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. 33 template <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 39 template <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 45 template <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. 50 static 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 61 static 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 75 static 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 82 static 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 93 static 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 } 104 105 static jbyte Memory_peekByte(JNIEnv*, jclass, jlong srcAddress) { 106 return *cast<const jbyte*>(srcAddress); 107 } 108 109 static 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 } 133 134 static void Memory_peekCharArray(JNIEnv* env, jclass, jlong srcAddress, jcharArray dst, jint dstOffset, jint count, jboolean swap) { 135 PEEKER(jchar, Char, jshort, swapShorts); 136 } 137 138 static void Memory_peekDoubleArray(JNIEnv* env, jclass, jlong srcAddress, jdoubleArray dst, jint dstOffset, jint count, jboolean swap) { 139 PEEKER(jdouble, Double, jlong, swapLongs); 140 } 141 142 static void Memory_peekFloatArray(JNIEnv* env, jclass, jlong srcAddress, jfloatArray dst, jint dstOffset, jint count, jboolean swap) { 143 PEEKER(jfloat, Float, jint, swapInts); 144 } 145 146 static void Memory_peekIntArray(JNIEnv* env, jclass, jlong srcAddress, jintArray dst, jint dstOffset, jint count, jboolean swap) { 147 PEEKER(jint, Int, jint, swapInts); 148 } 149 150 static void Memory_peekLongArray(JNIEnv* env, jclass, jlong srcAddress, jlongArray dst, jint dstOffset, jint count, jboolean swap) { 151 PEEKER(jlong, Long, jlong, swapLongs); 152 } 153 154 static void Memory_peekShortArray(JNIEnv* env, jclass, jlong srcAddress, jshortArray dst, jint dstOffset, jint count, jboolean swap) { 155 PEEKER(jshort, Short, jshort, swapShorts); 156 } 157 158 static void Memory_pokeByte(JNIEnv*, jclass, jlong dstAddress, jbyte value) { 159 *cast<jbyte*>(dstAddress) = value; 160 } 161 162 static 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 } 185 186 static void Memory_pokeCharArray(JNIEnv* env, jclass, jlong dstAddress, jcharArray src, jint srcOffset, jint count, jboolean swap) { 187 POKER(jchar, Char, jshort, swapShorts); 188 } 189 190 static void Memory_pokeDoubleArray(JNIEnv* env, jclass, jlong dstAddress, jdoubleArray src, jint srcOffset, jint count, jboolean swap) { 191 POKER(jdouble, Double, jlong, swapLongs); 192 } 193 194 static void Memory_pokeFloatArray(JNIEnv* env, jclass, jlong dstAddress, jfloatArray src, jint srcOffset, jint count, jboolean swap) { 195 POKER(jfloat, Float, jint, swapInts); 196 } 197 198 static void Memory_pokeIntArray(JNIEnv* env, jclass, jlong dstAddress, jintArray src, jint srcOffset, jint count, jboolean swap) { 199 POKER(jint, Int, jint, swapInts); 200 } 201 202 static void Memory_pokeLongArray(JNIEnv* env, jclass, jlong dstAddress, jlongArray src, jint srcOffset, jint count, jboolean swap) { 203 POKER(jlong, Long, jlong, swapLongs); 204 } 205 206 static void Memory_pokeShortArray(JNIEnv* env, jclass, jlong dstAddress, jshortArray src, jint srcOffset, jint count, jboolean swap) { 207 POKER(jshort, Short, jshort, swapShorts); 208 } 209 210 static jshort Memory_peekShortNative(JNIEnv*, jclass, jlong srcAddress) { 211 return get_unaligned<jshort>(cast<const jshort*>(srcAddress)); 212 } 213 214 static void Memory_pokeShortNative(JNIEnv*, jclass, jlong dstAddress, jshort value) { 215 put_unaligned<jshort>(cast<jshort*>(dstAddress), value); 216 } 217 218 static jint Memory_peekIntNative(JNIEnv*, jclass, jlong srcAddress) { 219 return get_unaligned<jint>(cast<const jint*>(srcAddress)); 220 } 221 222 static void Memory_pokeIntNative(JNIEnv*, jclass, jlong dstAddress, jint value) { 223 put_unaligned<jint>(cast<jint*>(dstAddress), value); 224 } 225 226 static jlong Memory_peekLongNative(JNIEnv*, jclass, jlong srcAddress) { 227 return get_unaligned<jlong>(cast<const jlong*>(srcAddress)); 228 } 229 230 static void Memory_pokeLongNative(JNIEnv*, jclass, jlong dstAddress, jlong value) { 231 put_unaligned<jlong>(cast<jlong*>(dstAddress), value); 232 } 233 234 static 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 } 255 256 static 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 } 272 273 static 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 } 289 290 static 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 }; 317 void register_libcore_io_Memory(JNIEnv* env) { 318 jniRegisterNativeMethods(env, "libcore/io/Memory", gMethods, NELEM(gMethods)); 319 } 320
