1 // Copyright (c) 2016 Google Inc. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 #ifndef TOOLS_IO_H_ 16 #define TOOLS_IO_H_ 17 18 #include <cstdint> 19 #include <cstdio> 20 #include <vector> 21 22 // Appends the content from the file named as |filename| to |data|, assuming 23 // each element in the file is of type |T|. The file is opened with the given 24 // |mode|. If |filename| is nullptr or "-", reads from the standard input, but 25 // reopened with the given mode. If any error occurs, writes error messages to 26 // standard error and returns false. 27 template <typename T> 28 bool ReadFile(const char* filename, const char* mode, std::vector<T>* data) { 29 const int buf_size = 1024; 30 const bool use_file = filename && strcmp("-", filename); 31 if (FILE* fp = 32 (use_file ? fopen(filename, mode) : freopen(nullptr, mode, stdin))) { 33 T buf[buf_size]; 34 while (size_t len = fread(buf, sizeof(T), buf_size, fp)) { 35 data->insert(data->end(), buf, buf + len); 36 } 37 if (ftell(fp) == -1L) { 38 if (ferror(fp)) { 39 fprintf(stderr, "error: error reading file '%s'\n", filename); 40 return false; 41 } 42 } else { 43 if (sizeof(T) != 1 && (ftell(fp) % sizeof(T))) { 44 fprintf( 45 stderr, 46 "error: file size should be a multiple of %zd; file '%s' corrupt\n", 47 sizeof(T), filename); 48 return false; 49 } 50 } 51 if (use_file) fclose(fp); 52 } else { 53 fprintf(stderr, "error: file does not exist '%s'\n", filename); 54 return false; 55 } 56 return true; 57 } 58 59 // Writes the given |data| into the file named as |filename| using the given 60 // |mode|, assuming |data| is an array of |count| elements of type |T|. If 61 // |filename| is nullptr or "-", writes to standard output. If any error occurs, 62 // returns false and outputs error message to standard error. 63 template <typename T> 64 bool WriteFile(const char* filename, const char* mode, const T* data, 65 size_t count) { 66 const bool use_stdout = 67 !filename || (filename[0] == '-' && filename[1] == '\0'); 68 if (FILE* fp = (use_stdout ? stdout : fopen(filename, mode))) { 69 size_t written = fwrite(data, sizeof(T), count, fp); 70 if (count != written) { 71 fprintf(stderr, "error: could not write to file '%s'\n", filename); 72 return false; 73 } 74 if (!use_stdout) fclose(fp); 75 } else { 76 fprintf(stderr, "error: could not open file '%s'\n", filename); 77 return false; 78 } 79 return true; 80 } 81 82 #endif // TOOLS_IO_H_ 83
