bitcoin/src/streams.cpp

67 lines
2.4 KiB
C++

// Copyright (c) 2009-present The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or https://opensource.org/license/mit/.
#include <span.h>
#include <streams.h>
#include <array>
std::size_t AutoFile::detail_fread(Span<std::byte> dst)
{
if (!m_file) throw std::ios_base::failure("AutoFile::read: file handle is nullptr");
if (m_xor.empty()) {
return std::fread(dst.data(), 1, dst.size(), m_file);
} else {
const auto init_pos{std::ftell(m_file)};
if (init_pos < 0) throw std::ios_base::failure("AutoFile::read: ftell failed");
std::size_t ret{std::fread(dst.data(), 1, dst.size(), m_file)};
util::Xor(dst.subspan(0, ret), m_xor, init_pos);
return ret;
}
}
void AutoFile::read(Span<std::byte> dst)
{
if (detail_fread(dst) != dst.size()) {
throw std::ios_base::failure(feof() ? "AutoFile::read: end of file" : "AutoFile::read: fread failed");
}
}
void AutoFile::ignore(size_t nSize)
{
if (!m_file) throw std::ios_base::failure("AutoFile::ignore: file handle is nullptr");
unsigned char data[4096];
while (nSize > 0) {
size_t nNow = std::min<size_t>(nSize, sizeof(data));
if (std::fread(data, 1, nNow, m_file) != nNow) {
throw std::ios_base::failure(feof() ? "AutoFile::ignore: end of file" : "AutoFile::ignore: fread failed");
}
nSize -= nNow;
}
}
void AutoFile::write(Span<const std::byte> src)
{
if (!m_file) throw std::ios_base::failure("AutoFile::write: file handle is nullptr");
if (m_xor.empty()) {
if (std::fwrite(src.data(), 1, src.size(), m_file) != src.size()) {
throw std::ios_base::failure("AutoFile::write: write failed");
}
} else {
auto current_pos{std::ftell(m_file)};
if (current_pos < 0) throw std::ios_base::failure("AutoFile::write: ftell failed");
std::array<std::byte, 4096> buf;
while (src.size() > 0) {
auto buf_now{Span{buf}.first(std::min<size_t>(src.size(), buf.size()))};
std::copy(src.begin(), src.begin() + buf_now.size(), buf_now.begin());
util::Xor(buf_now, m_xor, current_pos);
if (std::fwrite(buf_now.data(), 1, buf_now.size(), m_file) != buf_now.size()) {
throw std::ios_base::failure{"XorFile::write: failed"};
}
src = src.subspan(buf_now.size());
current_pos += buf_now.size();
}
}
}