File: catl.c 1 /* 2 The MIT License (MIT) 3 4 Copyright © 2020-2025 pacman64 5 6 Permission is hereby granted, free of charge, to any person obtaining a copy of 7 this software and associated documentation files (the “Software”), to deal 8 in the Software without restriction, including without limitation the rights to 9 use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies 10 of the Software, and to permit persons to whom the Software is furnished to do 11 so, subject to the following conditions: 12 13 The above copyright notice and this permission notice shall be included in all 14 copies or substantial portions of the Software. 15 16 THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 17 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 18 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 19 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 20 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 21 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 22 SOFTWARE. 23 */ 24 25 /* 26 You can build this command-line app by running 27 28 cc -Wall -s -O2 -o ./catl ./catl.c 29 */ 30 31 #include <fcntl.h> 32 #include <stdbool.h> 33 #include <stdio.h> 34 #include <stdlib.h> 35 #include <string.h> 36 37 #ifdef _WIN32 38 #include <windows.h> 39 #endif 40 41 const char* info = "" 42 "catl [filenames...]\n" 43 "\n" 44 "Concatenate lines from all the named sources given. The name `-` stands for\n" 45 "the standard input. When no names are given, the standard input is used by\n" 46 "default.\n" 47 ""; 48 49 const char* no_line_memory_msg = "can't get enough memory to read lines"; 50 51 // slice is a growable region of bytes in memory 52 typedef struct slice { 53 // ptr is the starting place of the region 54 unsigned char* ptr; 55 56 // len is how many bytes are currently being used 57 size_t len; 58 59 // cap is how many bytes the memory region has available 60 size_t cap; 61 } slice; 62 63 bool starts_with_bom(const unsigned char* b, const size_t n) { 64 return (n >= 3 && b[0] == 0xef && b[1] == 0xbb && b[2] == 0xbf); 65 } 66 67 // handle_reader skips leading UTF-8 BOMs (byte-order marks), and turns all 68 // CR-LF pairs into single LF bytes 69 bool handle_reader(FILE* w, FILE* r, slice* line) { 70 slice trimmed; 71 72 for (size_t i = 0; !feof(w); i++) { 73 int len = getline((char**)&line->ptr, &line->cap, r); 74 if (len < 0) { 75 break; 76 } 77 78 if (line->ptr == NULL) { 79 putc('\n', w); 80 fflush(w); 81 82 fprintf(stderr, "\x1b[31m%s\x1b[0m\n", no_line_memory_msg); 83 exit(1); 84 } 85 86 line->len = len; 87 trimmed.ptr = line->ptr; 88 trimmed.len = line->len; 89 90 // get rid of leading UTF-8 BOM (byte-order mark) if 1st line has it 91 if (i == 0 && starts_with_bom(trimmed.ptr, trimmed.len)) { 92 trimmed.ptr += 3; 93 trimmed.len -= 3; 94 len = trimmed.len; 95 } 96 97 const unsigned char* p = trimmed.ptr; 98 // get rid of trailing line-feeds and CRLF end-of-line byte-pairs 99 if (len >= 2 && p[len - 2] == '\r' && p[len - 1] == '\n') { 100 trimmed.len -= 2; 101 } else if (len >= 1 && p[len - 1] == '\n') { 102 trimmed.len--; 103 } 104 105 fwrite(trimmed.ptr, trimmed.len, 1, w); 106 putc('\n', w); 107 fflush(w); 108 } 109 110 return true; 111 } 112 113 // handle_file handles data from the filename given; returns false only when 114 // the file can't be opened 115 bool handle_file(FILE* w, char* fname, slice* line) { 116 FILE* f = fopen(fname, "rb"); 117 if (f == NULL) { 118 fprintf(stderr, "\x1b[31mcan't open file named %s\x1b[0m\n", fname); 119 return false; 120 } 121 122 const bool ok = handle_reader(w, f, line); 123 fclose(f); 124 return ok; 125 } 126 127 // run returns the number of errors 128 int run(int argc, char** argv, FILE* w) { 129 size_t dashes = 0; 130 for (int i = 1; i < argc; i++) { 131 if (argv[i][0] == '-' && argv[i][1] == 0) { 132 dashes++; 133 } 134 } 135 136 if (dashes > 1) { 137 const char* msg = "can't use the standard input (dash) more than once"; 138 fprintf(stderr, "\x1b[31m%s\x1b[0m\n", msg); 139 return 1; 140 } 141 142 slice line; 143 line.len = 0; 144 line.cap = 32 * 1024; 145 line.ptr = malloc(line.cap); 146 147 if (line.ptr == NULL) { 148 fprintf(stderr, "\x1b[31m%s\x1b[0m\n", no_line_memory_msg); 149 return 1; 150 } 151 152 // use stdin when not given any filepaths 153 if (argc <= 1) { 154 handle_reader(w, stdin, &line); 155 free(line.ptr); 156 return 0; 157 } 158 159 size_t errors = 0; 160 for (int i = 1; i < argc && !feof(stdout); i++) { 161 if (argv[i][0] == '-' && argv[i][1] == 0) { 162 if (!handle_reader(w, stdin, &line)) { 163 errors++; 164 } 165 continue; 166 } 167 168 if (!handle_file(w, argv[i], &line)) { 169 errors++; 170 } 171 } 172 173 free(line.ptr); 174 return errors; 175 } 176 177 int main(int argc, char** argv) { 178 #ifdef _WIN32 179 setmode(fileno(stdin), O_BINARY); 180 // ensure output lines end in LF instead of CRLF on windows 181 setmode(fileno(stdout), O_BINARY); 182 setmode(fileno(stderr), O_BINARY); 183 #endif 184 185 if (argc > 1) { 186 if ( 187 strcmp(argv[1], "-h") == 0 || 188 strcmp(argv[1], "-help") == 0 || 189 strcmp(argv[1], "--h") == 0 || 190 strcmp(argv[1], "--help") == 0 191 ) { 192 fprintf(stdout, "%s", info); 193 return 0; 194 } 195 } 196 197 return run(argc, argv, stdout) == 0 ? 0 : 1; 198 }