@zxing/library
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TypeScript port of ZXing multi-format 1D/2D barcode image processing library.
169 lines (168 loc) • 6.93 kB
JavaScript
/*
* Copyright 2013 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.
*/
// package com.google.zxing.aztec.encoder;
// import java.util.Deque;
// import java.util.LinkedList;
// import com.google.zxing.common.BitArray;
import BitArray from '../../common/BitArray';
import * as TokenHelpers from './TokenHelpers';
import * as C from './EncoderConstants';
import * as LatchTable from './LatchTable';
import * as ShiftTable from './ShiftTable';
import StringUtils from '../../common/StringUtils';
/**
* State represents all information about a sequence necessary to generate the current output.
* Note that a state is immutable.
*/
export default /*final*/ class State {
constructor(token, mode, binaryBytes, bitCount) {
this.token = token;
this.mode = mode;
this.binaryShiftByteCount = binaryBytes;
this.bitCount = bitCount;
// Make sure we match the token
// int binaryShiftBitCount = (binaryShiftByteCount * 8) +
// (binaryShiftByteCount === 0 ? 0 :
// binaryShiftByteCount <= 31 ? 10 :
// binaryShiftByteCount <= 62 ? 20 : 21);
// assert this.bitCount === token.getTotalBitCount() + binaryShiftBitCount;
}
getMode() {
return this.mode;
}
getToken() {
return this.token;
}
getBinaryShiftByteCount() {
return this.binaryShiftByteCount;
}
getBitCount() {
return this.bitCount;
}
// Create a new state representing this state with a latch to a (not
// necessary different) mode, and then a code.
latchAndAppend(mode, value) {
// assert binaryShiftByteCount === 0;
let bitCount = this.bitCount;
let token = this.token;
if (mode !== this.mode) {
let latch = LatchTable.LATCH_TABLE[this.mode][mode];
token = TokenHelpers.add(token, latch & 0xffff, latch >> 16);
bitCount += latch >> 16;
}
let latchModeBitCount = mode === C.MODE_DIGIT ? 4 : 5;
token = TokenHelpers.add(token, value, latchModeBitCount);
return new State(token, mode, 0, bitCount + latchModeBitCount);
}
// Create a new state representing this state, with a temporary shift
// to a different mode to output a single value.
shiftAndAppend(mode, value) {
// assert binaryShiftByteCount === 0 && this.mode !== mode;
let token = this.token;
let thisModeBitCount = this.mode === C.MODE_DIGIT ? 4 : 5;
// Shifts exist only to UPPER and PUNCT, both with tokens size 5.
token = TokenHelpers.add(token, ShiftTable.SHIFT_TABLE[this.mode][mode], thisModeBitCount);
token = TokenHelpers.add(token, value, 5);
return new State(token, this.mode, 0, this.bitCount + thisModeBitCount + 5);
}
// Create a new state representing this state, but an additional character
// output in Binary Shift mode.
addBinaryShiftChar(index) {
let token = this.token;
let mode = this.mode;
let bitCount = this.bitCount;
if (this.mode === C.MODE_PUNCT || this.mode === C.MODE_DIGIT) {
// assert binaryShiftByteCount === 0;
let latch = LatchTable.LATCH_TABLE[mode][C.MODE_UPPER];
token = TokenHelpers.add(token, latch & 0xffff, latch >> 16);
bitCount += latch >> 16;
mode = C.MODE_UPPER;
}
let deltaBitCount = this.binaryShiftByteCount === 0 || this.binaryShiftByteCount === 31
? 18
: this.binaryShiftByteCount === 62
? 9
: 8;
let result = new State(token, mode, this.binaryShiftByteCount + 1, bitCount + deltaBitCount);
if (result.binaryShiftByteCount === 2047 + 31) {
// The string is as long as it's allowed to be. We should end it.
result = result.endBinaryShift(index + 1);
}
return result;
}
// Create the state identical to this one, but we are no longer in
// Binary Shift mode.
endBinaryShift(index) {
if (this.binaryShiftByteCount === 0) {
return this;
}
let token = this.token;
token = TokenHelpers.addBinaryShift(token, index - this.binaryShiftByteCount, this.binaryShiftByteCount);
// assert token.getTotalBitCount() === this.bitCount;
return new State(token, this.mode, 0, this.bitCount);
}
// Returns true if "this" state is better (equal: or) to be in than "that"
// state under all possible circumstances.
isBetterThanOrEqualTo(other) {
let newModeBitCount = this.bitCount + (LatchTable.LATCH_TABLE[this.mode][other.mode] >> 16);
if (this.binaryShiftByteCount < other.binaryShiftByteCount) {
// add additional B/S encoding cost of other, if any
newModeBitCount +=
State.calculateBinaryShiftCost(other) -
State.calculateBinaryShiftCost(this);
}
else if (this.binaryShiftByteCount > other.binaryShiftByteCount &&
other.binaryShiftByteCount > 0) {
// maximum possible additional cost (it: h)
newModeBitCount += 10;
}
return newModeBitCount <= other.bitCount;
}
toBitArray(text) {
// Reverse the tokens, so that they are in the order that they should
// be output
let symbols = [];
for (let token = this.endBinaryShift(text.length).token; token !== null; token = token.getPrevious()) {
symbols.unshift(token);
}
let bitArray = new BitArray();
// Add each token to the result.
for (const symbol of symbols) {
symbol.appendTo(bitArray, text);
}
// assert bitArray.getSize() === this.bitCount;
return bitArray;
}
/**
* @Override
*/
toString() {
return StringUtils.format('%s bits=%d bytes=%d', C.MODE_NAMES[this.mode], this.bitCount, this.binaryShiftByteCount);
}
static calculateBinaryShiftCost(state) {
if (state.binaryShiftByteCount > 62) {
return 21; // B/S with extended length
}
if (state.binaryShiftByteCount > 31) {
return 20; // two B/S
}
if (state.binaryShiftByteCount > 0) {
return 10; // one B/S
}
return 0;
}
}
State.INITIAL_STATE = new State(C.EMPTY_TOKEN, C.MODE_UPPER, 0, 0);