1 /* $NetBSD: fparseln.c,v 1.9 1999/09/20 04:48:06 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 <stdio.h> 33 #include <string.h> 34 #include <stdlib.h> 35 #include <compat.h> 36 37 static int isescaped(const char *, const char *, int); 38 39 /* 40 * isescaped(): 41 * Return true if the character in *p that belongs to a string 42 * that starts in *sp, is escaped by the escape character esc. 43 */ 44 static int 45 isescaped(const char *sp, const char *p, int esc) 46 { 47 const char *cp; 48 size_t ne; 49 50 /* No escape character */ 51 if (esc == '\0') 52 return (1); 53 54 /* Count the number of escape characters that precede ours */ 55 for (ne = 0, cp = p; --cp >= sp && *cp == esc; ne++) 56 continue; 57 58 /* Return true if odd number of escape characters */ 59 return ((ne & 1) != 0); 60 } 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], int flags) 71 { 72 static const char dstr[3] = { '\\', '\\', '#' }; 73 74 size_t s, len; 75 char *buf; 76 char *ptr, *cp; 77 int cnt; 78 char esc, con, nl, com; 79 80 len = 0; 81 buf = NULL; 82 cnt = 1; 83 84 if (str == NULL) 85 str = dstr; 86 87 esc = str[0]; 88 con = str[1]; 89 com = str[2]; 90 /* 91 * XXX: it would be cool to be able to specify the newline character, 92 * but unfortunately, fgetln does not let us 93 */ 94 nl = '\n'; 95 96 while (cnt) { 97 cnt = 0; 98 99 if (lineno) 100 (*lineno)++; 101 102 if ((ptr = fgetln(fp, &s)) == NULL) 103 break; 104 105 if (s && com) { /* Check and eliminate comments */ 106 for (cp = ptr; cp < ptr + s; cp++) 107 if (*cp == com && !isescaped(ptr, cp, esc)) { 108 s = cp - ptr; 109 cnt = s == 0 && buf == NULL; 110 break; 111 } 112 } 113 114 if (s && nl) { /* Check and eliminate newlines */ 115 cp = &ptr[s - 1]; 116 117 if (*cp == nl) 118 s--; /* forget newline */ 119 } 120 121 if (s && con) { /* Check and eliminate continuations */ 122 cp = &ptr[s - 1]; 123 124 if (*cp == con && !isescaped(ptr, cp, esc)) { 125 s--; /* forget escape */ 126 cnt = 1; 127 } 128 } 129 130 if (s == 0 && buf != NULL) 131 continue; 132 133 if ((cp = realloc(buf, len + s + 1)) == NULL) { 134 free(buf); 135 return (NULL); 136 } 137 buf = cp; 138 139 (void) memcpy(buf + len, ptr, s); 140 len += s; 141 buf[len] = '\0'; 142 } 143 144 if ((flags & FPARSELN_UNESCALL) != 0 && esc && buf != NULL && 145 strchr(buf, esc) != NULL) { 146 ptr = cp = buf; 147 while (cp[0] != '\0') { 148 int skipesc; 149 150 while (cp[0] != '\0' && cp[0] != esc) 151 *ptr++ = *cp++; 152 if (cp[0] == '\0' || cp[1] == '\0') 153 break; 154 155 skipesc = 0; 156 if (cp[1] == com) 157 skipesc += (flags & FPARSELN_UNESCCOMM); 158 if (cp[1] == con) 159 skipesc += (flags & FPARSELN_UNESCCONT); 160 if (cp[1] == esc) 161 skipesc += (flags & FPARSELN_UNESCESC); 162 if (cp[1] != com && cp[1] != con && cp[1] != esc) 163 skipesc = (flags & FPARSELN_UNESCREST); 164 165 if (skipesc) 166 cp++; 167 else 168 *ptr++ = *cp++; 169 *ptr++ = *cp++; 170 } 171 *ptr = '\0'; 172 len = strlen(buf); 173 } 174 175 if (size) { 176 *size = len; 177 } 178 return (buf); 179 } 180 181 #ifdef TEST 182 183 int 184 main(int argc, 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 } 194 return (0); 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