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