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#include <u.h>
#include <libc.h>
#include <bio.h>
#include "libString.h"
struct Sinstack{
int depth;
Biobuf *fp[32]; /* hard limit to avoid infinite recursion */
};
/* initialize */
extern Sinstack *
s_allocinstack(char *file)
{
Sinstack *sp;
Biobuf *fp;
fp = Bopen(file, OREAD);
if(fp == nil)
return nil;
sp = malloc(sizeof *sp);
sp->depth = 0;
sp->fp[0] = fp;
return sp;
}
extern void
s_freeinstack(Sinstack *sp)
{
while(sp->depth >= 0)
Bterm(sp->fp[sp->depth--]);
free(sp);
}
/* Append an input line to a String.
*
* Empty lines and leading whitespace are removed.
*/
static char *
rdline(Biobuf *fp, String *to)
{
int c;
int len = 0;
c = Bgetc(fp);
/* eat leading white */
while(c==' ' || c=='\t' || c=='\n' || c=='\r')
c = Bgetc(fp);
if(c < 0)
return 0;
for(;;){
switch(c) {
case -1:
goto out;
case '\\':
c = Bgetc(fp);
if (c != '\n') {
s_putc(to, '\\');
s_putc(to, c);
len += 2;
}
break;
case '\r':
break;
case '\n':
if(len != 0)
goto out;
break;
default:
s_putc(to, c);
len++;
break;
}
c = Bgetc(fp);
}
out:
s_terminate(to);
return to->ptr - len;
}
/* Append an input line to a String.
*
* Returns a pointer to the character string (or 0).
* Leading whitespace and newlines are removed.
* Lines starting with #include cause us to descend into the new file.
* Empty lines and other lines starting with '#' are ignored.
*/
extern char *
s_rdinstack(Sinstack *sp, String *to)
{
char *p;
Biobuf *fp, *nfp;
s_terminate(to);
fp = sp->fp[sp->depth];
for(;;){
p = rdline(fp, to);
if(p == nil){
if(sp->depth == 0)
break;
Bterm(fp);
sp->depth--;
return s_rdinstack(sp, to);
}
if(strncmp(p, "#include", 8) == 0 && (p[8] == ' ' || p[8] == '\t')){
to->ptr = p;
p += 8;
/* sanity (and looping) */
if(sp->depth >= nelem(sp->fp))
sysfatal("s_rdinstack: includes too deep");
/* skip white */
while(*p == ' ' || *p == '\t')
p++;
nfp = Bopen(p, OREAD);
if(nfp == nil)
continue;
sp->depth++;
sp->fp[sp->depth] = nfp;
return s_rdinstack(sp, to);
}
/* got milk? */
if(*p != '#')
break;
/* take care of comments */
to->ptr = p;
s_terminate(to);
}
return p;
}
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