From 73a72c42e2be61a6ebd778343b345de3cc65ed00 Mon Sep 17 00:00:00 2001
From: Ingo Weinhold <ingo_weinhold@gmx.de>
Date: Wed, 10 Mar 2010 18:36:44 +0000
Subject: [PATCH] Added get_free_address_range() to get a free range in a given
 range array.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@35801 a95241bf-73f2-0310-859d-f6bbb57e9c96
---
 headers/private/kernel/boot/addr_range.h |  2 ++
 src/system/boot/loader/kernel_args.cpp   | 34 ++++++++++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/headers/private/kernel/boot/addr_range.h b/headers/private/kernel/boot/addr_range.h
index 201fb9fcc3..5367fde6a3 100644
--- a/headers/private/kernel/boot/addr_range.h
+++ b/headers/private/kernel/boot/addr_range.h
@@ -23,6 +23,8 @@ status_t insert_address_range(addr_range *ranges, uint32 *_numRanges, uint32 max
 	addr_t start, uint32 size);
 status_t remove_addr_range(addr_range *ranges, uint32 *_numRanges, uint32 maxRanges,
 	addr_t start, uint32 size);
+bool get_free_address_range(addr_range *ranges, uint32 numRanges, addr_t base,
+	size_t size, addr_t *_rangeBase);
 
 status_t insert_physical_memory_range(addr_t start, uint32 size);
 status_t insert_physical_allocated_range(addr_t start, uint32 size);
diff --git a/src/system/boot/loader/kernel_args.cpp b/src/system/boot/loader/kernel_args.cpp
index 96ec8125a8..f66014e0a2 100644
--- a/src/system/boot/loader/kernel_args.cpp
+++ b/src/system/boot/loader/kernel_args.cpp
@@ -180,6 +180,40 @@ remove_address_range(addr_range* ranges, uint32* _numRanges, uint32 maxRanges,
 }
 
 
+bool
+get_free_address_range(addr_range *ranges, uint32 numRanges, addr_t base,
+	size_t size, addr_t *_rangeBase)
+{
+	addr_t end = base + size - 1;
+	if (end < base)
+		return false;
+
+	// Note: We don't assume that the ranges are sorted, so we can't do this
+	// in a simple loop. Instead we restart the loop whenever our range
+	// intersects with an existing one.
+
+	for (uint32 i = 0; i < numRanges;) {
+		addr_t rangeStart = ranges[i].start;
+		addr_t rangeEnd = ranges[i].start + ranges[i].size - 1;
+
+		if (base <= rangeEnd && rangeStart <= end) {
+			base = rangeEnd + 1;
+			end = rangeEnd + size;
+			if (base == 0 || end < base)
+				return false;
+
+			i = 0;
+			continue;
+		}
+
+		i++;
+	}
+
+	*_rangeBase = base;
+	return true;
+}
+
+
 status_t
 insert_physical_memory_range(addr_t start, uint32 size)
 {