1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/skia/trunk/src/core/SkDescriptor.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,165 @@
1.4 +
1.5 +/*
1.6 + * Copyright 2006 The Android Open Source Project
1.7 + *
1.8 + * Use of this source code is governed by a BSD-style license that can be
1.9 + * found in the LICENSE file.
1.10 + */
1.11 +
1.12 +
1.13 +#ifndef SkDescriptor_DEFINED
1.14 +#define SkDescriptor_DEFINED
1.15 +
1.16 +#include "SkChecksum.h"
1.17 +#include "SkTypes.h"
1.18 +
1.19 +class SkDescriptor : SkNoncopyable {
1.20 +public:
1.21 + static size_t ComputeOverhead(int entryCount) {
1.22 + SkASSERT(entryCount >= 0);
1.23 + return sizeof(SkDescriptor) + entryCount * sizeof(Entry);
1.24 + }
1.25 +
1.26 + static SkDescriptor* Alloc(size_t length) {
1.27 + SkASSERT(SkAlign4(length) == length);
1.28 + SkDescriptor* desc = (SkDescriptor*)sk_malloc_throw(length);
1.29 + return desc;
1.30 + }
1.31 +
1.32 + static void Free(SkDescriptor* desc) {
1.33 + sk_free(desc);
1.34 + }
1.35 +
1.36 + void init() {
1.37 + fLength = sizeof(SkDescriptor);
1.38 + fCount = 0;
1.39 + }
1.40 +
1.41 + uint32_t getLength() const { return fLength; }
1.42 +
1.43 + void* addEntry(uint32_t tag, uint32_t length, const void* data = NULL) {
1.44 + SkASSERT(tag);
1.45 + SkASSERT(SkAlign4(length) == length);
1.46 + SkASSERT(this->findEntry(tag, NULL) == NULL);
1.47 +
1.48 + Entry* entry = (Entry*)((char*)this + fLength);
1.49 + entry->fTag = tag;
1.50 + entry->fLen = length;
1.51 + if (data) {
1.52 + memcpy(entry + 1, data, length);
1.53 + }
1.54 +
1.55 + fCount += 1;
1.56 + fLength += sizeof(Entry) + length;
1.57 + return (entry + 1); // return its data
1.58 + }
1.59 +
1.60 + void computeChecksum() {
1.61 + fChecksum = SkDescriptor::ComputeChecksum(this);
1.62 + }
1.63 +
1.64 +#ifdef SK_DEBUG
1.65 + void assertChecksum() const {
1.66 + SkASSERT(SkDescriptor::ComputeChecksum(this) == fChecksum);
1.67 + }
1.68 +#endif
1.69 +
1.70 + const void* findEntry(uint32_t tag, uint32_t* length) const {
1.71 + const Entry* entry = (const Entry*)(this + 1);
1.72 + int count = fCount;
1.73 +
1.74 + while (--count >= 0) {
1.75 + if (entry->fTag == tag) {
1.76 + if (length) {
1.77 + *length = entry->fLen;
1.78 + }
1.79 + return entry + 1;
1.80 + }
1.81 + entry = (const Entry*)((const char*)(entry + 1) + entry->fLen);
1.82 + }
1.83 + return NULL;
1.84 + }
1.85 +
1.86 + SkDescriptor* copy() const {
1.87 + SkDescriptor* desc = SkDescriptor::Alloc(fLength);
1.88 + memcpy(desc, this, fLength);
1.89 + return desc;
1.90 + }
1.91 +
1.92 + bool equals(const SkDescriptor& other) const {
1.93 + // probe to see if we have a good checksum algo
1.94 +// SkASSERT(a.fChecksum != b.fChecksum || memcmp(&a, &b, a.fLength) == 0);
1.95 +
1.96 + // the first value we should look at is the checksum, so this loop
1.97 + // should terminate early if they descriptors are different.
1.98 + // NOTE: if we wrote a sentinel value at the end of each, we chould
1.99 + // remove the aa < stop test in the loop...
1.100 + const uint32_t* aa = (const uint32_t*)this;
1.101 + const uint32_t* bb = (const uint32_t*)&other;
1.102 + const uint32_t* stop = (const uint32_t*)((const char*)aa + fLength);
1.103 + do {
1.104 + if (*aa++ != *bb++)
1.105 + return false;
1.106 + } while (aa < stop);
1.107 + return true;
1.108 + }
1.109 +
1.110 + uint32_t getChecksum() const { return fChecksum; }
1.111 +
1.112 + struct Entry {
1.113 + uint32_t fTag;
1.114 + uint32_t fLen;
1.115 + };
1.116 +
1.117 +#ifdef SK_DEBUG
1.118 + uint32_t getCount() const { return fCount; }
1.119 +#endif
1.120 +
1.121 +private:
1.122 + uint32_t fChecksum; // must be first
1.123 + uint32_t fLength; // must be second
1.124 + uint32_t fCount;
1.125 +
1.126 + static uint32_t ComputeChecksum(const SkDescriptor* desc) {
1.127 + const uint32_t* ptr = (const uint32_t*)desc + 1; // skip the checksum field
1.128 + size_t len = desc->fLength - sizeof(uint32_t);
1.129 + return SkChecksum::Compute(ptr, len);
1.130 + }
1.131 +
1.132 + // private so no one can create one except our factories
1.133 + SkDescriptor() {}
1.134 +};
1.135 +
1.136 +#include "SkScalerContext.h"
1.137 +
1.138 +class SkAutoDescriptor : SkNoncopyable {
1.139 +public:
1.140 + SkAutoDescriptor(size_t size) {
1.141 + if (size <= sizeof(fStorage)) {
1.142 + fDesc = (SkDescriptor*)(void*)fStorage;
1.143 + } else {
1.144 + fDesc = SkDescriptor::Alloc(size);
1.145 + }
1.146 + }
1.147 +
1.148 + ~SkAutoDescriptor() {
1.149 + if (fDesc != (SkDescriptor*)(void*)fStorage) {
1.150 + SkDescriptor::Free(fDesc);
1.151 + }
1.152 + }
1.153 +
1.154 + SkDescriptor* getDesc() const { return fDesc; }
1.155 +private:
1.156 + enum {
1.157 + kStorageSize = sizeof(SkDescriptor)
1.158 + + sizeof(SkDescriptor::Entry) + sizeof(SkScalerContext::Rec) // for rec
1.159 + + sizeof(SkDescriptor::Entry) + sizeof(void*) // for typeface
1.160 + + 32 // slop for occational small extras
1.161 + };
1.162 + SkDescriptor* fDesc;
1.163 + uint32_t fStorage[(kStorageSize + 3) >> 2];
1.164 +};
1.165 +#define SkAutoDescriptor(...) SK_REQUIRE_LOCAL_VAR(SkAutoDescriptor)
1.166 +
1.167 +
1.168 +#endif
