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tdevelop/lib/antlr/src/ANTLRUtil.cpp

164 lines
3.6 KiB

/* ANTLR Translator Generator
* Project led by Terence Parr at http://www.jGuru.com
* Software rights: http://www.antlr.org/license.html
*
* $Id$
*/
#include <antlr/config.h>
#include <antlr/IOException.h>
#include <iostream>
#include <cctype>
#include <string>
#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
namespace antlr {
#endif
/** Eat whitespace from the input stream
* @param is the stream to read from
*/
ANTLR_USE_NAMESPACE(std)istream& eatwhite( ANTLR_USE_NAMESPACE(std)istream& is )
{
char c;
while( is.get(c) )
{
#ifdef ANTLR_CCTYPE_NEEDS_STD
if( !ANTLR_USE_NAMESPACE(std)isspace(c) )
#else
if( !isspace(c) )
#endif
{
is.putback(c);
break;
}
}
return is;
}
/** Read a string enclosed by '"' from a stream. Also handles escaping of \".
* Skips leading whitespace.
* @param in the istream to read from.
* @returns the string read from file exclusive the '"'
* @throws IOException if string is badly formatted
*/
ANTLR_USE_NAMESPACE(std)string read_string( ANTLR_USE_NAMESPACE(std)istream& in )
{
char ch;
ANTLR_USE_NAMESPACE(std)string ret("");
// States for a simple state machine...
enum { START, READING, ESCAPE, FINISHED };
int state = START;
eatwhite(in);
while( state != FINISHED && in.get(ch) )
{
switch( state )
{
case START:
// start state: check wether starting with " then switch to READING
if( ch != '"' )
throw IOException("string must start with '\"'");
state = READING;
continue;
case READING:
// reading state: look out for escape sequences and closing "
if( ch == '\\' ) // got escape sequence
{
state = ESCAPE;
continue;
}
if( ch == '"' ) // close quote -> stop
{
state = FINISHED;
continue;
}
ret += ch; // else append...
continue;
case ESCAPE:
switch(ch)
{
case '\\':
ret += ch;
state = READING;
continue;
case '"':
ret += ch;
state = READING;
continue;
case '0':
ret += '\0';
state = READING;
continue;
default: // unrecognized escape is not mapped
ret += '\\';
ret += ch;
state = READING;
continue;
}
}
}
if( state != FINISHED )
throw IOException("badly formatted string: "+ret);
return ret;
}
/* Read a ([A-Z][0-9][a-z]_)* kindoff thing. Skips leading whitespace.
* @param in the istream to read from.
*/
ANTLR_USE_NAMESPACE(std)string read_identifier( ANTLR_USE_NAMESPACE(std)istream& in )
{
char ch;
ANTLR_USE_NAMESPACE(std)string ret("");
eatwhite(in);
while( in.get(ch) )
{
#ifdef ANTLR_CCTYPE_NEEDS_STD
if( ANTLR_USE_NAMESPACE(std)isupper(ch) ||
ANTLR_USE_NAMESPACE(std)islower(ch) ||
ANTLR_USE_NAMESPACE(std)isdigit(ch) ||
ch == '_' )
#else
if( isupper(ch) || islower(ch) || isdigit(ch) || ch == '_' )
#endif
ret += ch;
else
{
in.putback(ch);
break;
}
}
return ret;
}
/** Read a attribute="value" thing. Leading whitespace is skipped.
* Between attribute and '=' no whitespace is allowed. After the '=' it is
* permitted.
* @param in the istream to read from.
* @param attribute string the attribute name is put in
* @param value string the value of the attribute is put in
* @throws IOException if something is fishy. E.g. malformed quoting
* or missing '='
*/
void read_AttributeNValue( ANTLR_USE_NAMESPACE(std)istream& in,
ANTLR_USE_NAMESPACE(std)string& attribute,
ANTLR_USE_NAMESPACE(std)string& value )
{
attribute = read_identifier(in);
char ch;
if( in.get(ch) && ch == '=' )
value = read_string(in);
else
throw IOException("invalid attribute=value thing "+attribute);
}
#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
}
#endif