/*
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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 "ZXGenericGF.h"
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#import "ZXGenericGFPoly.h"
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#import "ZXIntArray.h"
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@interface ZXGenericGF ()
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@property (nonatomic, assign, readonly) int32_t *expTable;
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@property (nonatomic, assign, readonly) int32_t *logTable;
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@property (nonatomic, assign, readonly) int primitive;
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@end
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@implementation ZXGenericGF {
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ZXGenericGFPoly *_one;
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ZXGenericGFPoly *_zero;
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}
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- (id)initWithPrimitive:(int)primitive size:(int)size b:(int)b {
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if (self = [super init]) {
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_primitive = primitive;
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_size = size;
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_generatorBase = b;
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_expTable = (int32_t *)calloc(self.size, sizeof(int32_t));
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_logTable = (int32_t *)calloc(self.size, sizeof(int32_t));
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int32_t x = 1;
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for (int i = 0; i < self.size; i++) {
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_expTable[i] = x;
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x <<= 1; // we're assuming the generator alpha is 2
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if (x >= self.size) {
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x ^= (int32_t)self.primitive;
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x &= (int32_t)self.size - 1;
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}
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}
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for (int32_t i = 0; i < (int32_t)self.size-1; i++) {
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_logTable[_expTable[i]] = i;
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}
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// logTable[0] == 0 but this should never be used
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_zero = [[ZXGenericGFPoly alloc] initWithField:self coefficients:[[ZXIntArray alloc] initWithLength:1]];
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_one = [[ZXGenericGFPoly alloc] initWithField:self coefficients:[[ZXIntArray alloc] initWithInts:1, -1]];
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}
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return self;
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}
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+ (ZXGenericGF *)AztecData12 {
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static ZXGenericGF *AztecData12 = nil;
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static dispatch_once_t onceToken;
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dispatch_once(&onceToken, ^{
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AztecData12 = [[ZXGenericGF alloc] initWithPrimitive:0x1069 size:4096 b:1]; // x^12 + x^6 + x^5 + x^3 + 1
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});
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return AztecData12;
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}
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+ (ZXGenericGF *)AztecData10 {
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static ZXGenericGF *AztecData10 = nil;
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static dispatch_once_t onceToken;
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dispatch_once(&onceToken, ^{
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AztecData10 = [[ZXGenericGF alloc] initWithPrimitive:0x409 size:1024 b:1]; // x^10 + x^3 + 1
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});
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return AztecData10;
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}
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+ (ZXGenericGF *)AztecData6 {
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static ZXGenericGF *AztecData6 = nil;
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static dispatch_once_t onceToken;
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dispatch_once(&onceToken, ^{
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AztecData6 = [[ZXGenericGF alloc] initWithPrimitive:0x43 size:64 b:1]; // x^6 + x + 1
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});
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return AztecData6;
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}
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+ (ZXGenericGF *)AztecParam {
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static ZXGenericGF *AztecParam = nil;
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static dispatch_once_t onceToken;
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dispatch_once(&onceToken, ^{
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AztecParam = [[ZXGenericGF alloc] initWithPrimitive:0x13 size:16 b:1]; // x^4 + x + 1
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});
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return AztecParam;
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}
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+ (ZXGenericGF *)QrCodeField256 {
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static ZXGenericGF *QrCodeField256 = nil;
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static dispatch_once_t onceToken;
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dispatch_once(&onceToken, ^{
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QrCodeField256 = [[ZXGenericGF alloc] initWithPrimitive:0x011D size:256 b:0]; // x^8 + x^4 + x^3 + x^2 + 1
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});
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return QrCodeField256;
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}
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+ (ZXGenericGF *)DataMatrixField256 {
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static ZXGenericGF *DataMatrixField256 = nil;
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static dispatch_once_t onceToken;
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dispatch_once(&onceToken, ^{
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DataMatrixField256 = [[ZXGenericGF alloc] initWithPrimitive:0x012D size:256 b:1]; // x^8 + x^5 + x^3 + x^2 + 1
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});
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return DataMatrixField256;
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}
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+ (ZXGenericGF *)AztecData8 {
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return [self DataMatrixField256];
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}
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+ (ZXGenericGF *)MaxiCodeField64 {
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return [self AztecData6];
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}
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- (ZXGenericGFPoly *)buildMonomial:(int)degree coefficient:(int32_t)coefficient {
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if (degree < 0) {
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[NSException raise:NSInvalidArgumentException format:@"Degree must be greater than 0."];
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}
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if (coefficient == 0) {
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return self.zero;
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}
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ZXIntArray *coefficients = [[ZXIntArray alloc] initWithLength:degree + 1];
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coefficients.array[0] = coefficient;
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return [[ZXGenericGFPoly alloc] initWithField:self coefficients:coefficients];
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}
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+ (int32_t)addOrSubtract:(int32_t)a b:(int32_t)b {
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return a ^ b;
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}
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- (int32_t)exp:(int)a {
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return _expTable[a];
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}
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- (int32_t)log:(int)a {
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if (a == 0) {
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[NSException raise:NSInvalidArgumentException format:@"Argument must be non-zero."];
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}
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return _logTable[a];
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}
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- (int32_t)inverse:(int)a {
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if (a == 0) {
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[NSException raise:NSInvalidArgumentException format:@"Argument must be non-zero."];
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}
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return _expTable[_size - _logTable[a] - 1];
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}
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- (int32_t)multiply:(int)a b:(int)b {
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if (a == 0 || b == 0) {
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return 0;
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}
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return _expTable[(_logTable[a] + _logTable[b]) % (_size - 1)];
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}
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- (BOOL)isEqual:(ZXGenericGF *)object {
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return self.primitive == object.primitive && self.size == object.size;
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}
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- (NSString *)description {
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return [NSString stringWithFormat:@"GF(0x%X,%d)", self.primitive, self.size];
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}
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@end
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