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/*
* Copyright 2011 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkReader32.h"
#include "SkString.h"
#include "SkWriter32.h"
/*
* Strings are stored as: length[4-bytes] + string_data + '\0' + pad_to_mul_4
*/
const char* SkReader32::readString(size_t* outLen) {
size_t len = this->readU32();
const void* ptr = this->peek();
// skip over the string + '\0' and then pad to a multiple of 4
size_t alignedSize = SkAlign4(len + 1);
this->skip(alignedSize);
if (outLen) {
*outLen = len;
}
return (const char*)ptr;
}
size_t SkReader32::readIntoString(SkString* copy) {
size_t len;
const char* ptr = this->readString(&len);
if (copy) {
copy->set(ptr, len);
}
return len;
}
void SkWriter32::writeString(const char str[], size_t len) {
if (NULL == str) {
str = "";
len = 0;
}
if ((long)len < 0) {
len = strlen(str);
}
// [ 4 byte len ] [ str ... ] [1 - 4 \0s]
uint32_t* ptr = this->reservePad(sizeof(uint32_t) + len + 1);
*ptr = SkToU32(len);
char* chars = (char*)(ptr + 1);
memcpy(chars, str, len);
chars[len] = '\0';
}
size_t SkWriter32::WriteStringSize(const char* str, size_t len) {
if ((long)len < 0) {
SkASSERT(str);
len = strlen(str);
}
const size_t lenBytes = 4; // we use 4 bytes to record the length
// add 1 since we also write a terminating 0
return SkAlign4(lenBytes + len + 1);
}
void SkWriter32::growToAtLeast(size_t size) {
const bool wasExternal = (fExternal != NULL) && (fData == fExternal);
fCapacity = 4096 + SkTMax(size, fCapacity + (fCapacity / 2));
fInternal.realloc(fCapacity);
fData = fInternal.get();
if (wasExternal) {
// we were external, so copy in the data
memcpy(fData, fExternal, fUsed);
}
// Invalidate the snapshot, we know it is no longer useful.
fSnapshot.reset(NULL);
}
SkData* SkWriter32::snapshotAsData() const {
// get a non const version of this, we are only conceptually const
SkWriter32& mutable_this = *const_cast<SkWriter32*>(this);
// we use size change detection to invalidate the cached data
if ((fSnapshot.get() != NULL) && (fSnapshot->size() != fUsed)) {
mutable_this.fSnapshot.reset(NULL);
}
if (fSnapshot.get() == NULL) {
uint8_t* buffer = NULL;
if ((fExternal != NULL) && (fData == fExternal)) {
// We need to copy to an allocated buffer before returning.
buffer = (uint8_t*)sk_malloc_throw(fUsed);
memcpy(buffer, fData, fUsed);
} else {
buffer = mutable_this.fInternal.detach();
// prepare us to do copy on write, by pretending the data buffer
// is external and size limited
mutable_this.fData = buffer;
mutable_this.fCapacity = fUsed;
mutable_this.fExternal = buffer;
}
mutable_this.fSnapshot.reset(SkData::NewFromMalloc(buffer, fUsed));
}
return SkRef(fSnapshot.get()); // Take an extra ref for the caller.
}
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