1 /* $OpenBSD: fparseln.c,v 1.8 2023/01/04 13:00:11 jsg 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 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #include <stdio.h> 29 #include <string.h> 30 #include <stdlib.h> 31 32 #include "util.h" 33 34 static int isescaped(const char *, const char *, int); 35 36 /* isescaped(): 37 * Return true if the character in *p that belongs to a string 38 * that starts in *sp, is escaped by the escape character esc. 39 */ 40 static int 41 isescaped(const char *sp, const char *p, int esc) 42 { 43 const char *cp; 44 size_t ne; 45 46 /* No escape character */ 47 if (esc == '\0') 48 return 1; 49 50 /* Count the number of escape characters that precede ours */ 51 for (ne = 0, cp = p; --cp >= sp && *cp == esc; ne++) 52 continue; 53 54 /* Return true if odd number of escape characters */ 55 return (ne & 1) != 0; 56 } 57 58 59 /* fparseln(): 60 * Read a line from a file parsing continuations ending in \ 61 * and eliminating trailing newlines, or comments starting with 62 * the comment char. 63 */ 64 char * 65 fparseln(FILE *fp, size_t *size, size_t *lineno, const char str[3], 66 int flags) 67 { 68 static const char dstr[3] = { '\\', '\\', '#' }; 69 char *buf = NULL, *ptr, *cp, esc, con, nl, com; 70 size_t s, len = 0; 71 int cnt = 1; 72 73 if (str == NULL) 74 str = dstr; 75 76 esc = str[0]; 77 con = str[1]; 78 com = str[2]; 79 80 /* 81 * XXX: it would be cool to be able to specify the newline character, 82 * but unfortunately, fgetln does not let us 83 */ 84 nl = '\n'; 85 86 while (cnt) { 87 cnt = 0; 88 89 if (lineno) 90 (*lineno)++; 91 92 if ((ptr = fgetln(fp, &s)) == NULL) 93 break; 94 95 if (s && com) { /* Check and eliminate comments */ 96 for (cp = ptr; cp < ptr + s; cp++) 97 if (*cp == com && !isescaped(ptr, cp, esc)) { 98 s = cp - ptr; 99 cnt = s == 0 && buf == NULL; 100 break; 101 } 102 } 103 104 if (s && nl) { /* Check and eliminate newlines */ 105 cp = &ptr[s - 1]; 106 107 if (*cp == nl) 108 s--; /* forget newline */ 109 } 110 111 if (s && con) { /* Check and eliminate continuations */ 112 cp = &ptr[s - 1]; 113 114 if (*cp == con && !isescaped(ptr, cp, esc)) { 115 s--; /* forget escape */ 116 cnt = 1; 117 } 118 } 119 120 if (s == 0 && buf != NULL) 121 continue; 122 123 if ((cp = realloc(buf, len + s + 1)) == NULL) { 124 free(buf); 125 return NULL; 126 } 127 buf = cp; 128 129 (void) memcpy(buf + len, ptr, s); 130 len += s; 131 buf[len] = '\0'; 132 } 133 134 if ((flags & FPARSELN_UNESCALL) != 0 && esc && buf != NULL && 135 strchr(buf, esc) != NULL) { 136 ptr = cp = buf; 137 while (cp[0] != '\0') { 138 int skipesc; 139 140 while (cp[0] != '\0' && cp[0] != esc) 141 *ptr++ = *cp++; 142 if (cp[0] == '\0' || cp[1] == '\0') 143 break; 144 145 skipesc = 0; 146 if (cp[1] == com) 147 skipesc += (flags & FPARSELN_UNESCCOMM); 148 if (cp[1] == con) 149 skipesc += (flags & FPARSELN_UNESCCONT); 150 if (cp[1] == esc) 151 skipesc += (flags & FPARSELN_UNESCESC); 152 if (cp[1] != com && cp[1] != con && cp[1] != esc) 153 skipesc = (flags & FPARSELN_UNESCREST); 154 155 if (skipesc) 156 cp++; 157 else 158 *ptr++ = *cp++; 159 *ptr++ = *cp++; 160 } 161 *ptr = '\0'; 162 len = strlen(buf); 163 } 164 165 if (size) 166 *size = len; 167 return buf; 168 } 169 170 #ifdef TEST 171 172 int main(int, char **); 173 174 int 175 main(argc, argv) 176 int argc; 177 char **argv; 178 { 179 char *ptr; 180 size_t size, line; 181 182 line = 0; 183 while ((ptr = fparseln(stdin, &size, &line, NULL, 184 FPARSELN_UNESCALL)) != NULL) 185 printf("line %d (%d) |%s|\n", line, size, ptr); 186 return 0; 187 } 188 189 /* 190 191 # This is a test 192 line 1 193 line 2 \ 194 line 3 # Comment 195 line 4 \# Not comment \\\\ 196 197 # And a comment \ 198 line 5 \\\ 199 line 6 200 201 */ 202 203 #endif /* TEST */ 204