File: catl.c 1 /* 2 The MIT License (MIT) 3 4 Copyright © 2024 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* line_memory_error_msg = 42 "" 43 "\x1b[31mcan't get memory for the line-scanner\x1b[0m\n"; 44 45 // slice is a growable region of bytes in memory 46 typedef struct slice { 47 // ptr is the starting place of the region 48 unsigned char* ptr; 49 50 // len is how many bytes are currently being used 51 size_t len; 52 53 // cap is how many bytes the memory region has available 54 size_t cap; 55 } slice; 56 57 // init_slice is the constructor for type slice 58 void init_slice(slice* s, size_t cap) { 59 s->ptr = malloc(cap); 60 s->len = 0; 61 s->cap = cap; 62 } 63 64 bool starts_with_bom(const unsigned char* b, const size_t n) { 65 return (n >= 3 && b[0] == 0xef && b[1] == 0xbb && b[2] == 0xbf); 66 } 67 68 // handle_reader skips leading UTF-8 BOMs (byte-order marks), and turns all 69 // CR-LF pairs into single LF bytes 70 bool handle_reader(FILE* w, FILE* r, slice* line) { 71 slice trimmed; 72 73 for (size_t i = 0; !feof(w); i++) { 74 int len = getline((char**)&line->ptr, &line->cap, r); 75 if (len < 0) { 76 break; 77 } 78 79 if (line->ptr == NULL) { 80 putc('\n', w); 81 fprintf(stderr, line_memory_error_msg); 82 exit(1); 83 } 84 85 line->len = len; 86 trimmed.ptr = line->ptr; 87 trimmed.len = line->len; 88 89 // get rid of leading UTF-8 BOM (byte-order mark) if 1st line has it 90 if (i == 0 && starts_with_bom(trimmed.ptr, trimmed.len)) { 91 trimmed.ptr += 3; 92 trimmed.len -= 3; 93 len = trimmed.len; 94 } 95 96 const unsigned char* p = trimmed.ptr; 97 // get rid of trailing line-feeds and CRLF end-of-line byte-pairs 98 if (len >= 2 && p[len - 2] == '\r' && p[len - 1] == '\n') { 99 trimmed.len -= 2; 100 } else if (len >= 1 && p[len - 1] == '\n') { 101 trimmed.len--; 102 } 103 104 fwrite(trimmed.ptr, trimmed.len, 1, w); 105 putc('\n', w); 106 } 107 108 return true; 109 } 110 111 // handle_file handles data from the filename given; returns false only when 112 // the file can't be opened 113 bool handle_file(FILE* w, char* fname, slice* line) { 114 FILE* f = fopen(fname, "rb"); 115 if (f == NULL) { 116 fprintf(stderr, "\x1b[31mcan't open file named %s\x1b[0m\n", fname); 117 return false; 118 } 119 120 const bool ok = handle_reader(w, f, line); 121 fclose(f); 122 return ok; 123 } 124 125 // run returns the number of errors 126 int run(int argc, char** argv, FILE* w, slice* line) { 127 size_t dashes = 0; 128 for (int i = 1; i < argc; i++) { 129 if (argv[i][0] == '-' && argv[i][1] == 0) { 130 dashes++; 131 } 132 } 133 134 if (dashes > 1) { 135 const char* msg = "can't use a dash (stdin) as input more than once"; 136 fprintf(stderr, "\x1b[31m%s\x1b[0m\n", msg); 137 return 1; 138 } 139 140 // use stdin when not given any filepaths 141 if (argc <= 1) { 142 handle_reader(w, stdin, line); 143 return 0; 144 } 145 146 size_t errors = 0; 147 for (int i = 1; i < argc && !feof(stdout); i++) { 148 if (argv[i][0] == '-' && argv[i][1] == 0) { 149 if (!handle_reader(w, stdin, line)) { 150 errors++; 151 } 152 continue; 153 } 154 155 if (!handle_file(w, argv[i], line)) { 156 errors++; 157 } 158 } 159 160 return errors; 161 } 162 163 int main(int argc, char** argv) { 164 #ifdef _WIN32 165 setmode(fileno(stdin), O_BINARY); 166 // ensure output lines end in LF instead of CRLF on windows 167 setmode(fileno(stdout), O_BINARY); 168 setmode(fileno(stderr), O_BINARY); 169 #endif 170 171 slice line; 172 init_slice(&line, 32 * 1024); 173 if (line.ptr == NULL) { 174 fprintf(stderr, line_memory_error_msg); 175 return 1; 176 } 177 178 const int res = run(argc, argv, stdout, &line) == 0 ? 0 : 1; 179 free(line.ptr); 180 return res; 181 }