Files
react-native/ReactCommon/react/renderer/mapbuffer/MapBuffer.cpp
T
Andrei Shikov c338fff521 Cast MapBuffer bytes to struct to read header
Summary:
The struct is copied directly to the buffer, so it is safe to read it back.

Changelog: [Internal]

Reviewed By: javache

Differential Revision: D33624036

fbshipit-source-id: 7ee2b28b815690ab471832c0c622a075b5dd7d78
2022-01-18 08:04:54 -08:00

119 lines
3.0 KiB
C++

/*
* Copyright (c) Meta Platforms, Inc. and affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*/
#include "MapBuffer.h"
using namespace facebook::react;
namespace facebook {
namespace react {
// TODO T83483191: Extend MapBuffer C++ implementation to support basic random
// access
MapBuffer::MapBuffer(std::vector<uint8_t> data) : bytes_(std::move(data)) {
auto header = reinterpret_cast<Header const *>(bytes_.data());
count_ = header->count;
if (header->bufferSize != bytes_.size()) {
LOG(ERROR) << "Error: Data size does not match, expected "
<< header->bufferSize << " found: " << bytes_.size();
abort();
}
}
int32_t MapBuffer::getInt(Key key) const {
int32_t value = 0;
memcpy(
reinterpret_cast<uint8_t *>(&value),
bytes_.data() + getValueOffset(key),
INT_SIZE);
return value;
}
bool MapBuffer::getBool(Key key) const {
return getInt(key) != 0;
}
double MapBuffer::getDouble(Key key) const {
// TODO T83483191: extract this code into a "template method" and reuse it for
// other types
double value = 0;
memcpy(
reinterpret_cast<uint8_t *>(&value),
bytes_.data() + getValueOffset(key),
DOUBLE_SIZE);
return value;
}
int32_t MapBuffer::getDynamicDataOffset() const {
// The begininig of dynamic data can be calculated as the offset of the next
// key in the map
return getKeyOffset(count_);
}
std::string MapBuffer::getString(Key key) const {
// TODO T83483191:Add checks to verify that offsets are under the boundaries
// of the map buffer
int32_t dynamicDataOffset = getDynamicDataOffset();
int32_t stringLength = 0;
int32_t offset = getInt(key);
memcpy(
reinterpret_cast<uint8_t *>(&stringLength),
bytes_.data() + dynamicDataOffset + offset,
INT_SIZE);
char *value = new char[stringLength];
memcpy(
reinterpret_cast<char *>(value),
bytes_.data() + dynamicDataOffset + offset + INT_SIZE,
stringLength);
return std::string(value, 0, stringLength);
}
MapBuffer MapBuffer::getMapBuffer(Key key) const {
// TODO T83483191: Add checks to verify that offsets are under the boundaries
// of the map buffer
int32_t dynamicDataOffset = getDynamicDataOffset();
int32_t mapBufferLength = 0;
int32_t offset = getInt(key);
memcpy(
reinterpret_cast<uint8_t *>(&mapBufferLength),
bytes_.data() + dynamicDataOffset + offset,
INT_SIZE);
std::vector<uint8_t> value(mapBufferLength);
memcpy(
value.data(),
bytes_.data() + dynamicDataOffset + offset + INT_SIZE,
mapBufferLength);
return MapBuffer(std::move(value));
}
bool MapBuffer::isNull(Key key) const {
return getInt(key) == NULL_VALUE;
}
uint32_t MapBuffer::size() const {
return bytes_.size();
}
uint8_t const *MapBuffer::data() const {
return bytes_.data();
}
uint16_t MapBuffer::count() const {
return count_;
}
} // namespace react
} // namespace facebook