From 615575f7dca0e43ecb23c4ab1ea7fd2e93c4e3b4 Mon Sep 17 00:00:00 2001
From: rodri <rgl@antares-labs.eu>
Date: Fri, 23 Jul 2021 03:38:18 +0000
Subject: implemented a lobby for users waiting to join a party. brought the
 pack/unpack procedures from ssh(1).

---
 pack.c | 143 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 143 insertions(+)
 create mode 100644 pack.c

(limited to 'pack.c')

diff --git a/pack.c b/pack.c
new file mode 100644
index 0000000..5899dbd
--- /dev/null
+++ b/pack.c
@@ -0,0 +1,143 @@
+#include <u.h>
+#include <libc.h>
+#include "dat.h"
+#include "fns.h"
+
+/*
+ * these routines were taken directly from ssh(1).
+ * they serve as a reference.
+ */
+
+static int
+vpack(uchar *p, int n, char *fmt, va_list a)
+{
+	uchar *p0 = p, *e = p+n;
+	u32int u;
+//	mpint *m;
+	void *s;
+	int c;
+
+	for(;;){
+		switch(c = *fmt++){
+		case '\0':
+			return p - p0;
+		case '_':
+			if(++p > e) goto err;
+			break;
+		case '.':
+			*va_arg(a, void**) = p;
+			break;
+		case 'b':
+			if(p >= e) goto err;
+			*p++ = va_arg(a, int);
+			break;
+		case 'm':
+//			m = va_arg(a, mpint*);
+//			u = (mpsignif(m)+8)/8;
+			if(p+4 > e) goto err;
+//			PUT4(p, u), p += 4;
+			if(u > e-p) goto err;
+//			mptober(m, p, u), p += u;
+			break;
+		case '[':
+		case 's':
+			s = va_arg(a, void*);
+			u = va_arg(a, int);
+			if(c == 's'){
+				if(p+4 > e) goto err;
+//				PUT4(p, u), p += 4;
+			}
+			if(u > e-p) goto err;
+			memmove(p, s, u);
+			p += u;
+			break;
+		case 'u':
+			u = va_arg(a, int);
+			if(p+4 > e) goto err;
+//			PUT4(p, u), p += 4;
+			break;
+		}
+	}
+err:
+	return -1;
+}
+
+static int
+vunpack(uchar *p, int n, char *fmt, va_list a)
+{
+	uchar *p0 = p, *e = p+n;
+	u32int u;
+//	mpint *m;
+	void *s;
+
+	for(;;){
+		switch(*fmt++){
+		case '\0':
+			return p - p0;
+		case '_':
+			if(++p > e) goto err;
+			break;
+		case '.':
+			*va_arg(a, void**) = p;
+			break;
+		case 'b':
+			if(p >= e) goto err;
+			*va_arg(a, int*) = *p++;
+			break;
+		case 'm':
+			if(p+4 > e) goto err;
+//			u = GET4(p), p += 4;
+			if(u > e-p) goto err;
+//			m = va_arg(a, mpint*);
+//			betomp(p, u, m), p += u;
+			break;
+		case 's':
+			if(p+4 > e) goto err;
+//			u = GET4(p), p += 4;
+			if(u > e-p) goto err;
+			*va_arg(a, void**) = p;
+			*va_arg(a, int*) = u;
+			p += u;
+			break;
+		case '[':
+			s = va_arg(a, void*);
+			u = va_arg(a, int);
+			if(u > e-p) goto err;
+			memmove(s, p, u);
+			p += u;
+			break;
+		case 'u':
+			if(p+4 > e) goto err;
+//			u = GET4(p);
+			*va_arg(a, int*) = u;
+			p += 4;
+			break;
+		}
+	}
+err:
+	return -1;
+}
+
+int
+pack(uchar *p, int n, char *fmt, ...)
+{
+	va_list a;
+
+	va_start(a, fmt);
+	n = vpack(p, n, fmt, a);
+	va_end(a);
+
+	return n;
+}
+
+int
+unpack(uchar *p, int n, char *fmt, ...)
+{
+	va_list a;
+
+	va_start(a, fmt);
+	n = vunpack(p, n, fmt, a);
+	va_end(a);
+
+	return n;
+}
-- 
cgit v1.2.3