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/*
* Name: untrigraph.c
* Purpose: Remove trigraphs from C code.
* Author: Lars Wirzenius
* Version: "@(#)liwc:$Id: untrigraph.c,v 1.1.1.1 1996/09/16 18:19:51 liw Exp $"
*/
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <publib.h>
int untrigraph(FILE *, char *, void *);
int main(int argc, char **argv) {
set_progname(argv[0], "untrigraph");
if (main_filter(argc-1, argv+1, untrigraph, NULL) == -1)
return EXIT_FAILURE;
return EXIT_SUCCESS;
}
/*
* Name: untrigraph
* Purpose: Remove trigraphs from one file, output to stdout.
* Description: A sequence of four characters (c0, c1, c2, c3) is a
* trigraph, if c0 != '\\', c1==c2=='?' and c3 is one of the
* characters inside the string "()<>!'-=/".
*
* In the code below, c0 is the previous character we printed
* (possibly the result of a trigraph conversion).
*/
int untrigraph(FILE *f, char *fname, void *dummy) {
int c0, c1, c2, c3;
char tri[] = "()<>!'-=/"; /* list of trigraphs... */
char realchars[] = "[]{}|^~#\\"; /* ...and corresponding chars */
char *p;
c0 = c2 = c3 = EOF;
p = NULL;
if ((c1=getc(f)) != EOF && (c2=getc(f)) != EOF)
c3 = getc(f);
while (c1 != EOF) {
if (c0 == '\\' || c1 != '?' || c2 != '?' ||
(c3 != EOF && (p = strchr(tri, c3)) == NULL)) {
putchar(c1);
c0 = c1;
c1 = c2;
c2 = c3;
if (c3 != EOF)
c3 = getc(f);
} else { /* it's a trigraph! */
assert(p != NULL);
assert(p >= tri && p < tri + sizeof(tri) - 1);
c0 = realchars[p-tri];
putchar(c0);
c1 = c2 = c3 = EOF;
if ((c1=getc(f)) != EOF && (c2=getc(f)) != EOF)
c3 = getc(f);
}
}
if (ferror(f))
return -1;
if (fflush(stdout) == EOF || ferror(stdout))
return -1;
return 0;
}
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