3 * Copyright 2008 The Android Open Source Project
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
10 #ifndef SkReader32_DEFINED
11 #define SkReader32_DEFINED
21 class SkReader32 : SkNoncopyable {
23 SkReader32() : fCurr(NULL), fStop(NULL), fBase(NULL) {}
24 SkReader32(const void* data, size_t size) {
25 this->setMemory(data, size);
28 void setMemory(const void* data, size_t size) {
29 SkASSERT(ptr_align_4(data));
30 SkASSERT(SkAlign4(size) == size);
32 fBase = fCurr = (const char*)data;
33 fStop = (const char*)data + size;
36 size_t size() const { return fStop - fBase; }
37 size_t offset() const { return fCurr - fBase; }
38 bool eof() const { return fCurr >= fStop; }
39 const void* base() const { return fBase; }
40 const void* peek() const { return fCurr; }
42 size_t available() const { return fStop - fCurr; }
43 bool isAvailable(size_t size) const { return size <= this->available(); }
45 void rewind() { fCurr = fBase; }
47 void setOffset(size_t offset) {
48 SkASSERT(SkAlign4(offset) == offset);
49 SkASSERT(offset <= this->size());
50 fCurr = fBase + offset;
53 bool readBool() { return this->readInt() != 0; }
56 SkASSERT(ptr_align_4(fCurr));
57 int32_t value = *(const int32_t*)fCurr;
58 fCurr += sizeof(value);
59 SkASSERT(fCurr <= fStop);
65 // we presume this "if" is resolved at compile-time
66 if (4 == sizeof(void*)) {
69 memcpy(&ptr, fCurr, sizeof(void*));
71 fCurr += sizeof(void*);
75 SkScalar readScalar() {
76 SkASSERT(ptr_align_4(fCurr));
77 SkScalar value = *(const SkScalar*)fCurr;
78 fCurr += sizeof(value);
79 SkASSERT(fCurr <= fStop);
83 const void* skip(size_t size) {
84 SkASSERT(ptr_align_4(fCurr));
85 const void* addr = fCurr;
86 fCurr += SkAlign4(size);
87 SkASSERT(fCurr <= fStop);
91 template <typename T> const T& skipT() {
92 SkASSERT(SkAlign4(sizeof(T)) == sizeof(T));
93 return *(const T*)this->skip(sizeof(T));
96 void read(void* dst, size_t size) {
97 SkASSERT(0 == size || dst != NULL);
98 SkASSERT(ptr_align_4(fCurr));
99 memcpy(dst, fCurr, size);
100 fCurr += SkAlign4(size);
101 SkASSERT(fCurr <= fStop);
104 uint8_t readU8() { return (uint8_t)this->readInt(); }
105 uint16_t readU16() { return (uint16_t)this->readInt(); }
106 int32_t readS32() { return this->readInt(); }
107 uint32_t readU32() { return this->readInt(); }
109 bool readPath(SkPath* path) {
110 return this->readObjectFromMemory(path);
113 bool readMatrix(SkMatrix* matrix) {
114 return this->readObjectFromMemory(matrix);
117 bool readRRect(SkRRect* rrect) {
118 return this->readObjectFromMemory(rrect);
121 bool readRegion(SkRegion* rgn) {
122 return this->readObjectFromMemory(rgn);
126 * Read the length of a string (written by SkWriter32::writeString) into
127 * len (if len is not NULL) and return the null-ternimated address of the
128 * string within the reader's buffer.
130 const char* readString(size_t* len = NULL);
133 * Read the string (written by SkWriter32::writeString) and return it in
134 * copy (if copy is not null). Return the length of the string.
136 size_t readIntoString(SkString* copy);
139 template <typename T> bool readObjectFromMemory(T* obj) {
140 size_t size = obj->readFromMemory(this->peek(), this->available());
141 // If readFromMemory() fails (which means that available() was too small), it returns 0
142 bool success = (size > 0) && (size <= this->available()) && (SkAlign4(size) == size);
143 // In case of failure, we want to skip to the end
144 (void)this->skip(success ? size : this->available());
148 // these are always 4-byte aligned
149 const char* fCurr; // current position within buffer
150 const char* fStop; // end of buffer
151 const char* fBase; // beginning of buffer
154 static bool ptr_align_4(const void* ptr) {
155 return (((const char*)ptr - (const char*)NULL) & 3) == 0;