/*
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* Copyright 2007 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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/*namespace com.google.zxing.qrcode.decoder {*/
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import ErrorCorrectionLevel from './ErrorCorrectionLevel';
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import Integer from '../../util/Integer';
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/**
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* <p>Encapsulates a QR Code's format information, including the data mask used and
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* error correction level.</p>
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*
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* @author Sean Owen
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* @see DataMask
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* @see ErrorCorrectionLevel
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*/
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export default class FormatInformation {
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constructor(formatInfo /*int*/) {
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// Bits 3,4
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this.errorCorrectionLevel = ErrorCorrectionLevel.forBits((formatInfo >> 3) & 0x03);
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// Bottom 3 bits
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this.dataMask = /*(byte) */ (formatInfo & 0x07);
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}
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static numBitsDiffering(a /*int*/, b /*int*/) {
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return Integer.bitCount(a ^ b);
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}
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/**
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* @param maskedFormatInfo1 format info indicator, with mask still applied
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* @param maskedFormatInfo2 second copy of same info; both are checked at the same time
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* to establish best match
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* @return information about the format it specifies, or {@code null}
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* if doesn't seem to match any known pattern
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*/
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static decodeFormatInformation(maskedFormatInfo1 /*int*/, maskedFormatInfo2 /*int*/) {
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const formatInfo = FormatInformation.doDecodeFormatInformation(maskedFormatInfo1, maskedFormatInfo2);
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if (formatInfo !== null) {
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return formatInfo;
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}
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// Should return null, but, some QR codes apparently
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// do not mask this info. Try again by actually masking the pattern
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// first
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return FormatInformation.doDecodeFormatInformation(maskedFormatInfo1 ^ FormatInformation.FORMAT_INFO_MASK_QR, maskedFormatInfo2 ^ FormatInformation.FORMAT_INFO_MASK_QR);
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}
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static doDecodeFormatInformation(maskedFormatInfo1 /*int*/, maskedFormatInfo2 /*int*/) {
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// Find the int in FORMAT_INFO_DECODE_LOOKUP with fewest bits differing
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let bestDifference = Number.MAX_SAFE_INTEGER;
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let bestFormatInfo = 0;
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for (const decodeInfo of FormatInformation.FORMAT_INFO_DECODE_LOOKUP) {
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const targetInfo = decodeInfo[0];
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if (targetInfo === maskedFormatInfo1 || targetInfo === maskedFormatInfo2) {
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// Found an exact match
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return new FormatInformation(decodeInfo[1]);
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}
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let bitsDifference = FormatInformation.numBitsDiffering(maskedFormatInfo1, targetInfo);
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if (bitsDifference < bestDifference) {
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bestFormatInfo = decodeInfo[1];
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bestDifference = bitsDifference;
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}
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if (maskedFormatInfo1 !== maskedFormatInfo2) {
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// also try the other option
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bitsDifference = FormatInformation.numBitsDiffering(maskedFormatInfo2, targetInfo);
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if (bitsDifference < bestDifference) {
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bestFormatInfo = decodeInfo[1];
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bestDifference = bitsDifference;
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}
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}
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}
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// Hamming distance of the 32 masked codes is 7, by construction, so <= 3 bits
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// differing means we found a match
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if (bestDifference <= 3) {
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return new FormatInformation(bestFormatInfo);
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}
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return null;
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}
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getErrorCorrectionLevel() {
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return this.errorCorrectionLevel;
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}
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getDataMask() {
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return this.dataMask;
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}
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/*@Override*/
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hashCode() {
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return (this.errorCorrectionLevel.getBits() << 3) | this.dataMask;
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}
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/*@Override*/
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equals(o) {
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if (!(o instanceof FormatInformation)) {
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return false;
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}
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const other = o;
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return this.errorCorrectionLevel === other.errorCorrectionLevel &&
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this.dataMask === other.dataMask;
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}
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}
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FormatInformation.FORMAT_INFO_MASK_QR = 0x5412;
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/**
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* See ISO 18004:2006, Annex C, Table C.1
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*/
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FormatInformation.FORMAT_INFO_DECODE_LOOKUP = [
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Int32Array.from([0x5412, 0x00]),
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Int32Array.from([0x5125, 0x01]),
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Int32Array.from([0x5E7C, 0x02]),
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Int32Array.from([0x5B4B, 0x03]),
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Int32Array.from([0x45F9, 0x04]),
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Int32Array.from([0x40CE, 0x05]),
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Int32Array.from([0x4F97, 0x06]),
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Int32Array.from([0x4AA0, 0x07]),
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Int32Array.from([0x77C4, 0x08]),
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Int32Array.from([0x72F3, 0x09]),
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Int32Array.from([0x7DAA, 0x0A]),
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Int32Array.from([0x789D, 0x0B]),
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Int32Array.from([0x662F, 0x0C]),
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Int32Array.from([0x6318, 0x0D]),
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Int32Array.from([0x6C41, 0x0E]),
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Int32Array.from([0x6976, 0x0F]),
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Int32Array.from([0x1689, 0x10]),
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Int32Array.from([0x13BE, 0x11]),
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Int32Array.from([0x1CE7, 0x12]),
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Int32Array.from([0x19D0, 0x13]),
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Int32Array.from([0x0762, 0x14]),
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Int32Array.from([0x0255, 0x15]),
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Int32Array.from([0x0D0C, 0x16]),
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Int32Array.from([0x083B, 0x17]),
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Int32Array.from([0x355F, 0x18]),
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Int32Array.from([0x3068, 0x19]),
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Int32Array.from([0x3F31, 0x1A]),
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Int32Array.from([0x3A06, 0x1B]),
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Int32Array.from([0x24B4, 0x1C]),
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Int32Array.from([0x2183, 0x1D]),
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Int32Array.from([0x2EDA, 0x1E]),
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Int32Array.from([0x2BED, 0x1F]),
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];
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