[Boost-commit] svn:boost r53863 - in sandbox/monotonic: boost/monotonic libs/monotonic/test

Subject: [Boost-commit] svn:boost r53863 - in sandbox/monotonic: boost/monotonic libs/monotonic/test
From: christian.schladetsch_at_[hidden]
Date: 2009-06-13 04:51:58

Author: cschladetsch
Date: 2009-06-13 04:51:56 EDT (Sat, 13 Jun 2009)
New Revision: 53863
URL: http://svn.boost.org/trac/boost/changeset/53863

Log:
improvement to performance of alignment

Text files modified: 
   sandbox/monotonic/boost/monotonic/allocator.h      |     4 ++--                                    
   sandbox/monotonic/boost/monotonic/inline_storage.h |    21 ++++++++++++++++++---                   
   sandbox/monotonic/boost/monotonic/storage_base.h   |     4 ++--                                    
   sandbox/monotonic/libs/monotonic/test/main.cpp     |    14 ++++++++++++++                          
   4 files changed, 36 insertions(+), 7 deletions(-)

Modified: sandbox/monotonic/boost/monotonic/allocator.h
==============================================================================
--- sandbox/monotonic/boost/monotonic/allocator.h	(original)
+++ sandbox/monotonic/boost/monotonic/allocator.h	2009-06-13 04:51:56 EDT (Sat, 13 Jun 2009)
@@ -97,13 +97,13 @@
                                 return &x;
                         }
 
-			BOOST_STATIC_CONSTANT(size_t, alignment_mask = boost::aligned_storage<sizeof(T)>::alignment - 1);
+			BOOST_STATIC_CONSTANT(size_t, alignment = boost::aligned_storage<sizeof(T)>::alignment);
 
                         pointer allocate(size_type num, allocator<void>::const_pointer /*hint*/ = 0)
                         {
                                 BOOST_ASSERT(num > 0);
                                 BOOST_ASSERT(storage != 0);
-				return static_cast<T *>(storage->allocate(num*sizeof(T), alignment_mask));
+				return static_cast<T *>(storage->allocate(num*sizeof(T), alignment));
                         }
 
                         void deallocate(pointer p, size_type n)

Modified: sandbox/monotonic/boost/monotonic/inline_storage.h
==============================================================================
--- sandbox/monotonic/boost/monotonic/inline_storage.h	(original)
+++ sandbox/monotonic/boost/monotonic/inline_storage.h	2009-06-13 04:51:56 EDT (Sat, 13 Jun 2009)
@@ -42,6 +42,18 @@
                         {
                         }
 
+			buffer_type const &get_buffer()  const
+			{
+				return buffer;
+			}
+			const char *begin() const
+			{
+				return &buffer[0];
+			}
+			const char *end() const
+			{
+				return &buffer[N - 1];
+			}
                         void reset()
                         {
                                 cursor = 0;
@@ -57,12 +69,15 @@
                                 cursor = c;
                         }
 
-			/// allocate storage, given alignment mask
-			void *allocate(size_t num_bytes, size_t mask)
+			/// allocate storage, given alignment requirement
+			void *allocate(size_t num_bytes, size_t alignment)
                         {
                                 // ensure we return a point on an aligned boundary
-				size_t extra = num_bytes & mask;
+				size_t extra = cursor & (alignment - 1);
+				if (extra > 0)
+					extra = alignment - extra;
                                 size_t required = num_bytes + extra;
+				BOOST_ASSERT(cursor + required <= N);
 #ifdef BOOST_MONOTONIC_USE_AUTOBUFFER
                                 buffer.uninitialized_resize(buffer.size() + required);
 #endif

Modified: sandbox/monotonic/boost/monotonic/storage_base.h
==============================================================================
--- sandbox/monotonic/boost/monotonic/storage_base.h	(original)
+++ sandbox/monotonic/boost/monotonic/storage_base.h	2009-06-13 04:51:56 EDT (Sat, 13 Jun 2009)
@@ -12,8 +12,8 @@
                 /// base structure for inline_storage<N>
                 struct storage_base
                 {
-			// the number of bytes to allocate, and the bit-mask to use for correct byte-alignment
-			virtual void *allocate(size_t num_bytes, size_t mask) = 0;
+			// the number of bytes to allocate, and the alignment to use
+			virtual void *allocate(size_t num_bytes, size_t alignment) = 0;
 
                         virtual void deallocate(void *base, size_t num_bytes) = 0;
                         virtual size_t max_size() const = 0;

Modified: sandbox/monotonic/libs/monotonic/test/main.cpp
==============================================================================
--- sandbox/monotonic/libs/monotonic/test/main.cpp	(original)
+++ sandbox/monotonic/libs/monotonic/test/main.cpp	2009-06-13 04:51:56 EDT (Sat, 13 Jun 2009)
@@ -246,6 +246,20 @@
 void test_alignment()
 {
         monotonic::inline_storage<10000> storage;
+
+	// the two arguments to storage.allocate are the size, and the required alignment
+	void *P = storage.allocate(3, 4);
+	assert(P == storage.begin() + 0);
+	
+	P = storage.allocate(3, 4);
+	assert(P == storage.begin() + 4);
+	
+	P = storage.allocate(11, 4);
+	assert(P == storage.begin() + 8);
+
+	P = storage.allocate(11, 16);
+	assert(P == storage.begin() + 32);
+
         typedef boost::array<char, 3> c0;
         typedef boost::array<char, 6> c1;
         typedef boost::array<char, 11> c2;