1 /* $OpenBSD: fparseln.c,v 1.6 2005/08/02 21:46:23 espie Exp $ */ 2 /* $NetBSD: fparseln.c,v 1.7 1999/07/02 15:49:12 simonb Exp $ */ 3 4 /* 5 * Copyright (c) 1997 Christos Zoulas. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by Christos Zoulas. 18 * 4. The name of the author may not be used to endorse or promote products 19 * derived from this software without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 #include <sys/cdefs.h> 34 35 #include <stdio.h> 36 #include <string.h> 37 #include <stdlib.h> 38 39 #include "util.h" 40 41 static int isescaped(const char *, const char *, int); 42 43 /* isescaped(): 44 * Return true if the character in *p that belongs to a string 45 * that starts in *sp, is escaped by the escape character esc. 46 */ 47 static int 48 isescaped(const char *sp, const char *p, int esc) 49 { 50 const char *cp; 51 size_t ne; 52 53 /* No escape character */ 54 if (esc == '\0') 55 return 1; 56 57 /* Count the number of escape characters that precede ours */ 58 for (ne = 0, cp = p; --cp >= sp && *cp == esc; ne++) 59 continue; 60 61 /* Return true if odd number of escape characters */ 62 return (ne & 1) != 0; 63 } 64 65 66 /* fparseln(): 67 * Read a line from a file parsing continuations ending in \ 68 * and eliminating trailing newlines, or comments starting with 69 * the comment char. 70 */ 71 char * 72 fparseln(FILE *fp, size_t *size, size_t *lineno, const char str[3], 73 int flags) 74 { 75 static const char dstr[3] = { '\\', '\\', '#' }; 76 char *buf = NULL, *ptr, *cp, esc, con, nl, com; 77 size_t s, len = 0; 78 int cnt = 1; 79 80 if (str == NULL) 81 str = dstr; 82 83 esc = str[0]; 84 con = str[1]; 85 com = str[2]; 86 87 /* 88 * XXX: it would be cool to be able to specify the newline character, 89 * but unfortunately, fgetln does not let us 90 */ 91 nl = '\n'; 92 93 while (cnt) { 94 cnt = 0; 95 96 if (lineno) 97 (*lineno)++; 98 99 if ((ptr = fgetln(fp, &s)) == NULL) 100 break; 101 102 if (s && com) { /* Check and eliminate comments */ 103 for (cp = ptr; cp < ptr + s; cp++) 104 if (*cp == com && !isescaped(ptr, cp, esc)) { 105 s = cp - ptr; 106 cnt = s == 0 && buf == NULL; 107 break; 108 } 109 } 110 111 if (s && nl) { /* Check and eliminate newlines */ 112 cp = &ptr[s - 1]; 113 114 if (*cp == nl) 115 s--; /* forget newline */ 116 } 117 118 if (s && con) { /* Check and eliminate continuations */ 119 cp = &ptr[s - 1]; 120 121 if (*cp == con && !isescaped(ptr, cp, esc)) { 122 s--; /* forget escape */ 123 cnt = 1; 124 } 125 } 126 127 if (s == 0 && buf != NULL) 128 continue; 129 130 if ((cp = realloc(buf, len + s + 1)) == NULL) { 131 free(buf); 132 return NULL; 133 } 134 buf = cp; 135 136 (void) memcpy(buf + len, ptr, s); 137 len += s; 138 buf[len] = '\0'; 139 } 140 141 if ((flags & FPARSELN_UNESCALL) != 0 && esc && buf != NULL && 142 strchr(buf, esc) != NULL) { 143 ptr = cp = buf; 144 while (cp[0] != '\0') { 145 int skipesc; 146 147 while (cp[0] != '\0' && cp[0] != esc) 148 *ptr++ = *cp++; 149 if (cp[0] == '\0' || cp[1] == '\0') 150 break; 151 152 skipesc = 0; 153 if (cp[1] == com) 154 skipesc += (flags & FPARSELN_UNESCCOMM); 155 if (cp[1] == con) 156 skipesc += (flags & FPARSELN_UNESCCONT); 157 if (cp[1] == esc) 158 skipesc += (flags & FPARSELN_UNESCESC); 159 if (cp[1] != com && cp[1] != con && cp[1] != esc) 160 skipesc = (flags & FPARSELN_UNESCREST); 161 162 if (skipesc) 163 cp++; 164 else 165 *ptr++ = *cp++; 166 *ptr++ = *cp++; 167 } 168 *ptr = '\0'; 169 len = strlen(buf); 170 } 171 172 if (size) 173 *size = len; 174 return buf; 175 } 176 177 #ifdef TEST 178 179 int main(int, char **); 180 181 int 182 main(argc, argv) 183 int argc; 184 char **argv; 185 { 186 char *ptr; 187 size_t size, line; 188 189 line = 0; 190 while ((ptr = fparseln(stdin, &size, &line, NULL, 191 FPARSELN_UNESCALL)) != NULL) 192 printf("line %d (%d) |%s|\n", line, size, ptr); 193 return 0; 194 } 195 196 /* 197 198 # This is a test 199 line 1 200 line 2 \ 201 line 3 # Comment 202 line 4 \# Not comment \\\\ 203 204 # And a comment \ 205 line 5 \\\ 206 line 6 207 208 */ 209 210 #endif /* TEST */ 211