sinksource.cc

// Copyright 2013, Beeri 15.  All rights reserved.
// Author: Roman Gershman (romange@gmail.com)
//

#include "util/sinksource.h"
#include "base/logging.h"
#include "base/port.h"

namespace util {

Sink::WritableBuffer Sink::GetAppendBuffer(size_t min_capacity, WritableBuffer scratch,
                                           size_t /*desired_capacity_hint*/) {
  CHECK_GE(scratch.size(), min_capacity);
  return scratch;
}

Status Sink::Flush() { return Status::OK; }

StatusObject<size_t> Source::Read(const strings::MutableByteRange& range) {
  CHECK(!range.empty());

  size_t read = 0;
  if (!prepend_buf_.empty()) {
    if (prepend_buf_.size() >= range.size()) {
      memcpy(range.begin(), prepend_buf_.begin(), range.size());
      auto src = prepend_buf_.begin() + range.size();
      size_t new_size = prepend_buf_.size() - range.size();
      memmove(prepend_buf_.begin(), src, new_size);
      prepend_buf_.resize(new_size);

      return range.size();
    }

    memcpy(range.begin(), prepend_buf_.begin(), prepend_buf_.size());

    read = prepend_buf_.size();
    prepend_buf_.clear();
    DCHECK_LT(read, range.size());

  }
  if (eof_)
    return read;

  auto lrange = range.subpiece(read);
  while (true) {
    auto res = ReadInternal(lrange);
    if (!res.ok())
      return res;

    read += res.obj;
    eof_ = res.obj == 0;
    if (eof_ || res.obj == lrange.size())
      break;
    lrange = lrange.subpiece(res.obj);
  }
  return read;
}

StatusObject<size_t> StringSource::ReadInternal(const strings::MutableByteRange& range) {
  size_t to_fill = std::min<size_t>({range.size(), block_size_, input_.size()});
  memcpy(range.begin(), input_.begin(), to_fill);

  input_.remove_prefix(to_fill);
  return to_fill;
}

}  // namespace util