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

gfx/skia/trunk/src/core/SkAntiRun.h@129ffea94266 (annotated)

gfx/skia/trunk/src/core/SkAntiRun.h

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 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #ifndef SkAntiRun_DEFINED
 #define SkAntiRun_DEFINED
 #include "SkBlitter.h"
 /** Sparse array of run-length-encoded alpha (supersampling coverage) values.
     Sparseness allows us to independently compose several paths into the
     same SkAlphaRuns buffer.
 */
 class SkAlphaRuns {
 public:
     int16_t*    fRuns;
     uint8_t*     fAlpha;
     /// Returns true if the scanline contains only a single run,
     /// of alpha value 0.
     bool empty() const {
         SkASSERT(fRuns[0] > 0);
         return fAlpha[0] == 0 && fRuns[fRuns[0]] == 0;
     }
     /// Reinitialize for a new scanline.
     void    reset(int width);
     /**
      *  Insert into the buffer a run starting at (x-offsetX):
      *      if startAlpha > 0
      *          one pixel with value += startAlpha,
      *              max 255
      *      if middleCount > 0
      *          middleCount pixels with value += maxValue
      *      if stopAlpha > 0
      *          one pixel with value += stopAlpha
      *  Returns the offsetX value that should be passed on the next call,
      *  assuming we're on the same scanline. If the caller is switching
      *  scanlines, then offsetX should be 0 when this is called.
      */
     SK_ALWAYS_INLINE int add(int x, U8CPU startAlpha, int middleCount, U8CPU stopAlpha,
                              U8CPU maxValue, int offsetX) {
         SkASSERT(middleCount >= 0);
         SkASSERT(x >= 0 && x + (startAlpha != 0) + middleCount + (stopAlpha != 0) <= fWidth);
         SkASSERT(fRuns[offsetX] >= 0);
         int16_t*    runs = fRuns + offsetX;
         uint8_t*    alpha = fAlpha + offsetX;
         uint8_t*    lastAlpha = alpha;
         x -= offsetX;
         if (startAlpha) {
             SkAlphaRuns::Break(runs, alpha, x, 1);
             /*  I should be able to just add alpha[x] + startAlpha.
                 However, if the trailing edge of the previous span and the leading
                 edge of the current span round to the same super-sampled x value,
                 I might overflow to 256 with this add, hence the funny subtract (crud).
             */
             unsigned tmp = alpha[x] + startAlpha;
             SkASSERT(tmp <= 256);
             alpha[x] = SkToU8(tmp - (tmp >> 8));    // was (tmp >> 7), but that seems wrong if we're trying to catch 256
             runs += x + 1;
             alpha += x + 1;
             x = 0;
             lastAlpha += x; // we don't want the +1
             SkDEBUGCODE(this->validate();)
         }
         if (middleCount) {
             SkAlphaRuns::Break(runs, alpha, x, middleCount);
             alpha += x;
             runs += x;
             x = 0;
             do {
                 alpha[0] = SkToU8(alpha[0] + maxValue);
                 int n = runs[0];
                 SkASSERT(n <= middleCount);
                 alpha += n;
                 runs += n;
                 middleCount -= n;
             } while (middleCount > 0);
             SkDEBUGCODE(this->validate();)
             lastAlpha = alpha;
         }
         if (stopAlpha) {
             SkAlphaRuns::Break(runs, alpha, x, 1);
             alpha += x;
             alpha[0] = SkToU8(alpha[0] + stopAlpha);
             SkDEBUGCODE(this->validate();)
             lastAlpha = alpha;
         }
         return SkToS32(lastAlpha - fAlpha);  // new offsetX
     }
     SkDEBUGCODE(void assertValid(int y, int maxStep) const;)
     SkDEBUGCODE(void dump() const;)
     /**
      * Break the runs in the buffer at offsets x and x+count, properly
      * updating the runs to the right and left.
      *   i.e. from the state AAAABBBB, run-length encoded as A4B4,
      *   Break(..., 2, 5) would produce AAAABBBB rle as A2A2B3B1.
      * Allows add() to sum another run to some of the new sub-runs.
      *   i.e. adding ..CCCCC. would produce AADDEEEB, rle as A2D2E3B1.
      */
     static void Break(int16_t runs[], uint8_t alpha[], int x, int count) {
         SkASSERT(count > 0 && x >= 0);
         //  SkAlphaRuns::BreakAt(runs, alpha, x);
         //  SkAlphaRuns::BreakAt(&runs[x], &alpha[x], count);
         int16_t* next_runs = runs + x;
         uint8_t*  next_alpha = alpha + x;
         while (x > 0) {
             int n = runs[0];
             SkASSERT(n > 0);
             if (x < n) {
                 alpha[x] = alpha[0];
                 runs[0] = SkToS16(x);
                 runs[x] = SkToS16(n - x);
                 break;
             }
             runs += n;
             alpha += n;
             x -= n;
         }
         runs = next_runs;
         alpha = next_alpha;
         x = count;
         for (;;) {
             int n = runs[0];
             SkASSERT(n > 0);
             if (x < n) {
                 alpha[x] = alpha[0];
                 runs[0] = SkToS16(x);
                 runs[x] = SkToS16(n - x);
                 break;
             }
             x -= n;
             if (x <= 0) {
                 break;
             }
             runs += n;
             alpha += n;
         }
     }
     /**
      * Cut (at offset x in the buffer) a run into two shorter runs with
      * matching alpha values.
      * Used by the RectClipBlitter to trim a RLE encoding to match the
      * clipping rectangle.
      */
     static void BreakAt(int16_t runs[], uint8_t alpha[], int x) {
         while (x > 0) {
             int n = runs[0];
             SkASSERT(n > 0);
             if (x < n) {
                 alpha[x] = alpha[0];
                 runs[0] = SkToS16(x);
                 runs[x] = SkToS16(n - x);
                 break;
             }
             runs += n;
             alpha += n;
             x -= n;
         }
     }
 private:
     SkDEBUGCODE(int fWidth;)
     SkDEBUGCODE(void validate() const;)
 };
 #endif

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gfx/skia/trunk/src/core/SkAntiRun.h@129ffea94266 (annotated)

gfx/skia/trunk/src/core/SkAntiRun.h