bitcoin/src/util/string.cpp
Matthew Zipkin 43b4d0d2f3
string: add LineReader
This is a helper struct to parse HTTP messages from data in buffers
from sockets. HTTP messages begin with headers which are
CRLF-terminated lines (\n or \r\n) followed by an arbitrary amount of
body data. Whitespace is trimmed from the field lines but not the body.

https://httpwg.org/specs/rfc9110.html#rfc.section.5
2025-04-28 21:26:35 -04:00

54 lines
1.6 KiB
C++

// Copyright (c) 2019-2022 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include <util/string.h>
#include <regex>
#include <string>
namespace util {
void ReplaceAll(std::string& in_out, const std::string& search, const std::string& substitute)
{
if (search.empty()) return;
in_out = std::regex_replace(in_out, std::regex(search), substitute);
}
LineReader::LineReader(std::span<const std::byte> buffer, size_t max_read)
: start(buffer.begin()), end(buffer.end()), max_read(max_read), it(buffer.begin()) {}
std::optional<std::string> LineReader::ReadLine()
{
if (it == end) {
return std::nullopt;
}
auto line_start = it;
size_t count = 0;
while (it != end) {
char c = static_cast<char>(*it);
++it;
++count;
if (c == '\n') break;
if (count >= max_read) throw std::runtime_error("max_read exceeded by LineReader");
}
const std::string_view untrimmed_line(reinterpret_cast<const char *>(&*line_start), count);
const std::string_view line = TrimStringView(untrimmed_line); // delete trailing \r and/or \n
return std::string(line);
}
// Ignores max_read but won't overflow
std::string LineReader::ReadLength(size_t len)
{
if (len == 0) return "";
if (Left() < len) throw std::runtime_error("Not enough data in buffer");
std::string out(reinterpret_cast<const char*>(&(*it)), len);
it += len;
return out;
}
size_t LineReader::Left() const
{
return std::distance(it, end);
}
} // namespace util