From: short <>
Date: Tue, 4 Nov 2003 06:41:35 +0000 (+0000)
Subject: captive_shared_cache_map_object_FileSizes_changed(): Improved performance.
X-Git-Tag: captive-1_0_2~34
X-Git-Url: http://git.jankratochvil.net/?p=captive.git;a=commitdiff_plain;h=000196808efeead1b2aee0c3aaa0ef64c11ef335

captive_shared_cache_map_object_FileSizes_changed(): Improved performance.
 - Prevent continous reallocation to (n+1) size,
   we use now (n*2) sizes for logaritmic time complexity.
---

diff --git a/src/libcaptive/cc/sharedcachemap-priv.h b/src/libcaptive/cc/sharedcachemap-priv.h
index 1b353e8..af2fcac 100644
--- a/src/libcaptive/cc/sharedcachemap-priv.h
+++ b/src/libcaptive/cc/sharedcachemap-priv.h
@@ -54,11 +54,17 @@ struct _CaptiveSharedCacheMapObject {
 	 * as the offsets are usually PAGE_SIZE aligned due to pin-Bcb expectations.
 	 */
 	guint64 FileSize;	/* ==CC_FILE_SIZES.FileSize.QuadPart */
-	/* We use 'FileSize' instead of 'ValidDataLength' as I assume W32
+	/* We use do not use 'ValidDataLength' as I assume W32
 	 * automatically increases 'ValidDataLength' during Cache Manager write operations.
 	 * We do not increase it and therefore it is mostly useless for us.
 	 */
 	guint64 ValidDataLength;	/* ==CC_FILE_SIZES.ValidDataLength.QuadPart */
+	/* The real allocation size of 'buffer' and 'pages'.
+	 * Maintained by captive_shared_cache_map_object_FileSizes_changed()
+	 * to prevent continous reallocation to (n+1) size.
+	 * We use (n*2) sizes for logaritmic time complexity.
+	 */
+	guint64 alloc_length;
 	CACHE_MANAGER_CALLBACKS CallBacks;
 	VOID *LazyWriterContext;
 	gboolean PinAccess;
diff --git a/src/libcaptive/cc/sharedcachemap.c b/src/libcaptive/cc/sharedcachemap.c
index 28d2267..9ee7cd4 100644
--- a/src/libcaptive/cc/sharedcachemap.c
+++ b/src/libcaptive/cc/sharedcachemap.c
@@ -183,8 +183,6 @@ size_new_big:
 		}
 
 	if (size_old!=size_new) {
-gpointer buffer_new;
-
 		/* ntfs.sys of NT-5.1sp1 may extend StreamFileObject while dirty pins exist.
 		 * How to extend SharedCacheMap size without changing the memory location?
 		 * I hope ntfs.sys does not expect long-term absolute position of its
@@ -195,8 +193,17 @@ gpointer buffer_new;
 			g_assert(!captive_shared_cache_map_object->map);
 			g_assert(!g_hash_table_size(captive_shared_cache_map_object->pin_hash));
 			}
+		}
+
+	if (size_new > captive_shared_cache_map_object->alloc_length) {
+gpointer buffer_new;
+
+		size_new*=2;
+		size64_new*=2;
+		if (size_new!=size64_new)
+			goto size_new_big;
 
-		if (AllocationSize) {
+		if (size_new) {
 gpointer base;
 int errint;
 
@@ -226,10 +233,10 @@ int errint;
 		memcpy(buffer_new,captive_shared_cache_map_object->buffer,
 				MIN(AllocationSize,captive_shared_cache_map_object->AllocationSize));
 
-		if (captive_shared_cache_map_object->AllocationSize) {
+		if (captive_shared_cache_map_object->alloc_length) {
 int errint;
 
-			errint=munmap(captive_shared_cache_map_object->buffer,size_old);
+			errint=munmap(captive_shared_cache_map_object->buffer,captive_shared_cache_map_object->alloc_length);
 			g_assert(errint==0);
 			}
 
@@ -246,11 +253,14 @@ guint64 now;
 				}
 			}
 #endif
+
 		captive_shared_cache_map_object->pages=g_realloc(captive_shared_cache_map_object->pages,
 				size_new/PAGE_SIZE*sizeof(*captive_shared_cache_map_object->pages));
 		if (size_new>size_old)	/* prevent 'size_new-size_old' as it is unsigned! */
 			memset(captive_shared_cache_map_object->pages+(size_old/PAGE_SIZE),0,
 					(size_new-size_old)/PAGE_SIZE*sizeof(*captive_shared_cache_map_object->pages));
+
+		captive_shared_cache_map_object->alloc_length=size_new;
 		}
 
 	captive_shared_cache_map_object->AllocationSize=AllocationSize;