From 928adb6484b23f54301368e0398f64e5a7dbbaf5 Mon Sep 17 00:00:00 2001
From: Jo-Philipp Wich <jo@mein.io>
Date: Tue, 28 May 2019 17:50:37 +0200
Subject: [PATCH] luci-base: add client-side prng library

Introduce a new tools.prng JS library which implements the musl libc
srand() and rand() calls to produce identical pseudo random number
sequences in the browser which is needed for the string to color
conversion later on.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>
---
 .../luci-static/resources/tools/prng.js       | 93 +++++++++++++++++++
 1 file changed, 93 insertions(+)
 create mode 100644 modules/luci-base/htdocs/luci-static/resources/tools/prng.js

diff --git a/modules/luci-base/htdocs/luci-static/resources/tools/prng.js b/modules/luci-base/htdocs/luci-static/resources/tools/prng.js
new file mode 100644
index 000000000..752dc75ce
--- /dev/null
+++ b/modules/luci-base/htdocs/luci-static/resources/tools/prng.js
@@ -0,0 +1,93 @@
+'use strict';
+
+var s = [0x0000, 0x0000, 0x0000, 0x0000];
+
+function mul(a, b) {
+	var r = [0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000];
+
+	for (var j = 0; j < 4; j++) {
+		var k = 0;
+		for (var i = 0; i < 4; i++) {
+			var t = a[i] * b[j] + r[i+j] + k;
+			r[i+j] = t & 0xffff;
+			k = t >>> 16;
+		}
+		r[j+4] = k;
+	}
+
+	r.length = 4;
+
+	return r;
+}
+
+function add(a, n) {
+	var r = [0x0000, 0x0000, 0x0000, 0x0000],
+	    k = n;
+
+	for (var i = 0; i < 4; i++) {
+		var t = a[i] + k;
+		r[i] = t & 0xffff;
+		k = t >>> 16;
+	}
+
+	return r;
+}
+
+function shr(a, n) {
+	var r = [a[0], a[1], a[2], a[3], 0x0000],
+	    i = 4,
+	    k = 0;
+
+	for (; n > 16; n -= 16, i--)
+		for (var j = 0; j < 4; j++)
+			r[j] = r[j+1];
+
+	for (; i > 0; i--) {
+		var s = r[i-1];
+		r[i-1] = (s >>> n) | k;
+		k = ((s & ((1 << n) - 1)) << (16 - n));
+	}
+
+	r.length = 4;
+
+	return r;
+}
+
+return L.Class.extend({
+	seed: function(n) {
+		n = (n - 1)|0;
+		s[0] = n & 0xffff;
+		s[1] = n >>> 16;
+		s[2] = 0;
+		s[3] = 0;
+	},
+
+	int: function() {
+		s = mul(s, [0x7f2d, 0x4c95, 0xf42d, 0x5851]);
+		s = add(s, 1);
+
+		var r = shr(s, 33);
+		return (r[1] << 16) | r[0];
+	},
+
+	get: function() {
+		var r = (this.int() % 0x7fffffff) / 0x7fffffff, l, u;
+
+		switch (arguments.length) {
+		case 0:
+			return r;
+
+		case 1:
+			l = 1;
+			u = arguments[0]|0;
+			break;
+
+		case 2:
+			l = arguments[0]|0;
+			u = arguments[1]|0;
+			break;
+		}
+
+		return Math.floor(r * (u - l + 1)) + l;
+	}
+});
-- 
2.25.1