Add graph references

2026-06-28 13:49:01 +01:00
parent 0a9807e448
commit a11edf0c53
2578 changed files with 868045 additions and 0 deletions
@@ -0,0 +1,76 @@
+#include "f2c.h"
+#include "fio.h"
+#ifdef __cplusplus
+extern "C" {
+#endif
+#ifdef KR_headers
+integer f_back(a) alist *a;
+#else
+integer f_back(alist *a)
+#endif
+{	unit *b;
+	OFF_T v, w, x, y, z;
+	uiolen n;
+	FILE *f;
+
+	f__curunit = b = &f__units[a->aunit];	/* curunit for error messages */
+	if(a->aunit >= MXUNIT || a->aunit < 0)
+		err(a->aerr,101,"backspace")
+	if(b->useek==0) err(a->aerr,106,"backspace")
+	if(b->ufd == NULL) {
+		fk_open(1, 1, a->aunit);
+		return(0);
+		}
+	if(b->uend==1)
+	{	b->uend=0;
+		return(0);
+	}
+	if(b->uwrt) {
+		t_runc(a);
+		if (f__nowreading(b))
+			err(a->aerr,errno,"backspace")
+		}
+	f = b->ufd;	/* may have changed in t_runc() */
+	if(b->url>0)
+	{
+		x=FTELL(f);
+		y = x % b->url;
+		if(y == 0) x--;
+		x /= b->url;
+		x *= b->url;
+		(void) FSEEK(f,x,SEEK_SET);
+		return(0);
+	}
+
+	if(b->ufmt==0)
+	{	FSEEK(f,-(OFF_T)sizeof(uiolen),SEEK_CUR);
+		fread((char *)&n,sizeof(uiolen),1,f);
+		FSEEK(f,-(OFF_T)n-2*sizeof(uiolen),SEEK_CUR);
+		return(0);
+	}
+	w = x = FTELL(f);
+	z = 0;
+ loop:
+	while(x) {
+		x -= x < 64 ? x : 64;
+		FSEEK(f,x,SEEK_SET);
+		for(y = x; y < w; y++) {
+			if (getc(f) != '\n')
+				continue;
+			v = FTELL(f);
+			if (v == w) {
+				if (z)
+					goto break2;
+				goto loop;
+				}
+			z = v;
+			}
+		err(a->aerr,(EOF),"backspace")
+		}
+ break2:
+	FSEEK(f, z, SEEK_SET);
+	return 0;
+}
+#ifdef __cplusplus
+}
+#endif