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| /*
| * Copyright 2012 ZXing authors
| *
| * 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.
| */
|
| #import "ZXQRCodeErrorCorrectionLevel.h"
| #import "ZXQRCodeFormatInformation.h"
|
| const int ZX_FORMAT_INFO_MASK_QR = 0x5412;
|
| /**
| * See ISO 18004:2006, Annex C, Table C.1
| */
| const int ZX_FORMAT_INFO_DECODE_LOOKUP_LEN = 32;
| const int ZX_FORMAT_INFO_DECODE_LOOKUP[ZX_FORMAT_INFO_DECODE_LOOKUP_LEN][2] = {
| {0x5412, 0x00},
| {0x5125, 0x01},
| {0x5E7C, 0x02},
| {0x5B4B, 0x03},
| {0x45F9, 0x04},
| {0x40CE, 0x05},
| {0x4F97, 0x06},
| {0x4AA0, 0x07},
| {0x77C4, 0x08},
| {0x72F3, 0x09},
| {0x7DAA, 0x0A},
| {0x789D, 0x0B},
| {0x662F, 0x0C},
| {0x6318, 0x0D},
| {0x6C41, 0x0E},
| {0x6976, 0x0F},
| {0x1689, 0x10},
| {0x13BE, 0x11},
| {0x1CE7, 0x12},
| {0x19D0, 0x13},
| {0x0762, 0x14},
| {0x0255, 0x15},
| {0x0D0C, 0x16},
| {0x083B, 0x17},
| {0x355F, 0x18},
| {0x3068, 0x19},
| {0x3F31, 0x1A},
| {0x3A06, 0x1B},
| {0x24B4, 0x1C},
| {0x2183, 0x1D},
| {0x2EDA, 0x1E},
| {0x2BED, 0x1F},
| };
|
| /**
| * Offset i holds the number of 1 bits in the binary representation of i
| */
| const int ZX_BITS_SET_IN_HALF_BYTE[] = {0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4};
|
| @implementation ZXQRCodeFormatInformation
|
| - (id)initWithFormatInfo:(int)formatInfo {
| if (self = [super init]) {
| _errorCorrectionLevel = [ZXQRCodeErrorCorrectionLevel forBits:(formatInfo >> 3) & 0x03];
| _dataMask = (int8_t)(formatInfo & 0x07);
| }
|
| return self;
| }
|
| + (int)numBitsDiffering:(int)a b:(int)b {
| a ^= b;
| return ZX_BITS_SET_IN_HALF_BYTE[a & 0x0F] +
| ZX_BITS_SET_IN_HALF_BYTE[((int)((unsigned int)a) >> 4 & 0x0F)] +
| ZX_BITS_SET_IN_HALF_BYTE[((int)((unsigned int)a) >> 8 & 0x0F)] +
| ZX_BITS_SET_IN_HALF_BYTE[((int)((unsigned int)a) >> 12 & 0x0F)] +
| ZX_BITS_SET_IN_HALF_BYTE[((int)((unsigned int)a) >> 16 & 0x0F)] +
| ZX_BITS_SET_IN_HALF_BYTE[((int)((unsigned int)a) >> 20 & 0x0F)] +
| ZX_BITS_SET_IN_HALF_BYTE[((int)((unsigned int)a) >> 24 & 0x0F)] +
| ZX_BITS_SET_IN_HALF_BYTE[((int)((unsigned int)a) >> 28 & 0x0F)];
| }
|
| + (ZXQRCodeFormatInformation *)decodeFormatInformation:(int)maskedFormatInfo1 maskedFormatInfo2:(int)maskedFormatInfo2 {
| ZXQRCodeFormatInformation *formatInfo = [self doDecodeFormatInformation:maskedFormatInfo1 maskedFormatInfo2:maskedFormatInfo2];
| if (formatInfo != nil) {
| return formatInfo;
| }
| return [self doDecodeFormatInformation:maskedFormatInfo1 ^ ZX_FORMAT_INFO_MASK_QR maskedFormatInfo2:maskedFormatInfo2 ^ ZX_FORMAT_INFO_MASK_QR];
| }
|
| + (ZXQRCodeFormatInformation *)doDecodeFormatInformation:(int)maskedFormatInfo1 maskedFormatInfo2:(int)maskedFormatInfo2 {
| int bestDifference = INT_MAX;
| int bestFormatInfo = 0;
|
| for (int i = 0; i < ZX_FORMAT_INFO_DECODE_LOOKUP_LEN; i++) {
| int targetInfo = ZX_FORMAT_INFO_DECODE_LOOKUP[i][0];
| if (targetInfo == maskedFormatInfo1 || targetInfo == maskedFormatInfo2) {
| return [[ZXQRCodeFormatInformation alloc] initWithFormatInfo:ZX_FORMAT_INFO_DECODE_LOOKUP[i][1]];
| }
| int bitsDifference = [self numBitsDiffering:maskedFormatInfo1 b:targetInfo];
| if (bitsDifference < bestDifference) {
| bestFormatInfo = ZX_FORMAT_INFO_DECODE_LOOKUP[i][1];
| bestDifference = bitsDifference;
| }
| if (maskedFormatInfo1 != maskedFormatInfo2) {
| bitsDifference = [self numBitsDiffering:maskedFormatInfo2 b:targetInfo];
| if (bitsDifference < bestDifference) {
| bestFormatInfo = ZX_FORMAT_INFO_DECODE_LOOKUP[i][1];
| bestDifference = bitsDifference;
| }
| }
| }
|
| if (bestDifference <= 3) {
| return [[ZXQRCodeFormatInformation alloc] initWithFormatInfo:bestFormatInfo];
| }
| return nil;
| }
|
| - (NSUInteger)hash {
| return (self.errorCorrectionLevel.ordinal << 3) | (int)self.dataMask;
| }
|
| - (BOOL)isEqual:(id)o {
| if (![o isKindOfClass:[ZXQRCodeFormatInformation class]]) {
| return NO;
| }
| ZXQRCodeFormatInformation *other = (ZXQRCodeFormatInformation *)o;
| return self.errorCorrectionLevel == other.errorCorrectionLevel && self.dataMask == other.dataMask;
| }
|
| @end
|
|
