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// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you 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.
/** @ignore */
export function getBool(_data, _index, byte, bit) {
return (byte & 1 << bit) !== 0;
}
/** @ignore */
export function getBit(_data, _index, byte, bit) {
return (byte & 1 << bit) >> bit;
}
/** @ignore */
export function setBool(bytes, index, value) {
return value ?
!!(bytes[index >> 3] |= (1 << (index % 8))) || true :
!(bytes[index >> 3] &= ~(1 << (index % 8))) && false;
}
/** @ignore */
export function truncateBitmap(offset, length, bitmap) {
const alignedSize = (bitmap.byteLength + 7) & ~7;
if (offset > 0 || bitmap.byteLength < alignedSize) {
const bytes = new Uint8Array(alignedSize);
// If the offset is a multiple of 8 bits, it's safe to slice the bitmap
bytes.set(offset % 8 === 0 ? bitmap.subarray(offset >> 3) :
// Otherwise iterate each bit from the offset and return a new one
packBools(iterateBits(bitmap, offset, length, null, getBool)).subarray(0, alignedSize));
return bytes;
}
return bitmap;
}
/** @ignore */
export function packBools(values) {
let xs = [];
let i = 0, bit = 0, byte = 0;
for (const value of values) {
value && (byte |= 1 << bit);
if (++bit === 8) {
xs[i++] = byte;
byte = bit = 0;
}
}
if (i === 0 || bit > 0) {
xs[i++] = byte;
}
let b = new Uint8Array((xs.length + 7) & ~7);
b.set(xs);
return b;
}
/** @ignore */
export function* iterateBits(bytes, begin, length, context, get) {
let bit = begin % 8;
let byteIndex = begin >> 3;
let index = 0, remaining = length;
for (; remaining > 0; bit = 0) {
let byte = bytes[byteIndex++];
do {
yield get(context, index++, byte, bit);
} while (--remaining > 0 && ++bit < 8);
}
}
/**
* Compute the population count (the number of bits set to 1) for a range of bits in a Uint8Array.
* @param vector The Uint8Array of bits for which to compute the population count.
* @param lhs The range's left-hand side (or start) bit
* @param rhs The range's right-hand side (or end) bit
*/
/** @ignore */
export function popcnt_bit_range(data, lhs, rhs) {
if (rhs - lhs <= 0) {
return 0;
}
// If the bit range is less than one byte, sum the 1 bits in the bit range
if (rhs - lhs < 8) {
let sum = 0;
for (const bit of iterateBits(data, lhs, rhs - lhs, data, getBit)) {
sum += bit;
}
return sum;
}
// Get the next lowest multiple of 8 from the right hand side
const rhsInside = rhs >> 3 << 3;
// Get the next highest multiple of 8 from the left hand side
const lhsInside = lhs + (lhs % 8 === 0 ? 0 : 8 - lhs % 8);
return (
// Get the popcnt of bits between the left hand side, and the next highest multiple of 8
popcnt_bit_range(data, lhs, lhsInside) +
// Get the popcnt of bits between the right hand side, and the next lowest multiple of 8
popcnt_bit_range(data, rhsInside, rhs) +
// Get the popcnt of all bits between the left and right hand sides' multiples of 8
popcnt_array(data, lhsInside >> 3, (rhsInside - lhsInside) >> 3));
}
/** @ignore */
export function popcnt_array(arr, byteOffset, byteLength) {
let cnt = 0, pos = byteOffset | 0;
const view = new DataView(arr.buffer, arr.byteOffset, arr.byteLength);
const len = byteLength === void 0 ? arr.byteLength : pos + byteLength;
while (len - pos >= 4) {
cnt += popcnt_uint32(view.getUint32(pos));
pos += 4;
}
while (len - pos >= 2) {
cnt += popcnt_uint32(view.getUint16(pos));
pos += 2;
}
while (len - pos >= 1) {
cnt += popcnt_uint32(view.getUint8(pos));
pos += 1;
}
return cnt;
}
/** @ignore */
export function popcnt_uint32(uint32) {
let i = uint32 | 0;
i = i - ((i >>> 1) & 0x55555555);
i = (i & 0x33333333) + ((i >>> 2) & 0x33333333);
return (((i + (i >>> 4)) & 0x0F0F0F0F) * 0x01010101) >>> 24;
}
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