1 /* $NetBSD: fparseln.c,v 1.1 2002/11/30 03:04:45 lukem Exp $ */ 2 3 /* 4 * Copyright (c) 1997 Christos Zoulas. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. All advertising materials mentioning features or use of this software 15 * must display the following acknowledgement: 16 * This product includes software developed by Christos Zoulas. 17 * 4. The name of the author may not be used to endorse or promote products 18 * derived from this software without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 21 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 22 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 23 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 24 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 25 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 27 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 29 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 #if defined(LIBC_SCCS) && !defined(lint) 34 __RCSID("$NetBSD: fparseln.c,v 1.1 2002/11/30 03:04:45 lukem Exp $"); 35 #endif /* LIBC_SCCS and not lint */ 36 37 #include "namespace.h" 38 39 #include <assert.h> 40 #include <errno.h> 41 #include <stdio.h> 42 #include <string.h> 43 #include <stdlib.h> 44 45 #ifdef __weak_alias 46 __weak_alias(fparseln,_fparseln) 47 #endif 48 49 #if ! HAVE_FPARSELN 50 51 static int isescaped(const char *, const char *, int); 52 53 /* isescaped(): 54 * Return true if the character in *p that belongs to a string 55 * that starts in *sp, is escaped by the escape character esc. 56 */ 57 static int 58 isescaped(const char *sp, const char *p, int esc) 59 { 60 const char *cp; 61 size_t ne; 62 63 _DIAGASSERT(sp != NULL); 64 _DIAGASSERT(p != NULL); 65 66 /* No escape character */ 67 if (esc == '\0') 68 return 1; 69 70 /* Count the number of escape characters that precede ours */ 71 for (ne = 0, cp = p; --cp >= sp && *cp == esc; ne++) 72 continue; 73 74 /* Return true if odd number of escape characters */ 75 return (ne & 1) != 0; 76 } 77 78 79 /* fparseln(): 80 * Read a line from a file parsing continuations ending in \ 81 * and eliminating trailing newlines, or comments starting with 82 * the comment char. 83 */ 84 char * 85 fparseln(FILE *fp, size_t *size, size_t *lineno, const char str[3], int flags) 86 { 87 static const char dstr[3] = { '\\', '\\', '#' }; 88 89 size_t s, len; 90 char *buf; 91 char *ptr, *cp; 92 int cnt; 93 char esc, con, nl, com; 94 95 _DIAGASSERT(fp != NULL); 96 97 len = 0; 98 buf = NULL; 99 cnt = 1; 100 101 if (str == NULL) 102 str = dstr; 103 104 esc = str[0]; 105 con = str[1]; 106 com = str[2]; 107 /* 108 * XXX: it would be cool to be able to specify the newline character, 109 * but unfortunately, fgetln does not let us 110 */ 111 nl = '\n'; 112 113 while (cnt) { 114 cnt = 0; 115 116 if (lineno) 117 (*lineno)++; 118 119 if ((ptr = fgetln(fp, &s)) == NULL) 120 break; 121 122 if (s && com) { /* Check and eliminate comments */ 123 for (cp = ptr; cp < ptr + s; cp++) 124 if (*cp == com && !isescaped(ptr, cp, esc)) { 125 s = cp - ptr; 126 cnt = s == 0 && buf == NULL; 127 break; 128 } 129 } 130 131 if (s && nl) { /* Check and eliminate newlines */ 132 cp = &ptr[s - 1]; 133 134 if (*cp == nl) 135 s--; /* forget newline */ 136 } 137 138 if (s && con) { /* Check and eliminate continuations */ 139 cp = &ptr[s - 1]; 140 141 if (*cp == con && !isescaped(ptr, cp, esc)) { 142 s--; /* forget escape */ 143 cnt = 1; 144 } 145 } 146 147 if (s == 0 && buf != NULL) 148 continue; 149 150 if ((cp = realloc(buf, len + s + 1)) == NULL) { 151 free(buf); 152 return NULL; 153 } 154 buf = cp; 155 156 (void) memcpy(buf + len, ptr, s); 157 len += s; 158 buf[len] = '\0'; 159 } 160 161 if ((flags & FPARSELN_UNESCALL) != 0 && esc && buf != NULL && 162 strchr(buf, esc) != NULL) { 163 ptr = cp = buf; 164 while (cp[0] != '\0') { 165 int skipesc; 166 167 while (cp[0] != '\0' && cp[0] != esc) 168 *ptr++ = *cp++; 169 if (cp[0] == '\0' || cp[1] == '\0') 170 break; 171 172 skipesc = 0; 173 if (cp[1] == com) 174 skipesc += (flags & FPARSELN_UNESCCOMM); 175 if (cp[1] == con) 176 skipesc += (flags & FPARSELN_UNESCCONT); 177 if (cp[1] == esc) 178 skipesc += (flags & FPARSELN_UNESCESC); 179 if (cp[1] != com && cp[1] != con && cp[1] != esc) 180 skipesc = (flags & FPARSELN_UNESCREST); 181 182 if (skipesc) 183 cp++; 184 else 185 *ptr++ = *cp++; 186 *ptr++ = *cp++; 187 } 188 *ptr = '\0'; 189 len = strlen(buf); 190 } 191 192 if (size) 193 *size = len; 194 return buf; 195 } 196 197 #ifdef TEST 198 199 int main(int, char **); 200 201 int 202 main(int argc, char **argv) 203 { 204 char *ptr; 205 size_t size, line; 206 207 line = 0; 208 while ((ptr = fparseln(stdin, &size, &line, NULL, 209 FPARSELN_UNESCALL)) != NULL) 210 printf("line %d (%d) |%s|\n", line, size, ptr); 211 return 0; 212 } 213 214 /* 215 216 # This is a test 217 line 1 218 line 2 \ 219 line 3 # Comment 220 line 4 \# Not comment \\\\ 221 222 # And a comment \ 223 line 5 \\\ 224 line 6 225 226 */ 227 228 #endif /* TEST */ 229 #endif /* ! HAVE_FPARSELN */ 230