1/*
2 * Copyright (C) 2007 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#define LOG_TAG "Memory"
18
19#include "JNIHelp.h"
20#include "JniConstants.h"
21#include "nativehelper/jni_macros.h"
22#include "Portability.h"
23#include "ScopedBytes.h"
24#include "ScopedPrimitiveArray.h"
25
26#include <errno.h>
27#include <stdlib.h>
28#include <string.h>
29#include <sys/mman.h>
30
31// Use packed structures for access to unaligned data on targets with alignment restrictions.
32// The compiler will generate appropriate code to access these structures without
33// generating alignment exceptions.
34template <typename T> static inline T get_unaligned(const T* address) {
35    struct unaligned { T v; } __attribute__ ((packed));
36    const unaligned* p = reinterpret_cast<const unaligned*>(address);
37    return p->v;
38}
39
40template <typename T> static inline void put_unaligned(T* address, T v) {
41    struct unaligned { T v; } __attribute__ ((packed));
42    unaligned* p = reinterpret_cast<unaligned*>(address);
43    p->v = v;
44}
45
46template <typename T> static T cast(jlong address) {
47    return reinterpret_cast<T>(static_cast<uintptr_t>(address));
48}
49
50// Byte-swap 2 jshort values packed in a jint.
51static inline jint bswap_2x16(jint v) {
52    // v is initially ABCD
53#if defined(__mips__) && defined(__mips_isa_rev) && (__mips_isa_rev >= 2)
54    __asm__ volatile ("wsbh %0, %0" : "+r" (v));  // v=BADC
55#else
56    v = bswap_32(v);                              // v=DCBA
57    v = (v << 16) | ((v >> 16) & 0xffff);         // v=BADC
58#endif
59    return v;
60}
61
62static inline void swapShorts(jshort* dstShorts, const jshort* srcShorts, size_t count) {
63    // Do 32-bit swaps as long as possible...
64    jint* dst = reinterpret_cast<jint*>(dstShorts);
65    const jint* src = reinterpret_cast<const jint*>(srcShorts);
66    for (size_t i = 0; i < count / 2; ++i) {
67        jint v = get_unaligned<jint>(src++);
68        put_unaligned<jint>(dst++, bswap_2x16(v));
69    }
70    if ((count % 2) != 0) {
71      jshort v = get_unaligned<jshort>(reinterpret_cast<const jshort*>(src));
72      put_unaligned<jshort>(reinterpret_cast<jshort*>(dst), bswap_16(v));
73    }
74}
75
76static inline void swapInts(jint* dstInts, const jint* srcInts, size_t count) {
77    for (size_t i = 0; i < count; ++i) {
78        jint v = get_unaligned<int>(srcInts++);
79        put_unaligned<jint>(dstInts++, bswap_32(v));
80    }
81}
82
83static inline void swapLongs(jlong* dstLongs, const jlong* srcLongs, size_t count) {
84    jint* dst = reinterpret_cast<jint*>(dstLongs);
85    const jint* src = reinterpret_cast<const jint*>(srcLongs);
86    for (size_t i = 0; i < count; ++i) {
87        jint v1 = get_unaligned<jint>(src++);
88        jint v2 = get_unaligned<jint>(src++);
89        put_unaligned<jint>(dst++, bswap_32(v2));
90        put_unaligned<jint>(dst++, bswap_32(v1));
91    }
92}
93
94static void Memory_memmove(JNIEnv* env, jclass, jobject dstObject, jint dstOffset, jobject srcObject, jint srcOffset, jlong length) {
95    ScopedBytesRW dstBytes(env, dstObject);
96    if (dstBytes.get() == NULL) {
97        return;
98    }
99    ScopedBytesRO srcBytes(env, srcObject);
100    if (srcBytes.get() == NULL) {
101        return;
102    }
103    memmove(dstBytes.get() + dstOffset, srcBytes.get() + srcOffset, length);
104}
105
106static jbyte Memory_peekByte(JNIEnv*, jclass, jlong srcAddress) {
107    return *cast<const jbyte*>(srcAddress);
108}
109
110static void Memory_peekByteArray(JNIEnv* env, jclass, jlong srcAddress, jbyteArray dst, jint dstOffset, jint byteCount) {
111    env->SetByteArrayRegion(dst, dstOffset, byteCount, cast<const jbyte*>(srcAddress));
112}
113
114// Implements the peekXArray methods:
115// - For unswapped access, we just use the JNI SetXArrayRegion functions.
116// - For swapped access, we use GetXArrayElements and our own copy-and-swap routines.
117//   GetXArrayElements is disproportionately cheap on Dalvik because it doesn't copy (as opposed
118//   to Hotspot, which always copies). The SWAP_FN copies and swaps in one pass, which is cheaper
119//   than copying and then swapping in a second pass. Depending on future VM/GC changes, the
120//   swapped case might need to be revisited.
121#define PEEKER(SCALAR_TYPE, JNI_NAME, SWAP_TYPE, SWAP_FN) { \
122    if (swap) { \
123        Scoped ## JNI_NAME ## ArrayRW elements(env, dst); \
124        if (elements.get() == NULL) { \
125            return; \
126        } \
127        const SWAP_TYPE* src = cast<const SWAP_TYPE*>(srcAddress); \
128        SWAP_FN(reinterpret_cast<SWAP_TYPE*>(elements.get()) + dstOffset, src, count); /*NOLINT*/ \
129    } else { \
130        const SCALAR_TYPE* src = cast<const SCALAR_TYPE*>(srcAddress); \
131        env->Set ## JNI_NAME ## ArrayRegion(dst, dstOffset, count, src); \
132    } \
133}
134
135static void Memory_peekCharArray(JNIEnv* env, jclass, jlong srcAddress, jcharArray dst, jint dstOffset, jint count, jboolean swap) {
136    PEEKER(jchar, Char, jshort, swapShorts);
137}
138
139static void Memory_peekDoubleArray(JNIEnv* env, jclass, jlong srcAddress, jdoubleArray dst, jint dstOffset, jint count, jboolean swap) {
140    PEEKER(jdouble, Double, jlong, swapLongs);
141}
142
143static void Memory_peekFloatArray(JNIEnv* env, jclass, jlong srcAddress, jfloatArray dst, jint dstOffset, jint count, jboolean swap) {
144    PEEKER(jfloat, Float, jint, swapInts);
145}
146
147static void Memory_peekIntArray(JNIEnv* env, jclass, jlong srcAddress, jintArray dst, jint dstOffset, jint count, jboolean swap) {
148    PEEKER(jint, Int, jint, swapInts);
149}
150
151static void Memory_peekLongArray(JNIEnv* env, jclass, jlong srcAddress, jlongArray dst, jint dstOffset, jint count, jboolean swap) {
152    PEEKER(jlong, Long, jlong, swapLongs);
153}
154
155static void Memory_peekShortArray(JNIEnv* env, jclass, jlong srcAddress, jshortArray dst, jint dstOffset, jint count, jboolean swap) {
156    PEEKER(jshort, Short, jshort, swapShorts);
157}
158
159static void Memory_pokeByte(JNIEnv*, jclass, jlong dstAddress, jbyte value) {
160    *cast<jbyte*>(dstAddress) = value;
161}
162
163static void Memory_pokeByteArray(JNIEnv* env, jclass, jlong dstAddress, jbyteArray src, jint offset, jint length) {
164    env->GetByteArrayRegion(src, offset, length, cast<jbyte*>(dstAddress));
165}
166
167// Implements the pokeXArray methods:
168// - For unswapped access, we just use the JNI GetXArrayRegion functions.
169// - For swapped access, we use GetXArrayElements and our own copy-and-swap routines.
170//   GetXArrayElements is disproportionately cheap on Dalvik because it doesn't copy (as opposed
171//   to Hotspot, which always copies). The SWAP_FN copies and swaps in one pass, which is cheaper
172//   than copying and then swapping in a second pass. Depending on future VM/GC changes, the
173//   swapped case might need to be revisited.
174#define POKER(SCALAR_TYPE, JNI_NAME, SWAP_TYPE, SWAP_FN) { \
175    if (swap) { \
176        Scoped ## JNI_NAME ## ArrayRO elements(env, src); \
177        if (elements.get() == NULL) { \
178            return; \
179        } \
180        const SWAP_TYPE* src = reinterpret_cast<const SWAP_TYPE*>(elements.get()) + srcOffset; \
181        SWAP_FN(cast<SWAP_TYPE*>(dstAddress), src, count); /*NOLINT*/ \
182    } else { \
183        env->Get ## JNI_NAME ## ArrayRegion(src, srcOffset, count, cast<SCALAR_TYPE*>(dstAddress)); /*NOLINT*/ \
184    } \
185}
186
187static void Memory_pokeCharArray(JNIEnv* env, jclass, jlong dstAddress, jcharArray src, jint srcOffset, jint count, jboolean swap) {
188    POKER(jchar, Char, jshort, swapShorts);
189}
190
191static void Memory_pokeDoubleArray(JNIEnv* env, jclass, jlong dstAddress, jdoubleArray src, jint srcOffset, jint count, jboolean swap) {
192    POKER(jdouble, Double, jlong, swapLongs);
193}
194
195static void Memory_pokeFloatArray(JNIEnv* env, jclass, jlong dstAddress, jfloatArray src, jint srcOffset, jint count, jboolean swap) {
196    POKER(jfloat, Float, jint, swapInts);
197}
198
199static void Memory_pokeIntArray(JNIEnv* env, jclass, jlong dstAddress, jintArray src, jint srcOffset, jint count, jboolean swap) {
200    POKER(jint, Int, jint, swapInts);
201}
202
203static void Memory_pokeLongArray(JNIEnv* env, jclass, jlong dstAddress, jlongArray src, jint srcOffset, jint count, jboolean swap) {
204    POKER(jlong, Long, jlong, swapLongs);
205}
206
207static void Memory_pokeShortArray(JNIEnv* env, jclass, jlong dstAddress, jshortArray src, jint srcOffset, jint count, jboolean swap) {
208    POKER(jshort, Short, jshort, swapShorts);
209}
210
211static jshort Memory_peekShortNative(JNIEnv*, jclass, jlong srcAddress) {
212    return get_unaligned<jshort>(cast<const jshort*>(srcAddress));
213}
214
215static void Memory_pokeShortNative(JNIEnv*, jclass, jlong dstAddress, jshort value) {
216    put_unaligned<jshort>(cast<jshort*>(dstAddress), value);
217}
218
219static jint Memory_peekIntNative(JNIEnv*, jclass, jlong srcAddress) {
220    return get_unaligned<jint>(cast<const jint*>(srcAddress));
221}
222
223static void Memory_pokeIntNative(JNIEnv*, jclass, jlong dstAddress, jint value) {
224    put_unaligned<jint>(cast<jint*>(dstAddress), value);
225}
226
227static jlong Memory_peekLongNative(JNIEnv*, jclass, jlong srcAddress) {
228    return get_unaligned<jlong>(cast<const jlong*>(srcAddress));
229}
230
231static void Memory_pokeLongNative(JNIEnv*, jclass, jlong dstAddress, jlong value) {
232    put_unaligned<jlong>(cast<jlong*>(dstAddress), value);
233}
234
235static void unsafeBulkCopy(jbyte* dst, const jbyte* src, jint byteCount,
236        jint sizeofElement, jboolean swap) {
237    if (!swap) {
238        memcpy(dst, src, byteCount);
239        return;
240    }
241
242    if (sizeofElement == 2) {
243        jshort* dstShorts = reinterpret_cast<jshort*>(dst);
244        const jshort* srcShorts = reinterpret_cast<const jshort*>(src);
245        swapShorts(dstShorts, srcShorts, byteCount / 2);
246    } else if (sizeofElement == 4) {
247        jint* dstInts = reinterpret_cast<jint*>(dst);
248        const jint* srcInts = reinterpret_cast<const jint*>(src);
249        swapInts(dstInts, srcInts, byteCount / 4);
250    } else if (sizeofElement == 8) {
251        jlong* dstLongs = reinterpret_cast<jlong*>(dst);
252        const jlong* srcLongs = reinterpret_cast<const jlong*>(src);
253        swapLongs(dstLongs, srcLongs, byteCount / 8);
254    }
255}
256
257static void Memory_unsafeBulkGet(JNIEnv* env, jclass, jobject dstObject, jint dstOffset,
258        jint byteCount, jbyteArray srcArray, jint srcOffset, jint sizeofElement, jboolean swap) {
259    ScopedByteArrayRO srcBytes(env, srcArray);
260    if (srcBytes.get() == NULL) {
261        return;
262    }
263    jarray dstArray = reinterpret_cast<jarray>(dstObject);
264    jbyte* dstBytes = reinterpret_cast<jbyte*>(env->GetPrimitiveArrayCritical(dstArray, NULL));
265    if (dstBytes == NULL) {
266        return;
267    }
268    jbyte* dst = dstBytes + dstOffset*sizeofElement;
269    const jbyte* src = srcBytes.get() + srcOffset;
270    unsafeBulkCopy(dst, src, byteCount, sizeofElement, swap);
271    env->ReleasePrimitiveArrayCritical(dstArray, dstBytes, 0);
272}
273
274static void Memory_unsafeBulkPut(JNIEnv* env, jclass, jbyteArray dstArray, jint dstOffset,
275        jint byteCount, jobject srcObject, jint srcOffset, jint sizeofElement, jboolean swap) {
276    ScopedByteArrayRW dstBytes(env, dstArray);
277    if (dstBytes.get() == NULL) {
278        return;
279    }
280    jarray srcArray = reinterpret_cast<jarray>(srcObject);
281    jbyte* srcBytes = reinterpret_cast<jbyte*>(env->GetPrimitiveArrayCritical(srcArray, NULL));
282    if (srcBytes == NULL) {
283        return;
284    }
285    jbyte* dst = dstBytes.get() + dstOffset;
286    const jbyte* src = srcBytes + srcOffset*sizeofElement;
287    unsafeBulkCopy(dst, src, byteCount, sizeofElement, swap);
288    env->ReleasePrimitiveArrayCritical(srcArray, srcBytes, 0);
289}
290
291static JNINativeMethod gMethods[] = {
292    NATIVE_METHOD(Memory, memmove, "(Ljava/lang/Object;ILjava/lang/Object;IJ)V"),
293    FAST_NATIVE_METHOD(Memory, peekByte, "(J)B"),
294    NATIVE_METHOD(Memory, peekByteArray, "(J[BII)V"),
295    NATIVE_METHOD(Memory, peekCharArray, "(J[CIIZ)V"),
296    NATIVE_METHOD(Memory, peekDoubleArray, "(J[DIIZ)V"),
297    NATIVE_METHOD(Memory, peekFloatArray, "(J[FIIZ)V"),
298    FAST_NATIVE_METHOD(Memory, peekIntNative, "(J)I"),
299    NATIVE_METHOD(Memory, peekIntArray, "(J[IIIZ)V"),
300    FAST_NATIVE_METHOD(Memory, peekLongNative, "(J)J"),
301    NATIVE_METHOD(Memory, peekLongArray, "(J[JIIZ)V"),
302    FAST_NATIVE_METHOD(Memory, peekShortNative, "(J)S"),
303    NATIVE_METHOD(Memory, peekShortArray, "(J[SIIZ)V"),
304    FAST_NATIVE_METHOD(Memory, pokeByte, "(JB)V"),
305    NATIVE_METHOD(Memory, pokeByteArray, "(J[BII)V"),
306    NATIVE_METHOD(Memory, pokeCharArray, "(J[CIIZ)V"),
307    NATIVE_METHOD(Memory, pokeDoubleArray, "(J[DIIZ)V"),
308    NATIVE_METHOD(Memory, pokeFloatArray, "(J[FIIZ)V"),
309    FAST_NATIVE_METHOD(Memory, pokeIntNative, "(JI)V"),
310    NATIVE_METHOD(Memory, pokeIntArray, "(J[IIIZ)V"),
311    FAST_NATIVE_METHOD(Memory, pokeLongNative, "(JJ)V"),
312    NATIVE_METHOD(Memory, pokeLongArray, "(J[JIIZ)V"),
313    FAST_NATIVE_METHOD(Memory, pokeShortNative, "(JS)V"),
314    NATIVE_METHOD(Memory, pokeShortArray, "(J[SIIZ)V"),
315    NATIVE_METHOD(Memory, unsafeBulkGet, "(Ljava/lang/Object;II[BIIZ)V"),
316    NATIVE_METHOD(Memory, unsafeBulkPut, "([BIILjava/lang/Object;IIZ)V"),
317};
318void register_libcore_io_Memory(JNIEnv* env) {
319    jniRegisterNativeMethods(env, "libcore/io/Memory", gMethods, NELEM(gMethods));
320}
321