From 09fb7d4bbce5fe8c5c1142a9744646e5de7dd1d2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Axel=20D=C3=B6rfler?= <axeld@pinc-software.de>
Date: Tue, 16 Sep 2003 02:33:48 +0000
Subject: [PATCH] Implemented hash functions for DirectoryBlock. Added
 HashIterator::InitCheck() method (as the allocation of the buffer might
 fail). Added a HashIterator::Goto() method to jump to the specified index in
 the hash (handy for hash lookup).

git-svn-id: file:///srv/svn/repos/haiku/trunk/current@4707 a95241bf-73f2-0310-859d-f6bbb57e9c96
---
 .../file_systems/amiga_ffs/amiga_ffs.cpp      | 41 +++++++++++++++++--
 .../loader/file_systems/amiga_ffs/amiga_ffs.h |  5 ++-
 2 files changed, 42 insertions(+), 4 deletions(-)

diff --git a/src/kernel/boot/loader/file_systems/amiga_ffs/amiga_ffs.cpp b/src/kernel/boot/loader/file_systems/amiga_ffs/amiga_ffs.cpp
index 501ae8f8c5..2eb59db91c 100644
--- a/src/kernel/boot/loader/file_systems/amiga_ffs/amiga_ffs.cpp
+++ b/src/kernel/boot/loader/file_systems/amiga_ffs/amiga_ffs.cpp
@@ -73,10 +73,30 @@ BaseBlock::ValidateCheckSum() const
 //	#pragma mark -
 
 
-int32 
-DirectoryBlock::HashIndexFor(const char *name)
+char 
+DirectoryBlock::ToUpperChar(int32 type, char c) const
 {
-	return 0;
+	// Taken from Ralph Babel's "The Amiga Guru Book" (1993), section 15.3.4.3
+
+	if (type == DT_AMIGA_OFS || type == DT_AMIGA_FFS)
+		return c >= 'a' && c <= 'z' ? c + ('A' - 'a') : c;
+
+	return (c >= '\340' && c <= '\376' && c != '\367')
+		|| (c >= 'a' && c <= 'z') ? c + ('A' - 'a') : c;
+}
+
+
+int32 
+DirectoryBlock::HashIndexFor(int32 type, const char *name) const
+{
+	int32 hash = strlen(name);
+	
+	while (name[0]) {
+		hash = (hash * 13 + ToUpperChar(type, name[0])) & 0x7ff;
+		name++;
+	}
+
+	return hash % HashSize();
 }
 
 
@@ -131,6 +151,21 @@ HashIterator::~HashIterator()
 }
 
 
+status_t 
+HashIterator::InitCheck()
+{
+	return fData != NULL ? B_OK : B_NO_MEMORY;
+}
+
+
+void 
+HashIterator::Goto(int32 index)
+{
+	fCurrent = index;
+	fBlock = fDirectory.HashValueAt(index);
+}
+
+
 NodeBlock *
 HashIterator::GetNext(int32 &block)
 {
diff --git a/src/kernel/boot/loader/file_systems/amiga_ffs/amiga_ffs.h b/src/kernel/boot/loader/file_systems/amiga_ffs/amiga_ffs.h
index 44b447247c..8858fb4e4c 100644
--- a/src/kernel/boot/loader/file_systems/amiga_ffs/amiga_ffs.h
+++ b/src/kernel/boot/loader/file_systems/amiga_ffs/amiga_ffs.h
@@ -87,7 +87,8 @@ class DirectoryBlock : public NodeBlock {
 		DirectoryBlock(int32 blockSize) : NodeBlock(blockSize) {}
 		DirectoryBlock(void *data, int32 blockSize) : NodeBlock(data, blockSize) {}
 
-		int32 HashIndexFor(const char *name);
+		char ToUpperChar(int32 type, char c) const;
+		int32 HashIndexFor(int32 type, const char *name) const;
 
 		int32 HashValueAt(int32 index) const;
 		int32 NextHashValue(int32 &index) const;
@@ -143,6 +144,8 @@ class HashIterator {
 		HashIterator(int32 device, DirectoryBlock &node);
 		~HashIterator();
 
+		status_t InitCheck();
+		void Goto(int32 index);
 		NodeBlock *GetNext(int32 &block);
 		void Rewind();