1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/skia/trunk/src/core/SkOffsetTable.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,115 @@
1.4 +/*
1.5 + * Copyright 2014 Google Inc.
1.6 + *
1.7 + * Use of this source code is governed by a BSD-style license that can be
1.8 + * found in the LICENSE file.
1.9 + */
1.10 +
1.11 +#ifndef SkOffsetTable_DEFINED
1.12 +#define SkOffsetTable_DEFINED
1.13 +
1.14 +#include "SkRefCnt.h"
1.15 +#include "SkTDArray.h"
1.16 +
1.17 +// A 2D table of skp offsets. Each row is indexed by an int. This is used
1.18 +// to store the command offsets that reference a particular bitmap using
1.19 +// the bitmap's index in the bitmap heap as the 'id' here. It has to be
1.20 +// ref-countable so SkPicturePlayback can take ownership of it.
1.21 +// Note that this class assumes that the ids are densely packed.
1.22 +
1.23 +// TODO: This needs to be sped up. We could replace the offset table with
1.24 +// a hash table.
1.25 +class SkOffsetTable : public SkRefCnt {
1.26 +public:
1.27 + SkOffsetTable() {}
1.28 + ~SkOffsetTable() {
1.29 + fOffsetArrays.deleteAll();
1.30 + }
1.31 +
1.32 + // Record that this 'id' is used by the command starting at this 'offset'.
1.33 + // Offsets for a given 'id' should always be added in increasing order.
1.34 + void add(int id, size_t offset) {
1.35 + if (id >= fOffsetArrays.count()) {
1.36 + int oldCount = fOffsetArrays.count();
1.37 + fOffsetArrays.setCount(id+1);
1.38 + for (int i = oldCount; i <= id; ++i) {
1.39 + fOffsetArrays[i] = NULL;
1.40 + }
1.41 + }
1.42 +
1.43 + if (NULL == fOffsetArrays[id]) {
1.44 + fOffsetArrays[id] = SkNEW(OffsetArray);
1.45 + }
1.46 + fOffsetArrays[id]->add(offset);
1.47 + }
1.48 +
1.49 + int numIDs() const {
1.50 + return fOffsetArrays.count();
1.51 + }
1.52 +
1.53 + // Do the offsets of any commands referencing this ID fall in the
1.54 + // range [min, max] (both inclusive)
1.55 + bool overlap(int id, size_t min, size_t max) {
1.56 + SkASSERT(id < fOffsetArrays.count());
1.57 +
1.58 + if (NULL == fOffsetArrays[id]) {
1.59 + return false;
1.60 + }
1.61 +
1.62 + // If this id has an offset array it should have at least one use
1.63 + SkASSERT(fOffsetArrays[id]->count() > 0);
1.64 + if (max < fOffsetArrays[id]->min() || min > fOffsetArrays[id]->max()) {
1.65 + return false;
1.66 + }
1.67 +
1.68 + return true;
1.69 + }
1.70 +
1.71 + bool includes(int id, size_t offset) {
1.72 + SkASSERT(id < fOffsetArrays.count());
1.73 +
1.74 + OffsetArray* array = fOffsetArrays[id];
1.75 +
1.76 + for (int i = 0; i < array->fOffsets.count(); ++i) {
1.77 + if (array->fOffsets[i] == offset) {
1.78 + return true;
1.79 + } else if (array->fOffsets[i] > offset) {
1.80 + return false;
1.81 + }
1.82 + }
1.83 +
1.84 + // Calls to 'includes' should be gaurded by an overlap() call, so we
1.85 + // should always find something.
1.86 + SkASSERT(0);
1.87 + return false;
1.88 + }
1.89 +
1.90 +protected:
1.91 + class OffsetArray {
1.92 + public:
1.93 + void add(size_t offset) {
1.94 + SkASSERT(fOffsets.count() == 0 || offset > this->max());
1.95 + *fOffsets.append() = offset;
1.96 + }
1.97 + size_t min() const {
1.98 + SkASSERT(fOffsets.count() > 0);
1.99 + return fOffsets[0];
1.100 + }
1.101 + size_t max() const {
1.102 + SkASSERT(fOffsets.count() > 0);
1.103 + return fOffsets[fOffsets.count()-1];
1.104 + }
1.105 + int count() const {
1.106 + return fOffsets.count();
1.107 + }
1.108 +
1.109 + SkTDArray<size_t> fOffsets;
1.110 + };
1.111 +
1.112 + SkTDArray<OffsetArray*> fOffsetArrays;
1.113 +
1.114 +private:
1.115 + typedef SkRefCnt INHERITED;
1.116 +};
1.117 +
1.118 +#endif
