ZXingObjC/pdf417/encoder/ZXPDF417HighLevelEncoder.m - nest-mobile-client-iphone/4.5.2/ZXingObjC - Git at Google

 /*
  * Copyright 2006 Jeremias Maerki in part, and ZXing Authors in part
  *
  * 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.
  */

 #import "ZXErrors.h"
 #import "ZXPDF417HighLevelEncoder.h"

 /**
  * code for Text compaction
  */
 const int TEXT_COMPACTION = 0;

 /**
  * code for Byte compaction
  */
 const int BYTE_COMPACTION = 1;

 /**
  * code for Numeric compaction
  */
 const int NUMERIC_COMPACTION = 2;

 /**
  * Text compaction submode Alpha
  */
 const int SUBMODE_ALPHA = 0;

 /**
  * Text compaction submode Lower
  */
 const int SUBMODE_LOWER = 1;

 /**
  * Text compaction submode Mixed
  */
 const int SUBMODE_MIXED = 2;

 /**
  * Text compaction submode Punctuation
  */
 const int SUBMODE_PUNCTUATION = 3;

 /**
  * mode latch to Text Compaction mode
  */
 const int LATCH_TO_TEXT = 900;

 /**
  * mode latch to Byte Compaction mode (number of characters NOT a multiple of 6)
  */
 const int LATCH_TO_BYTE_PADDED = 901;

 /**
  * mode latch to Numeric Compaction mode
  */
 const int LATCH_TO_NUMERIC = 902;

 /**
  * mode shift to Byte Compaction mode
  */
 const int SHIFT_TO_BYTE = 913;

 /**
  * mode latch to Byte Compaction mode (number of characters a multiple of 6)
  */
 const int LATCH_TO_BYTE = 924;

 /**
  * Raw code table for text compaction Mixed sub-mode
  */
 const int TEXT_MIXED_RAW_LEN = 30;
 const int8_t TEXT_MIXED_RAW[TEXT_MIXED_RAW_LEN] = {
   48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 38, 13, 9, 44, 58,
   35, 45, 46, 36, 47, 43, 37, 42, 61, 94, 0, 32, 0, 0, 0};

 /**
  * Raw code table for text compaction: Punctuation sub-mode
  */
 const int TEXT_PUNCTUATION_RAW_LEN = 30;
 const int8_t TEXT_PUNCTUATION_RAW[TEXT_PUNCTUATION_RAW_LEN] = {
   59, 60, 62, 64, 91, 92, 93, 95, 96, 126, 33, 13, 9, 44, 58,
   10, 45, 46, 36, 47, 34, 124, 42, 40, 41, 63, 123, 125, 39, 0};

 const int MIXED_TABLE_LEN = 128;
 unichar MIXED_TABLE[MIXED_TABLE_LEN];

 const int PUNCTUATION_LEN = 128;
 unichar PUNCTUATION[PUNCTUATION_LEN];

 @implementation ZXPDF417HighLevelEncoder

 + (void)initialize {
   //Construct inverse lookups
   for (int i = 0; i < MIXED_TABLE_LEN; i++) {
     MIXED_TABLE[i] = 0xFF;
   }
   for (int8_t i = 0; i < TEXT_MIXED_RAW_LEN; i++) {
     int8_t b = TEXT_MIXED_RAW[i];
     if (b > 0) {
       MIXED_TABLE[b] = i;
     }
   }
   for (int i = 0; i < PUNCTUATION_LEN; i++) {
     PUNCTUATION[i] = 0xFF;
   }
   for (int8_t i = 0; i < TEXT_PUNCTUATION_RAW_LEN; i++) {
     int8_t b = TEXT_PUNCTUATION_RAW[i];
     if (b > 0) {
       PUNCTUATION[b] = i;
     }
   }
 }

 /**
  * Converts the message to a byte array using the default encoding (cp437) as defined by the
  * specification
  */
 + (int8_t *)bytesForMessage:(NSString *)msg {
   return (int8_t *)[[msg dataUsingEncoding:(NSStringEncoding) 0x80000400] bytes];
 }

 /**
  * Performs high-level encoding of a PDF417 message using the algorithm described in annex P
  * of ISO/IEC 15438:2001(E).  If byte compaction has been selected, then only byte compaction
  * is used.
  */
 + (NSString *)encodeHighLevel:(NSString *)msg compaction:(ZXCompaction)compaction error:(NSError **)error {
   int8_t *bytes = NULL; //Fill later and only if needed

   //the codewords 0..928 are encoded as Unicode characters
   NSMutableString *sb = [NSMutableString stringWithCapacity:msg.length];

   NSUInteger len = msg.length;
   int p = 0;
   int textSubMode = SUBMODE_ALPHA;

   // User selected encoding mode
   if (compaction == ZX_COMPACTION_TEXT) {
     [self encodeText:msg startpos:p count:(int)len buffer:sb initialSubmode:textSubMode];
   } else if (compaction == ZX_COMPACTION_BYTE) {
     bytes = [self bytesForMessage:msg];
     [self encodeBinary:bytes startpos:p count:(int)msg.length startmode:BYTE_COMPACTION buffer:sb];
   } else if (compaction == ZX_COMPACTION_NUMERIC) {
     [sb appendFormat:@"%C", (unichar) LATCH_TO_NUMERIC];
     [self encodeNumeric:msg startpos:p count:(int)len buffer:sb];
   } else {
     int encodingMode = TEXT_COMPACTION; //Default mode, see 4.4.2.1
     while (p < len) {
       int n = [self determineConsecutiveDigitCount:msg startpos:p];
       if (n >= 13) {
         [sb appendFormat:@"%C", (unichar) LATCH_TO_NUMERIC];
         encodingMode = NUMERIC_COMPACTION;
         textSubMode = SUBMODE_ALPHA; //Reset after latch
         [self encodeNumeric:msg startpos:p count:n buffer:sb];
         p += n;
       } else {
         int t = [self determineConsecutiveTextCount:msg startpos:p];
         if (t >= 5 || n == len) {
           if (encodingMode != TEXT_COMPACTION) {
             [sb appendFormat:@"%C", (unichar) LATCH_TO_TEXT];
             encodingMode = TEXT_COMPACTION;
             textSubMode = SUBMODE_ALPHA; //start with submode alpha after latch
           }
           textSubMode = [self encodeText:msg startpos:p count:t buffer:sb initialSubmode:textSubMode];
           p += t;
         } else {
           if (bytes == NULL) {
             bytes = [self bytesForMessage:msg];
           }
           int b = [self determineConsecutiveBinaryCount:msg bytes:bytes startpos:p error:error];
           if (b == -1) {
             return nil;
           } else if (b == 0) {
             b = 1;
           }
           if (b == 1 && encodingMode == TEXT_COMPACTION) {
             //Switch for one byte (instead of latch)
             [self encodeBinary:bytes startpos:p count:1 startmode:TEXT_COMPACTION buffer:sb];
           } else {
             //Mode latch performed by encodeBinary
             [self encodeBinary:bytes startpos:p count:b startmode:encodingMode buffer:sb];
             encodingMode = BYTE_COMPACTION;
             textSubMode = SUBMODE_ALPHA; //Reset after latch
           }
           p += b;
         }
       }
     }
   }

   return sb;
 }

 /**
  * Encode parts of the message using Text Compaction as described in ISO/IEC 15438:2001(E),
  * chapter 4.4.2.
  */
 + (int)encodeText:(NSString *)msg startpos:(int)startpos count:(int)count buffer:(NSMutableString *)sb initialSubmode:(int)initialSubmode {
   NSMutableString *tmp = [NSMutableString stringWithCapacity:count];
   int submode = initialSubmode;
   int idx = 0;
   while (true) {
     unichar ch = [msg characterAtIndex:startpos + idx];
     switch (submode) {
       case SUBMODE_ALPHA:
         if ([self isAlphaUpper:ch]) {
           if (ch == ' ') {
             [tmp appendFormat:@"%C", (unichar) 26]; //space
           } else {
             [tmp appendFormat:@"%C", (unichar) (ch - 65)];
           }
         } else {
           if ([self isAlphaLower:ch]) {
             submode = SUBMODE_LOWER;
             [tmp appendFormat:@"%C", (unichar) 27]; //ll
             continue;
           } else if ([self isMixed:ch]) {
             submode = SUBMODE_MIXED;
             [tmp appendFormat:@"%C", (unichar) 28]; //ml
             continue;
           } else {
             [tmp appendFormat:@"%C", (unichar) 29]; //ps
             [tmp appendFormat:@"%C", PUNCTUATION[ch]];
             break;
           }
         }
         break;
       case SUBMODE_LOWER:
         if ([self isAlphaLower:ch]) {
           if (ch == ' ') {
             [tmp appendFormat:@"%C", (unichar) 26]; //space
           } else {
             [tmp appendFormat:@"%C", (unichar) (ch - 97)];
           }
         } else {
           if ([self isAlphaUpper:ch]) {
             [tmp appendFormat:@"%C", (unichar) 27]; //as
             [tmp appendFormat:@"%C", (unichar) (ch - 65)];
             //space cannot happen here, it is also in "Lower"
             break;
           } else if ([self isMixed:ch]) {
             submode = SUBMODE_MIXED;
             [tmp appendFormat:@"%C", (unichar) 28]; //ml
             continue;
           } else {
             [tmp appendFormat:@"%C", (unichar) 29]; //ps
             [tmp appendFormat:@"%C", PUNCTUATION[ch]];
             break;
           }
         }
         break;
       case SUBMODE_MIXED:
         if ([self isMixed:ch]) {
           [tmp appendFormat:@"%C", MIXED_TABLE[ch]]; //as
         } else {
           if ([self isAlphaUpper:ch]) {
             submode = SUBMODE_ALPHA;
             [tmp appendFormat:@"%C", (unichar) 28]; //al
             continue;
           } else if ([self isAlphaLower:ch]) {
             submode = SUBMODE_LOWER;
             [tmp appendFormat:@"%C", (unichar) 27]; //ll
             continue;
           } else {
             if (startpos + idx + 1 < count) {
               char next = [msg characterAtIndex:startpos + idx + 1];
               if ([self isPunctuation:next]) {
                 submode = SUBMODE_PUNCTUATION;
                 [tmp appendFormat:@"%C", (unichar) 25]; //pl
                 continue;
               }
             }
             [tmp appendFormat:@"%C", (unichar) 29]; //ps
             [tmp appendFormat:@"%C", PUNCTUATION[ch]];
           }
         }
         break;
       default: //SUBMODE_PUNCTUATION
         if ([self isPunctuation:ch]) {
           [tmp appendFormat:@"%C", PUNCTUATION[ch]];
         } else {
           submode = SUBMODE_ALPHA;
           [tmp appendFormat:@"%C", (unichar) 29]; //al
           continue;
         }
     }
     idx++;
     if (idx >= count) {
       break;
     }
   }
   unichar h = 0;
   NSUInteger len = tmp.length;
   for (int i = 0; i < len; i++) {
     BOOL odd = (i % 2) != 0;
     if (odd) {
       h = (unichar) ((h * 30) + [tmp characterAtIndex:i]);
       [sb appendFormat:@"%C", h];
     } else {
       h = [tmp characterAtIndex:i];
     }
   }
   if ((len % 2) != 0) {
     [sb appendFormat:@"%C", (unichar) ((h * 30) + 29)]; //ps
   }
   return submode;
 }

 /**
  * Encode parts of the message using Byte Compaction as described in ISO/IEC 15438:2001(E),
  * chapter 4.4.3. The Unicode characters will be converted to binary using the cp437
  * codepage.
  */
 + (void)encodeBinary:(int8_t *)bytes startpos:(int)startpos count:(int)count startmode:(int)startmode buffer:(NSMutableString *)sb {
   if (count == 1 && startmode == TEXT_COMPACTION) {
     [sb appendFormat:@"%C", (unichar) SHIFT_TO_BYTE];
   }

   int idx = startpos;
   // Encode sixpacks
   if (count >= 6) {
     [sb appendFormat:@"%C", (unichar) LATCH_TO_BYTE];
     const int charsLen = 5;
     unichar chars[charsLen];
     memset(chars, 0, charsLen * sizeof(unichar));
     while ((startpos + count - idx) >= 6) {
       long t = 0;
       for (int i = 0; i < 6; i++) {
         t <<= 8;
         t += bytes[idx + i] & 0xff;
       }
       for (int i = 0; i < 5; i++) {
         chars[i] = (unichar) (t % 900);
         t /= 900;
       }
       for (int i = charsLen - 1; i >= 0; i--) {
         [sb appendFormat:@"%C", chars[i]];
       }
       idx += 6;
     }
   }
   //Encode rest (remaining n<5 bytes if any)
   if (idx < startpos + count) {
     [sb appendFormat:@"%C", (unichar) LATCH_TO_BYTE_PADDED];
   }
   for (int i = idx; i < startpos + count; i++) {
     int ch = bytes[i] & 0xff;
     [sb appendFormat:@"%C", (unichar)ch];
   }
 }

 + (void)encodeNumeric:(NSString *)msg startpos:(int)startpos count:(int)count buffer:(NSMutableString *)sb {
   int idx = 0;
   NSMutableString *tmp = [NSMutableString stringWithCapacity:count / 3 + 1];
   while (idx < count - 1) {
     [tmp setString:@""];
     int len = MIN(44, count - idx);
     NSString *part = [@"1" stringByAppendingString:[msg substringWithRange:NSMakeRange(startpos + idx, len)]];
     long long bigint = [part longLongValue];
     do {
       long c = bigint % 900;
       [tmp appendFormat:@"%C", (unichar) c];
       bigint /= 900;
     } while (bigint != 0);

     //Reverse temporary string
     for (int i = (int)tmp.length - 1; i >= 0; i--) {
       [sb appendFormat:@"%C", [tmp characterAtIndex:i]];
     }
     idx += len;
   }
 }

 + (BOOL)isDigit:(char)ch {
   return ch >= '0' && ch <= '9';
 }

 + (BOOL)isAlphaUpper:(char)ch {
   return ch == ' ' || (ch >= 'A' && ch <= 'Z');
 }

 + (BOOL)isAlphaLower:(char)ch {
   return ch == ' ' || (ch >= 'a' && ch <= 'z');
 }

 + (BOOL)isMixed:(char)ch {
   return MIXED_TABLE[ch] != 0xFF;
 }

 + (BOOL)isPunctuation:(char)ch {
   return PUNCTUATION[ch] != 0xFF;
 }

 + (BOOL)isText:(char)ch {
   return ch == '\t' || ch == '\n' || ch == '\r' || (ch >= 32 && ch <= 126);
 }

 /**
  * Determines the number of consecutive characters that are encodable using numeric compaction.
  */
 + (int)determineConsecutiveDigitCount:(NSString *)msg startpos:(int)startpos {
   int count = 0;
   NSUInteger len = msg.length;
   int idx = startpos;
   if (idx < len) {
     char ch = [msg characterAtIndex:idx];
     while ([self isDigit:ch] && idx < len) {
       count++;
       idx++;
       if (idx < len) {
         ch = [msg characterAtIndex:idx];
       }
     }
   }
   return count;
 }

 /**
  * Determines the number of consecutive characters that are encodable using text compaction.
  *
  * @param msg      the message
  * @param startpos the start position within the message
  * @return the requested character count
  */
 + (int)determineConsecutiveTextCount:(NSString *)msg startpos:(int)startpos {
   NSUInteger len = msg.length;
   int idx = startpos;
   while (idx < len) {
     char ch = [msg characterAtIndex:idx];
     int numericCount = 0;
     while (numericCount < 13 && [self isDigit:ch] && idx < len) {
       numericCount++;
       idx++;
       if (idx < len) {
         ch = [msg characterAtIndex:idx];
       }
     }
     if (numericCount >= 13) {
       return idx - startpos - numericCount;
     }
     if (numericCount > 0) {
       //Heuristic: All text-encodable chars or digits are binary encodable
       continue;
     }
     ch = [msg characterAtIndex:idx];

     //Check if character is encodable
     if (![self isText:ch]) {
       break;
     }
     idx++;
   }
   return idx - startpos;
 }

 /**
  * Determines the number of consecutive characters that are encodable using binary compaction.
  */
 + (int)determineConsecutiveBinaryCount:(NSString *)msg bytes:(int8_t *)bytes startpos:(int)startpos error:(NSError **)error {
   NSUInteger len = msg.length;
   int idx = startpos;
   while (idx < len) {
     char ch = [msg characterAtIndex:idx];
     int numericCount = 0;

     while (numericCount < 13 && [self isDigit:ch]) {
       numericCount++;
       //textCount++;
       int i = idx + numericCount;
       if (i >= len) {
         break;
       }
       ch = [msg characterAtIndex:i];
     }
     if (numericCount >= 13) {
       return idx - startpos;
     }
     int textCount = 0;
     while (textCount < 5 && [self isText:ch]) {
       textCount++;
       int i = idx + textCount;
       if (i >= len) {
         break;
       }
       ch = [msg characterAtIndex:i];
     }
     if (textCount >= 5) {
       return idx - startpos;
     }
     ch = [msg characterAtIndex:idx];

     //Check if character is encodable
     //Sun returns a ASCII 63 (?) for a character that cannot be mapped. Let's hope all
     //other VMs do the same
     if (bytes[idx] == 63 && ch != '?') {
       NSDictionary *userInfo = @{NSLocalizedDescriptionKey: [NSString stringWithFormat:@"Non-encodable character detected: %c (Unicode: %C)", ch, (unichar)ch]};

       if (error) *error = [[NSError alloc] initWithDomain:ZXErrorDomain code:ZXWriterError userInfo:userInfo];
       return -1;
     }
     idx++;
   }
   return idx - startpos;
 }

 @end
	/*
	* Copyright 2006 Jeremias Maerki in part, and ZXing Authors in part
	*
	* 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.
	*/

	#import "ZXErrors.h"
	#import "ZXPDF417HighLevelEncoder.h"

	/**
	* code for Text compaction
	*/
	const int TEXT_COMPACTION = 0;

	/**
	* code for Byte compaction
	*/
	const int BYTE_COMPACTION = 1;

	/**
	* code for Numeric compaction
	*/
	const int NUMERIC_COMPACTION = 2;

	/**
	* Text compaction submode Alpha
	*/
	const int SUBMODE_ALPHA = 0;

	/**
	* Text compaction submode Lower
	*/
	const int SUBMODE_LOWER = 1;

	/**
	* Text compaction submode Mixed
	*/
	const int SUBMODE_MIXED = 2;

	/**
	* Text compaction submode Punctuation
	*/
	const int SUBMODE_PUNCTUATION = 3;

	/**
	* mode latch to Text Compaction mode
	*/
	const int LATCH_TO_TEXT = 900;

	/**
	* mode latch to Byte Compaction mode (number of characters NOT a multiple of 6)
	*/
	const int LATCH_TO_BYTE_PADDED = 901;

	/**
	* mode latch to Numeric Compaction mode
	*/
	const int LATCH_TO_NUMERIC = 902;

	/**
	* mode shift to Byte Compaction mode
	*/
	const int SHIFT_TO_BYTE = 913;

	/**
	* mode latch to Byte Compaction mode (number of characters a multiple of 6)
	*/
	const int LATCH_TO_BYTE = 924;

	/**
	* Raw code table for text compaction Mixed sub-mode
	*/
	const int TEXT_MIXED_RAW_LEN = 30;
	const int8_t TEXT_MIXED_RAW[TEXT_MIXED_RAW_LEN] = {
	48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 38, 13, 9, 44, 58,
	35, 45, 46, 36, 47, 43, 37, 42, 61, 94, 0, 32, 0, 0, 0};

	/**
	* Raw code table for text compaction: Punctuation sub-mode
	*/
	const int TEXT_PUNCTUATION_RAW_LEN = 30;
	const int8_t TEXT_PUNCTUATION_RAW[TEXT_PUNCTUATION_RAW_LEN] = {
	59, 60, 62, 64, 91, 92, 93, 95, 96, 126, 33, 13, 9, 44, 58,
	10, 45, 46, 36, 47, 34, 124, 42, 40, 41, 63, 123, 125, 39, 0};

	const int MIXED_TABLE_LEN = 128;
	unichar MIXED_TABLE[MIXED_TABLE_LEN];

	const int PUNCTUATION_LEN = 128;
	unichar PUNCTUATION[PUNCTUATION_LEN];

	@implementation ZXPDF417HighLevelEncoder

	+ (void)initialize {
	//Construct inverse lookups
	for (int i = 0; i < MIXED_TABLE_LEN; i++) {
	MIXED_TABLE[i] = 0xFF;
	}
	for (int8_t i = 0; i < TEXT_MIXED_RAW_LEN; i++) {
	int8_t b = TEXT_MIXED_RAW[i];
	if (b > 0) {
	MIXED_TABLE[b] = i;
	}
	}
	for (int i = 0; i < PUNCTUATION_LEN; i++) {
	PUNCTUATION[i] = 0xFF;
	}
	for (int8_t i = 0; i < TEXT_PUNCTUATION_RAW_LEN; i++) {
	int8_t b = TEXT_PUNCTUATION_RAW[i];
	if (b > 0) {
	PUNCTUATION[b] = i;
	}
	}
	}

	/**
	* Converts the message to a byte array using the default encoding (cp437) as defined by the
	* specification
	*/
	+ (int8_t )bytesForMessage:(NSString )msg {
	return (int8_t *)[[msg dataUsingEncoding:(NSStringEncoding) 0x80000400] bytes];
	}

	/**
	* Performs high-level encoding of a PDF417 message using the algorithm described in annex P
	* of ISO/IEC 15438:2001(E). If byte compaction has been selected, then only byte compaction
	* is used.
	*/
	+ (NSString )encodeHighLevel:(NSString )msg compaction:(ZXCompaction)compaction error:(NSError **)error {
	int8_t *bytes = NULL; //Fill later and only if needed

	//the codewords 0..928 are encoded as Unicode characters
	NSMutableString *sb = [NSMutableString stringWithCapacity:msg.length];

	NSUInteger len = msg.length;
	int p = 0;
	int textSubMode = SUBMODE_ALPHA;

	// User selected encoding mode
	if (compaction == ZX_COMPACTION_TEXT) {
	[self encodeText:msg startpos:p count:(int)len buffer:sb initialSubmode:textSubMode];
	} else if (compaction == ZX_COMPACTION_BYTE) {
	bytes = [self bytesForMessage:msg];
	[self encodeBinary:bytes startpos:p count:(int)msg.length startmode:BYTE_COMPACTION buffer:sb];
	} else if (compaction == ZX_COMPACTION_NUMERIC) {
	[sb appendFormat:@"%C", (unichar) LATCH_TO_NUMERIC];
	[self encodeNumeric:msg startpos:p count:(int)len buffer:sb];
	} else {
	int encodingMode = TEXT_COMPACTION; //Default mode, see 4.4.2.1
	while (p < len) {
	int n = [self determineConsecutiveDigitCount:msg startpos:p];
	if (n >= 13) {
	[sb appendFormat:@"%C", (unichar) LATCH_TO_NUMERIC];
	encodingMode = NUMERIC_COMPACTION;
	textSubMode = SUBMODE_ALPHA; //Reset after latch
	[self encodeNumeric:msg startpos:p count:n buffer:sb];
	p += n;
	} else {
	int t = [self determineConsecutiveTextCount:msg startpos:p];
	if (t >= 5 \|\| n == len) {
	if (encodingMode != TEXT_COMPACTION) {
	[sb appendFormat:@"%C", (unichar) LATCH_TO_TEXT];
	encodingMode = TEXT_COMPACTION;
	textSubMode = SUBMODE_ALPHA; //start with submode alpha after latch
	}
	textSubMode = [self encodeText:msg startpos:p count:t buffer:sb initialSubmode:textSubMode];
	p += t;
	} else {
	if (bytes == NULL) {
	bytes = [self bytesForMessage:msg];
	}
	int b = [self determineConsecutiveBinaryCount:msg bytes:bytes startpos:p error:error];
	if (b == -1) {
	return nil;
	} else if (b == 0) {
	b = 1;
	}
	if (b == 1 && encodingMode == TEXT_COMPACTION) {
	//Switch for one byte (instead of latch)
	[self encodeBinary:bytes startpos:p count:1 startmode:TEXT_COMPACTION buffer:sb];
	} else {
	//Mode latch performed by encodeBinary
	[self encodeBinary:bytes startpos:p count:b startmode:encodingMode buffer:sb];
	encodingMode = BYTE_COMPACTION;
	textSubMode = SUBMODE_ALPHA; //Reset after latch
	}
	p += b;
	}
	}
	}
	}

	return sb;
	}

	/**
	* Encode parts of the message using Text Compaction as described in ISO/IEC 15438:2001(E),
	* chapter 4.4.2.
	*/
	+ (int)encodeText:(NSString )msg startpos:(int)startpos count:(int)count buffer:(NSMutableString )sb initialSubmode:(int)initialSubmode {
	NSMutableString *tmp = [NSMutableString stringWithCapacity:count];
	int submode = initialSubmode;
	int idx = 0;
	while (true) {
	unichar ch = [msg characterAtIndex:startpos + idx];
	switch (submode) {
	case SUBMODE_ALPHA:
	if ([self isAlphaUpper:ch]) {
	if (ch == ' ') {
	[tmp appendFormat:@"%C", (unichar) 26]; //space
	} else {
	[tmp appendFormat:@"%C", (unichar) (ch - 65)];
	}
	} else {
	if ([self isAlphaLower:ch]) {
	submode = SUBMODE_LOWER;
	[tmp appendFormat:@"%C", (unichar) 27]; //ll
	continue;
	} else if ([self isMixed:ch]) {
	submode = SUBMODE_MIXED;
	[tmp appendFormat:@"%C", (unichar) 28]; //ml
	continue;
	} else {
	[tmp appendFormat:@"%C", (unichar) 29]; //ps
	[tmp appendFormat:@"%C", PUNCTUATION[ch]];
	break;
	}
	}
	break;
	case SUBMODE_LOWER:
	if ([self isAlphaLower:ch]) {
	if (ch == ' ') {
	[tmp appendFormat:@"%C", (unichar) 26]; //space
	} else {
	[tmp appendFormat:@"%C", (unichar) (ch - 97)];
	}
	} else {
	if ([self isAlphaUpper:ch]) {
	[tmp appendFormat:@"%C", (unichar) 27]; //as
	[tmp appendFormat:@"%C", (unichar) (ch - 65)];
	//space cannot happen here, it is also in "Lower"
	break;
	} else if ([self isMixed:ch]) {
	submode = SUBMODE_MIXED;
	[tmp appendFormat:@"%C", (unichar) 28]; //ml
	continue;
	} else {
	[tmp appendFormat:@"%C", (unichar) 29]; //ps
	[tmp appendFormat:@"%C", PUNCTUATION[ch]];
	break;
	}
	}
	break;
	case SUBMODE_MIXED:
	if ([self isMixed:ch]) {
	[tmp appendFormat:@"%C", MIXED_TABLE[ch]]; //as
	} else {
	if ([self isAlphaUpper:ch]) {
	submode = SUBMODE_ALPHA;
	[tmp appendFormat:@"%C", (unichar) 28]; //al
	continue;
	} else if ([self isAlphaLower:ch]) {
	submode = SUBMODE_LOWER;
	[tmp appendFormat:@"%C", (unichar) 27]; //ll
	continue;
	} else {
	if (startpos + idx + 1 < count) {
	char next = [msg characterAtIndex:startpos + idx + 1];
	if ([self isPunctuation:next]) {
	submode = SUBMODE_PUNCTUATION;
	[tmp appendFormat:@"%C", (unichar) 25]; //pl
	continue;
	}
	}
	[tmp appendFormat:@"%C", (unichar) 29]; //ps
	[tmp appendFormat:@"%C", PUNCTUATION[ch]];
	}
	}
	break;
	default: //SUBMODE_PUNCTUATION
	if ([self isPunctuation:ch]) {
	[tmp appendFormat:@"%C", PUNCTUATION[ch]];
	} else {
	submode = SUBMODE_ALPHA;
	[tmp appendFormat:@"%C", (unichar) 29]; //al
	continue;
	}
	}
	idx++;
	if (idx >= count) {
	break;
	}
	}
	unichar h = 0;
	NSUInteger len = tmp.length;
	for (int i = 0; i < len; i++) {
	BOOL odd = (i % 2) != 0;
	if (odd) {
	h = (unichar) ((h * 30) + [tmp characterAtIndex:i]);
	[sb appendFormat:@"%C", h];
	} else {
	h = [tmp characterAtIndex:i];
	}
	}
	if ((len % 2) != 0) {
	[sb appendFormat:@"%C", (unichar) ((h * 30) + 29)]; //ps
	}
	return submode;
	}

	/**
	* Encode parts of the message using Byte Compaction as described in ISO/IEC 15438:2001(E),
	* chapter 4.4.3. The Unicode characters will be converted to binary using the cp437
	* codepage.
	*/
	+ (void)encodeBinary:(int8_t )bytes startpos:(int)startpos count:(int)count startmode:(int)startmode buffer:(NSMutableString )sb {
	if (count == 1 && startmode == TEXT_COMPACTION) {
	[sb appendFormat:@"%C", (unichar) SHIFT_TO_BYTE];
	}

	int idx = startpos;
	// Encode sixpacks
	if (count >= 6) {
	[sb appendFormat:@"%C", (unichar) LATCH_TO_BYTE];
	const int charsLen = 5;
	unichar chars[charsLen];
	memset(chars, 0, charsLen * sizeof(unichar));
	while ((startpos + count - idx) >= 6) {
	long t = 0;
	for (int i = 0; i < 6; i++) {
	t <<= 8;
	t += bytes[idx + i] & 0xff;
	}
	for (int i = 0; i < 5; i++) {
	chars[i] = (unichar) (t % 900);
	t /= 900;
	}
	for (int i = charsLen - 1; i >= 0; i--) {
	[sb appendFormat:@"%C", chars[i]];
	}
	idx += 6;
	}
	}
	//Encode rest (remaining n<5 bytes if any)
	if (idx < startpos + count) {
	[sb appendFormat:@"%C", (unichar) LATCH_TO_BYTE_PADDED];
	}
	for (int i = idx; i < startpos + count; i++) {
	int ch = bytes[i] & 0xff;
	[sb appendFormat:@"%C", (unichar)ch];
	}
	}

	+ (void)encodeNumeric:(NSString )msg startpos:(int)startpos count:(int)count buffer:(NSMutableString )sb {
	int idx = 0;
	NSMutableString *tmp = [NSMutableString stringWithCapacity:count / 3 + 1];
	while (idx < count - 1) {
	[tmp setString:@""];
	int len = MIN(44, count - idx);
	NSString *part = [@"1" stringByAppendingString:[msg substringWithRange:NSMakeRange(startpos + idx, len)]];
	long long bigint = [part longLongValue];
	do {
	long c = bigint % 900;
	[tmp appendFormat:@"%C", (unichar) c];
	bigint /= 900;
	} while (bigint != 0);

	//Reverse temporary string
	for (int i = (int)tmp.length - 1; i >= 0; i--) {
	[sb appendFormat:@"%C", [tmp characterAtIndex:i]];
	}
	idx += len;
	}
	}

	+ (BOOL)isDigit:(char)ch {
	return ch >= '0' && ch <= '9';
	}

	+ (BOOL)isAlphaUpper:(char)ch {
	return ch == ' ' \|\| (ch >= 'A' && ch <= 'Z');
	}

	+ (BOOL)isAlphaLower:(char)ch {
	return ch == ' ' \|\| (ch >= 'a' && ch <= 'z');
	}

	+ (BOOL)isMixed:(char)ch {
	return MIXED_TABLE[ch] != 0xFF;
	}

	+ (BOOL)isPunctuation:(char)ch {
	return PUNCTUATION[ch] != 0xFF;
	}

	+ (BOOL)isText:(char)ch {
	return ch == '\t' \|\| ch == '\n' \|\| ch == '\r' \|\| (ch >= 32 && ch <= 126);
	}

	/**
	* Determines the number of consecutive characters that are encodable using numeric compaction.
	*/
	+ (int)determineConsecutiveDigitCount:(NSString *)msg startpos:(int)startpos {
	int count = 0;
	NSUInteger len = msg.length;
	int idx = startpos;
	if (idx < len) {
	char ch = [msg characterAtIndex:idx];
	while ([self isDigit:ch] && idx < len) {
	count++;
	idx++;
	if (idx < len) {
	ch = [msg characterAtIndex:idx];
	}
	}
	}
	return count;
	}

	/**
	* Determines the number of consecutive characters that are encodable using text compaction.
	*
	* @param msg the message
	* @param startpos the start position within the message
	* @return the requested character count
	*/
	+ (int)determineConsecutiveTextCount:(NSString *)msg startpos:(int)startpos {
	NSUInteger len = msg.length;
	int idx = startpos;
	while (idx < len) {
	char ch = [msg characterAtIndex:idx];
	int numericCount = 0;
	while (numericCount < 13 && [self isDigit:ch] && idx < len) {
	numericCount++;
	idx++;
	if (idx < len) {
	ch = [msg characterAtIndex:idx];
	}
	}
	if (numericCount >= 13) {
	return idx - startpos - numericCount;
	}
	if (numericCount > 0) {
	//Heuristic: All text-encodable chars or digits are binary encodable
	continue;
	}
	ch = [msg characterAtIndex:idx];

	//Check if character is encodable
	if (![self isText:ch]) {
	break;
	}
	idx++;
	}
	return idx - startpos;
	}

	/**
	* Determines the number of consecutive characters that are encodable using binary compaction.
	*/
	+ (int)determineConsecutiveBinaryCount:(NSString )msg bytes:(int8_t )bytes startpos:(int)startpos error:(NSError **)error {
	NSUInteger len = msg.length;
	int idx = startpos;
	while (idx < len) {
	char ch = [msg characterAtIndex:idx];
	int numericCount = 0;

	while (numericCount < 13 && [self isDigit:ch]) {
	numericCount++;
	//textCount++;
	int i = idx + numericCount;
	if (i >= len) {
	break;
	}
	ch = [msg characterAtIndex:i];
	}
	if (numericCount >= 13) {
	return idx - startpos;
	}
	int textCount = 0;
	while (textCount < 5 && [self isText:ch]) {
	textCount++;
	int i = idx + textCount;
	if (i >= len) {
	break;
	}
	ch = [msg characterAtIndex:i];
	}
	if (textCount >= 5) {
	return idx - startpos;
	}
	ch = [msg characterAtIndex:idx];

	//Check if character is encodable
	//Sun returns a ASCII 63 (?) for a character that cannot be mapped. Let's hope all
	//other VMs do the same
	if (bytes[idx] == 63 && ch != '?') {
	NSDictionary *userInfo = @{NSLocalizedDescriptionKey: [NSString stringWithFormat:@"Non-encodable character detected: %c (Unicode: %C)", ch, (unichar)ch]};

	if (error) *error = [[NSError alloc] initWithDomain:ZXErrorDomain code:ZXWriterError userInfo:userInfo];
	return -1;
	}
	idx++;
	}
	return idx - startpos;
	}

	@end