1 /* $NetBSD: fparseln.c,v 1.7 2007/03/08 19:57:53 drochner 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 __FBSDID("$FreeBSD$"); 34 35 #include <sys/types.h> 36 #include <assert.h> 37 #include <errno.h> 38 #include <stdio.h> 39 #include <string.h> 40 #include <stdlib.h> 41 #include <libutil.h> 42 43 static int isescaped(const char *, const char *, int); 44 45 /* isescaped(): 46 * Return true if the character in *p that belongs to a string 47 * that starts in *sp, is escaped by the escape character esc. 48 */ 49 static int 50 isescaped(const char *sp, const char *p, int esc) 51 { 52 const char *cp; 53 size_t ne; 54 55 #if 0 56 _DIAGASSERT(sp != NULL); 57 _DIAGASSERT(p != NULL); 58 #endif 59 60 /* No escape character */ 61 if (esc == '\0') 62 return 0; 63 64 /* Count the number of escape characters that precede ours */ 65 for (ne = 0, cp = p; --cp >= sp && *cp == esc; ne++) 66 continue; 67 68 /* Return true if odd number of escape characters */ 69 return (ne & 1) != 0; 70 } 71 72 73 /* fparseln(): 74 * Read a line from a file parsing continuations ending in \ 75 * and eliminating trailing newlines, or comments starting with 76 * the comment char. 77 */ 78 char * 79 fparseln(FILE *fp, size_t *size, size_t *lineno, const char str[3], int flags) 80 { 81 static const char dstr[3] = { '\\', '\\', '#' }; 82 83 size_t s, len; 84 char *buf; 85 char *ptr, *cp; 86 int cnt; 87 char esc, con, nl, com; 88 #ifdef FSTACK 89 #define MAXLINELEN 4096 90 char fbuf[MAXLINELEN]; 91 #endif 92 93 #if 0 94 _DIAGASSERT(fp != NULL); 95 #endif 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 #ifndef FSTACK 120 if ((ptr = fgetln(fp, &s)) == NULL) 121 break; 122 #else 123 if (fgets(fbuf, MAXLINELEN, fp) == NULL) 124 break; 125 fbuf[strcspn(fbuf, "\n")] = '\0'; 126 ptr = fbuf; 127 #endif 128 129 if (s && com) { /* Check and eliminate comments */ 130 for (cp = ptr; cp < ptr + s; cp++) 131 if (*cp == com && !isescaped(ptr, cp, esc)) { 132 s = cp - ptr; 133 cnt = s == 0 && buf == NULL; 134 break; 135 } 136 } 137 138 if (s && nl) { /* Check and eliminate newlines */ 139 cp = &ptr[s - 1]; 140 141 if (*cp == nl) 142 s--; /* forget newline */ 143 } 144 145 if (s && con) { /* Check and eliminate continuations */ 146 cp = &ptr[s - 1]; 147 148 if (*cp == con && !isescaped(ptr, cp, esc)) { 149 s--; /* forget continuation char */ 150 cnt = 1; 151 } 152 } 153 154 if (s == 0) { 155 /* 156 * nothing to add, skip realloc except in case 157 * we need a minimal buf to return an empty line 158 */ 159 if (cnt || buf != NULL) 160 continue; 161 } 162 163 if ((cp = realloc(buf, len + s + 1)) == NULL) { 164 free(buf); 165 return NULL; 166 } 167 buf = cp; 168 169 (void) memcpy(buf + len, ptr, s); 170 len += s; 171 buf[len] = '\0'; 172 } 173 174 if ((flags & FPARSELN_UNESCALL) != 0 && esc && buf != NULL && 175 strchr(buf, esc) != NULL) { 176 ptr = cp = buf; 177 while (cp[0] != '\0') { 178 int skipesc; 179 180 while (cp[0] != '\0' && cp[0] != esc) 181 *ptr++ = *cp++; 182 if (cp[0] == '\0' || cp[1] == '\0') 183 break; 184 185 skipesc = 0; 186 if (cp[1] == com) 187 skipesc += (flags & FPARSELN_UNESCCOMM); 188 if (cp[1] == con) 189 skipesc += (flags & FPARSELN_UNESCCONT); 190 if (cp[1] == esc) 191 skipesc += (flags & FPARSELN_UNESCESC); 192 if (cp[1] != com && cp[1] != con && cp[1] != esc) 193 skipesc = (flags & FPARSELN_UNESCREST); 194 195 if (skipesc) 196 cp++; 197 else 198 *ptr++ = *cp++; 199 *ptr++ = *cp++; 200 } 201 *ptr = '\0'; 202 len = strlen(buf); 203 } 204 205 if (size) 206 *size = len; 207 return buf; 208 } 209 210 #ifdef TEST 211 212 int 213 main(int argc, char *argv[]) 214 { 215 char *ptr; 216 size_t size, line; 217 218 line = 0; 219 while ((ptr = fparseln(stdin, &size, &line, NULL, 220 FPARSELN_UNESCALL)) != NULL) 221 printf("line %d (%d) |%s|\n", line, size, ptr); 222 return 0; 223 } 224 225 /* 226 227 # This is a test 228 line 1 229 line 2 \ 230 line 3 # Comment 231 line 4 \# Not comment \\\\ 232 233 # And a comment \ 234 line 5 \\\ 235 line 6 236 237 */ 238 239 #endif /* TEST */ 240