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/* This software was written by Dirk Engling <erdgeist@erdgeist.org>
It is considered beerware. Prost. Skol. Cheers or whatever.
$id$ */
#include "scan.h"
#include "scan_urlencoded_query.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&param=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,
0,7,8,8,8,7,0,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,4,7,6,
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;
}
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 '?':
/* XXX to help us parse path?param=value?param=value?... sent by µTorrent 1600
do not return an error but silently terminate
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;
}
ssize_t scan_fixed_ip( char *data, size_t len, unsigned char ip[4] ) {
int u, i;
for( i=0; i<4; ++i ) {
ssize_t j = scan_fixed_int( data, len, &u );
if( j == (ssize_t)len ) return len;
ip[i] = u;
data += len - j;
len = j;
if ( i<3 ) {
if( !len || *data != '.') return -1;
--len; ++data;
}
}
return len;
}
const char *g_version_scan_urlencoded_query_c = "$Source: /home/cvsroot/opentracker/scan_urlencoded_query.c,v $: $Revision: 1.26 $\n";