@zxing/library
Version:
TypeScript port of ZXing multi-format 1D/2D barcode image processing library.
255 lines (254 loc) • 11.5 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.
*/
var __values = (this && this.__values) || function(o) {
var s = typeof Symbol === "function" && Symbol.iterator, m = s && o[s], i = 0;
if (m) return m.call(o);
if (o && typeof o.length === "number") return {
next: function () {
if (o && i >= o.length) o = void 0;
return { value: o && o[i++], done: !o };
}
};
throw new TypeError(s ? "Object is not iterable." : "Symbol.iterator is not defined.");
};
// import java.util.Collection;
// import java.util.Collections;
import Collections from '../../util/Collections';
// import java.util.Comparator;
// import java.util.Iterator;
// import java.util.LinkedList;
import State from './State';
import * as C from './EncoderConstants';
import * as CharMap from './CharMap';
import * as ShiftTable from './ShiftTable';
import StringUtils from '../../common/StringUtils';
/**
* This produces nearly optimal encodings of text into the first-level of
* encoding used by Aztec code.
*
* It uses a dynamic algorithm. For each prefix of the string, it determines
* a set of encodings that could lead to this prefix. We repeatedly add a
* character and generate a new set of optimal encodings until we have read
* through the entire input.
*
* @author Frank Yellin
* @author Rustam Abdullaev
*/
var HighLevelEncoder = /** @class */ (function () {
function HighLevelEncoder(text) {
this.text = text;
}
/**
* @return text represented by this encoder encoded as a {@link BitArray}
*/
HighLevelEncoder.prototype.encode = function () {
var spaceCharCode = StringUtils.getCharCode(' ');
var lineBreakCharCode = StringUtils.getCharCode('\n');
var states = Collections.singletonList(State.INITIAL_STATE);
for (var index = 0; index < this.text.length; index++) {
var pairCode = void 0;
var nextChar = index + 1 < this.text.length ? this.text[index + 1] : 0;
switch (this.text[index]) {
case StringUtils.getCharCode('\r'):
pairCode = nextChar === lineBreakCharCode ? 2 : 0;
break;
case StringUtils.getCharCode('.'):
pairCode = nextChar === spaceCharCode ? 3 : 0;
break;
case StringUtils.getCharCode(','):
pairCode = nextChar === spaceCharCode ? 4 : 0;
break;
case StringUtils.getCharCode(':'):
pairCode = nextChar === spaceCharCode ? 5 : 0;
break;
default:
pairCode = 0;
}
if (pairCode > 0) {
// We have one of the four special PUNCT pairs. Treat them specially.
// Get a new set of states for the two new characters.
states = HighLevelEncoder.updateStateListForPair(states, index, pairCode);
index++;
}
else {
// Get a new set of states for the new character.
states = this.updateStateListForChar(states, index);
}
}
// We are left with a set of states. Find the shortest one.
var minState = Collections.min(states, function (a, b) {
return a.getBitCount() - b.getBitCount();
});
// Convert it to a bit array, and return.
return minState.toBitArray(this.text);
};
// We update a set of states for a new character by updating each state
// for the new character, merging the results, and then removing the
// non-optimal states.
HighLevelEncoder.prototype.updateStateListForChar = function (states, index) {
var e_1, _a;
var result = [];
try {
for (var states_1 = __values(states), states_1_1 = states_1.next(); !states_1_1.done; states_1_1 = states_1.next()) {
var state = states_1_1.value /*State*/;
this.updateStateForChar(state, index, result);
}
}
catch (e_1_1) { e_1 = { error: e_1_1 }; }
finally {
try {
if (states_1_1 && !states_1_1.done && (_a = states_1.return)) _a.call(states_1);
}
finally { if (e_1) throw e_1.error; }
}
return HighLevelEncoder.simplifyStates(result);
};
// Return a set of states that represent the possible ways of updating this
// state for the next character. The resulting set of states are added to
// the "result" list.
HighLevelEncoder.prototype.updateStateForChar = function (state, index, result) {
var ch = (this.text[index] & 0xff);
var charInCurrentTable = CharMap.CHAR_MAP[state.getMode()][ch] > 0;
var stateNoBinary = null;
for (var mode /*int*/ = 0; mode <= C.MODE_PUNCT; mode++) {
var charInMode = CharMap.CHAR_MAP[mode][ch];
if (charInMode > 0) {
if (stateNoBinary == null) {
// Only create stateNoBinary the first time it's required.
stateNoBinary = state.endBinaryShift(index);
}
// Try generating the character by latching to its mode
if (!charInCurrentTable ||
mode === state.getMode() ||
mode === C.MODE_DIGIT) {
// If the character is in the current table, we don't want to latch to
// any other mode except possibly digit (which uses only 4 bits). Any
// other latch would be equally successful *after* this character, and
// so wouldn't save any bits.
var latchState = stateNoBinary.latchAndAppend(mode, charInMode);
result.push(latchState);
}
// Try generating the character by switching to its mode.
if (!charInCurrentTable &&
ShiftTable.SHIFT_TABLE[state.getMode()][mode] >= 0) {
// It never makes sense to temporarily shift to another mode if the
// character exists in the current mode. That can never save bits.
var shiftState = stateNoBinary.shiftAndAppend(mode, charInMode);
result.push(shiftState);
}
}
}
if (state.getBinaryShiftByteCount() > 0 ||
CharMap.CHAR_MAP[state.getMode()][ch] === 0) {
// It's never worthwhile to go into binary shift mode if you're not already
// in binary shift mode, and the character exists in your current mode.
// That can never save bits over just outputting the char in the current mode.
var binaryState = state.addBinaryShiftChar(index);
result.push(binaryState);
}
};
HighLevelEncoder.updateStateListForPair = function (states, index, pairCode) {
var e_2, _a;
var result = [];
try {
for (var states_2 = __values(states), states_2_1 = states_2.next(); !states_2_1.done; states_2_1 = states_2.next()) {
var state = states_2_1.value /*State*/;
this.updateStateForPair(state, index, pairCode, result);
}
}
catch (e_2_1) { e_2 = { error: e_2_1 }; }
finally {
try {
if (states_2_1 && !states_2_1.done && (_a = states_2.return)) _a.call(states_2);
}
finally { if (e_2) throw e_2.error; }
}
return this.simplifyStates(result);
};
HighLevelEncoder.updateStateForPair = function (state, index, pairCode, result) {
var stateNoBinary = state.endBinaryShift(index);
// Possibility 1. Latch to C.MODE_PUNCT, and then append this code
result.push(stateNoBinary.latchAndAppend(C.MODE_PUNCT, pairCode));
if (state.getMode() !== C.MODE_PUNCT) {
// Possibility 2. Shift to C.MODE_PUNCT, and then append this code.
// Every state except C.MODE_PUNCT (handled above) can shift
result.push(stateNoBinary.shiftAndAppend(C.MODE_PUNCT, pairCode));
}
if (pairCode === 3 || pairCode === 4) {
// both characters are in DIGITS. Sometimes better to just add two digits
var digitState = stateNoBinary
.latchAndAppend(C.MODE_DIGIT, 16 - pairCode) // period or comma in DIGIT
.latchAndAppend(C.MODE_DIGIT, 1); // space in DIGIT
result.push(digitState);
}
if (state.getBinaryShiftByteCount() > 0) {
// It only makes sense to do the characters as binary if we're already
// in binary mode.
var binaryState = state
.addBinaryShiftChar(index)
.addBinaryShiftChar(index + 1);
result.push(binaryState);
}
};
HighLevelEncoder.simplifyStates = function (states) {
var e_3, _a, e_4, _b;
var result = [];
try {
for (var states_3 = __values(states), states_3_1 = states_3.next(); !states_3_1.done; states_3_1 = states_3.next()) {
var newState = states_3_1.value;
var add = true;
var _loop_1 = function (oldState) {
if (oldState.isBetterThanOrEqualTo(newState)) {
add = false;
return "break";
}
if (newState.isBetterThanOrEqualTo(oldState)) {
// iterator.remove();
result = result.filter(function (x) { return x !== oldState; }); // remove old state
}
};
try {
for (var result_1 = (e_4 = void 0, __values(result)), result_1_1 = result_1.next(); !result_1_1.done; result_1_1 = result_1.next()) {
var oldState = result_1_1.value;
var state_1 = _loop_1(oldState);
if (state_1 === "break")
break;
}
}
catch (e_4_1) { e_4 = { error: e_4_1 }; }
finally {
try {
if (result_1_1 && !result_1_1.done && (_b = result_1.return)) _b.call(result_1);
}
finally { if (e_4) throw e_4.error; }
}
if (add) {
result.push(newState);
}
}
}
catch (e_3_1) { e_3 = { error: e_3_1 }; }
finally {
try {
if (states_3_1 && !states_3_1.done && (_a = states_3.return)) _a.call(states_3);
}
finally { if (e_3) throw e_3.error; }
}
return result;
};
return HighLevelEncoder;
}());
export default HighLevelEncoder;