Bell 32V development

Work on file usr/src/libI77/due.c

Co-Authored-By: John Reiser <jfr@research.uucp>
Synthesized-from: 32v

diff --git a/usr/src/libI77/due.c b/usr/src/libI77/due.c
new file mode 100644 (file)
index 0000000..dae2cc6
--- /dev/null
+++ b/usr/src/libI77/due.c
@@ -0,0 +1,48 @@
+#include "fio.h"
+s_rdue(a) cilist *a;
+{
+       int n;
+       if(n=c_due(a,READ)) return(n);
+       reading=1;
+       if(curunit->uwrt) nowreading(curunit);
+       return(0);
+}
+s_wdue(a) cilist *a;
+{
+       int n;
+       if(n=c_due(a,WRITE)) return(n);
+       reading=0;
+       if(!curunit->uwrt) nowwriting(curunit);
+       return(0);
+}
+c_due(a,flag) cilist *a;
+{
+       if(!init) f_init();
+       if(a->ciunit>=MXUNIT || a->ciunit<0)
+               err(a->cierr,101,"startio");
+       recpos=sequential=formatted=0;
+       external=1;
+       curunit = &units[a->ciunit];
+       elist=a;
+       if(curunit->ufd==NULL && fk_open(flag,DIR,UNF,a->ciunit) ) err(a->cierr,104,"due");
+       cf=curunit->ufd;
+       if(curunit->ufmt) err(a->cierr,102,"cdue")
+       if(!curunit->useek) err(a->cierr,104,"cdue")
+       if(curunit->ufd==NULL) err(a->cierr,114,"cdue")
+       fseek(cf,(long)(a->cirec-1)*curunit->url,0);
+       curunit->uend = 0;
+       return(0);
+}
+e_rdue()
+{
+       if(curunit->url==1 || recpos==curunit->url)
+               return(0);
+       fseek(cf,(long)(curunit->url-recpos),1);
+       if(ftell(cf)%curunit->url)
+               err(elist->cierr,200,"syserr");
+       return(0);
+}
+e_wdue()
+{
+       return(e_rdue());
+}