//
// Copyright (C) 2026 The Android Open Source Project
//
// 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 "cuttlefish/io/read_exact.h"

#include <stddef.h>
#include <stdint.h>

#include "cuttlefish/io/io.h"
#include "cuttlefish/result/expect.h"
#include "cuttlefish/result/result_type.h"

namespace cuttlefish {

Result<void> ReadExact(Reader& reader, char* buf, size_t size) {
  while (size > 0) {
    size_t data_read = CF_EXPECT(reader.Read((void*)buf, size));
    CF_EXPECT_GT(data_read, 0, "EOF, still want to read " << size);
    buf += data_read;
    size -= data_read;
  }
  return {};
}

Result<void> PReadExact(const ReaderSeeker& reader, char* buf, size_t size,
                        uint64_t offset) {
  while (size > 0) {
    size_t data_read = CF_EXPECT(reader.PRead((void*)buf, size, offset));
    CF_EXPECT_GT(data_read, 0, "EOF, still want to read " << size);
    buf += data_read;
    size -= data_read;
    offset += data_read;
  }
  return {};
}

}  // namespace cuttlefish
