1 /* $OpenBSD: fparseln.c,v 1.7 2012/12/05 23:20:06 deraadt 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 <stdio.h> 34 #include <string.h> 35 #include <stdlib.h> 36 37 #include "util.h" 38 39 static int isescaped(const char *, const char *, int); 40 41 /* isescaped(): 42 * Return true if the character in *p that belongs to a string 43 * that starts in *sp, is escaped by the escape character esc. 44 */ 45 static int 46 isescaped(const char *sp, const char *p, int esc) 47 { 48 const char *cp; 49 size_t ne; 50 51 /* No escape character */ 52 if (esc == '\0') 53 return 1; 54 55 /* Count the number of escape characters that precede ours */ 56 for (ne = 0, cp = p; --cp >= sp && *cp == esc; ne++) 57 continue; 58 59 /* Return true if odd number of escape characters */ 60 return (ne & 1) != 0; 61 } 62 63 64 /* fparseln(): 65 * Read a line from a file parsing continuations ending in \ 66 * and eliminating trailing newlines, or comments starting with 67 * the comment char. 68 */ 69 char * 70 fparseln(FILE *fp, size_t *size, size_t *lineno, const char str[3], 71 int flags) 72 { 73 static const char dstr[3] = { '\\', '\\', '#' }; 74 char *buf = NULL, *ptr, *cp, esc, con, nl, com; 75 size_t s, len = 0; 76 int cnt = 1; 77 78 if (str == NULL) 79 str = dstr; 80 81 esc = str[0]; 82 con = str[1]; 83 com = str[2]; 84 85 /* 86 * XXX: it would be cool to be able to specify the newline character, 87 * but unfortunately, fgetln does not let us 88 */ 89 nl = '\n'; 90 91 while (cnt) { 92 cnt = 0; 93 94 if (lineno) 95 (*lineno)++; 96 97 if ((ptr = fgetln(fp, &s)) == NULL) 98 break; 99 100 if (s && com) { /* Check and eliminate comments */ 101 for (cp = ptr; cp < ptr + s; cp++) 102 if (*cp == com && !isescaped(ptr, cp, esc)) { 103 s = cp - ptr; 104 cnt = s == 0 && buf == NULL; 105 break; 106 } 107 } 108 109 if (s && nl) { /* Check and eliminate newlines */ 110 cp = &ptr[s - 1]; 111 112 if (*cp == nl) 113 s--; /* forget newline */ 114 } 115 116 if (s && con) { /* Check and eliminate continuations */ 117 cp = &ptr[s - 1]; 118 119 if (*cp == con && !isescaped(ptr, cp, esc)) { 120 s--; /* forget escape */ 121 cnt = 1; 122 } 123 } 124 125 if (s == 0 && buf != NULL) 126 continue; 127 128 if ((cp = realloc(buf, len + s + 1)) == NULL) { 129 free(buf); 130 return NULL; 131 } 132 buf = cp; 133 134 (void) memcpy(buf + len, ptr, s); 135 len += s; 136 buf[len] = '\0'; 137 } 138 139 if ((flags & FPARSELN_UNESCALL) != 0 && esc && buf != NULL && 140 strchr(buf, esc) != NULL) { 141 ptr = cp = buf; 142 while (cp[0] != '\0') { 143 int skipesc; 144 145 while (cp[0] != '\0' && cp[0] != esc) 146 *ptr++ = *cp++; 147 if (cp[0] == '\0' || cp[1] == '\0') 148 break; 149 150 skipesc = 0; 151 if (cp[1] == com) 152 skipesc += (flags & FPARSELN_UNESCCOMM); 153 if (cp[1] == con) 154 skipesc += (flags & FPARSELN_UNESCCONT); 155 if (cp[1] == esc) 156 skipesc += (flags & FPARSELN_UNESCESC); 157 if (cp[1] != com && cp[1] != con && cp[1] != esc) 158 skipesc = (flags & FPARSELN_UNESCREST); 159 160 if (skipesc) 161 cp++; 162 else 163 *ptr++ = *cp++; 164 *ptr++ = *cp++; 165 } 166 *ptr = '\0'; 167 len = strlen(buf); 168 } 169 170 if (size) 171 *size = len; 172 return buf; 173 } 174 175 #ifdef TEST 176 177 int main(int, char **); 178 179 int 180 main(argc, argv) 181 int argc; 182 char **argv; 183 { 184 char *ptr; 185 size_t size, line; 186 187 line = 0; 188 while ((ptr = fparseln(stdin, &size, &line, NULL, 189 FPARSELN_UNESCALL)) != NULL) 190 printf("line %d (%d) |%s|\n", line, size, ptr); 191 return 0; 192 } 193 194 /* 195 196 # This is a test 197 line 1 198 line 2 \ 199 line 3 # Comment 200 line 4 \# Not comment \\\\ 201 202 # And a comment \ 203 line 5 \\\ 204 line 6 205 206 */ 207 208 #endif /* TEST */ 209