Code93Reader.cpp Example File

appdemos/qtws/QZXing/zxing/zxing/oned/Code93Reader.cpp
 // -*- mode:c++; tab-width:2; indent-tabs-mode:nil; c-basic-offset:2 -*-
 /*
  *  Copyright 2010 ZXing authors All rights reserved.
  *
  * 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.
  */

 #include "Code93Reader.h"
 #include <zxing/oned/OneDResultPoint.h>
 #include <zxing/common/Array.h>
 #include <zxing/ReaderException.h>
 #include <zxing/FormatException.h>
 #include <zxing/NotFoundException.h>
 #include <zxing/ChecksumException.h>
 #include <math.h>
 #include <limits.h>

 using std::vector;
 using std::string;
 using zxing::Ref;
 using zxing::Result;
 using zxing::String;
 using zxing::NotFoundException;
 using zxing::ChecksumException;
 using zxing::oned::Code93Reader;

 // VC++
 using zxing::BitArray;

 namespace {
   char const ALPHABET[] =
     "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ-. $/+%abcd*";
   string ALPHABET_STRING (ALPHABET);

   /**
    * These represent the encodings of characters, as patterns of wide and narrow bars.
    * The 9 least-significant bits of each int correspond to the pattern of wide and narrow.
    */
   int const CHARACTER_ENCODINGS[] = {
     0x114, 0x148, 0x144, 0x142, 0x128, 0x124, 0x122, 0x150, 0x112, 0x10A, // 0-9
     0x1A8, 0x1A4, 0x1A2, 0x194, 0x192, 0x18A, 0x168, 0x164, 0x162, 0x134, // A-J
     0x11A, 0x158, 0x14C, 0x146, 0x12C, 0x116, 0x1B4, 0x1B2, 0x1AC, 0x1A6, // K-T
     0x196, 0x19A, 0x16C, 0x166, 0x136, 0x13A, // U-Z
     0x12E, 0x1D4, 0x1D2, 0x1CA, 0x16E, 0x176, 0x1AE, // - - %
     0x126, 0x1DA, 0x1D6, 0x132, 0x15E, // Control chars? $-*
   };
   int const CHARACTER_ENCODINGS_LENGTH =
     (int)sizeof(CHARACTER_ENCODINGS)/sizeof(CHARACTER_ENCODINGS[0]);
   const int ASTERISK_ENCODING = CHARACTER_ENCODINGS[47];
 }

 Code93Reader::Code93Reader() {
   decodeRowResult.reserve(20);
   counters.resize(6);
 }

 Ref<Result> Code93Reader::decodeRow(int rowNumber, Ref<BitArray> row, zxing::DecodeHints /*hints*/) {
   Range start (findAsteriskPattern(row));
   // Read off white space
   int nextStart = row->getNextSet(start[1]);
   int end = row->getSize();

   vector<int>& theCounters (counters);
   { // Arrays.fill(counters, 0);
     int size = theCounters.size();
     theCounters.resize(0);
     theCounters.resize(size); }
   string& result (decodeRowResult);
   result.clear();

   char decodedChar;
   int lastStart;
   do {
     recordPattern(row, nextStart, theCounters);
     int pattern = toPattern(theCounters);
     if (pattern < 0) {
       throw NotFoundException();
     }
     decodedChar = patternToChar(pattern);
     result.append(1, decodedChar);
     lastStart = nextStart;
     for(int i=0, e=theCounters.size(); i < e; ++i) {
       nextStart += theCounters[i];
     }
     // Read off white space
     nextStart = row->getNextSet(nextStart);
   } while (decodedChar != '*');
   result.resize(result.length() - 1); // remove asterisk

   // Look for whitespace after pattern:
   int lastPatternSize = 0;
   for (int i = 0, e = theCounters.size(); i < e; i++) {
     lastPatternSize += theCounters[i];
   }

   // Should be at least one more black module
   if (nextStart == end || !row->get(nextStart)) {
     throw NotFoundException();
   }

   if (result.length() < 2) {
     // false positive -- need at least 2 checksum digits
     throw NotFoundException();
   }

   checkChecksums(result);
   // Remove checksum digits
   result.resize(result.length() - 2);

   Ref<String> resultString = decodeExtended(result);

   float left = (float) (start[1] + start[0]) / 2.0f;
   float right = lastStart + lastPatternSize / 2.0f;

   ArrayRef< Ref<ResultPoint> > resultPoints (2);
   resultPoints[0] =
     Ref<OneDResultPoint>(new OneDResultPoint(left, (float) rowNumber));
   resultPoints[1] =
     Ref<OneDResultPoint>(new OneDResultPoint(right, (float) rowNumber));

   return Ref<Result>(new Result(
                        resultString,
                        ArrayRef<byte>(),
                        resultPoints,
                        BarcodeFormat::CODE_93));
 }

 Code93Reader::Range Code93Reader::findAsteriskPattern(Ref<BitArray> row)  {
   int width = row->getSize();
   int rowOffset = row->getNextSet(0);

   { // Arrays.fill(counters, 0);
     int size = counters.size();
     counters.resize(0);
     counters.resize(size); }
   vector<int>& theCounters (counters);

   int patternStart = rowOffset;
   bool isWhite = false;
   int patternLength = theCounters.size();

   int counterPosition = 0;
   for (int i = rowOffset; i < width; i++) {
     if (row->get(i) ^ isWhite) {
       theCounters[counterPosition]++;
     } else {
       if (counterPosition == patternLength - 1) {
         if (toPattern(theCounters) == ASTERISK_ENCODING) {
           return Range(patternStart, i);
         }
         patternStart += theCounters[0] + theCounters[1];
         for (int y = 2; y < patternLength; y++) {
           theCounters[y - 2] = theCounters[y];
         }
         theCounters[patternLength - 2] = 0;
         theCounters[patternLength - 1] = 0;
         counterPosition--;
       } else {
         counterPosition++;
       }
       theCounters[counterPosition] = 1;
       isWhite = !isWhite;
     }
   }
   throw NotFoundException();
 }

 int Code93Reader::toPattern(vector<int>& counters) {
   int max = counters.size();
   int sum = 0;
   for(int i=0, e=counters.size(); i<e; ++i) {
     sum += counters[i];
   }
   int pattern = 0;
   for (int i = 0; i < max; i++) {
     int scaledShifted = (counters[i] << INTEGER_MATH_SHIFT) * 9 / sum;
     int scaledUnshifted = scaledShifted >> INTEGER_MATH_SHIFT;
     if ((scaledShifted & 0xFF) > 0x7F) {
       scaledUnshifted++;
     }
     if (scaledUnshifted < 1 || scaledUnshifted > 4) {
       return -1;
     }
     if ((i & 0x01) == 0) {
       for (int j = 0; j < scaledUnshifted; j++) {
         pattern = (pattern << 1) | 0x01;
       }
     } else {
       pattern <<= scaledUnshifted;
     }
   }
   return pattern;
 }

 char Code93Reader::patternToChar(int pattern)  {
   for (int i = 0; i < CHARACTER_ENCODINGS_LENGTH; i++) {
     if (CHARACTER_ENCODINGS[i] == pattern) {
       return ALPHABET[i];
     }
   }
   throw NotFoundException();
 }

 Ref<String> Code93Reader::decodeExtended(string const& encoded)  {
   int length = encoded.length();
   string decoded;
   for (int i = 0; i < length; i++) {
     char c = encoded[i];
     if (c >= 'a' && c <= 'd') {
       if (i >= length - 1) {
         throw FormatException::getFormatInstance();
       }
       char next = encoded[i + 1];
       char decodedChar = '\0';
       switch (c) {
       case 'd':
         // +A to +Z map to a to z
         if (next >= 'A' && next <= 'Z') {
           decodedChar = (byte) (next + 32);
         } else {
           throw FormatException::getFormatInstance();
         }
         break;
       case 'a':
         // $A to $Z map to control codes SH to SB
         if (next >= 'A' && next <= 'Z') {
           decodedChar = (byte) (next - 64);
         } else {
           throw FormatException::getFormatInstance();
         }
         break;
       case 'b':
         // %A to %E map to control codes ESC to US
         if (next >= 'A' && next <= 'E') {
           decodedChar = (byte) (next - 38);
         } else if (next >= 'F' && next <= 'W') {
           decodedChar = (byte) (next - 11);
         } else {
           throw FormatException::getFormatInstance();
         }
         break;
       case 'c':
         // /A to /O map to ! to , and /Z maps to :
         if (next >= 'A' && next <= 'O') {
           decodedChar = (byte) (next - 32);
         } else if (next == 'Z') {
           decodedChar = ':';
         } else {
           throw FormatException::getFormatInstance();
         }
         break;
       }
       decoded.append(1, decodedChar);
       // bump up i again since we read two characters
       i++;
     } else {
       decoded.append(1, c);
     }
   }
   return Ref<String>(new String(decoded));
 }

 void Code93Reader::checkChecksums(string const& result) {
   int length = result.length();
   checkOneChecksum(result, length - 2, 20);
   checkOneChecksum(result, length - 1, 15);
 }

 void Code93Reader::checkOneChecksum(string const& result,
                                     int checkPosition,
                                     int weightMax) {
   int weight = 1;
   int total = 0;
   for (int i = checkPosition - 1; i >= 0; i--) {
     total += weight * ALPHABET_STRING.find_first_of(result[i]);
     if (++weight > weightMax) {
       weight = 1;
     }
   }
   if (result[checkPosition] != ALPHABET[total % 47]) {
     throw ChecksumException();
   }
 }
Code93Reader.cpp Example File

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