From f28d1108b2d9dd9e14187fd5729b004c679303a3 Mon Sep 17 00:00:00 2001
From: "rogerl%netscape.com" <rogerl%netscape.com>
Date: Wed, 9 Jul 2003 22:56:56 +0000
Subject: [PATCH] Fixed 54/53 bit bug in random() Added start of
 runtimestrings...

---
 js2/src/js2math.cpp        | 10 ++--
 js2/src/js2runtimestring.h | 99 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 104 insertions(+), 5 deletions(-)
 create mode 100644 js2/src/js2runtimestring.h

diff --git a/js2/src/js2math.cpp b/js2/src/js2math.cpp
index 46862e5f7c1..91a7b5a6fa2 100644
--- a/js2/src/js2math.cpp
+++ b/js2/src/js2math.cpp
@@ -218,8 +218,8 @@ static void random_init(JS2Metadata *meta)
     meta->rngInitialized = true;
 
     /* meta->rngMultiplier = 0x5DEECE66DL */
-    JSLL_ISHL(tmp, 0x5D, 32);
-    JSLL_UI2L(tmp2, 0xEECE66DL);
+    JSLL_ISHL(tmp, 0x5, 32);
+    JSLL_UI2L(tmp2, 0xDEECE66DL);
     JSLL_OR(meta->rngMultiplier, tmp, tmp2);
 
     /* meta->rngAddend = 0xBL */
@@ -230,8 +230,8 @@ static void random_init(JS2Metadata *meta)
     JSLL_SHL(tmp2, tmp, 48);
     JSLL_SUB(meta->rngMask, tmp2, tmp);
 
-    /* meta->rngDscale = (jsdouble)(1L << 54) */
-    JSLL_SHL(tmp2, tmp, 54);
+    /* meta->rngDscale = (jsdouble)(1L << 53) */
+    JSLL_SHL(tmp2, tmp, 53);
     JSLL_L2D(meta->rngDscale, tmp2);
 
     /* Finally, set the seed from current time. */
@@ -257,7 +257,7 @@ static float64 random_nextDouble(JS2Metadata *meta)
     int64 tmp, tmp2;
     float64 d;
 
-    JSLL_ISHL(tmp, random_next(meta, 27), 27);
+    JSLL_ISHL(tmp, random_next(meta, 26), 27);
     JSLL_UI2L(tmp2, random_next(meta, 27));
     JSLL_ADD(tmp, tmp, tmp2);
     JSLL_L2D(d, tmp);
diff --git a/js2/src/js2runtimestring.h b/js2/src/js2runtimestring.h
new file mode 100644
index 00000000000..d002ba0597c
--- /dev/null
+++ b/js2/src/js2runtimestring.h
@@ -0,0 +1,99 @@
+class JS2StringElement {
+public:
+
+	JS2StringElement(uint16 length) : length(length), chars(new jschar[length]) { }
+
+	JS2StringElement(uint16 length, jschar *source) : length(length), chars(new jschar[length]) { for (uint16 i = 0; i < length; i++) chars[i] = source[i]; }
+
+	uint16 getLength() const { return length; }
+	jschar *getChars() const { return chars; }
+
+
+	void insert(uint16 index, uint16 length, jschar *text)
+	{
+		for (uint16 i = 0; i < length; i++, index++)
+			chars[index] = text[i];
+	}
+
+private:
+	uint16 length;
+	jschar *chars;
+
+};
+
+
+class JS2String {
+public:
+
+	JS2String(uint16 length, jschar *text) : count(1), contents[0] = new JS2StringElement(length, text) { }
+
+
+	JS2String(const JS2String &a, const JS2String &b) 
+	{
+		count = a.getCount() + b.getCount();
+		if (count <= 4) {
+			uint16 i;
+			for (i = 0; i < a.getCount(); i++)
+				contents[i] = a.contents[i];
+			for (uint16 j = 0; j < b.getCount(); j++, i++)
+				contents[i] = b.contents[j];
+		}
+		else {
+			count = 1;
+			contents[0] = new JS2StringElement(a.getLength() + b.getLength());
+			uint16 i;
+			uint16 index = 0;
+			for (i = 0; i < a.getCount(); i++) {
+				contents[0]->insert(index, a.contents[i]->getLength(), a.contents[i]->getChars());
+				index += a.contents[i]->getLength();
+			}
+			for (i = 0; i < b.getCount(); i++) {
+				contents[0]->insert(index, b.contents[i]->getLength(), b.contents[i]->getChars());
+				index += b.contents[i]->getLength()
+			}
+		}
+	}
+
+	void add(const JS2String &a)
+	{
+		ASSERT((count + a.count) <= 4);
+		for (uint16 i = 0; i < a.count; i++, count++)
+			contents[count] = a.contents[i];
+	}
+
+	uint16 getCount() const 	{ return count; }
+
+	uint16 getLength() const 	{ uint16 t = 0; for (uint16 i = 0; i < count; i++) t += contents[i]->getLength(); return t; }
+
+	void collapse()		
+	{ 
+		if (count > 1) {
+			JS2StringElement *t = new JS2StringElement(getLength());
+			for (uint16 i = 0; i < count; i++) {
+				t->insert(index, contents[i]->getLength(), contents[i]->getChars());
+				index += contents[i]->getLength();
+			}
+			count = 1;
+			contents[0] = t;
+		}
+	}
+
+	jschar *getChars()	{ collapse(); return contents[0]->getChars(); }
+
+private:
+	uint16 count;
+	JS2StringElement *contents[4];
+
+};
+
+
+JS2String &operator +(const JS2String &a, const JS2String &b) { return JS2String(a, b); }
+JS2String &operator +=(const JS2String &a, const JS2String &b)
+{
+	if ((a.getCount() + b.getCount) <= 4) {
+		a.add(b);
+		return a;
+	}
+	else
+		return JS2String(a, b);
+}