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// Copyright (c) 2016 Google Inc.
//
// 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.
#ifndef TOOLS_IO_H_
#define TOOLS_IO_H_
#include <cstdint>
#include <cstdio>
#include <cstring>
#include <vector>
// Appends the content from the file named as |filename| to |data|, assuming
// each element in the file is of type |T|. The file is opened with the given
// |mode|. If |filename| is nullptr or "-", reads from the standard input, but
// reopened with the given mode. If any error occurs, writes error messages to
// standard error and returns false.
template <typename T>
bool ReadFile(const char* filename, const char* mode, std::vector<T>* data) {
const int buf_size = 1024;
const bool use_file = filename && strcmp("-", filename);
if (FILE* fp =
(use_file ? fopen(filename, mode) : freopen(nullptr, mode, stdin))) {
T buf[buf_size];
while (size_t len = fread(buf, sizeof(T), buf_size, fp)) {
data->insert(data->end(), buf, buf + len);
}
if (ftell(fp) == -1L) {
if (ferror(fp)) {
fprintf(stderr, "error: error reading file '%s'\n", filename);
if (use_file) fclose(fp);
return false;
}
} else {
if (sizeof(T) != 1 && (ftell(fp) % sizeof(T))) {
fprintf(
stderr,
"error: file size should be a multiple of %zd; file '%s' corrupt\n",
sizeof(T), filename);
if (use_file) fclose(fp);
return false;
}
}
if (use_file) fclose(fp);
} else {
fprintf(stderr, "error: file does not exist '%s'\n", filename);
return false;
}
return true;
}
// Writes the given |data| into the file named as |filename| using the given
// |mode|, assuming |data| is an array of |count| elements of type |T|. If
// |filename| is nullptr or "-", writes to standard output. If any error occurs,
// returns false and outputs error message to standard error.
template <typename T>
bool WriteFile(const char* filename, const char* mode, const T* data,
size_t count) {
const bool use_stdout =
!filename || (filename[0] == '-' && filename[1] == '\0');
if (FILE* fp = (use_stdout ? stdout : fopen(filename, mode))) {
size_t written = fwrite(data, sizeof(T), count, fp);
if (count != written) {
fprintf(stderr, "error: could not write to file '%s'\n", filename);
if (!use_stdout) fclose(fp);
return false;
}
if (!use_stdout) fclose(fp);
} else {
fprintf(stderr, "error: could not open file '%s'\n", filename);
return false;
}
return true;
}
#endif // TOOLS_IO_H_