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This commit is contained in:
kaashoek 1987-11-25 11:49:48 +00:00
parent f1aba7c217
commit a057f8e72c
1 changed files with 50 additions and 19 deletions
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69
util/ceg/EM_parser/common/scan.c
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@ -1,14 +1,40 @@
#include <stdio.h> #include <stdio.h>
FILE *infile = stdin; /* This file contains the scanner for mylex(), the following functions and
* variables are exported :
*
* int yylineno; - The current line number.
*
* char scanc(); - Return next character.
*
* backc( c); - Push back one character.
* char c;
*
* FILE *switch_input( new); - Scanner will from now on read from
* FILE *new; - 'new', old input-file is returned.
*
* The scanner must perform a lookahead of more than one character, so it uses
* it's own internal buffer.
*/
#define BUF_SIZE 16
char buf[BUF_SIZE], /* Bufer to save backc()-characters */
*bufptr = buf; /* Pointer to space for backc()-character */
int yylineno = 1; int yylineno = 1;
char nextc() /********* Internal variables + functions ***********************/
#define BUF_SIZE 16
static char buf[BUF_SIZE], /* Bufer to save backc()-characters */
*bufptr = buf; /* Pointer to space for backc()-character */
static FILE *infile = stdin;
static char nextc()
{ {
if ( bufptr > buf) if ( bufptr > buf)
return( *--bufptr); return( *--bufptr);
@ -17,25 +43,15 @@ char nextc()
} }
backc( c) /***************************************************************/
char c;
{
if ( bufptr > buf + BUF_SIZE)
error( "backc(), no space in buffer left!");
else {
if ( c == '\n')
yylineno--;
*bufptr++ = c;
}
}
char scanc() char scanc()
/* Get next character, but delete al C-comments */ /* Get next character, but delete al C-comments and count lines */
{ {
char c; char c, nextc();
c = nextc(); c = nextc();
while ( c == '/') { while ( c == '/') {
@ -56,10 +72,25 @@ char scanc()
} }
backc( c)
char c;
{
if ( bufptr >= buf + BUF_SIZE)
error( "backc(), no space in buffer left!");
else {
if ( c == '\n')
yylineno--;
*bufptr++ = c;
}
}
FILE *switch_input( new) FILE *switch_input( new)
FILE *new; FILE *new;
/* Return the current FILE, if buf[] can't be cleaned NULL will be returned */ /* Switch to a new input file, try to save the lookahead-characters in buf[]
* by calling ungetc(). If they can't be saved return NULL.
*/
{ {
char *ptr; FILE *old; char *ptr; FILE *old;