blob: ae114d8f74416b9ace72d2b6273690b00cd65fef [file] [log] [blame]
// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#include "vm/bitmap.h"
#include "platform/assert.h"
#include "vm/object.h"
namespace dart {
void BitmapBuilder::SetLength(intptr_t new_length) {
// When this function is used to shorten the length, affected bits in the
// backing store need to be cleared because the implementation assumes it.
if (new_length < length_) {
// Byte offset containing the first bit to be cleared.
intptr_t byte_offset = new_length >> kBitsPerByteLog2;
if (byte_offset < data_size_in_bytes_) {
// First bit index (in the byte) to be cleared.
intptr_t bit_index = new_length & (kBitsPerByte - 1);
intptr_t mask = (1 << bit_index) - 1;
data_[byte_offset] &= mask;
// Clear the rest.
++byte_offset;
if (byte_offset < data_size_in_bytes_) {
memset(&data_[byte_offset], 0, data_size_in_bytes_ - byte_offset);
}
}
}
length_ = new_length;
}
bool BitmapBuilder::Get(intptr_t bit_offset) const {
ASSERT(InRange(bit_offset));
intptr_t byte_offset = bit_offset >> kBitsPerByteLog2;
// Bits not covered by the backing store are implicitly false.
return (byte_offset < data_size_in_bytes_) && GetBit(bit_offset);
}
void BitmapBuilder::Set(intptr_t bit_offset, bool value) {
ASSERT(bit_offset >= 0);
if (!InRange(bit_offset)) {
length_ = bit_offset + 1;
// Bits not covered by the backing store are implicitly false.
if (!value) return;
// Grow the backing store if necessary.
intptr_t byte_offset = bit_offset >> kBitsPerByteLog2;
if (byte_offset >= data_size_in_bytes_) {
uint8_t* old_data = data_;
intptr_t old_size = data_size_in_bytes_;
data_size_in_bytes_ =
Utils::RoundUp(byte_offset + 1, kIncrementSizeInBytes);
ASSERT(data_size_in_bytes_ > 0);
data_ = Isolate::Current()->current_zone()->Alloc<uint8_t>(
data_size_in_bytes_);
ASSERT(data_ != NULL);
memmove(data_, old_data, old_size);
memset(&data_[old_size], 0, (data_size_in_bytes_ - old_size));
}
}
SetBit(bit_offset, value);
}
void BitmapBuilder::SetRange(intptr_t min, intptr_t max, bool value) {
for (intptr_t i = min; i <= max; i++) {
Set(i, value);
}
}
bool BitmapBuilder::GetBit(intptr_t bit_offset) const {
ASSERT(InRange(bit_offset));
intptr_t byte_offset = bit_offset >> kBitsPerByteLog2;
ASSERT(byte_offset < data_size_in_bytes_);
intptr_t bit_remainder = bit_offset & (kBitsPerByte - 1);
uint8_t mask = 1U << bit_remainder;
ASSERT(data_ != NULL);
return ((data_[byte_offset] & mask) != 0);
}
void BitmapBuilder::SetBit(intptr_t bit_offset, bool value) {
ASSERT(InRange(bit_offset));
int byte_offset = bit_offset >> kBitsPerByteLog2;
ASSERT(byte_offset < data_size_in_bytes_);
int bit_remainder = bit_offset & (kBitsPerByte - 1);
uint8_t mask = 1U << bit_remainder;
ASSERT(data_ != NULL);
if (value) {
data_[byte_offset] |= mask;
} else {
data_[byte_offset] &= ~mask;
}
}
} // namespace dart