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#include "SkWriter32.h"
struct SkWriter32::Block {
Block* fNext;
size_t fSize;
size_t fAllocated;
size_t available() const { return fSize - fAllocated; }
char* base() { return (char*)(this + 1); }
const char* base() const { return (const char*)(this + 1); }
uint32_t* alloc(size_t size) {
SkASSERT(SkAlign4(size) == size);
SkASSERT(this->available() >= size);
void* ptr = this->base() + fAllocated;
fAllocated += size;
SkASSERT(fAllocated <= fSize);
return (uint32_t*)ptr;
}
uint32_t* peek32(size_t offset) {
SkASSERT(offset <= fAllocated + 4);
void* ptr = this->base() + offset;
return (uint32_t*)ptr;
}
static Block* Create(size_t size) {
SkASSERT(SkAlign4(size) == size);
Block* block = (Block*)sk_malloc_throw(sizeof(Block) + size);
block->fNext = NULL;
block->fSize = size;
block->fAllocated = 0;
return block;
}
};
///////////////////////////////////////////////////////////////////////////////
SkWriter32::~SkWriter32() {
this->reset();
}
void SkWriter32::reset() {
Block* block = fHead;
while (block) {
Block* next = block->fNext;
sk_free(block);
block = next;
}
fSize = 0;
fHead = fTail = NULL;
fSingleBlock = NULL;
}
void SkWriter32::reset(void* block, size_t size) {
this->reset();
SkASSERT(0 == ((fSingleBlock - (char*)0) & 3)); // need 4-byte alignment
fSingleBlock = (char*)block;
fSingleBlockSize = (size & ~3);
}
uint32_t* SkWriter32::reserve(size_t size) {
SkASSERT(SkAlign4(size) == size);
if (fSingleBlock) {
uint32_t* ptr = (uint32_t*)(fSingleBlock + fSize);
fSize += size;
SkASSERT(fSize <= fSingleBlockSize);
return ptr;
}
Block* block = fTail;
if (NULL == block) {
SkASSERT(NULL == fHead);
fHead = fTail = block = Block::Create(SkMax32(size, fMinSize));
} else if (block->available() < size) {
fTail = Block::Create(SkMax32(size, fMinSize));
block->fNext = fTail;
block = fTail;
}
fSize += size;
return block->alloc(size);
}
uint32_t* SkWriter32::peek32(size_t offset) {
SkASSERT(SkAlign4(offset) == offset);
SkASSERT(offset <= fSize);
if (fSingleBlock) {
return (uint32_t*)(fSingleBlock + offset);
}
Block* block = fHead;
SkASSERT(NULL != block);
while (offset >= block->fAllocated) {
offset -= block->fAllocated;
block = block->fNext;
SkASSERT(NULL != block);
}
return block->peek32(offset);
}
void SkWriter32::flatten(void* dst) const {
if (fSingleBlock) {
memcpy(dst, fSingleBlock, fSize);
return;
}
const Block* block = fHead;
SkDEBUGCODE(size_t total = 0;)
while (block) {
size_t allocated = block->fAllocated;
memcpy(dst, block->base(), allocated);
dst = (char*)dst + allocated;
block = block->fNext;
SkDEBUGCODE(total += allocated;)
SkASSERT(total <= fSize);
}
SkASSERT(total == fSize);
}
void SkWriter32::writePad(const void* src, size_t size) {
size_t alignedSize = SkAlign4(size);
char* dst = (char*)this->reserve(alignedSize);
memcpy(dst, src, size);
dst += size;
int n = alignedSize - size;
while (--n >= 0) {
*dst++ = 0;
}
}
#include "SkStream.h"
size_t SkWriter32::readFromStream(SkStream* stream, size_t length) {
if (fSingleBlock) {
SkASSERT(fSingleBlockSize >= fSize);
size_t remaining = fSingleBlockSize - fSize;
if (length > remaining) {
length = remaining;
}
stream->read(fSingleBlock + fSize, length);
fSize += length;
return length;
}
char scratch[1024];
const size_t MAX = sizeof(scratch);
size_t remaining = length;
while (remaining != 0) {
size_t n = remaining;
if (n > MAX) {
n = MAX;
}
size_t bytes = stream->read(scratch, n);
this->writePad(scratch, bytes);
remaining -= bytes;
if (bytes != n) {
break;
}
}
return length - remaining;
}
bool SkWriter32::writeToStream(SkWStream* stream) {
if (fSingleBlock) {
return stream->write(fSingleBlock, fSize);
}
const Block* block = fHead;
while (block) {
if (!stream->write(block->base(), block->fAllocated)) {
return false;
}
block = block->fNext;
}
return true;
}
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