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/*
* Partial printf implementation.
*/
#define BUFLEN 1024
#include <stdio.h>
typedef void (*WriteFunc)( char *data, int len );
struct format
{
char buf[BUFLEN+1];
int buflen;
WriteFunc write;
int flags;
int width;
int prec;
int cs;
};
void do_conv( struct format *fsm, char c )
{
printf( "flags: %x\n", fsm->flags );
printf( "width: %i\n", fsm->width );
printf( "prec: %i\n", fsm->prec );
printf( "conv: %c\n", c );
printf( "\n" );
}
#define FL_HASH 0x01
#define FL_ZERO 0x02
#define FL_DASH 0x04
#define FL_SPACE 0x08
#define FL_PLUS 0x10
#define FL_HAS_WIDTH 0x0100
#define FL_WIDTH_ARG 0x0200
#define FL_HAS_PREC 0x0400
#define FL_PREC_ARG 0x0800
#define FL_LEN_H 0x010000
#define FL_LEN_HH 0x020000
#define FL_LEN_L 0x040000
#define FL_LEN_LL 0x080000
%%{
machine format;
access fsm->;
action clear {
fsm->flags = 0;
fsm->width = 0;
fsm->prec = 0;
}
# A non-zero number.
nznum = [1-9] [0-9]*;
# Width
action width_num { fsm->width = 10 * fsm->width + (fc-'0'); }
action width_arg { fsm->flags |= FL_WIDTH_ARG; }
action width { fsm->flags |= FL_HAS_WIDTH; }
width = ( ( nznum $width_num | '*' @width_arg ) %width )?;
# Precision
action prec_num { fsm->prec = 10 * fsm->prec + (fc-'0'); }
action prec_arg { fsm->flags |= FL_PREC_ARG; }
action prec { fsm->flags |= FL_HAS_PREC; }
precision = ( '.' ( digit* $prec_num %prec | '*' @prec_arg ) )?;
# Flags
action flags_hash { fsm->flags |= FL_HASH; }
action flags_zero { fsm->flags |= FL_ZERO; }
action flags_dash { fsm->flags |= FL_DASH; }
action flags_space { fsm->flags |= FL_SPACE; }
action flags_plus { fsm->flags |= FL_PLUS; }
flags = (
'#' @flags_hash |
'0' @flags_zero |
'-' @flags_dash |
' ' @flags_space |
'+' @flags_plus )*;
action length_h { fsm->flags |= FL_LEN_H; }
action length_l { fsm->flags |= FL_LEN_L; }
action length_hh { fsm->flags |= FL_LEN_HH; }
action length_ll { fsm->flags |= FL_LEN_LL; }
# Must use leaving transitions on 'h' and 'l' because they are
# prefixes for 'hh' and 'll'.
length = (
'h' %length_h |
'l' %length_l |
'hh' @length_hh |
'll' @length_ll )?;
action conversion {
do_conv( fsm, fc );
}
conversion = [diouxXcsp] @conversion;
fmt_spec =
'%' @clear
flags
width
precision
length
conversion;
action emit {
if ( fsm->buflen == BUFLEN ) {
fsm->write( fsm->buf, fsm->buflen );
fsm->buflen = 0;
}
fsm->buf[fsm->buflen++] = fc;
}
action finish_ok {
if ( fsm->buflen > 0 )
fsm->write( fsm->buf, fsm->buflen );
}
action finish_err {
printf("EOF IN FORMAT\n");
}
action err_char {
printf("ERROR ON CHAR: 0x%x\n", fc );
}
main := (
[^%] @emit |
'%%' @emit |
fmt_spec
)* @/finish_err %/finish_ok $!err_char;
}%%
%% write data;
void format_init( struct format *fsm )
{
fsm->buflen = 0;
%% write init;
}
void format_execute( struct format *fsm, const char *data, int len, int isEof )
{
const char *p = data;
const char *pe = data + len;
const char *eof = isEof ? pe : 0;
%% write exec;
}
int format_finish( struct format *fsm )
{
if ( fsm->cs == format_error )
return -1;
if ( fsm->cs >= format_first_final )
return 1;
return 0;
}
#define INPUT_BUFSIZE 2048
struct format fsm;
char buf[INPUT_BUFSIZE];
void write(char *data, int len )
{
fwrite( data, 1, len, stdout );
}
int main()
{
fsm.write = write;
format_init( &fsm );
while ( 1 ) {
int len = fread( buf, 1, INPUT_BUFSIZE, stdin );
int eof = len != INPUT_BUFSIZE;
format_execute( &fsm, buf, len, eof );
if ( eof )
break;
}
if ( format_finish( &fsm ) <= 0 )
printf("FAIL\n");
return 0;
}
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