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/*-
* Copyright (c) 2019 Christos Zoulas
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Parse CSV object serialization format (RFC-4180, RFC-7111)
*/
#ifndef TEST
#include "file.h"
#ifndef lint
FILE_RCSID("@(#)$File: is_csv.c,v 1.10 2022/09/24 20:30:13 christos Exp $")
#endif
#include <string.h>
#include "magic.h"
#else
#include <sys/types.h>
#endif
#ifdef DEBUG
#include <stdio.h>
#define DPRINTF(fmt, ...) printf(fmt, __VA_ARGS__)
#else
#define DPRINTF(fmt, ...)
#endif
/*
* if CSV_LINES == 0:
* check all the lines in the buffer
* otherwise:
* check only up-to the number of lines specified
*
* the last line count is always ignored if it does not end in CRLF
*/
#ifndef CSV_LINES
#define CSV_LINES 10
#endif
static int csv_parse(const unsigned char *, const unsigned char *);
static const unsigned char *
eatquote(const unsigned char *uc, const unsigned char *ue)
{
int quote = 0;
while (uc < ue) {
unsigned char c = *uc++;
if (c != '"') {
// We already got one, done.
if (quote) {
return --uc;
}
continue;
}
if (quote) {
// quote-quote escapes
quote = 0;
continue;
}
// first quote
quote = 1;
}
return ue;
}
static int
csv_parse(const unsigned char *uc, const unsigned char *ue)
{
size_t nf = 0, tf = 0, nl = 0;
while (uc < ue) {
switch (*uc++) {
case '"':
// Eat until the matching quote
uc = eatquote(uc, ue);
break;
case ',':
nf++;
break;
case '\n':
DPRINTF("%zu %zu %zu\n", nl, nf, tf);
nl++;
#if CSV_LINES
if (nl == CSV_LINES)
return tf != 0 && tf == nf;
#endif
if (tf == 0) {
// First time and no fields, give up
if (nf == 0)
return 0;
// First time, set the number of fields
tf = nf;
} else if (tf != nf) {
// Field number mismatch, we are done.
return 0;
}
nf = 0;
break;
default:
break;
}
}
return tf && nl > 2;
}
#ifndef TEST
int
file_is_csv(struct magic_set *ms, const struct buffer *b, int looks_text)
{
const unsigned char *uc = CAST(const unsigned char *, b->fbuf);
const unsigned char *ue = uc + b->flen;
int mime = ms->flags & MAGIC_MIME;
if (!looks_text)
return 0;
if ((ms->flags & (MAGIC_APPLE|MAGIC_EXTENSION)) != 0)
return 0;
if (!csv_parse(uc, ue))
return 0;
if (mime == MAGIC_MIME_ENCODING)
return 1;
if (mime) {
if (file_printf(ms, "text/csv") == -1)
return -1;
return 1;
}
if (file_printf(ms, "CSV text") == -1)
return -1;
return 1;
}
#else
#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdint.h>
#include <err.h>
int
main(int argc, char *argv[])
{
int fd;
struct stat st;
unsigned char *p;
if ((fd = open(argv[1], O_RDONLY)) == -1)
err(EXIT_FAILURE, "Can't open `%s'", argv[1]);
if (fstat(fd, &st) == -1)
err(EXIT_FAILURE, "Can't stat `%s'", argv[1]);
if ((p = CAST(char *, malloc(st.st_size))) == NULL)
err(EXIT_FAILURE, "Can't allocate %jd bytes",
(intmax_t)st.st_size);
if (read(fd, p, st.st_size) != st.st_size)
err(EXIT_FAILURE, "Can't read %jd bytes",
(intmax_t)st.st_size);
printf("is csv %d\n", csv_parse(p, p + st.st_size));
return 0;
}
#endif
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