1 /* $NetBSD: is_csv.c,v 1.6 2026/06/10 20:54:16 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 2019 Christos Zoulas 5 * 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 NETBSD FOUNDATION, INC. AND CONTRIBUTORS 17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 /* 30 * Parse CSV object serialization format (RFC-4180, RFC-7111) 31 */ 32 33 #ifndef TEST 34 #include "file.h" 35 36 #ifndef lint 37 #if 0 38 FILE_RCSID("@(#)$File: is_csv.c,v 1.16 2026/06/02 17:50:54 christos Exp $") 39 #else 40 __RCSID("$NetBSD: is_csv.c,v 1.6 2026/06/10 20:54:16 christos Exp $"); 41 #endif 42 #endif 43 44 #include <string.h> 45 #include "magic.h" 46 #else 47 #define CAST(a, b) ((a)(b)) 48 #include <sys/types.h> 49 #endif 50 51 52 #ifdef DEBUG 53 #include <stdio.h> 54 #define DPRINTF(fmt, ...) printf(fmt, __VA_ARGS__) 55 #else 56 #define DPRINTF(fmt, ...) 57 #endif 58 59 /* 60 * if CSV_LINES == 0: 61 * check all the lines in the buffer 62 * otherwise: 63 * check only up-to the number of lines specified 64 * 65 * the last line count is always ignored if it does not end in CRLF 66 */ 67 #ifndef CSV_LINES 68 #define CSV_LINES 10 69 #endif 70 71 static int csv_parse(const unsigned char *, const unsigned char *); 72 73 static const unsigned char * 74 eatquote(const unsigned char *uc, const unsigned char *ue) 75 { 76 int quote = 0; 77 78 while (uc < ue) { 79 unsigned char c = *uc++; 80 if (c != '"') { 81 // We already got one, done. 82 if (quote) { 83 return --uc; 84 } 85 continue; 86 } 87 if (quote) { 88 // quote-quote escapes 89 quote = 0; 90 continue; 91 } 92 // first quote 93 quote = 1; 94 } 95 return ue; 96 } 97 98 static int 99 csv_parse(const unsigned char *uc, const unsigned char *ue) 100 { 101 size_t nf = 0, tf = 0, nl = 0; 102 103 while (uc < ue) { 104 switch (*uc++) { 105 case '"': 106 // Eat until the matching quote 107 uc = eatquote(uc, ue); 108 break; 109 case ',': 110 nf++; 111 break; 112 case '\n': 113 DPRINTF("nl=%zu nf=%zu tf=%zu\n", nl, nf, tf); 114 nl++; 115 #if CSV_LINES 116 if (nl == CSV_LINES) 117 return tf > 1 && tf == nf; 118 #endif 119 if (tf == 0) { 120 // First time and no fields, give up 121 if (nf == 0) 122 return 0; 123 // First time, set the number of fields 124 tf = nf; 125 } else if (tf != nf) { 126 // Field number mismatch, we are done. 127 return 0; 128 } 129 nf = 0; 130 break; 131 default: 132 break; 133 } 134 } 135 DPRINTF("tf=%zu>1 nl=%zu>=2\n", tf, nl); 136 return tf >= 1 && nl >= 2; 137 } 138 139 #ifndef TEST 140 int 141 file_is_csv(struct magic_set *ms, const struct buffer *b, int looks_text, 142 const char *code) 143 { 144 const unsigned char *uc = CAST(const unsigned char *, b->fbuf); 145 const unsigned char *ue = uc + b->flen; 146 int mime = ms->flags & MAGIC_MIME; 147 148 if (!looks_text) 149 return 0; 150 151 if ((ms->flags & (MAGIC_APPLE|MAGIC_EXTENSION)) != 0) 152 return 0; 153 154 if (!csv_parse(uc, ue)) 155 return 0; 156 157 if (mime == MAGIC_MIME_ENCODING) 158 return 1; 159 160 if (mime) { 161 if (file_printf(ms, "text/csv") == -1) 162 return -1; 163 return 1; 164 } 165 166 if (file_printf(ms, "CSV %s%stext", code ? code : "", 167 code ? " " : "") == -1) 168 return -1; 169 170 return 1; 171 } 172 173 #else 174 175 #include <sys/types.h> 176 #include <sys/stat.h> 177 #include <stdio.h> 178 #include <fcntl.h> 179 #include <unistd.h> 180 #include <stdlib.h> 181 #include <stdint.h> 182 #include <err.h> 183 184 int 185 main(int argc, char *argv[]) 186 { 187 int fd; 188 struct stat st; 189 unsigned char *p; 190 191 if ((fd = open(argv[1], O_RDONLY)) == -1) 192 err(EXIT_FAILURE, "Can't open `%s'", argv[1]); 193 194 if (fstat(fd, &st) == -1) 195 err(EXIT_FAILURE, "Can't stat `%s'", argv[1]); 196 197 if ((p = CAST(unsigned char *, malloc(st.st_size))) == NULL) 198 err(EXIT_FAILURE, "Can't allocate %jd bytes", 199 (intmax_t)st.st_size); 200 if (read(fd, p, st.st_size) != st.st_size) 201 err(EXIT_FAILURE, "Can't read %jd bytes", 202 (intmax_t)st.st_size); 203 printf("is csv %d\n", csv_parse(p, p + st.st_size)); 204 return 0; 205 } 206 #endif 207
Indexes created Sun Sep 13 00:25:22 UTC 2026