blob: 862ff736396d5f3250584ff1a41ab1182e544598 [file] [log] [blame]
/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "memory_region.h"
#include <stdint.h>
#include <string.h>
namespace art {
void MemoryRegion::CopyFrom(size_t offset, const MemoryRegion& from) const {
CHECK(from.pointer() != nullptr);
CHECK_GT(from.size(), 0U);
CHECK_GE(this->size(), from.size());
CHECK_LE(offset, this->size() - from.size());
memmove(reinterpret_cast<void*>(begin() + offset), from.pointer(), from.size());
}
void MemoryRegion::StoreBits(uintptr_t bit_offset, uint32_t value, size_t length) {
DCHECK_LE(value, MaxInt<uint32_t>(length));
DCHECK_LE(length, BitSizeOf<uint32_t>());
DCHECK_LE(bit_offset + length, size_in_bits());
if (length == 0) {
return;
}
// Bits are stored in this order {7 6 5 4 3 2 1 0}.
// How many remaining bits in current byte is (bit_offset % kBitsPerByte) + 1.
uint8_t* out = ComputeInternalPointer<uint8_t>(bit_offset >> kBitsPerByteLog2);
size_t orig_len = length;
uint32_t orig_value = value;
uintptr_t bit_remainder = bit_offset % kBitsPerByte;
while (true) {
const uintptr_t remaining_bits = kBitsPerByte - bit_remainder;
if (length <= remaining_bits) {
// Length is smaller than all of remainder bits.
size_t mask = ((1 << length) - 1) << bit_remainder;
*out = (*out & ~mask) | (value << bit_remainder);
break;
}
// Copy remaining bits in current byte.
size_t value_mask = (1 << remaining_bits) - 1;
*out = (*out & ~(value_mask << bit_remainder)) | ((value & value_mask) << bit_remainder);
value >>= remaining_bits;
bit_remainder = 0;
length -= remaining_bits;
++out;
}
DCHECK_EQ(LoadBits(bit_offset, orig_len), orig_value) << bit_offset << " " << orig_len;
}
} // namespace art