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1 /*
2  * Copyright (C) 2014 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #include <stdint.h>
18 #include <stdlib.h>
19 #include <string.h>
20 #include <sys/mman.h>
21 #include <sys/types.h>
22 
23 #include <cutils/memory.h>
24 #include <gtest/gtest.h>
25 
26 #define FENCEPOST_LENGTH 8
27 
28 #define MAX_TEST_SIZE (64*1024)
29 // Choose values that have no repeating byte values.
30 #define MEMSET16_PATTERN 0xb139
31 #define MEMSET32_PATTERN 0x48193a27
32 
33 enum test_e {
34   MEMSET16 = 0,
35   MEMSET32,
36 };
37 
38 static int g_memset16_aligns[][2] = {
39   { 2, 0 },
40   { 4, 0 },
41   { 8, 0 },
42   { 16, 0 },
43   { 32, 0 },
44   { 64, 0 },
45   { 128, 0 },
46 
47   { 4, 2 },
48 
49   { 8, 2 },
50   { 8, 4 },
51   { 8, 6 },
52 
53   { 128, 2 },
54   { 128, 4 },
55   { 128, 6 },
56   { 128, 8 },
57   { 128, 10 },
58   { 128, 12 },
59   { 128, 14 },
60   { 128, 16 },
61 };
62 
63 static int g_memset32_aligns[][2] = {
64   { 4, 0 },
65   { 8, 0 },
66   { 16, 0 },
67   { 32, 0 },
68   { 64, 0 },
69   { 128, 0 },
70 
71   { 8, 4 },
72 
73   { 128, 4 },
74   { 128, 8 },
75   { 128, 12 },
76   { 128, 16 },
77 };
78 
GetIncrement(size_t len,size_t min_incr)79 static size_t GetIncrement(size_t len, size_t min_incr) {
80   if (len >= 4096) {
81     return 1024;
82   } else if (len >= 1024) {
83     return 256;
84   }
85   return min_incr;
86 }
87 
88 // Return a pointer into the current buffer with the specified alignment.
GetAlignedPtr(void * orig_ptr,int alignment,int or_mask)89 static void *GetAlignedPtr(void *orig_ptr, int alignment, int or_mask) {
90   uint64_t ptr = reinterpret_cast<uint64_t>(orig_ptr);
91   if (alignment > 0) {
92       // When setting the alignment, set it to exactly the alignment chosen.
93       // The pointer returned will be guaranteed not to be aligned to anything
94       // more than that.
95       ptr += alignment - (ptr & (alignment - 1));
96       ptr |= alignment | or_mask;
97   }
98 
99   return reinterpret_cast<void*>(ptr);
100 }
101 
SetFencepost(uint8_t * buffer)102 static void SetFencepost(uint8_t *buffer) {
103   for (int i = 0; i < FENCEPOST_LENGTH; i += 2) {
104     buffer[i] = 0xde;
105     buffer[i+1] = 0xad;
106   }
107 }
108 
VerifyFencepost(uint8_t * buffer)109 static void VerifyFencepost(uint8_t *buffer) {
110   for (int i = 0; i < FENCEPOST_LENGTH; i += 2) {
111     if (buffer[i] != 0xde || buffer[i+1] != 0xad) {
112       uint8_t expected_value;
113       if (buffer[i] == 0xde) {
114         i++;
115         expected_value = 0xad;
116       } else {
117         expected_value = 0xde;
118       }
119       ASSERT_EQ(expected_value, buffer[i]);
120     }
121   }
122 }
123 
RunMemsetTests(test_e test_type,uint32_t value,int align[][2],size_t num_aligns)124 void RunMemsetTests(test_e test_type, uint32_t value, int align[][2], size_t num_aligns) {
125   size_t min_incr = 4;
126   if (test_type == MEMSET16) {
127     min_incr = 2;
128     value |= value << 16;
129   }
130   uint32_t* expected_buf = new uint32_t[MAX_TEST_SIZE/sizeof(uint32_t)];
131   for (size_t i = 0; i < MAX_TEST_SIZE/sizeof(uint32_t); i++) {
132     expected_buf[i] = value;
133   }
134 
135   // Allocate one large buffer with lots of extra space so that we can
136   // guarantee that all possible alignments will fit.
137   uint8_t *buf = new uint8_t[3*MAX_TEST_SIZE];
138   uint8_t *buf_align;
139   for (size_t i = 0; i < num_aligns; i++) {
140     size_t incr = min_incr;
141     for (size_t len = incr; len <= MAX_TEST_SIZE; len += incr) {
142       incr = GetIncrement(len, min_incr);
143 
144       buf_align = reinterpret_cast<uint8_t*>(GetAlignedPtr(
145           buf+FENCEPOST_LENGTH, align[i][0], align[i][1]));
146 
147       SetFencepost(&buf_align[-FENCEPOST_LENGTH]);
148       SetFencepost(&buf_align[len]);
149 
150       memset(buf_align, 0xff, len);
151       if (test_type == MEMSET16) {
152         android_memset16(reinterpret_cast<uint16_t*>(buf_align), value, len);
153       } else {
154         android_memset32(reinterpret_cast<uint32_t*>(buf_align), value, len);
155       }
156       ASSERT_EQ(0, memcmp(expected_buf, buf_align, len))
157           << "Failed size " << len << " align " << align[i][0] << " " << align[i][1] << "\n";
158 
159       VerifyFencepost(&buf_align[-FENCEPOST_LENGTH]);
160       VerifyFencepost(&buf_align[len]);
161     }
162   }
163   delete expected_buf;
164   delete buf;
165 }
166 
TEST(libcutils,android_memset16_non_zero)167 TEST(libcutils, android_memset16_non_zero) {
168   RunMemsetTests(MEMSET16, MEMSET16_PATTERN, g_memset16_aligns, sizeof(g_memset16_aligns)/sizeof(int[2]));
169 }
170 
TEST(libcutils,android_memset16_zero)171 TEST(libcutils, android_memset16_zero) {
172   RunMemsetTests(MEMSET16, 0, g_memset16_aligns, sizeof(g_memset16_aligns)/sizeof(int[2]));
173 }
174 
TEST(libcutils,android_memset32_non_zero)175 TEST(libcutils, android_memset32_non_zero) {
176   RunMemsetTests(MEMSET32, MEMSET32_PATTERN, g_memset32_aligns, sizeof(g_memset32_aligns)/sizeof(int[2]));
177 }
178 
TEST(libcutils,android_memset32_zero)179 TEST(libcutils, android_memset32_zero) {
180   RunMemsetTests(MEMSET32, 0, g_memset32_aligns, sizeof(g_memset32_aligns)/sizeof(int[2]));
181 }
182