/*
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* Copyright 2012 ZXing authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#import "ZXBitArray.h"
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#import "ZXByteArray.h"
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#import "ZXIntArray.h"
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@interface ZXBitArray ()
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@property (nonatomic, assign) int32_t *bits;
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@property (nonatomic, assign) int bitsLength;
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@property (nonatomic, assign) int size;
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@end
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@implementation ZXBitArray
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- (id)init {
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if (self = [super init]) {
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_size = 0;
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_bits = (int32_t *)calloc(1, sizeof(int32_t));
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_bitsLength = 1;
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}
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return self;
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}
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// For testing only
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- (id)initWithBits:(ZXIntArray *)bits size:(int)size {
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if (self = [self initWithSize:size]) {
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_bits = bits.array;
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_bits = (int32_t *)malloc(bits.length * sizeof(int32_t));
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memcpy(_bits, bits.array, bits.length * sizeof(int32_t));
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_bitsLength = bits.length;
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}
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return self;
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}
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- (id)initWithSize:(int)size {
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if (self = [super init]) {
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_size = size;
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_bitsLength = (size + 31) / 32;
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_bits = (int32_t *)calloc(_bitsLength, sizeof(int32_t));
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}
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return self;
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}
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- (void)dealloc {
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if (_bits != NULL) {
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free(_bits);
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_bits = NULL;
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}
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}
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- (int)sizeInBytes {
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return (self.size + 7) / 8;
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}
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- (void)ensureCapacity:(int)size {
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if (size > self.bitsLength * 32) {
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int newBitsLength = (size + 31) / 32;
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self.bits = realloc(self.bits, newBitsLength * sizeof(int32_t));
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memset(self.bits + self.bitsLength, 0, (newBitsLength - self.bitsLength) * sizeof(int32_t));
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self.bitsLength = newBitsLength;
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}
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}
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- (BOOL)get:(int)i {
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return (_bits[i / 32] & (1 << (i & 0x1F))) != 0;
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}
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- (void)set:(int)i {
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_bits[i / 32] |= 1 << (i & 0x1F);
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}
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- (void)flip:(int)i {
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_bits[i / 32] ^= 1 << (i & 0x1F);
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}
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- (int)nextSet:(int)from {
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if (from >= self.size) {
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return self.size;
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}
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int bitsOffset = from / 32;
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int32_t currentBits = self.bits[bitsOffset];
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// mask off lesser bits first
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currentBits &= ~((1 << (from & 0x1F)) - 1);
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while (currentBits == 0) {
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if (++bitsOffset == self.bitsLength) {
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return self.size;
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}
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currentBits = self.bits[bitsOffset];
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}
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int result = (bitsOffset * 32) + [self numberOfTrailingZeros:currentBits];
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return result > self.size ? self.size : result;
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}
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- (int)nextUnset:(int)from {
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if (from >= self.size) {
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return self.size;
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}
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int bitsOffset = from / 32;
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int32_t currentBits = ~self.bits[bitsOffset];
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// mask off lesser bits first
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currentBits &= ~((1 << (from & 0x1F)) - 1);
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while (currentBits == 0) {
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if (++bitsOffset == self.bitsLength) {
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return self.size;
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}
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currentBits = ~self.bits[bitsOffset];
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}
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int result = (bitsOffset * 32) + [self numberOfTrailingZeros:currentBits];
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return result > self.size ? self.size : result;
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}
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- (void)setBulk:(int)i newBits:(int32_t)newBits {
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_bits[i / 32] = newBits;
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}
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- (void)setRange:(int)start end:(int)end {
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if (end < start) {
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@throw [NSException exceptionWithName:NSInvalidArgumentException reason:@"Start greater than end" userInfo:nil];
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}
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if (end == start) {
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return;
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}
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end--; // will be easier to treat this as the last actually set bit -- inclusive
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int firstInt = start / 32;
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int lastInt = end / 32;
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for (int i = firstInt; i <= lastInt; i++) {
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int firstBit = i > firstInt ? 0 : start & 0x1F;
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int lastBit = i < lastInt ? 31 : end & 0x1F;
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int32_t mask;
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if (lastBit > 31) {
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@throw [NSException exceptionWithName:NSInvalidArgumentException reason:@"Bit-shift operand does not support more than 31 bits" userInfo:nil];
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}
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if (firstBit == 0 && lastBit == 31) {
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mask = -1;
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} else {
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mask = 0;
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for (int j = firstBit; j <= lastBit; j++) {
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mask |= 1 << j;
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}
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}
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_bits[i] |= mask;
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}
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}
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- (void)clear {
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memset(self.bits, 0, self.bitsLength * sizeof(int32_t));
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}
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- (BOOL)isRange:(int)start end:(int)end value:(BOOL)value {
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if (end < start) {
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@throw [NSException exceptionWithName:NSInvalidArgumentException reason:@"Start greater than end" userInfo:nil];
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}
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if (end == start) {
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return YES; // empty range matches
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}
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end--; // will be easier to treat this as the last actually set bit -- inclusive
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int firstInt = start / 32;
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int lastInt = end / 32;
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for (int i = firstInt; i <= lastInt; i++) {
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int firstBit = i > firstInt ? 0 : start & 0x1F;
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int lastBit = i < lastInt ? 31 : end & 0x1F;
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int32_t mask;
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if (lastBit > 31) {
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@throw [NSException exceptionWithName:NSInvalidArgumentException reason:@"Bit-shift operand does not support more than 31 bits" userInfo:nil];
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}
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if (firstBit == 0 && lastBit == 31) {
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mask = -1;
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} else {
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mask = 0;
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for (int j = firstBit; j <= lastBit; j++) {
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mask |= 1 << j;
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}
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}
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// Return false if we're looking for 1s and the masked bits[i] isn't all 1s (that is,
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// equals the mask, or we're looking for 0s and the masked portion is not all 0s
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if ((_bits[i] & mask) != (value ? mask : 0)) {
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return NO;
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}
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}
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return YES;
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}
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- (void)appendBit:(BOOL)bit {
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[self ensureCapacity:self.size + 1];
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if (bit) {
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self.bits[self.size / 32] |= 1 << (self.size & 0x1F);
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}
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self.size++;
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}
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- (void)appendBits:(int32_t)value numBits:(int)numBits {
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if (numBits < 0 || numBits > 32) {
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@throw [NSException exceptionWithName:NSInvalidArgumentException
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reason:@"Num bits must be between 0 and 32"
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userInfo:nil];
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}
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[self ensureCapacity:self.size + numBits];
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for (int numBitsLeft = numBits; numBitsLeft > 0; numBitsLeft--) {
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[self appendBit:((value >> (numBitsLeft - 1)) & 0x01) == 1];
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}
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}
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- (void)appendBitArray:(ZXBitArray *)other {
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int otherSize = [other size];
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[self ensureCapacity:self.size + otherSize];
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for (int i = 0; i < otherSize; i++) {
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[self appendBit:[other get:i]];
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}
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}
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- (void)xor:(ZXBitArray *)other {
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if (self.bitsLength != other.bitsLength) {
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@throw [NSException exceptionWithName:NSInvalidArgumentException
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reason:@"Sizes don't match"
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userInfo:nil];
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}
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for (int i = 0; i < self.bitsLength; i++) {
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// The last byte could be incomplete (i.e. not have 8 bits in
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// it) but there is no problem since 0 XOR 0 == 0.
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self.bits[i] ^= other.bits[i];
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}
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}
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- (void)toBytes:(int)bitOffset array:(ZXByteArray *)array offset:(int)offset numBytes:(int)numBytes {
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for (int i = 0; i < numBytes; i++) {
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int32_t theByte = 0;
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for (int j = 0; j < 8; j++) {
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if ([self get:bitOffset]) {
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theByte |= 1 << (7 - j);
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}
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bitOffset++;
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}
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array.array[offset + i] = (int8_t) theByte;
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}
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}
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- (ZXIntArray *)bitArray {
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ZXIntArray *array = [[ZXIntArray alloc] initWithLength:self.bitsLength];
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memcpy(array.array, self.bits, array.length * sizeof(int32_t));
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return array;
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}
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- (BOOL)isEqual:(id)o {
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if (![o isKindOfClass:[ZXBitArray class]]) {
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return NO;
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}
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ZXBitArray *other = (ZXBitArray *)o;
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return self.size == other.size && memcmp(self.bits, other.bits, self.bitsLength) != 0;
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}
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- (NSUInteger)hash {
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return 31 * self.size;
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}
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- (void)reverse {
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int32_t *newBits = (int32_t *)calloc(self.bitsLength, sizeof(int32_t));
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int size = self.size;
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// reverse all int's first
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int len = ((size-1) / 32);
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int oldBitsLen = len + 1;
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for (int i = 0; i < oldBitsLen; i++) {
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long x = (long) self.bits[i];
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x = ((x >> 1) & 0x55555555L) | ((x & 0x55555555L) << 1);
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x = ((x >> 2) & 0x33333333L) | ((x & 0x33333333L) << 2);
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x = ((x >> 4) & 0x0f0f0f0fL) | ((x & 0x0f0f0f0fL) << 4);
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x = ((x >> 8) & 0x00ff00ffL) | ((x & 0x00ff00ffL) << 8);
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x = ((x >> 16) & 0x0000ffffL) | ((x & 0x0000ffffL) << 16);
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newBits[len - i] = (int32_t) x;
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}
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// now correct the int's if the bit size isn't a multiple of 32
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if (size != oldBitsLen * 32) {
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int leftOffset = oldBitsLen * 32 - size;
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int mask = 1;
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for (int i = 0; i < 31 - leftOffset; i++) {
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mask = (mask << 1) | 1;
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}
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int32_t currentInt = (newBits[0] >> leftOffset) & mask;
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for (int i = 1; i < oldBitsLen; i++) {
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int32_t nextInt = newBits[i];
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currentInt |= nextInt << (32 - leftOffset);
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newBits[i - 1] = currentInt;
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currentInt = (nextInt >> leftOffset) & mask;
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}
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newBits[oldBitsLen - 1] = currentInt;
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}
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if (self.bits != NULL) {
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free(self.bits);
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}
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self.bits = newBits;
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}
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- (NSString *)description {
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NSMutableString *result = [NSMutableString string];
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for (int i = 0; i < self.size; i++) {
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if ((i & 0x07) == 0) {
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[result appendString:@" "];
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}
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[result appendString:[self get:i] ? @"X" : @"."];
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}
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return result;
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}
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// Ported from OpenJDK Integer.numberOfTrailingZeros implementation
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- (int32_t)numberOfTrailingZeros:(int32_t)i {
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int32_t y;
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if (i == 0) return 32;
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int32_t n = 31;
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y = i <<16; if (y != 0) { n = n -16; i = y; }
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y = i << 8; if (y != 0) { n = n - 8; i = y; }
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y = i << 4; if (y != 0) { n = n - 4; i = y; }
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y = i << 2; if (y != 0) { n = n - 2; i = y; }
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return n - (int32_t)((uint32_t)(i << 1) >> 31);
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}
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- (id)copyWithZone:(NSZone *)zone {
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ZXBitArray *copy = [[ZXBitArray allocWithZone:zone] initWithSize:self.size];
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memcpy(copy.bits, self.bits, self.size * sizeof(int32_t));
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return copy;
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}
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@end
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