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/*
* A C++ scanner. Uses the longest match construction.
* << <= <<= >> >= >>= are left out since angle brackets are used in templates.
*/
#include <string.h>
#include <stdlib.h>
#include <iostream>
#define TK_Dlit 256
#define TK_Slit 257
#define TK_Float 258
#define TK_Id 259
#define TK_NameSep 260
#define TK_Arrow 261
#define TK_PlusPlus 262
#define TK_MinusMinus 263
#define TK_ArrowStar 264
#define TK_DotStar 265
#define TK_ShiftLeft 266
#define TK_ShiftRight 267
#define TK_IntegerDecimal 268
#define TK_IntegerOctal 269
#define TK_IntegerHex 270
#define TK_EqualsEquals 271
#define TK_NotEquals 272
#define TK_AndAnd 273
#define TK_OrOr 274
#define TK_MultAssign 275
#define TK_DivAssign 276
#define TK_PercentAssign 277
#define TK_PlusAssign 278
#define TK_MinusAssign 279
#define TK_AmpAssign 280
#define TK_CaretAssign 281
#define TK_BarAssign 282
#define TK_DotDotDot 283
#define TK_Whitespace 284
#define TK_Comment 285
#define BUFSIZE 16384
/* EOF char used to flush out that last token. This should be a whitespace
* token. */
#define LAST_CHAR 0
using std::cerr;
using std::cout;
using std::cin;
using std::endl;
static char buf[BUFSIZE];
static int line = 1, col = 1;
static char *ts, *te;
static int act, have = 0;
static int cs;
%%{
machine Scanner;
write data nofinal;
# Floating literals.
fract_const = digit* '.' digit+ | digit+ '.';
exponent = [eE] [+\-]? digit+;
float_suffix = [flFL];
c_comment :=
any* :>> '*/'
@{ fgoto main; };
main := |*
# Single and double literals.
( 'L'? "'" ( [^'\\\n] | /\\./ )* "'" )
{token( TK_Slit );};
( 'L'? '"' ( [^"\\\n] | /\\./ )* '"' )
{token( TK_Dlit );};
# Identifiers
( [a-zA-Z_] [a-zA-Z0-9_]* )
{token( TK_Id );};
# Floating literals.
( fract_const exponent? float_suffix? | digit+ exponent float_suffix? )
{token( TK_Float );};
# Integer decimal. Leading part buffered by float.
( ( '0' | [1-9] [0-9]* ) [ulUL]{0,3} )
{token( TK_IntegerDecimal );};
# Integer octal. Leading part buffered by float.
( '0' [0-9]+ [ulUL]{0,2} )
{token( TK_IntegerOctal );};
# Integer hex. Leading 0 buffered by float.
( '0' ( 'x' [0-9a-fA-F]+ [ulUL]{0,2} ) )
{token( TK_IntegerHex );};
# Only buffer the second item, first buffered by symbol. */
'::' {token( TK_NameSep );};
'==' {token( TK_EqualsEquals );};
'!=' {token( TK_NotEquals );};
'&&' {token( TK_AndAnd );};
'||' {token( TK_OrOr );};
'*=' {token( TK_MultAssign );};
'/=' {token( TK_DivAssign );};
'%=' {token( TK_PercentAssign );};
'+=' {token( TK_PlusAssign );};
'-=' {token( TK_MinusAssign );};
'&=' {token( TK_AmpAssign );};
'^=' {token( TK_CaretAssign );};
'|=' {token( TK_BarAssign );};
'++' {token( TK_PlusPlus );};
'--' {token( TK_MinusMinus );};
'->' {token( TK_Arrow );};
'->*' {token( TK_ArrowStar );};
'.*' {token( TK_DotStar );};
# Three char compounds, first item already buffered. */
'...' {token( TK_DotDotDot );};
# Single char symbols.
( punct - [_"'] ) {token( ts[0] );};
# Comments and whitespace.
'/*' { fgoto c_comment; };
'//' [^\n]* '\n';
( any - 33..126 )+;
*|;
}%%
void token( int tok )
{
char *data = ts;
int len = te - ts;
cout << '<' << tok << "> ";
cout.write( data, len );
cout << '\n';
/* Count newlines and columns. This code is here mainly for having some
* code in the token routine when commenting out the above output during
* performance testing. */
for ( int i = 0; i < len; i ++ ) {
if ( data[i] == '\n' ) {
line += 1;
col = 1;
}
else {
col += 1;
}
}
}
int main()
{
std::ios::sync_with_stdio(false);
%% write init;
/* Do the first read. */
bool done = false;
while ( !done ) {
char *p = buf + have;
int space = BUFSIZE - have;
if ( space == 0 ) {
/* We filled up the buffer trying to scan a token. */
cerr << "OUT OF BUFFER SPACE" << endl;
exit(1);
}
cin.read( p, space );
int len = cin.gcount();
char *pe = p + len;
char *eof = 0;
/* If we see eof then append the EOF char. */
if ( cin.eof() ) {
eof = pe;
done = true;
}
%% write exec;
/* Check if we failed. */
if ( cs == Scanner_error ) {
/* Machine failed before finding a token. */
cerr << "PARSE ERROR" << endl;
exit(1);
}
/* Now set up the prefix. */
if ( ts == 0 )
have = 0;
else {
/* There is data that needs to be shifted over. */
have = pe - ts;
memmove( buf, ts, have );
te -= (ts-buf);
ts = buf;
}
}
return 0;
}
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