From 5a54e156e5b96ef240ce432a09f18dea364dcd47 Mon Sep 17 00:00:00 2001
From: Ingo Weinhold <ingo_weinhold@gmx.de>
Date: Sat, 16 Jul 2011 13:51:50 +0200
Subject: [PATCH] Add HashValue() methods to BString

---
 headers/os/support/String.h | 10 ++++++++++
 src/kits/support/String.cpp | 17 +++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/headers/os/support/String.h b/headers/os/support/String.h
index 47260f1c5a..f3d5ae61d7 100644
--- a/headers/os/support/String.h
+++ b/headers/os/support/String.h
@@ -30,6 +30,9 @@ public:
 								int32 charCount) const;
 			bool			IsEmpty() const;
 
+			uint32			HashValue() const;
+	static	uint32			HashValue(const char* string);
+
 			// Assignment
 			BString&		operator=(const BString& string);
 			BString&		operator=(const char* string);
@@ -416,6 +419,13 @@ BString::String() const
 }
 
 
+inline uint32
+BString::HashValue() const
+{
+	return HashValue(String());
+}
+
+
 inline BString &
 BString::SetTo(const char* string)
 {
diff --git a/src/kits/support/String.cpp b/src/kits/support/String.cpp
index e1be1c00a4..e153e7ef47 100644
--- a/src/kits/support/String.cpp
+++ b/src/kits/support/String.cpp
@@ -282,6 +282,23 @@ BString::CountBytes(int32 fromCharOffset, int32 charCount) const
 }
 
 
+/*static*/ uint32
+BString::HashValue(const char* string)
+{
+	// from the Dragon Book: a slightly modified hashpjw()
+    uint32 h = 0;
+    if (string != NULL) {
+        for (; *string; string++) {
+            uint32 g = h & 0xf0000000;
+            if (g)
+                h ^= g >> 24;
+            h = (h << 4) + *string;
+        }
+    }
+    return h;
+}
+
+
 //	#pragma mark - Assignment