michael@0: /*
michael@0:  * Copyright 2013 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: #include "SkBitmap.h"
michael@0: #include "SkErrorInternals.h"
michael@0: #include "SkValidatingReadBuffer.h"
michael@0: #include "SkStream.h"
michael@0: #include "SkTypeface.h"
michael@0: 
michael@0: SkValidatingReadBuffer::SkValidatingReadBuffer(const void* data, size_t size) :
michael@0:     fError(false) {
michael@0:     this->setMemory(data, size);
michael@0:     this->setFlags(SkReadBuffer::kValidation_Flag);
michael@0: }
michael@0: 
michael@0: SkValidatingReadBuffer::~SkValidatingReadBuffer() {
michael@0: }
michael@0: 
michael@0: bool SkValidatingReadBuffer::validate(bool isValid) {
michael@0:     if (!fError && !isValid) {
michael@0:         // When an error is found, send the read cursor to the end of the stream
michael@0:         fReader.skip(fReader.available());
michael@0:         fError = true;
michael@0:     }
michael@0:     return !fError;
michael@0: }
michael@0: 
michael@0: bool SkValidatingReadBuffer::isValid() const {
michael@0:     return !fError;
michael@0: }
michael@0: 
michael@0: void SkValidatingReadBuffer::setMemory(const void* data, size_t size) {
michael@0:     this->validate(IsPtrAlign4(data) && (SkAlign4(size) == size));
michael@0:     if (!fError) {
michael@0:         fReader.setMemory(data, size);
michael@0:     }
michael@0: }
michael@0: 
michael@0: const void* SkValidatingReadBuffer::skip(size_t size) {
michael@0:     size_t inc = SkAlign4(size);
michael@0:     const void* addr = fReader.peek();
michael@0:     this->validate(IsPtrAlign4(addr) && fReader.isAvailable(inc));
michael@0:     if (!fError) {
michael@0:         fReader.skip(size);
michael@0:     }
michael@0:     return addr;
michael@0: }
michael@0: 
michael@0: // All the methods in this file funnel down into either readInt(), readScalar() or skip(),
michael@0: // followed by a memcpy. So we've got all our validation in readInt(), readScalar() and skip();
michael@0: // if they fail they'll return a zero value or skip nothing, respectively, and set fError to
michael@0: // true, which the caller should check to see if an error occurred during the read operation.
michael@0: 
michael@0: bool SkValidatingReadBuffer::readBool() {
michael@0:     uint32_t value = this->readInt();
michael@0:     // Boolean value should be either 0 or 1
michael@0:     this->validate(!(value & ~1));
michael@0:     return value != 0;
michael@0: }
michael@0: 
michael@0: SkColor SkValidatingReadBuffer::readColor() {
michael@0:     return this->readInt();
michael@0: }
michael@0: 
michael@0: SkFixed SkValidatingReadBuffer::readFixed() {
michael@0:     return this->readInt();
michael@0: }
michael@0: 
michael@0: int32_t SkValidatingReadBuffer::readInt() {
michael@0:     const size_t inc = sizeof(int32_t);
michael@0:     this->validate(IsPtrAlign4(fReader.peek()) && fReader.isAvailable(inc));
michael@0:     return fError ? 0 : fReader.readInt();
michael@0: }
michael@0: 
michael@0: SkScalar SkValidatingReadBuffer::readScalar() {
michael@0:     const size_t inc = sizeof(SkScalar);
michael@0:     this->validate(IsPtrAlign4(fReader.peek()) && fReader.isAvailable(inc));
michael@0:     return fError ? 0 : fReader.readScalar();
michael@0: }
michael@0: 
michael@0: uint32_t SkValidatingReadBuffer::readUInt() {
michael@0:     return this->readInt();
michael@0: }
michael@0: 
michael@0: int32_t SkValidatingReadBuffer::read32() {
michael@0:     return this->readInt();
michael@0: }
michael@0: 
michael@0: void SkValidatingReadBuffer::readString(SkString* string) {
michael@0:     const size_t len = this->readInt();
michael@0:     const void* ptr = fReader.peek();
michael@0:     const char* cptr = (const char*)ptr;
michael@0: 
michael@0:     // skip over the string + '\0' and then pad to a multiple of 4
michael@0:     const size_t alignedSize = SkAlign4(len + 1);
michael@0:     this->skip(alignedSize);
michael@0:     if (!fError) {
michael@0:         this->validate(cptr[len] == '\0');
michael@0:     }
michael@0:     if (!fError) {
michael@0:         string->set(cptr, len);
michael@0:     }
michael@0: }
michael@0: 
michael@0: void* SkValidatingReadBuffer::readEncodedString(size_t* length, SkPaint::TextEncoding encoding) {
michael@0:     const int32_t encodingType = this->readInt();
michael@0:     this->validate(encodingType == encoding);
michael@0:     *length = this->readInt();
michael@0:     const void* ptr = this->skip(SkAlign4(*length));
michael@0:     void* data = NULL;
michael@0:     if (!fError) {
michael@0:         data = sk_malloc_throw(*length);
michael@0:         memcpy(data, ptr, *length);
michael@0:     }
michael@0:     return data;
michael@0: }
michael@0: 
michael@0: void SkValidatingReadBuffer::readPoint(SkPoint* point) {
michael@0:     point->fX = this->readScalar();
michael@0:     point->fY = this->readScalar();
michael@0: }
michael@0: 
michael@0: void SkValidatingReadBuffer::readMatrix(SkMatrix* matrix) {
michael@0:     size_t size = 0;
michael@0:     if (!fError) {
michael@0:         size = matrix->readFromMemory(fReader.peek(), fReader.available());
michael@0:         this->validate((SkAlign4(size) == size) && (0 != size));
michael@0:     }
michael@0:     if (!fError) {
michael@0:         (void)this->skip(size);
michael@0:     }
michael@0: }
michael@0: 
michael@0: void SkValidatingReadBuffer::readIRect(SkIRect* rect) {
michael@0:     const void* ptr = this->skip(sizeof(SkIRect));
michael@0:     if (!fError) {
michael@0:         memcpy(rect, ptr, sizeof(SkIRect));
michael@0:     }
michael@0: }
michael@0: 
michael@0: void SkValidatingReadBuffer::readRect(SkRect* rect) {
michael@0:     const void* ptr = this->skip(sizeof(SkRect));
michael@0:     if (!fError) {
michael@0:         memcpy(rect, ptr, sizeof(SkRect));
michael@0:     }
michael@0: }
michael@0: 
michael@0: void SkValidatingReadBuffer::readRegion(SkRegion* region) {
michael@0:     size_t size = 0;
michael@0:     if (!fError) {
michael@0:         size = region->readFromMemory(fReader.peek(), fReader.available());
michael@0:         this->validate((SkAlign4(size) == size) && (0 != size));
michael@0:     }
michael@0:     if (!fError) {
michael@0:         (void)this->skip(size);
michael@0:     }
michael@0: }
michael@0: 
michael@0: void SkValidatingReadBuffer::readPath(SkPath* path) {
michael@0:     size_t size = 0;
michael@0:     if (!fError) {
michael@0:         size = path->readFromMemory(fReader.peek(), fReader.available());
michael@0:         this->validate((SkAlign4(size) == size) && (0 != size));
michael@0:     }
michael@0:     if (!fError) {
michael@0:         (void)this->skip(size);
michael@0:     }
michael@0: }
michael@0: 
michael@0: bool SkValidatingReadBuffer::readArray(void* value, size_t size, size_t elementSize) {
michael@0:     const uint32_t count = this->getArrayCount();
michael@0:     this->validate(size == count);
michael@0:     (void)this->skip(sizeof(uint32_t)); // Skip array count
michael@0:     const size_t byteLength = count * elementSize;
michael@0:     const void* ptr = this->skip(SkAlign4(byteLength));
michael@0:     if (!fError) {
michael@0:         memcpy(value, ptr, byteLength);
michael@0:         return true;
michael@0:     }
michael@0:     return false;
michael@0: }
michael@0: 
michael@0: bool SkValidatingReadBuffer::readByteArray(void* value, size_t size) {
michael@0:     return readArray(static_cast<unsigned char*>(value), size, sizeof(unsigned char));
michael@0: }
michael@0: 
michael@0: bool SkValidatingReadBuffer::readColorArray(SkColor* colors, size_t size) {
michael@0:     return readArray(colors, size, sizeof(SkColor));
michael@0: }
michael@0: 
michael@0: bool SkValidatingReadBuffer::readIntArray(int32_t* values, size_t size) {
michael@0:     return readArray(values, size, sizeof(int32_t));
michael@0: }
michael@0: 
michael@0: bool SkValidatingReadBuffer::readPointArray(SkPoint* points, size_t size) {
michael@0:     return readArray(points, size, sizeof(SkPoint));
michael@0: }
michael@0: 
michael@0: bool SkValidatingReadBuffer::readScalarArray(SkScalar* values, size_t size) {
michael@0:     return readArray(values, size, sizeof(SkScalar));
michael@0: }
michael@0: 
michael@0: uint32_t SkValidatingReadBuffer::getArrayCount() {
michael@0:     const size_t inc = sizeof(uint32_t);
michael@0:     fError = fError || !IsPtrAlign4(fReader.peek()) || !fReader.isAvailable(inc);
michael@0:     return fError ? 0 : *(uint32_t*)fReader.peek();
michael@0: }
michael@0: 
michael@0: void SkValidatingReadBuffer::readBitmap(SkBitmap* bitmap) {
michael@0:     const int width = this->readInt();
michael@0:     const int height = this->readInt();
michael@0:     const bool useBitmapHeap = this->readBool();
michael@0:     const size_t length = this->readUInt();
michael@0:     // A size of zero means the SkBitmap was simply flattened.
michael@0:     if (!this->validate(!useBitmapHeap && (0 == length))) {
michael@0:         return;
michael@0:     }
michael@0:     bitmap->unflatten(*this);
michael@0:     this->validate((bitmap->width() == width) && (bitmap->height() == height));
michael@0: }
michael@0: 
michael@0: SkTypeface* SkValidatingReadBuffer::readTypeface() {
michael@0:     // TODO: Implement this (securely) when needed
michael@0:     return NULL;
michael@0: }
michael@0: 
michael@0: bool SkValidatingReadBuffer::validateAvailable(size_t size) {
michael@0:     return this->validate((size <= SK_MaxU32) && fReader.isAvailable(static_cast<uint32_t>(size)));
michael@0: }
michael@0: 
michael@0: SkFlattenable* SkValidatingReadBuffer::readFlattenable(SkFlattenable::Type type) {
michael@0:     SkString name;
michael@0:     this->readString(&name);
michael@0:     if (fError) {
michael@0:         return NULL;
michael@0:     }
michael@0: 
michael@0:     // Is this the type we wanted ?
michael@0:     const char* cname = name.c_str();
michael@0:     SkFlattenable::Type baseType;
michael@0:     if (!SkFlattenable::NameToType(cname, &baseType) || (baseType != type)) {
michael@0:         return NULL;
michael@0:     }
michael@0: 
michael@0:     SkFlattenable::Factory factory = SkFlattenable::NameToFactory(cname);
michael@0:     if (NULL == factory) {
michael@0:         return NULL; // writer failed to give us the flattenable
michael@0:     }
michael@0: 
michael@0:     // if we get here, factory may still be null, but if that is the case, the
michael@0:     // failure was ours, not the writer.
michael@0:     SkFlattenable* obj = NULL;
michael@0:     uint32_t sizeRecorded = this->readUInt();
michael@0:     if (factory) {
michael@0:         uint32_t offset = fReader.offset();
michael@0:         obj = (*factory)(*this);
michael@0:         // check that we read the amount we expected
michael@0:         uint32_t sizeRead = fReader.offset() - offset;
michael@0:         this->validate(sizeRecorded == sizeRead);
michael@0:         if (fError) {
michael@0:             // we could try to fix up the offset...
michael@0:             delete obj;
michael@0:             obj = NULL;
michael@0:         }
michael@0:     } else {
michael@0:         // we must skip the remaining data
michael@0:         this->skip(sizeRecorded);
michael@0:         SkASSERT(false);
michael@0:     }
michael@0:     return obj;
michael@0: }