/* * 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. */ namespace com.google.zxing.oned { using System; using System.Text; using com.google.zxing.common; public sealed class Code128Reader : AbstractOneDReader { private static int[][] CODE_PATTERNS = new int[][]{ new int[]{2, 1, 2, 2, 2, 2}, // 0 new int[]{2, 2, 2, 1, 2, 2}, new int[]{2, 2, 2, 2, 2, 1}, new int[]{1, 2, 1, 2, 2, 3}, new int[]{1, 2, 1, 3, 2, 2}, new int[]{1, 3, 1, 2, 2, 2}, // 5 new int[]{1, 2, 2, 2, 1, 3}, new int[]{1, 2, 2, 3, 1, 2}, new int[]{1, 3, 2, 2, 1, 2}, new int[]{2, 2, 1, 2, 1, 3}, new int[]{2, 2, 1, 3, 1, 2}, // 10 new int[]{2, 3, 1, 2, 1, 2}, new int[]{1, 1, 2, 2, 3, 2}, new int[]{1, 2, 2, 1, 3, 2}, new int[]{1, 2, 2, 2, 3, 1}, new int[]{1, 1, 3, 2, 2, 2}, // 15 new int[]{1, 2, 3, 1, 2, 2}, new int[]{1, 2, 3, 2, 2, 1}, new int[]{2, 2, 3, 2, 1, 1}, new int[]{2, 2, 1, 1, 3, 2}, new int[]{2, 2, 1, 2, 3, 1}, // 20 new int[]{2, 1, 3, 2, 1, 2}, new int[]{2, 2, 3, 1, 1, 2}, new int[]{3, 1, 2, 1, 3, 1}, new int[]{3, 1, 1, 2, 2, 2}, new int[]{3, 2, 1, 1, 2, 2}, // 25 new int[]{3, 2, 1, 2, 2, 1}, new int[]{3, 1, 2, 2, 1, 2}, new int[]{3, 2, 2, 1, 1, 2}, new int[]{3, 2, 2, 2, 1, 1}, new int[]{2, 1, 2, 1, 2, 3}, // 30 new int[]{2, 1, 2, 3, 2, 1}, new int[]{2, 3, 2, 1, 2, 1}, new int[]{1, 1, 1, 3, 2, 3}, new int[]{1, 3, 1, 1, 2, 3}, new int[]{1, 3, 1, 3, 2, 1}, // 35 new int[]{1, 1, 2, 3, 1, 3}, new int[]{1, 3, 2, 1, 1, 3}, new int[]{1, 3, 2, 3, 1, 1}, new int[]{2, 1, 1, 3, 1, 3}, new int[]{2, 3, 1, 1, 1, 3}, // 40 new int[]{2, 3, 1, 3, 1, 1}, new int[]{1, 1, 2, 1, 3, 3}, new int[]{1, 1, 2, 3, 3, 1}, new int[]{1, 3, 2, 1, 3, 1}, new int[]{1, 1, 3, 1, 2, 3}, // 45 new int[]{1, 1, 3, 3, 2, 1}, new int[]{1, 3, 3, 1, 2, 1}, new int[]{3, 1, 3, 1, 2, 1}, new int[]{2, 1, 1, 3, 3, 1}, new int[]{2, 3, 1, 1, 3, 1}, // 50 new int[]{2, 1, 3, 1, 1, 3}, new int[]{2, 1, 3, 3, 1, 1}, new int[]{2, 1, 3, 1, 3, 1}, new int[]{3, 1, 1, 1, 2, 3}, new int[]{3, 1, 1, 3, 2, 1}, // 55 new int[]{3, 3, 1, 1, 2, 1}, new int[]{3, 1, 2, 1, 1, 3}, new int[]{3, 1, 2, 3, 1, 1}, new int[]{3, 3, 2, 1, 1, 1}, new int[]{3, 1, 4, 1, 1, 1}, // 60 new int[]{2, 2, 1, 4, 1, 1}, new int[]{4, 3, 1, 1, 1, 1}, new int[]{1, 1, 1, 2, 2, 4}, new int[]{1, 1, 1, 4, 2, 2}, new int[] {1, 2, 1, 1, 2, 4}, // 65 new int[]{1, 2, 1, 4, 2, 1}, new int[]{1, 4, 1, 1, 2, 2}, new int[]{1, 4, 1, 2, 2, 1}, new int[]{1, 1, 2, 2, 1, 4}, new int[]{1, 1, 2, 4, 1, 2}, // 70 new int[]{1, 2, 2, 1, 1, 4}, new int[]{1, 2, 2, 4, 1, 1}, new int[]{1, 4, 2, 1, 1, 2}, new int[]{1, 4, 2, 2, 1, 1}, new int[]{2, 4, 1, 2, 1, 1}, // 75 new int[]{2, 2, 1, 1, 1, 4}, new int[]{4, 1, 3, 1, 1, 1}, new int[]{2, 4, 1, 1, 1, 2}, new int[]{1, 3, 4, 1, 1, 1}, new int[]{1, 1, 1, 2, 4, 2}, // 80 new int[]{1, 2, 1, 1, 4, 2}, new int[]{1, 2, 1, 2, 4, 1}, new int[]{1, 1, 4, 2, 1, 2}, new int[]{1, 2, 4, 1, 1, 2}, new int[]{1, 2, 4, 2, 1, 1}, // 85 new int[]{4, 1, 1, 2, 1, 2}, new int[]{4, 2, 1, 1, 1, 2}, new int[]{4, 2, 1, 2, 1, 1}, new int[]{2, 1, 2, 1, 4, 1}, new int[]{2, 1, 4, 1, 2, 1}, // 90 new int[]{4, 1, 2, 1, 2, 1}, new int[]{1, 1, 1, 1, 4, 3}, new int[]{1, 1, 1, 3, 4, 1}, new int[]{1, 3, 1, 1, 4, 1}, new int[]{1, 1, 4, 1, 1, 3}, // 95 new int[]{1, 1, 4, 3, 1, 1}, new int[]{4, 1, 1, 1, 1, 3}, new int[]{4, 1, 1, 3, 1, 1}, new int[]{1, 1, 3, 1, 4, 1}, new int[]{1, 1, 4, 1, 3, 1}, // 100 new int[]{3, 1, 1, 1, 4, 1}, new int[]{4, 1, 1, 1, 3, 1}, new int[]{2, 1, 1, 4, 1, 2}, new int[]{2, 1, 1, 2, 1, 4}, new int[]{2, 1, 1, 2, 3, 2}, // 105 new int[]{2, 3, 3, 1, 1, 1, 2} }; private static int MAX_AVG_VARIANCE = (int) (PATTERN_MATCH_RESULT_SCALE_FACTOR * 0.25f); private static int MAX_INDIVIDUAL_VARIANCE = (int) (PATTERN_MATCH_RESULT_SCALE_FACTOR * 0.7f); private const int CODE_SHIFT = 98; private const int CODE_CODE_C = 99; private const int CODE_CODE_B = 100; private const int CODE_CODE_A = 101; private const int CODE_FNC_1 = 102; private const int CODE_FNC_2 = 97; private const int CODE_FNC_3 = 96; private const int CODE_FNC_4_A = 101; private const int CODE_FNC_4_B = 100; private const int CODE_START_A = 103; private const int CODE_START_B = 104; private const int CODE_START_C = 105; private const int CODE_STOP = 106; private static int[] findStartPattern(BitArray row) { int width = row.getSize(); int rowOffset = 0; while (rowOffset < width) { if (row.get(rowOffset)) { break; } rowOffset++; } int counterPosition = 0; int[] counters = new int[6]; int patternStart = rowOffset; bool isWhite = false; int patternLength = counters.Length; for (int i = rowOffset; i < width; i++) { bool pixel = row.get(i); if ((!pixel && isWhite) || (pixel && !isWhite)) { counters[counterPosition]++; } else { if (counterPosition == patternLength - 1) { int bestVariance = MAX_AVG_VARIANCE; int bestMatch = -1; for (int startCode = CODE_START_A; startCode <= CODE_START_C; startCode++) { int variance = patternMatchVariance(counters, CODE_PATTERNS[startCode], MAX_INDIVIDUAL_VARIANCE); if (variance < bestVariance) { bestVariance = variance; bestMatch = startCode; } } if (bestMatch >= 0) { // Look for whitespace before start pattern, >= 50% of width of start pattern if (row.isRange(Math.Max(0, patternStart - (i - patternStart) / 2), patternStart, false)) { return new int[]{patternStart, i, bestMatch}; } } patternStart += counters[0] + counters[1]; for (int y = 2; y < patternLength; y++) { counters[y - 2] = counters[y]; } counters[patternLength - 2] = 0; counters[patternLength - 1] = 0; counterPosition--; } else { counterPosition++; } counters[counterPosition] = 1; isWhite = !isWhite; } } throw new ReaderException(); } private static int decodeCode(BitArray row, int[] counters, int rowOffset) { recordPattern(row, rowOffset, counters); int bestVariance = MAX_AVG_VARIANCE; // worst variance we'll accept int bestMatch = -1; for (int d = 0; d < CODE_PATTERNS.Length; d++) { int[] pattern = CODE_PATTERNS[d]; int variance = patternMatchVariance(counters, pattern, MAX_INDIVIDUAL_VARIANCE); if (variance < bestVariance) { bestVariance = variance; bestMatch = d; } } // TODO We're overlooking the fact that the STOP pattern has 7 values, not 6 if (bestMatch >= 0) { return bestMatch; } else { throw new ReaderException(); } } public override Result decodeRow(int rowNumber, BitArray row, System.Collections.Hashtable hints) { int[] startPatternInfo = findStartPattern(row); int startCode = startPatternInfo[2]; int codeSet; switch (startCode) { case CODE_START_A: codeSet = CODE_CODE_A; break; case CODE_START_B: codeSet = CODE_CODE_B; break; case CODE_START_C: codeSet = CODE_CODE_C; break; default: throw new ReaderException(); } bool done = false; bool isNextShifted = false; StringBuilder result = new StringBuilder(); int lastStart = startPatternInfo[0]; int nextStart = startPatternInfo[1]; int[] counters = new int[6]; int lastCode = 0; int code = 0; int checksumTotal = startCode; int multiplier = 0; bool lastCharacterWasPrintable = true; while (!done) { bool unshift = isNextShifted; isNextShifted = false; // Save off last code lastCode = code; // Decode another code from image code = decodeCode(row, counters, nextStart); // Remember whether the last code was printable or not (excluding CODE_STOP) if (code != CODE_STOP) { lastCharacterWasPrintable = true; } // Add to checksum computation (if not CODE_STOP of course) if (code != CODE_STOP) { multiplier++; checksumTotal += multiplier * code; } // Advance to where the next code will to start lastStart = nextStart; for (int i = 0; i < counters.Length; i++) { nextStart += counters[i]; } // Take care of illegal start codes switch (code) { case CODE_START_A: case CODE_START_B: case CODE_START_C: throw new ReaderException(); } switch (codeSet) { case CODE_CODE_A: if (code < 64) { result.Append((char) (' ' + code)); } else if (code < 96) { result.Append((char) (code - 64)); } else { // Don't let CODE_STOP, which always appears, affect whether whether we think the last code // was printable or not if (code != CODE_STOP) { lastCharacterWasPrintable = false; } switch (code) { case CODE_FNC_1: case CODE_FNC_2: case CODE_FNC_3: case CODE_FNC_4_A: // do nothing? break; case CODE_SHIFT: isNextShifted = true; codeSet = CODE_CODE_B; break; case CODE_CODE_B: codeSet = CODE_CODE_B; break; case CODE_CODE_C: codeSet = CODE_CODE_C; break; case CODE_STOP: done = true; break; } } break; case CODE_CODE_B: if (code < 96) { result.Append((char) (' ' + code)); } else { if (code != CODE_STOP) { lastCharacterWasPrintable = false; } switch (code) { case CODE_FNC_1: case CODE_FNC_2: case CODE_FNC_3: case CODE_FNC_4_B: // do nothing? break; case CODE_SHIFT: isNextShifted = true; codeSet = CODE_CODE_C; break; case CODE_CODE_A: codeSet = CODE_CODE_A; break; case CODE_CODE_C: codeSet = CODE_CODE_C; break; case CODE_STOP: done = true; break; } } break; case CODE_CODE_C: if (code < 100) { if (code < 10) { result.Append('0'); } result.Append(code); } else { if (code != CODE_STOP) { lastCharacterWasPrintable = false; } switch (code) { case CODE_FNC_1: // do nothing? break; case CODE_CODE_A: codeSet = CODE_CODE_A; break; case CODE_CODE_B: codeSet = CODE_CODE_B; break; case CODE_STOP: done = true; break; } } break; } // Unshift back to another code set if we were shifted if (unshift) { switch (codeSet) { case CODE_CODE_A: codeSet = CODE_CODE_C; break; case CODE_CODE_B: codeSet = CODE_CODE_A; break; case CODE_CODE_C: codeSet = CODE_CODE_B; break; } } } // Check for ample whitespice following pattern, but, to do this we first need to remember that we // fudged decoding CODE_STOP since it actually has 7 bars, not 6. There is a black bar left to read off. // Would be slightly better to properly read. Here we just skip it: while (row.get(nextStart)) { nextStart++; } if (!row.isRange(nextStart, Math.Min(row.getSize(), nextStart + (nextStart - lastStart) / 2), false)) { throw new ReaderException(); } // Pull out from sum the value of the penultimate check code checksumTotal -= multiplier * lastCode; // lastCode is the checksum then: if (checksumTotal % 103 != lastCode) { throw new ReaderException(); } // Need to pull out the check digits from string int resultLength = result.Length; // Only bother if, well, the result had at least one character, and if the checksum digit happened // to be a printable character. If it was just interpreted as a control code, nothing to remove if (resultLength > 0 && lastCharacterWasPrintable) { if (codeSet == CODE_CODE_C) { result.Remove(resultLength - 2, resultLength); } else { result.Remove(resultLength - 1, resultLength); } } String resultString = result.ToString(); if (resultString.Length == 0) { // Almost surely a false positive throw new ReaderException(); } float left = (float) (startPatternInfo[1] + startPatternInfo[0]) / 2.0f; float right = (float) (nextStart + lastStart) / 2.0f; return new Result( resultString, null, new ResultPoint[]{ new GenericResultPoint(left, (float) rowNumber), new GenericResultPoint(right, (float) rowNumber)}, BarcodeFormat.CODE_128); } } }