/*

 * Copyright 2017 WebAssembly Community Group participants

 *

 * 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 "wabt/lexer-source.h"

#include <algorithm>

namespace wabt {

LexerSource::LexerSource(const void* data, Offset size)

    : data_(data), size_(size), read_offset_(0) {}

std::unique_ptr<LexerSource> LexerSource::Clone() {

  LexerSource* result = new LexerSource(data_, size_);

  result->read_offset_ = read_offset_;

  return std::unique_ptr<LexerSource>(result);

}

Result LexerSource::Tell(Offset* out_offset) {

  *out_offset = read_offset_;

  return Result::Ok;

}

size_t LexerSource::Fill(void* dest, Offset size) {

  Offset read_size = std::min(size, size_ - read_offset_);

  if (read_size > 0) {

    const void* src = static_cast<const char*>(data_) + read_offset_;

    memcpy(dest, src, read_size);

    read_offset_ += read_size;

  }

  return read_size;

}

Result LexerSource::Seek(Offset offset) {

  if (offset < size_) {

    read_offset_ = offset;

    return Result::Ok;

  }

  return Result::Error;

}

Result LexerSource::ReadRange(OffsetRange range, std::vector<char>* out_data) {

  OffsetRange clamped = range;

  clamped.start = std::min(clamped.start, size_);

  clamped.end = std::min(clamped.end, size_);

  if (clamped.size()) {

    out_data->resize(clamped.size());

    const void* src = static_cast<const char*>(data_) + clamped.start;

    memcpy(out_data->data(), src, clamped.size());

  }

  return Result::Ok;

}

}  // namespace wabt