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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
#ifndef BUFFER_READER_H_
#define BUFFER_READER_H_
#include <string.h>
#include "mozilla/EndianUtils.h"
#include "nscore.h"
#include "nsTArray.h"
#include "MediaData.h"
#include "MediaSpan.h"
#include "mozilla/Logging.h"
#include "mozilla/Result.h"
namespace mozilla {
extern mozilla::LazyLogModule gMP4MetadataLog;
class MOZ_RAII BufferReader {
public:
BufferReader() : mPtr(nullptr), mRemaining(0), mLength(0) {}
BufferReader(const uint8_t* aData, size_t aSize)
: mPtr(aData), mRemaining(aSize), mLength(aSize) {}
template <size_t S>
explicit BufferReader(const AutoTArray<uint8_t, S>& aData)
: mPtr(aData.Elements()),
mRemaining(aData.Length()),
mLength(aData.Length()) {}
explicit BufferReader(const nsTArray<uint8_t>& aData)
: mPtr(aData.Elements()),
mRemaining(aData.Length()),
mLength(aData.Length()) {}
explicit BufferReader(const mozilla::MediaByteBuffer* aData)
: mPtr(aData->Elements()),
mRemaining(aData->Length()),
mLength(aData->Length()) {}
explicit BufferReader(const mozilla::MediaSpan& aData)
: mPtr(aData.Elements()),
mRemaining(aData.Length()),
mLength(aData.Length()) {}
explicit BufferReader(const Span<const uint8_t>& aData)
: mPtr(aData.Elements()),
mRemaining(aData.Length()),
mLength(aData.Length()) {}
void SetData(const nsTArray<uint8_t>& aData) {
MOZ_ASSERT(!mPtr && !mRemaining);
mPtr = aData.Elements();
mRemaining = aData.Length();
mLength = mRemaining;
}
~BufferReader() = default;
size_t Offset() const { return mLength - mRemaining; }
size_t Remaining() const { return mRemaining; }
mozilla::Result<uint8_t, nsresult> ReadU8() {
auto ptr = Read(1);
if (!ptr) {
MOZ_LOG(gMP4MetadataLog, mozilla::LogLevel::Error,
("%s: failure", __func__));
return mozilla::Err(NS_ERROR_FAILURE);
}
return *ptr;
}
mozilla::Result<uint16_t, nsresult> ReadU16() {
auto ptr = Read(2);
if (!ptr) {
MOZ_LOG(gMP4MetadataLog, mozilla::LogLevel::Error,
("%s: failure", __func__));
return mozilla::Err(NS_ERROR_FAILURE);
}
return mozilla::BigEndian::readUint16(ptr);
}
mozilla::Result<int16_t, nsresult> ReadLE16() {
auto ptr = Read(2);
if (!ptr) {
MOZ_LOG(gMP4MetadataLog, mozilla::LogLevel::Error,
("%s: failure", __func__));
return mozilla::Err(NS_ERROR_FAILURE);
}
return mozilla::LittleEndian::readInt16(ptr);
}
mozilla::Result<uint32_t, nsresult> ReadU24() {
auto ptr = Read(3);
if (!ptr) {
MOZ_LOG(gMP4MetadataLog, mozilla::LogLevel::Error,
("%s: failure", __func__));
return mozilla::Err(NS_ERROR_FAILURE);
}
return ptr[0] << 16 | ptr[1] << 8 | ptr[2];
}
mozilla::Result<int32_t, nsresult> Read24() {
return ReadU24().map([](uint32_t x) { return (int32_t)x; });
}
mozilla::Result<int32_t, nsresult> ReadLE24() {
auto ptr = Read(3);
if (!ptr) {
MOZ_LOG(gMP4MetadataLog, mozilla::LogLevel::Error,
("%s: failure", __func__));
return mozilla::Err(NS_ERROR_FAILURE);
}
int32_t result = int32_t(ptr[2] << 16 | ptr[1] << 8 | ptr[0]);
if (result & 0x00800000u) {
result -= 0x1000000;
}
return result;
}
mozilla::Result<uint32_t, nsresult> ReadU32() {
auto ptr = Read(4);
if (!ptr) {
MOZ_LOG(gMP4MetadataLog, mozilla::LogLevel::Error,
("%s: failure", __func__));
return mozilla::Err(NS_ERROR_FAILURE);
}
return mozilla::BigEndian::readUint32(ptr);
}
mozilla::Result<int32_t, nsresult> Read32() {
auto ptr = Read(4);
if (!ptr) {
MOZ_LOG(gMP4MetadataLog, mozilla::LogLevel::Error,
("%s: failure", __func__));
return mozilla::Err(NS_ERROR_FAILURE);
}
return mozilla::BigEndian::readInt32(ptr);
}
mozilla::Result<uint32_t, nsresult> ReadLEU32() {
auto ptr = Read(4);
if (!ptr) {
MOZ_LOG(gMP4MetadataLog, mozilla::LogLevel::Error,
("%s: failure", __func__));
return mozilla::Err(NS_ERROR_FAILURE);
}
return mozilla::LittleEndian::readUint32(ptr);
}
mozilla::Result<uint64_t, nsresult> ReadU64() {
auto ptr = Read(8);
if (!ptr) {
MOZ_LOG(gMP4MetadataLog, mozilla::LogLevel::Error,
("%s: failure", __func__));
return mozilla::Err(NS_ERROR_FAILURE);
}
return mozilla::BigEndian::readUint64(ptr);
}
mozilla::Result<int64_t, nsresult> Read64() {
auto ptr = Read(8);
if (!ptr) {
MOZ_LOG(gMP4MetadataLog, mozilla::LogLevel::Error,
("%s: failure", __func__));
return mozilla::Err(NS_ERROR_FAILURE);
}
return mozilla::BigEndian::readInt64(ptr);
}
const uint8_t* Read(size_t aCount) {
if (aCount > mRemaining) {
mPtr += mRemaining;
mRemaining = 0;
return nullptr;
}
mRemaining -= aCount;
const uint8_t* result = mPtr;
mPtr += aCount;
return result;
}
const uint8_t* Rewind(size_t aCount) {
MOZ_ASSERT(aCount <= Offset());
size_t rewind = Offset();
if (aCount < rewind) {
rewind = aCount;
}
mRemaining += rewind;
mPtr -= rewind;
return mPtr;
}
mozilla::Result<uint8_t, nsresult> PeekU8() const {
auto ptr = Peek(1);
if (!ptr) {
MOZ_LOG(gMP4MetadataLog, mozilla::LogLevel::Error,
("%s: failure", __func__));
return mozilla::Err(NS_ERROR_FAILURE);
}
return *ptr;
}
mozilla::Result<uint16_t, nsresult> PeekU16() const {
auto ptr = Peek(2);
if (!ptr) {
MOZ_LOG(gMP4MetadataLog, mozilla::LogLevel::Error,
("%s: failure", __func__));
return mozilla::Err(NS_ERROR_FAILURE);
}
return mozilla::BigEndian::readUint16(ptr);
}
mozilla::Result<uint32_t, nsresult> PeekU24() const {
auto ptr = Peek(3);
if (!ptr) {
MOZ_LOG(gMP4MetadataLog, mozilla::LogLevel::Error,
("%s: failure", __func__));
return mozilla::Err(NS_ERROR_FAILURE);
}
return ptr[0] << 16 | ptr[1] << 8 | ptr[2];
}
mozilla::Result<int32_t, nsresult> Peek24() const {
return PeekU24().map([](uint32_t x) { return (int32_t)x; });
}
mozilla::Result<uint32_t, nsresult> PeekU32() {
auto ptr = Peek(4);
if (!ptr) {
MOZ_LOG(gMP4MetadataLog, mozilla::LogLevel::Error,
("%s: failure", __func__));
return mozilla::Err(NS_ERROR_FAILURE);
}
return mozilla::BigEndian::readUint32(ptr);
}
const uint8_t* Peek(size_t aCount) const {
if (aCount > mRemaining) {
return nullptr;
}
return mPtr;
}
const uint8_t* Seek(size_t aOffset) {
if (aOffset >= mLength) {
MOZ_LOG(gMP4MetadataLog, mozilla::LogLevel::Error,
("%s: failure, offset: %zu", __func__, aOffset));
return nullptr;
}
mPtr = mPtr - Offset() + aOffset;
mRemaining = mLength - aOffset;
return mPtr;
}
const uint8_t* Reset() {
mPtr -= Offset();
mRemaining = mLength;
return mPtr;
}
uint32_t Align() const { return 4 - ((intptr_t)mPtr & 3); }
template <typename T>
bool CanReadType() const {
return mRemaining >= sizeof(T);
}
template <typename T>
T ReadType() {
auto ptr = Read(sizeof(T));
if (!ptr) {
MOZ_LOG(gMP4MetadataLog, mozilla::LogLevel::Error,
("%s: failure", __func__));
return 0;
}
// handle unaligned accesses by memcpying
T ret;
memcpy(&ret, ptr, sizeof(T));
return ret;
}
template <typename T>
[[nodiscard]] bool ReadArray(nsTArray<T>& aDest, size_t aLength) {
auto ptr = Read(aLength * sizeof(T));
if (!ptr) {
MOZ_LOG(gMP4MetadataLog, mozilla::LogLevel::Error,
("%s: failure", __func__));
return false;
}
aDest.Clear();
aDest.AppendElements(reinterpret_cast<const T*>(ptr), aLength);
return true;
}
template <typename T>
[[nodiscard]] bool ReadArray(FallibleTArray<T>& aDest, size_t aLength) {
auto ptr = Read(aLength * sizeof(T));
if (!ptr) {
MOZ_LOG(gMP4MetadataLog, mozilla::LogLevel::Error,
("%s: failure", __func__));
return false;
}
aDest.Clear();
if (!aDest.SetCapacity(aLength, mozilla::fallible)) {
return false;
}
MOZ_ALWAYS_TRUE(aDest.AppendElements(reinterpret_cast<const T*>(ptr),
aLength, mozilla::fallible));
return true;
}
template <typename T>
mozilla::Result<Span<const T>, nsresult> ReadSpan(size_t aLength) {
auto ptr = Read(aLength * sizeof(T));
if (!ptr) {
MOZ_LOG(gMP4MetadataLog, mozilla::LogLevel::Error,
("%s: failure", __func__));
return mozilla::Err(NS_ERROR_FAILURE);
}
return Span(reinterpret_cast<const T*>(ptr), aLength);
}
private:
const uint8_t* mPtr;
size_t mRemaining;
size_t mLength;
};
} // namespace mozilla
#endif