char-buffer.cpp
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//===-- lib/Parser/char-buffer.cpp ----------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "flang/Parser/char-buffer.h"
#include "flang/Common/idioms.h"
#include <algorithm>
#include <cstddef>
#include <cstring>
namespace Fortran::parser {
char *CharBuffer::FreeSpace(std::size_t &n) {
int offset{LastBlockOffset()};
if (blocks_.empty()) {
blocks_.emplace_front();
last_ = blocks_.begin();
lastBlockEmpty_ = true;
} else if (offset == 0 && !lastBlockEmpty_) {
last_ = blocks_.emplace_after(last_);
lastBlockEmpty_ = true;
}
n = Block::capacity - offset;
return last_->data + offset;
}
void CharBuffer::Claim(std::size_t n) {
if (n > 0) {
bytes_ += n;
lastBlockEmpty_ = false;
}
}
std::size_t CharBuffer::Put(const char *data, std::size_t n) {
std::size_t chunk;
for (std::size_t at{0}; at < n; at += chunk) {
char *to{FreeSpace(chunk)};
chunk = std::min(n - at, chunk);
Claim(chunk);
std::memcpy(to, data + at, chunk);
}
return bytes_ - n;
}
std::size_t CharBuffer::Put(const std::string &str) {
return Put(str.data(), str.size());
}
std::string CharBuffer::Marshal() const {
std::string result;
std::size_t bytes{bytes_};
result.reserve(bytes);
for (const Block &block : blocks_) {
std::size_t chunk{std::min(bytes, Block::capacity)};
for (std::size_t j{0}; j < chunk; ++j) {
result += block.data[j];
}
bytes -= chunk;
}
result.shrink_to_fit();
CHECK(result.size() == bytes_);
return result;
}
} // namespace Fortran::parser