From ee2739787f1e996739541bb60e6003b892497e03 Mon Sep 17 00:00:00 2001
From: Bram Moolenaar <Bram@vim.org>
Date: Sat, 2 Jan 2016 21:11:51 +0100
Subject: patch 7.4.1033 Problem:    Memory use on MS-Windows is very
 conservative. Solution:   Use the global memory status to estimate amount of
 memory.             (Mike Williams)

---
 src/os_win32.c         | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++
 src/os_win32.h         |  2 ++
 src/proto/os_win32.pro |  1 +
 src/version.c          |  2 ++
 4 files changed, 65 insertions(+)

diff --git a/src/os_win32.c b/src/os_win32.c
index 2cfd8f34ae..69623f9808 100644
--- a/src/os_win32.c
+++ b/src/os_win32.c
@@ -5858,6 +5858,66 @@ mch_breakcheck(void)
 #endif
 }
 
+/* physical RAM to leave for the OS */
+#define WINNT_RESERVE_BYTES     (256*1024*1024)
+#define WIN95_RESERVE_BYTES       (8*1024*1024)
+
+/*
+ * How much main memory in KiB that can be used by VIM.
+ */
+/*ARGSUSED*/
+    long_u
+mch_total_mem(int special)
+{
+    PlatformId();
+#if (defined(_MSC_VER) && (WINVER > 0x0400)) || defined(MEMORYSTATUSEX)
+    if (g_PlatformId == VER_PLATFORM_WIN32_NT)
+    {
+	MEMORYSTATUSEX  ms;
+
+	/* Need to use GlobalMemoryStatusEx() when there is more memory than
+	 * what fits in 32 bits. But it's not always available. */
+	ms.dwLength = sizeof(MEMORYSTATUSEX);
+	GlobalMemoryStatusEx(&ms);
+	if (ms.ullAvailVirtual < ms.ullTotalPhys)
+	{
+	    /* Process address space fits in physical RAM, use all of it. */
+	    return (long_u)(ms.ullAvailVirtual / 1024);
+	}
+	if (ms.ullTotalPhys <= WINNT_RESERVE_BYTES)
+	{
+	    /* Catch old NT box or perverse hardware setup. */
+	    return (long_u)((ms.ullTotalPhys / 2) / 1024);
+	}
+	/* Use physical RAM less reserve for OS + data. */
+	return (long_u)((ms.ullTotalPhys - WINNT_RESERVE_BYTES) / 1024);
+    }
+    else
+#endif
+    {
+	/* Pre-XP or 95 OS handling. */
+	MEMORYSTATUS    ms;
+	long_u		os_reserve_bytes;
+
+	ms.dwLength = sizeof(MEMORYSTATUS);
+	GlobalMemoryStatus(&ms);
+	if (ms.dwAvailVirtual < ms.dwTotalPhys)
+	{
+	    /* Process address space fits in physical RAM, use all of it. */
+	    return (long_u)(ms.dwAvailVirtual / 1024);
+	}
+	os_reserve_bytes = (g_PlatformId == VER_PLATFORM_WIN32_NT)
+	    ? WINNT_RESERVE_BYTES
+	    : WIN95_RESERVE_BYTES;
+	if (ms.dwTotalPhys <= os_reserve_bytes)
+	{
+	    /* Catch old boxes or perverse hardware setup. */
+	    return (long_u)((ms.dwTotalPhys / 2) / 1024);
+	}
+	/* Use physical RAM less reserve for OS + data. */
+	return (long_u)((ms.dwTotalPhys - os_reserve_bytes) / 1024);
+    }
+}
 
 #ifdef FEAT_MBYTE
 /*
diff --git a/src/os_win32.h b/src/os_win32.h
index 8553910e3d..a6ac891765 100644
--- a/src/os_win32.h
+++ b/src/os_win32.h
@@ -78,6 +78,8 @@
 # define BREAKCHECK_SKIP    1	/* call mch_breakcheck() each time, it's fast */
 #endif
 
+#define HAVE_TOTAL_MEM
+
 #define HAVE_PUTENV		/* at least Bcc 5.2 and MSC have it */
 
 #ifdef FEAT_GUI_W32
diff --git a/src/proto/os_win32.pro b/src/proto/os_win32.pro
index 1431f69da5..5816fc91c4 100644
--- a/src/proto/os_win32.pro
+++ b/src/proto/os_win32.pro
@@ -43,6 +43,7 @@ void mch_write __ARGS((char_u *s, int len));
 void mch_delay __ARGS((long msec, int ignoreinput));
 int mch_remove __ARGS((char_u *name));
 void mch_breakcheck __ARGS((void));
+long_u mch_total_mem __ARGS((int special));
 int mch_wrename __ARGS((WCHAR *wold, WCHAR *wnew));
 int mch_rename __ARGS((const char *pszOldFile, const char *pszNewFile));
 char *default_shell __ARGS((void));
diff --git a/src/version.c b/src/version.c
index 72aa418d54..e49fadb618 100644
--- a/src/version.c
+++ b/src/version.c
@@ -741,6 +741,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1033,
 /**/
     1032,
 /**/
-- 
cgit v1.2.3