fold.c revision 1.2
1 /*- 2 * Copyright (c) 1990 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Kevin Ruddy. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #ifndef lint 38 char copyright[] = 39 "@(#) Copyright (c) 1990 The Regents of the University of California.\n\ 40 All rights reserved.\n"; 41 #endif /* not lint */ 42 43 #ifndef lint 44 static char sccsid[] = "@(#)fold.c 5.5 (Berkeley) 6/1/90"; 45 #endif /* not lint */ 46 47 #include <stdio.h> 48 #include <stdlib.h> 49 #include <string.h> 50 #include <errno.h> 51 52 #define DEFLINEWIDTH 80 53 54 static void fold (); 55 static int new_column_position (); 56 int count_bytes = 0; 57 int split_words = 0; 58 59 int 60 main(argc, argv) 61 int argc; 62 char **argv; 63 { 64 register int ch; 65 int width; 66 char *p; 67 68 width = -1; 69 while ((ch = getopt(argc, argv, "0123456789bsw:")) != EOF) 70 switch (ch) { 71 case 'b': 72 count_bytes = 1; 73 break; 74 case 's': 75 split_words = 1; 76 break; 77 case 'w': 78 if ((width = atoi(optarg)) <= 0) { 79 (void)fprintf(stderr, 80 "fold: illegal width value.\n"); 81 exit(1); 82 } 83 break; 84 case '0': case '1': case '2': case '3': case '4': 85 case '5': case '6': case '7': case '8': case '9': 86 if (width == -1) { 87 p = argv[optind - 1]; 88 if (p[0] == '-' && p[1] == ch && !p[2]) 89 width = atoi(++p); 90 else 91 width = atoi(argv[optind] + 1); 92 } 93 break; 94 default: 95 (void)fprintf(stderr, 96 "usage: fold [-w width] [file ...]\n"); 97 exit(1); 98 } 99 argv += optind; 100 argc -= optind; 101 102 if (width == -1) 103 width = DEFLINEWIDTH; 104 105 if (!*argv) 106 fold(width); 107 else for (; *argv; ++argv) 108 if (!freopen(*argv, "r", stdin)) { 109 (void)fprintf(stderr, 110 "fold: %s: %s\n", *argv, strerror(errno)); 111 exit(1); 112 } else 113 fold(width); 114 exit(0); 115 } 116 117 /* 118 * Fold the contents of standard input to fit within WIDTH columns 119 * (or bytes) and write to standard output. 120 * 121 * If split_words is set, split the line at the last space character 122 * on the line. This flag necessitates storing the line in a buffer 123 * until the current column > width, or a newline or EOF is read. 124 * 125 * The buffer can grow larger than WIDTH due to backspaces and carriage 126 * returns embedded in the input stream. 127 */ 128 static void 129 fold(width) 130 register int width; 131 { 132 static char *buf = NULL; 133 static int buf_max = 0; 134 register int ch, col; 135 register int indx; 136 137 col = indx = 0; 138 while ((ch = getchar()) != EOF) { 139 if (ch == '\n') { 140 if (indx != 0) 141 fwrite (buf, 1, indx, stdout); 142 putchar('\n'); 143 col = indx = 0; 144 continue; 145 } 146 147 col = new_column_position (col, ch); 148 if (col > width) { 149 int i, last_space; 150 151 if (split_words) { 152 for (i = 0, last_space = -1; i < indx; i++) 153 if(buf[i] == ' ') last_space = i; 154 } 155 156 if (split_words && last_space != -1) { 157 last_space++; 158 159 fwrite (buf, 1, last_space, stdout); 160 memmove (buf, buf+last_space, indx-last_space); 161 162 indx -= last_space; 163 col = 0; 164 for (i = 0; i < indx; i++) { 165 col = new_column_position (col, ch); 166 } 167 } else { 168 fwrite (buf, 1, indx, stdout); 169 col = indx = 0; 170 } 171 putchar('\n'); 172 173 /* calculate the column position for the next line. */ 174 col = new_column_position (col, ch); 175 } 176 177 if (indx + 1 > buf_max) { 178 /* Allocate buffer in LINE_MAX increments */ 179 buf_max += 2048; 180 if((buf = realloc (buf, buf_max)) == NULL) { 181 (void)fprintf(stderr, "%s\n", strerror(errno)); 182 exit(1); 183 } 184 } 185 buf[indx++] = ch; 186 } 187 188 if (indx != 0) 189 fwrite (buf, 1, indx, stdout); 190 } 191 192 /* 193 * calculate the column position 194 */ 195 static int 196 new_column_position (col, ch) 197 int col; 198 int ch; 199 { 200 if (!count_bytes) { 201 switch (ch) { 202 case '\b': 203 if (col > 0) 204 --col; 205 break; 206 case '\r': 207 col = 0; 208 break; 209 case '\t': 210 col = (col + 8) & ~7; 211 break; 212 default: 213 ++col; 214 break; 215 } 216 } else { 217 ++col; 218 } 219 220 return col; 221 } 222
Indexes created Mon Sep 22 10:09:38 GMT 2025