void IOBuf::coalesceAndReallocate(size_t newHeadroom,
size_t newLength,
IOBuf* end,
size_t newTailroom) {
uint64_t newCapacity = newLength + newHeadroom + newTailroom;
if (newCapacity > UINT32_MAX) {
throw std::overflow_error("IOBuf chain too large to coalesce");
}
// Allocate space for the coalesced buffer.
// We always convert to an external buffer, even if we happened to be an
// internal buffer before.
uint8_t* newBuf;
SharedInfo* newInfo;
uint32_t actualCapacity;
allocExtBuffer(newCapacity, &newBuf, &newInfo, &actualCapacity);
// Copy the data into the new buffer
uint8_t* newData = newBuf + newHeadroom;
uint8_t* p = newData;
IOBuf* current = this;
size_t remaining = newLength;
do {
assert(current->length_ <= remaining);
remaining -= current->length_;
memcpy(p, current->data_, current->length_);
p += current->length_;
current = current->next_;
} while (current != end);
assert(remaining == 0);
// Point at the new buffer
decrementRefcount();
// Make sure kFlagUserOwned, kFlagMaybeShared, and kFlagFreeSharedInfo
// are all cleared.
flags_ = 0;
capacity_ = actualCapacity;
type_ = kExtAllocated;
buf_ = newBuf;
sharedInfo_ = newInfo;
data_ = newData;
length_ = newLength;
// Separate from the rest of our chain.
// Since we don't store the unique_ptr returned by separateChain(),
// this will immediately delete the returned subchain.
if (isChained()) {
(void)separateChain(next_, current->prev_);
}
}
void IOBuf::coalesceAndReallocate(size_t newHeadroom,
size_t newLength,
IOBuf* end,
size_t newTailroom) {
uint64_t newCapacity = newLength + newHeadroom + newTailroom;
// Allocate space for the coalesced buffer.
// We always convert to an external buffer, even if we happened to be an
// internal buffer before.
uint8_t* newBuf;
SharedInfo* newInfo;
uint64_t actualCapacity;
allocExtBuffer(newCapacity, &newBuf, &newInfo, &actualCapacity);
// Copy the data into the new buffer
uint8_t* newData = newBuf + newHeadroom;
uint8_t* p = newData;
IOBuf* current = this;
size_t remaining = newLength;
do {
if (current->length_ > 0) {
assert(current->length_ <= remaining);
assert(current->data_ != nullptr);
remaining -= current->length_;
memcpy(p, current->data_, current->length_);
p += current->length_;
}
current = current->next_;
} while (current != end);
assert(remaining == 0);
// Point at the new buffer
decrementRefcount();
// Make sure kFlagMaybeShared and kFlagFreeSharedInfo are all cleared.
setFlagsAndSharedInfo(0, newInfo);
capacity_ = actualCapacity;
buf_ = newBuf;
data_ = newData;
length_ = newLength;
// Separate from the rest of our chain.
// Since we don't store the unique_ptr returned by separateChain(),
// this will immediately delete the returned subchain.
if (isChained()) {
(void)separateChain(next_, current->prev_);
}
}