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/* This software was written by Dirk Engling <erdgeist@erdgeist.org>
It is considered beerware. Prost. Skol. Cheers or whatever.
$id$ */
/* Opentracker */
#include "scan_urlencoded_query.h"
/* Libwofat */
#include "scan.h"
/* System */
#include <string.h>
/* Idea is to do a in place replacement or guarantee at least
strlen( string ) bytes in deststring
watch http://www.ietf.org/rfc/rfc2396.txt
unreserved = alphanum | mark
mark = "-" | "_" | "." | "!" | "~" | "*" | "'" | "(" | ")"
we add '%' to the matrix to not stop at encoded chars.
After losing too many requests to being too strict, add the following characters to reserved matrix
relax = "+" | "," | "/" | ";" | "<" | ">" | ":"
*/
/* This matrix holds for each ascii character the information,
whether it is a non-terminating character for on of the three
scan states we are in, that is 'path', 'param' and 'value' from
/path?param=value¶m=value, it is encoded in bit 0, 1 and 2
respectively
The top bit of lower nibble indicates, whether this character is
a hard terminator, ie. \0, \n or \s, where the whole scanning
process should terminate
*/
static const unsigned char is_unreserved[256] = {
8,0,0,0,0,0,0,0,0,0,8,0,0,8,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
8,7,8,8,8,7,0,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,4,7,6,
4,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,8,8,8,8,7,
8,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,8,8,8,7,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
};
/* Do a fast nibble to hex representation conversion */
static unsigned char fromhex(unsigned char x) {
x -= '0';
if (x <= 9)
return x;
x &= ~0x20;
x -= 'A' - '0';
if (x < 6)
return x + 10;
return 0xff;
}
/* Skip the value of a param=value pair */
void scan_urlencoded_skipvalue(char **string) {
const unsigned char *s = *(const unsigned char **)string;
unsigned char f;
/* Since we are asked to skip the 'value', we assume to stop at
terminators for a 'value' string position */
while ((f = is_unreserved[*s++]) & SCAN_SEARCHPATH_VALUE)
;
/* If we stopped at a hard terminator like \0 or \n, make the
next scan_urlencoded_query encounter it again */
if (f & SCAN_SEARCHPATH_TERMINATOR)
--s;
*string = (char *)s;
}
int scan_find_keywords(const ot_keywords *keywords, char **string, SCAN_SEARCHPATH_FLAG flags) {
char *deststring = *string;
ssize_t match_length = scan_urlencoded_query(string, deststring, flags);
if (match_length < 0)
return match_length;
if (match_length == 0)
return -3;
while (keywords->key) {
if (!strncmp(keywords->key, deststring, match_length) && !keywords->key[match_length])
return keywords->value;
keywords++;
}
return -3;
}
ssize_t scan_urlencoded_query(char **string, char *deststring, SCAN_SEARCHPATH_FLAG flags) {
const unsigned char *s = *(const unsigned char **)string;
unsigned char *d = (unsigned char *)deststring;
unsigned char b, c;
/* This is the main decoding loop.
'flag' determines, which characters are non-terminating in current context
(ie. stop at '=' and '&' if scanning for a 'param'; stop at '?' if scanning for the path )
*/
while (is_unreserved[c = *s++] & flags) {
/* When encountering an url escaped character, try to decode */
if (c == '%') {
if ((b = fromhex(*s++)) == 0xff)
return -1;
if ((c = fromhex(*s++)) == 0xff)
return -1;
c |= (b << 4);
}
/* Write (possibly decoded) character to output */
*d++ = c;
}
switch (c) {
case 0:
case '\r':
case '\n':
case ' ':
/* If we started scanning on a hard terminator, indicate we've finished */
if (d == (unsigned char *)deststring)
return -2;
/* Else make the next call to scan_urlencoded_param encounter it again */
--s;
break;
case '?':
if (flags != SCAN_PATH)
return -1;
break;
case '=':
if (flags != SCAN_SEARCHPATH_PARAM)
return -1;
break;
case '&':
if (flags == SCAN_PATH)
return -1;
if (flags == SCAN_SEARCHPATH_PARAM)
--s;
break;
default:
return -1;
}
*string = (char *)s;
return d - (unsigned char *)deststring;
}
ssize_t scan_fixed_int(char *data, size_t len, int *tmp) {
int minus = 0;
*tmp = 0;
if (*data == '-')
--len, ++data, ++minus;
while ((len > 0) && (*data >= '0') && (*data <= '9')) {
--len;
*tmp = 10 * *tmp + *data++ - '0';
}
if (minus)
*tmp = -*tmp;
return len;
}
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