Neon instructions detect without using NDK so it will work within Android, and on other linux arm based platforms and builds

BUG=none
TEST=none
Review URL: https://webrtc-codereview.appspot.com/358008

git-svn-id: http://libyuv.googlecode.com/svn/trunk@153 16f28f9a-4ce2-e073-06de-1de4eb20be90

README.chromium

@@ -1,6 +1,6 @@
 Name: libyuv
 URL: http://code.google.com/p/libyuv/
-Version: 152
+Version: 154
 License: BSD
 License File: LICENSE
 

include/libyuv/version.h

@@ -16,7 +16,7 @@ namespace libyuv {
 extern "C" {
 #endif
 
-#define LIBYUV_VERSION 152
+#define LIBYUV_VERSION 153
 
 #ifdef __cplusplus
 }  // extern "C"

libyuv_test.gyp

@@ -23,6 +23,7 @@
 
          # sources
          'unit_test/compare_test.cc',
+         'unit_test/cpu_test.cc',
          'unit_test/planar_test.cc',
          'unit_test/rotate_test.cc',
          'unit_test/scale_test.cc',

source/cpu_id.cc

@@ -14,9 +14,10 @@
 #ifdef _MSC_VER
 #include <intrin.h>  // For __cpuid()
 #endif
-#if defined(__ANDROID__) && defined(NDK_ROOT)
-#include <cpu-features.h>  // For android_getCpuFeatures()
-#endif
+
+// For ArmCpuCaps() but unittested on all platforms
+#include <stdio.h>
+#include <string.h>
 
 #include "libyuv/basic_types.h"  // For CPU_X86
 
@@ -46,6 +47,26 @@ namespace libyuv {
 extern "C" {
 #endif
 
+// based on libvpx arm_cpudetect.c
+int ArmCpuCaps(const char* cpuinfoname) {
+  int flags = 0;
+  FILE* fin = fopen(cpuinfoname, "r");
+  if (fin) {
+    char buf[512];
+    while (fgets(buf, 511, fin)) {
+      if (memcmp(buf, "Features", 8) == 0) {
+        char* p = strstr(buf, " neon");
+        if (p && (p[5] == ' ' || p[5] == '\n')) {
+          flags |= kCpuHasNEON;
+          break;
+        }
+      }
+    }
+    fclose(fin);
+  }
+  return flags;
+}
+
 // CPU detect function for SIMD instruction sets.
 int cpu_info_ = 0;
 
@@ -65,10 +86,8 @@ int InitCpuFlags() {
   if (getenv("LIBYUV_DISABLE_SSSE3")) {
     cpu_info_ &= ~kCpuHasSSSE3;
   }
-#elif defined(__ANDROID__) && defined(__ARM_NEON__) && defined(NDK_ROOT)
-  uint64_t features = android_getCpuFeatures();
-  cpu_info_ = ((features & ANDROID_CPU_ARM_FEATURE_NEON) ? kCpuHasNEON : 0) |
-              kCpuInitialized;
+#elif if defined(__linux__) && defined(__ARM_NEON__)
+  cpu_info_ = ArmCpuCaps("/proc/cpuinfo") | kCpuInitialized;
 #elif defined(__ARM_NEON__)
   // gcc -mfpu=neon defines __ARM_NEON__
   // Enable Neon if you want support for Neon and Arm, and use MaskCpuFlags

unit_test/cpu_test.cc

@@ -0,0 +1,28 @@
+/*
+ *  Copyright (c) 2012 The LibYuv project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "unit_test.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "libyuv/basic_types.h"
+#include "libyuv/cpu_id.h"
+
+namespace libyuv {
+
+extern "C" int ArmCpuCaps(const char* cpuinfoname);
+
+TEST_F(libyuvTest, TestLinuxNeon) {
+  EXPECT_EQ(0,ArmCpuCaps("testdata/arm_v7.txt"));
+  EXPECT_NE(kCpuHasNEON,ArmCpuCaps("testdata/tegra3.txt"));
+}
+
+}  // namespace libyuv

unit_test/testdata/arm_v7.txt

@@ -0,0 +1,12 @@
+Processor	: ARMv7 Processor rev 5 (v7l)
+BogoMIPS	: 795.44
+Features	: swp half thumb fastmult vfp edsp iwmmxt thumbee vfpv3 vfpv3d16 
+CPU implementer	: 0x56
+CPU architecture: 7
+CPU variant	: 0x0
+CPU part	: 0x581
+CPU revision	: 5
+
+Hardware	: OLPC XO-1.75
+Revision	: 0000
+Serial		: 0000000000000000

unit_test/testdata/tegra3.txt

@@ -0,0 +1,23 @@
+Processor       : ARMv7 Processor rev 9 (v7l)
+processor       : 0
+BogoMIPS        : 1992.29
+
+processor       : 1
+BogoMIPS        : 1992.29
+
+processor       : 2
+BogoMIPS        : 1992.29
+
+processor       : 3
+BogoMIPS        : 1992.29
+
+Features        : swp half thumb fastmult vfp edsp neon vfpv3
+CPU implementer : 0×41
+CPU architecture: 7
+CPU variant     : 0×2
+CPU part        : 0xc09
+CPU revision    : 9
+
+Hardware        : cardhu
+Revision        : 0000
+

unit_test/unit_test.h

@@ -35,6 +35,8 @@ static double get_time()
     return double(t.QuadPart)/double(f.QuadPart);
 }
 
+#define random rand
+#define srandom srand
 #else
 
 #include <sys/time.h>