ifdef GATHER_STATS
     static int gMemSetBuckets[129];
     static int gMemCpyBuckets[129];
     static int gCounter;
 static void register_memset_count(int n) {
     SkASSERT((unsigned)n <= 128);
     gMemSetBuckets[n] += 1;
     gCounter += 1;
     if ((gCounter & 0xFF) == 0) {
         SkDebugf("----- packbits memset stats: ");
         for (size_t i = 0; i < SK_ARRAY_COUNT(gMemSetBuckets); i++) {
             if (gMemSetBuckets[i]) {
                 SkDebugf(" %d:%d", i, gMemSetBuckets[i]);
             }
         }
     }
 }
 static void register_memcpy_count(int n) {
     SkASSERT((unsigned)n <= 128);
     gMemCpyBuckets[n] += 1;
     gCounter += 1;
     if ((gCounter & 0x1FF) == 0) {
         SkDebugf("----- packbits memcpy stats: ");
         for (size_t i = 0; i < SK_ARRAY_COUNT(gMemCpyBuckets); i++) {
             if (gMemCpyBuckets[i]) {
                 SkDebugf(" %d:%d", i, gMemCpyBuckets[i]);
             }
         }
     }
 }
 #else
 #define register_memset_count(n)
 #define register_memcpy_count(n)
 #endif
 ///////////////////////////////////////////////////////////////////////////////
 size_t SkPackBits::ComputeMaxSize16(int count) {
     // worst case is the number of 16bit values (times 2) +
     // 1 byte per (up to) 128 entries.
     return ((count + 127) >> 7) + (count << 1);
 }
 size_t SkPackBits::ComputeMaxSize8(int count) {
     // worst case is the number of 8bit values + 1 byte per (up to) 128 entries.
     return ((count + 127) >> 7) + count;
 }
 static uint8_t* flush_same16(uint8_t dst[], uint16_t value, int count) {
     while (count > 0) {
         int n = count;
         if (n > 128) {
             n = 128;
         }
         *dst++ = (uint8_t)(n - 1);
         *dst++ = (uint8_t)(value >> 8);
         *dst++ = (uint8_t)value;
         count -= n;
     }
     return dst;
 }
 static uint8_t* flush_same8(uint8_t dst[], uint8_t value, int count) {
     while (count > 0) {
         int n = count;
         if (n > 128) {
             n = 128;
         }
         *dst++ = (uint8_t)(n - 1);
         *dst++ = (uint8_t)value;
         count -= n;
     }
     return dst;
 }
 static uint8_t* flush_diff16(uint8_t* SK_RESTRICT dst,
                              const uint16_t* SK_RESTRICT src, int count) {
     while (count > 0) {
         int n = count;
         if (n > 128) {
             n = 128;
         }
         *dst++ = (uint8_t)(n + 127);
         PB_MEMCPY(dst, src, n * sizeof(uint16_t));
         src += n;
         dst += n * sizeof(uint16_t);
         count -= n;
     }
     return dst;
 }
 static uint8_t* flush_diff8(uint8_t* SK_RESTRICT dst,
                             const uint8_t* SK_RESTRICT src, int count) {
     while (count > 0) {
         int n = count;
         if (n > 128) {
             n = 128;
         }
         *dst++ = (uint8_t)(n + 127);
         PB_MEMCPY(dst, src, n);
         src += n;
         dst += n;
         count -= n;
     }
     return dst;
 }
 size_t SkPackBits::Pack16(const uint16_t* SK_RESTRICT src, int count,
                           uint8_t* SK_RESTRICT dst) {
     uint8_t* origDst = dst;
     const uint16_t* stop = src + count;
     for (;;) {
         count = stop - src;
         SkASSERT(count >= 0);
         if (count == 0) {
             return dst - origDst;
         }
         if (1 == count) {
             *dst++ = 0;
             *dst++ = (uint8_t)(*src >> 8);
             *dst++ = (uint8_t)*src;
             return dst - origDst;
         }
         unsigned value = *src;
         const uint16_t* s = src + 1;
         if (*s == value) { // accumulate same values...
             do {
                 s++;
                 if (s == stop) {
                     break;
                 }
             } while (*s == value);
             dst = flush_same16(dst, value, s - src);
         } else {    // accumulate diff values...
             do {
                 if (++s == stop) {
                     goto FLUSH_DIFF;
                 }
             } while (*s != s[-1]);
             s -= 1; // back up so we don't grab one of the "same" values that follow
         FLUSH_DIFF:
             dst = flush_diff16(dst, src, s - src);
         }
         src = s;
     }
 }
 size_t SkPackBits::Pack8(const uint8_t* SK_RESTRICT src, int count,
                          uint8_t* SK_RESTRICT dst) {
     uint8_t* origDst = dst;
     const uint8_t* stop = src + count;
     for (;;) {
         count = stop - src;
         SkASSERT(count >= 0);
         if (count == 0) {
             return dst - origDst;
         }
         if (1 == count) {
             *dst++ = 0;
             *dst++ = *src;
             return dst - origDst;
         }
         unsigned value = *src;
         const uint8_t* s = src + 1;
         if (*s == value) { // accumulate same values...
             do {
                 s++;
                 if (s == stop) {
                     break;
                 }
             } while (*s == value);
             dst = flush_same8(dst, value, s - src);
         } else {    // accumulate diff values...
             do {
                 if (++s == stop) {
                     goto FLUSH_DIFF;
                 }
                 // only stop if we hit 3 in a row,
                 // otherwise we get bigger than compuatemax
             } while (*s != s[-1] || s[-1] != s[-2]);
             s -= 2; // back up so we don't grab the "same" values that follow
         FLUSH_DIFF:
             dst = flush_diff8(dst, src, s - src);
         }
         src = s;
     }
 }
 #include "SkUtils.h"
 int SkPackBits::Unpack16(const uint8_t* SK_RESTRICT src, size_t srcSize,
                          uint16_t* SK_RESTRICT dst) {
     uint16_t* origDst = dst;
     const uint8_t* stop = src + srcSize;
     while (src < stop) {
         unsigned n = *src++;
         if (n <= 127) {   // repeat count (n + 1)
             n += 1;
             sk_memset16(dst, (src[0] << 8) | src[1], n);
             src += 2;
         } else {    // same count (n - 127)
             n -= 127;
             PB_MEMCPY(dst, src, n * sizeof(uint16_t));
             src += n * sizeof(uint16_t);
         }
         dst += n;
     }
     SkASSERT(src == stop);
     return dst - origDst;
 }
 int SkPackBits::Unpack8(const uint8_t* SK_RESTRICT src, size_t srcSize,
                         uint8_t* SK_RESTRICT dst) {
     uint8_t* origDst = dst;
     const uint8_t* stop = src + srcSize;
     while (src < stop) {
         unsigned n = *src++;
         if (n <= 127) {   // repeat count (n + 1)
             n += 1;
             PB_MEMSET(dst, *src++, n);
         } else {    // same count (n - 127)
             n -= 127;
             PB_MEMCPY(dst, src, n);
             src += n;
         }
         dst += n;
     }
     SkASSERT(src == stop);
     return dst - origDst;
 }
 enum UnpackState {
     CLEAN_STATE,
     REPEAT_BYTE_STATE,
     COPY_SRC_STATE
 };
 void SkPackBits::Unpack8(uint8_t* SK_RESTRICT dst, size_t dstSkip,
                          size_t dstWrite, const uint8_t* SK_RESTRICT src) {
     if (dstWrite == 0) {
         return;
     }
     UnpackState state = CLEAN_STATE;
     size_t      stateCount = 0;
     // state 1: do the skip-loop
     while (dstSkip > 0) {
         unsigned n = *src++;
         if (n <= 127) {   // repeat count (n + 1)
             n += 1;
             if (n > dstSkip) {
                 state = REPEAT_BYTE_STATE;
                 stateCount = n - dstSkip;
                 n = dstSkip;
                 // we don't increment src here, since its needed in stage 2
             } else {
                 src++;  // skip the src byte
             }
         } else {    // same count (n - 127)
             n -= 127;
             if (n > dstSkip) {
                 state = COPY_SRC_STATE;
                 stateCount = n - dstSkip;
                 n = dstSkip;
             }
             src += n;
         }
         dstSkip -= n;
     }
     // stage 2: perform any catchup from the skip-stage
     if (stateCount > dstWrite) {
         stateCount = dstWrite;
     }
     switch (state) {
         case REPEAT_BYTE_STATE:
             SkASSERT(stateCount > 0);
             register_memset_count(stateCount);
             PB_MEMSET(dst, *src++, stateCount);
             break;
         case COPY_SRC_STATE:
             SkASSERT(stateCount > 0);
             register_memcpy_count(stateCount);
             PB_MEMCPY(dst, src, stateCount);
             src += stateCount;
             break;
         default:
             SkASSERT(stateCount == 0);
             break;
     }
     dst += stateCount;
     dstWrite -= stateCount;
     // copy at most dstWrite bytes into dst[]
     while (dstWrite > 0) {
         unsigned n = *src++;
         if (n <= 127) {   // repeat count (n + 1)
             n += 1;
             if (n > dstWrite) {
                 n = dstWrite;
             }
             register_memset_count(n);
             PB_MEMSET(dst, *src++, n);
         } else {    // same count (n - 127)
             n -= 127;
             if (n > dstWrite) {
                 n = dstWrite;
             }
             register_memcpy_count(n);
             PB_MEMCPY(dst, src, n);
             src += n;
         }
         dst += n;
         dstWrite -= n;
     }
     SkASSERT(0 == dstWrite);
 }

The Tor Browser / annotate

gfx/skia/trunk/src/core/SkPackBits.cpp@129ffea94266 (annotated)

gfx/skia/trunk/src/core/SkPackBits.cpp