transmission/libtransmission/xml.c

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2006-09-25 18:37:45 +00:00
/******************************************************************************
* $Id$
*
* Copyright (c) 2006 Transmission authors and contributors
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*****************************************************************************/
#include "transmission.h"
/* http://www.w3.org/TR/2004/REC-xml-20040204/ */
#define WS( cc ) \
( ' ' == (cc) || '\t' == (cc) || '\n' == (cc) || '\r' == (cc) )
#define TAGBEGIN '<'
#define TAGEND '>'
#define TAGCLOSE '/'
#define NAMESPACESEP ':'
#define SQUOTEC '\''
#define DQUOTEC '"'
#define SQUOTES "'"
#define DQUOTES "\""
#define COMMENTBEGIN "<!--"
#define COMMENTEND "-->"
#define PROCINSTBEGIN "<?"
#define PROCINSTEND "?>"
#define CDATABEGIN "<![CDATA["
#define CDATAEND "]]>"
#define BANGBEGIN "<!"
#define BANGEND ">"
#define CHECKNULL( bb, ee, rr ) \
{ if( NULL == (bb) || (ee) <= (bb) ) return (rr); }
#define justskip( bb, ee, ap, ot, ct ) \
( skipthingy( (bb), (ee), (ap), (ot), (ct), NULL, NULL ) )
static char *
catrange( char * str, const char * begin, const char * end );
static int
skipall( const char * begin, const char * end, const char ** afterpos );
static int
nexttag( const char * begin, const char * end, const char ** tagpos );
static int
overtag( const char * begin, const char * end, const char ** overpos );
static int
tagname( const char * begin, const char * end,
const char ** tagstart, const char ** namestart, int * namelen );
static int
skipthingy( const char * begin, const char * end, const char ** afterpos,
const char * openthingy, const char * closethingy,
const char ** databegin, const char ** dataend );
/* XXX check document charset, in http headers and/or <?xml> tag */
const char *
tr_xmlFindTag( const char * begin, const char * end, const char * tag )
{
const char * name;
int len;
CHECKNULL( begin, end, NULL );
while( tagname( begin, end, &begin, &name, &len ) )
{
assert( NULL != begin && NULL != name && 0 < len );
if( 0 == tr_strncasecmp( tag, name, len ) )
{
return begin;
}
begin = tr_xmlSkipTag( begin, end );
}
return NULL;
}
const char *
tr_xmlTagName( const char * begin, const char * end, int * len )
{
CHECKNULL( begin, end, NULL );
if( tagname( begin, end, NULL, &begin, len ) )
{
return begin;
}
return NULL;
}
const char *
tr_xmlTagContents( const char * begin, const char * end )
{
CHECKNULL( begin, end, NULL );
if( nexttag( begin, end, &begin ) && overtag( begin, end, &begin ) )
{
begin = NULL;
}
return begin;
}
int
tr_xmlVerifyContents( const char * begin, const char * end, const char * data,
int ignorecase )
{
int len;
CHECKNULL( begin, end, 1 );
len = strlen( data );
while( end > begin && WS( *begin ) )
{
begin++;
}
if( end - begin > len )
{
if( ignorecase )
{
return ( 0 != tr_strncasecmp( begin, data, len ) );
}
else
{
return ( 0 != memcmp( begin, data, len ) );
}
}
return 1;
}
const char *
tr_xmlSkipTag( const char * begin, const char * end )
{
CHECKNULL( begin, end, NULL );
if( nexttag( begin, end, &begin ) )
{
if( overtag( begin, end, &begin ) )
{
return begin;
}
while( NULL != begin )
{
if( nexttag( begin, end, &begin ) )
{
begin = tr_xmlSkipTag( begin, end );
}
else
{
CHECKNULL( begin, end, NULL );
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overtag( begin, end, &begin );
return begin;
}
}
}
return NULL;
}
char *
tr_xmlDupContents( const char * begin, const char * end )
{
const char * ii, * cbegin, * cend;
char * ret;
int len;
CHECKNULL( begin, end, NULL );
ret = NULL;
len = strlen( CDATABEGIN );
while( end > begin )
{
ii = memchr( begin, TAGBEGIN, end - begin );
if( NULL == ii )
{
free( ret );
return NULL;
}
/* XXX expand entity references and such here */
ret = catrange( ret, begin, ii );
if( NULL == ret )
{
return NULL;
}
if( !skipthingy( ii, end, &begin, CDATABEGIN, CDATAEND,
&cbegin, &cend ) )
{
ret = catrange( ret, cbegin, cend );
if( NULL == ret )
{
return NULL;
}
}
else if( skipall( ii, end, &begin ) )
{
if( end > ii + 1 && TAGCLOSE == ii[1] )
{
return ret;
}
begin = tr_xmlSkipTag( ii, end );
}
}
free( ret );
return NULL;
}
static char *
catrange( char * str, const char * begin, const char * end )
{
int len;
char * ret;
if( NULL == str )
{
return tr_strndup( begin, end - begin );
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}
len = strlen( str );
ret = realloc( str, len + end - begin + 1 );
if( NULL == ret )
{
free( str );
return NULL;
}
memcpy( ret + len, begin, end - begin );
ret[len + end - begin] = '\0';
return ret;
}
static int
skipall( const char * begin, const char * end, const char ** afterpos )
{
return ( justskip( begin, end, afterpos, COMMENTBEGIN, COMMENTEND ) &&
justskip( begin, end, afterpos, CDATABEGIN, CDATAEND ) &&
justskip( begin, end, afterpos, PROCINSTBEGIN, PROCINSTEND ) &&
justskip( begin, end, afterpos, BANGBEGIN, BANGEND ) );
}
/* returns true if a tag was found and it's a start or empty element tag */
static int
nexttag( const char * begin, const char * end, const char ** tagpos )
{
*tagpos = NULL;
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CHECKNULL( begin, end, 0 );
while( end > begin )
{
begin = memchr( begin, TAGBEGIN, end - begin );
CHECKNULL( begin, end, 0 );
if( justskip( begin, end, &begin, COMMENTBEGIN, COMMENTEND ) &&
justskip( begin, end, &begin, CDATABEGIN, CDATAEND ) &&
justskip( begin, end, &begin, PROCINSTBEGIN, PROCINSTEND ) &&
justskip( begin, end, &begin, BANGBEGIN, BANGEND ) )
{
*tagpos = begin;
begin++;
return ( end > begin && TAGCLOSE != *begin );
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}
}
return 0;
}
/* returns true if the tag is an empty element such as <foo/> */
static int
overtag( const char * begin, const char * end, const char ** overpos )
{
const char * ii;
assert( NULL != begin && end > begin && TAGBEGIN == *begin );
ii = begin + 1;
while( end > ii )
{
switch( *ii )
{
case DQUOTEC:
justskip( ii, end, &ii, DQUOTES, DQUOTES );
break;
case SQUOTEC:
justskip( ii, end, &ii, SQUOTES, SQUOTES );
break;
case TAGEND:
*overpos = ii + 1;
for( ii--; begin < ii; ii-- )
{
if( TAGCLOSE == *ii )
{
return 1;
}
if( !WS( *ii ) )
{
break;
}
}
return 0;
default:
ii++;
break;
}
}
*overpos = NULL;
return 0;
}
static int
tagname( const char * begin, const char * end,
const char ** tagstart, const char ** namestart, int * namelen )
{
const char * name, * ii;
CHECKNULL( begin, end, 0 );
if( nexttag( begin, end, &begin ) )
{
assert( NULL != begin && TAGBEGIN == *begin );
ii = begin + 1;
while( end > ii && WS( *ii ) )
{
ii++;
}
name = ii;
while( end > ii && TAGEND != *ii && !WS( *ii ) )
{
if( NAMESPACESEP == *ii )
{
name = ii + 1;
}
ii++;
}
if( end > ii && ii > name )
{
if( NULL != tagstart )
{
*tagstart = begin;
}
if( NULL != namestart )
{
*namestart = name;
}
if( NULL != namelen )
{
*namelen = ii - name;
}
return 1;
}
}
return 0;
}
static int
skipthingy( const char * begin, const char * end, const char ** afterpos,
const char * openthingy, const char * closethingy,
const char ** databegin, const char ** dataend )
{
int len;
CHECKNULL( begin, end, 1 );
len = strlen( openthingy );
if( 0 != memcmp( begin, openthingy, MIN( end - begin, len ) ) )
{
return 1;
}
if( NULL != afterpos )
{
*afterpos = NULL;
}
if( NULL != databegin )
{
*databegin = NULL;
}
if( NULL != dataend )
{
*dataend = NULL;
}
if( end - begin <= len )
{
return 0;
}
begin += len;
if( NULL != databegin )
{
*databegin = begin;
}
len = strlen( closethingy );
begin = tr_memmem( begin, end - begin, closethingy, len );
if( NULL != dataend )
{
*dataend = begin;
}
if( NULL != afterpos && NULL != begin )
{
*afterpos = ( begin + len >= end ? NULL : begin + len );
}
return 0;
}