src/text_utils.cc

// Copyright 2026 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "text_utils.h"

#include <cstring>

#include "disk_interface.h"

TextLineSplitter::TextLineSplitter(StringPiece input)
    : p_(input.str_), limit_(input.str_ + input.size()) {}

bool TextLineSplitter::GetNextLine(StringPiece* line) {
  if (p_ == limit_)
    return false;

  const char* start = p_;
  const char* newline =
      static_cast<const char*>(::memchr(p_, '\n', limit_ - p_));
  if (newline) {
    p_ = newline + 1;
  } else {
    newline = p_ = limit_;
  }
  if (newline > start && newline[-1] == '\r')
    newline -= 1;
  *line = StringPiece(start, newline - start);
  return true;
}

TextFileParser::TextFileParser(DiskInterface& disk_interface)
    : disk_interface_(disk_interface) {}

bool TextFileParser::Reset(const char* input_file, std::string* error) {
  content_.clear();
  lines_.clear();
  if (disk_interface_.ReadFile(input_file, &content_, error) !=
      FileReader::Okay) {
    return false;
  }
  StringPiece target;
  TextLineSplitter splitter(content_);
  while (splitter.GetNextLine(&target)) {
    if (!target.empty())
      lines_.push_back(target);
  }
  return true;
}

StringPiece StripStringPiece(StringPiece input) {
  auto IsWhitespace = [](char ch) {
    return ch == ' ' || ch == '\t' || ch == '\n' || ch == '\r';
  };
  size_t start = 0;
  while (start < input.len_ && IsWhitespace(input.str_[start])) {
    ++start;
  }
  size_t end = input.len_;
  while (end > start && IsWhitespace(input.str_[end - 1])) {
    --end;
  }
  return StringPiece(input.str_ + start, end - start);
}