1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/skia/trunk/src/core/SkBuffer.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,170 @@
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 SkBuffer_DEFINED
1.14 +#define SkBuffer_DEFINED
1.15 +
1.16 +#include "SkScalar.h"
1.17 +
1.18 +/** \class SkRBuffer
1.19 +
1.20 + Light weight class for reading data from a memory block.
1.21 + The RBuffer is given the buffer to read from, with either a specified size
1.22 + or no size (in which case no range checking is performed). It is iillegal
1.23 + to attempt to read a value from an empty RBuffer (data == null).
1.24 +*/
1.25 +class SkRBuffer : SkNoncopyable {
1.26 +public:
1.27 + SkRBuffer() : fData(0), fPos(0), fStop(0) {}
1.28 + /** Initialize RBuffer with a data pointer, but no specified length.
1.29 + This signals the RBuffer to not perform range checks during reading.
1.30 + */
1.31 + SkRBuffer(const void* data) {
1.32 + fData = (const char*)data;
1.33 + fPos = (const char*)data;
1.34 + fStop = 0; // no bounds checking
1.35 + }
1.36 + /** Initialize RBuffer with a data point and length.
1.37 + */
1.38 + SkRBuffer(const void* data, size_t size) {
1.39 + SkASSERT(data != 0 || size == 0);
1.40 + fData = (const char*)data;
1.41 + fPos = (const char*)data;
1.42 + fStop = (const char*)data + size;
1.43 + }
1.44 +
1.45 + virtual ~SkRBuffer() { }
1.46 +
1.47 + /** Return the number of bytes that have been read from the beginning
1.48 + of the data pointer.
1.49 + */
1.50 + size_t pos() const { return fPos - fData; }
1.51 + /** Return the total size of the data pointer. Only defined if the length was
1.52 + specified in the constructor or in a call to reset().
1.53 + */
1.54 + size_t size() const { return fStop - fData; }
1.55 + /** Return true if the buffer has read to the end of the data pointer.
1.56 + Only defined if the length was specified in the constructor or in a call
1.57 + to reset(). Always returns true if the length was not specified.
1.58 + */
1.59 + bool eof() const { return fPos >= fStop; }
1.60 +
1.61 + /** Read the specified number of bytes from the data pointer. If buffer is not
1.62 + null, copy those bytes into buffer.
1.63 + */
1.64 + virtual bool read(void* buffer, size_t size) {
1.65 + if (size) {
1.66 + this->readNoSizeCheck(buffer, size);
1.67 + }
1.68 + return true;
1.69 + }
1.70 +
1.71 + const void* skip(size_t size); // return start of skipped data
1.72 + size_t skipToAlign4();
1.73 +
1.74 + bool readPtr(void** ptr) { return read(ptr, sizeof(void*)); }
1.75 + bool readScalar(SkScalar* x) { return read(x, 4); }
1.76 + bool readU32(uint32_t* x) { return read(x, 4); }
1.77 + bool readS32(int32_t* x) { return read(x, 4); }
1.78 + bool readU16(uint16_t* x) { return read(x, 2); }
1.79 + bool readS16(int16_t* x) { return read(x, 2); }
1.80 + bool readU8(uint8_t* x) { return read(x, 1); }
1.81 + bool readBool(bool* x) {
1.82 + uint8_t u8;
1.83 + if (this->readU8(&u8)) {
1.84 + *x = (u8 != 0);
1.85 + return true;
1.86 + }
1.87 + return false;
1.88 + }
1.89 +
1.90 +protected:
1.91 + void readNoSizeCheck(void* buffer, size_t size);
1.92 +
1.93 + const char* fData;
1.94 + const char* fPos;
1.95 + const char* fStop;
1.96 +};
1.97 +
1.98 +/** \class SkRBufferWithSizeCheck
1.99 +
1.100 + Same as SkRBuffer, except that a size check is performed before the read operation and an
1.101 + error is set if the read operation is attempting to read past the end of the data.
1.102 +*/
1.103 +class SkRBufferWithSizeCheck : public SkRBuffer {
1.104 +public:
1.105 + SkRBufferWithSizeCheck(const void* data, size_t size) : SkRBuffer(data, size), fError(false) {}
1.106 +
1.107 + /** Read the specified number of bytes from the data pointer. If buffer is not
1.108 + null and the number of bytes to read does not overflow this object's data,
1.109 + copy those bytes into buffer.
1.110 + */
1.111 + virtual bool read(void* buffer, size_t size) SK_OVERRIDE;
1.112 +
1.113 + /** Returns whether or not a read operation attempted to read past the end of the data.
1.114 + */
1.115 + bool isValid() const { return !fError; }
1.116 +private:
1.117 + bool fError;
1.118 +};
1.119 +
1.120 +/** \class SkWBuffer
1.121 +
1.122 + Light weight class for writing data to a memory block.
1.123 + The WBuffer is given the buffer to write into, with either a specified size
1.124 + or no size, in which case no range checking is performed. An empty WBuffer
1.125 + is legal, in which case no data is ever written, but the relative pos()
1.126 + is updated.
1.127 +*/
1.128 +class SkWBuffer : SkNoncopyable {
1.129 +public:
1.130 + SkWBuffer() : fData(0), fPos(0), fStop(0) {}
1.131 + SkWBuffer(void* data) { reset(data); }
1.132 + SkWBuffer(void* data, size_t size) { reset(data, size); }
1.133 +
1.134 + void reset(void* data) {
1.135 + fData = (char*)data;
1.136 + fPos = (char*)data;
1.137 + fStop = 0; // no bounds checking
1.138 + }
1.139 +
1.140 + void reset(void* data, size_t size) {
1.141 + SkASSERT(data != 0 || size == 0);
1.142 + fData = (char*)data;
1.143 + fPos = (char*)data;
1.144 + fStop = (char*)data + size;
1.145 + }
1.146 +
1.147 + size_t pos() const { return fPos - fData; }
1.148 + void* skip(size_t size); // return start of skipped data
1.149 +
1.150 + void write(const void* buffer, size_t size) {
1.151 + if (size) {
1.152 + this->writeNoSizeCheck(buffer, size);
1.153 + }
1.154 + }
1.155 +
1.156 + size_t padToAlign4();
1.157 +
1.158 + void writePtr(const void* x) { this->writeNoSizeCheck(&x, sizeof(x)); }
1.159 + void writeScalar(SkScalar x) { this->writeNoSizeCheck(&x, 4); }
1.160 + void write32(int32_t x) { this->writeNoSizeCheck(&x, 4); }
1.161 + void write16(int16_t x) { this->writeNoSizeCheck(&x, 2); }
1.162 + void write8(int8_t x) { this->writeNoSizeCheck(&x, 1); }
1.163 + void writeBool(bool x) { this->write8(x); }
1.164 +
1.165 +private:
1.166 + void writeNoSizeCheck(const void* buffer, size_t size);
1.167 +
1.168 + char* fData;
1.169 + char* fPos;
1.170 + char* fStop;
1.171 +};
1.172 +
1.173 +#endif
