text: /*
   * Copyright 2012 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.
   */
  
  @class ZXBitArray, ZXByteMatrix, ZXQRCodeErrorCorrectionLevel, ZXQRCodeVersion;
  
  @interface ZXQRCodeMatrixUtil : NSObject
  
  // Set all cells to -1.  -1 means that the cell is empty (not set yet).
  + (void)clearMatrix:(ZXByteMatrix *)matrix;
  
  // Build 2D matrix of QR Code from "dataBits" with "ecLevel", "version" and "getMaskPattern". On
  // success, store the result in "matrix" and return true.
  + (BOOL)buildMatrix:(ZXBitArray *)dataBits ecLevel:(ZXQRCodeErrorCorrectionLevel *)ecLevel version:(ZXQRCodeVersion *)version maskPattern:(int)maskPattern matrix:(ZXByteMatrix *)matrix error:(NSError **)error;
  
  // Embed basic patterns. On success, modify the matrix and return true.
  // The basic patterns are:
  // - Position detection patterns
  // - Timing patterns
  // - Dark dot at the left bottom corner
  // - Position adjustment patterns, if need be
  + (BOOL)embedBasicPatterns:(ZXQRCodeVersion *)version matrix:(ZXByteMatrix *)matrix error:(NSError **)error;
  
  // Embed type information. On success, modify the matrix.
  + (BOOL)embedTypeInfo:(ZXQRCodeErrorCorrectionLevel *)ecLevel maskPattern:(int)maskPattern matrix:(ZXByteMatrix *)matrix error:(NSError **)error;
  
  // Embed version information if need be. On success, modify the matrix and return true.
  // See 8.10 of JISX0510:2004 (p.47) for how to embed version information.
  + (BOOL)maybeEmbedVersionInfo:(ZXQRCodeVersion *)version matrix:(ZXByteMatrix *)matrix error:(NSError **)error;
  
  // Embed "dataBits" using "getMaskPattern". On success, modify the matrix and return true.
  // For debugging purposes, it skips masking process if "getMaskPattern" is -1.
  // See 8.7 of JISX0510:2004 (p.38) for how to embed data bits.
  + (BOOL)embedDataBits:(ZXBitArray *)dataBits maskPattern:(int)maskPattern matrix:(ZXByteMatrix *)matrix error:(NSError **)error;
  
  // Return the position of the most significant bit set (to one) in the "value". The most
  // significant bit is position 32. If there is no bit set, return 0. Examples:
  // - findMSBSet(0) => 0
  // - findMSBSet(1) => 1
  // - findMSBSet(255) => 8
  + (int)findMSBSet:(int)value;
  
  // Calculate BCH (Bose-Chaudhuri-Hocquenghem) code for "value" using polynomial "poly". The BCH
  // code is used for encoding type information and version information.
  // Example: Calculation of version information of 7.
  // f(x) is created from 7.
  //   - 7 = 000111 in 6 bits
  //   - f(x) = x^2 + x^1 + x^0
  // g(x) is given by the standard (p. 67)
  //   - g(x) = x^12 + x^11 + x^10 + x^9 + x^8 + x^5 + x^2 + 1
  // Multiply f(x) by x^(18 - 6)
  //   - f'(x) = f(x) * x^(18 - 6)
  //   - f'(x) = x^14 + x^13 + x^12
  // Calculate the remainder of f'(x) / g(x)
  //         x^2
  //         __________________________________________________
  //   g(x) )x^14 + x^13 + x^12
  //         x^14 + x^13 + x^12 + x^11 + x^10 + x^7 + x^4 + x^2
  //         --------------------------------------------------
  //                              x^11 + x^10 + x^7 + x^4 + x^2
  //
  // The remainder is x^11 + x^10 + x^7 + x^4 + x^2
  // Encode it in binary: 110010010100
  // The return value is 0xc94 (1100 1001 0100)
  //
  // Since all coefficients in the polynomials are 1 or 0, we can do the calculation by bit
  // operations. We don't care if cofficients are positive or negative.
  + (int)calculateBCHCode:(int)value poly:(int)poly;
  
  // Make bit vector of type information. On success, store the result in "bits" and return true.
  // Encode error correction level and mask pattern. See 8.9 of
  // JISX0510:2004 (p.45) for details.
  + (BOOL)makeTypeInfoBits:(ZXQRCodeErrorCorrectionLevel *)ecLevel maskPattern:(int)maskPattern bits:(ZXBitArray *)bits error:(NSError **)error;
  
  // Make bit vector of version information. On success, store the result in "bits" and return true.
  // See 8.10 of JISX0510:2004 (p.45) for details.
  + (BOOL)makeVersionInfoBits:(ZXQRCodeVersion *)version bits:(ZXBitArray *)bits error:(NSError **)error;
  
  @end
  