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/*
* Copyright (c) 2020, the SerenityOS developers.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <AK/Concepts.h>
#include <AK/Forward.h>
#include <AK/Span.h>
#include <AK/StdLibExtras.h>
namespace AK::Detail {
class Stream {
public:
virtual ~Stream()
{
ASSERT(!error() && !fatal());
}
bool error() const { return m_error; }
bool fatal() const { return m_fatal; }
bool handle_error() { return exchange(m_error, false); }
protected:
mutable bool m_error { false };
mutable bool m_fatal { false };
};
}
namespace AK {
class InputStream : public AK::Detail::Stream {
public:
virtual size_t read(Bytes) = 0;
virtual bool read_or_error(Bytes) = 0;
virtual bool eof() const = 0;
virtual bool discard_or_error(size_t count) = 0;
};
template<Concepts::Integral Integral>
InputStream& operator>>(InputStream& stream, Integral& value)
{
stream.read_or_error({ &value, sizeof(value) });
return stream;
}
#ifndef KERNEL
template<Concepts::FloatingPoint FloatingPoint>
InputStream& operator>>(InputStream& stream, FloatingPoint& value)
{
stream.read_or_error({ &value, sizeof(value) });
return stream;
}
#endif
inline InputStream& operator>>(InputStream& stream, bool& value)
{
stream.read_or_error({ &value, sizeof(value) });
return stream;
}
inline InputStream& operator>>(InputStream& stream, Bytes bytes)
{
stream.read_or_error(bytes);
return stream;
}
class InputMemoryStream final : public InputStream {
friend InputMemoryStream& operator>>(InputMemoryStream& stream, String& string);
public:
InputMemoryStream(ReadonlyBytes bytes)
: m_bytes(bytes)
{
}
bool eof() const override { return m_offset >= m_bytes.size(); }
size_t read(Bytes bytes) override
{
const auto count = min(bytes.size(), remaining());
__builtin_memcpy(bytes.data(), m_bytes.data() + m_offset, count);
m_offset += count;
return count;
}
bool read_or_error(Bytes bytes) override
{
if (remaining() < bytes.size()) {
m_error = true;
return false;
}
__builtin_memcpy(bytes.data(), m_bytes.data() + m_offset, bytes.size());
m_offset += bytes.size();
return true;
}
bool discard_or_error(size_t count) override
{
if (remaining() < count) {
m_error = true;
return false;
}
m_offset += count;
return true;
}
void seek(size_t offset)
{
ASSERT(offset < m_bytes.size());
m_offset = offset;
}
u8 peek_or_error() const
{
if (remaining() == 0) {
m_error = true;
return 0;
}
return m_bytes[m_offset];
}
// FIXME: Duplicated from AK::BufferStream::read_LEB128_unsigned.
// LEB128 is a variable-length encoding for integers
bool read_LEB128_unsigned(size_t& result)
{
const auto backup = m_offset;
result = 0;
size_t num_bytes = 0;
while (true) {
// Note. The implementation in AK::BufferStream::read_LEB128_unsigned read one
// past the end, this is fixed here.
if (eof()) {
m_offset = backup;
m_error = true;
return false;
}
const u8 byte = m_bytes[m_offset];
result = (result) | (static_cast<size_t>(byte & ~(1 << 7)) << (num_bytes * 7));
++m_offset;
if (!(byte & (1 << 7)))
break;
++num_bytes;
}
return true;
}
// FIXME: Duplicated from AK::BufferStream::read_LEB128_signed.
// LEB128 is a variable-length encoding for integers
bool read_LEB128_signed(ssize_t& result)
{
const auto backup = m_offset;
result = 0;
size_t num_bytes = 0;
u8 byte = 0;
do {
// Note. The implementation in AK::BufferStream::read_LEB128_unsigned read one
// past the end, this is fixed here.
if (eof()) {
m_offset = backup;
m_error = true;
return false;
}
byte = m_bytes[m_offset];
result = (result) | (static_cast<size_t>(byte & ~(1 << 7)) << (num_bytes * 7));
++m_offset;
++num_bytes;
} while (byte & (1 << 7));
if (num_bytes * 7 < sizeof(size_t) * 4 && (byte & 0x40)) {
// sign extend
result |= ((size_t)(-1) << (num_bytes * 7));
}
return true;
}
ReadonlyBytes bytes() const { return m_bytes; }
size_t offset() const { return m_offset; }
size_t remaining() const { return m_bytes.size() - m_offset; }
private:
ReadonlyBytes m_bytes;
size_t m_offset { 0 };
};
}
using AK::InputMemoryStream;
using AK::InputStream;
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