GenCode128 project (barcode generation) added.

GenCode128/Code128Code.cs

@@ -0,0 +1,139 @@
+namespace GenCode128
+{
+    /// <summary>
+    /// Static tools for determining codes for individual characters in the content
+    /// </summary>
+    public static class Code128Code
+    {
+        private const int CShift = 98;
+        private const int CCodeA = 101;
+        private const int CCodeB = 100;
+        private const int CStartA = 103;
+        private const int CStartB = 104;
+        private const int CStop = 106;
+        
+        /// <summary>
+        /// Indicates which code sets can represent a character -- CodeA, CodeB, or either
+        /// </summary>
+        public enum CodeSetAllowed
+        {
+            CodeA,
+            CodeB,
+            CodeAorB
+        }
+
+        /// <summary>
+        /// Get the Code128 code value(s) to represent an ASCII character, with 
+        /// optional look-ahead for length optimization
+        /// </summary>
+        /// <param name="charAscii">The ASCII value of the character to translate</param>
+        /// <param name="lookAheadAscii">The next character in sequence (or -1 if none)</param>
+        /// <param name="currentCodeSet">The current codeset, that the returned codes need to follow;
+        /// if the returned codes change that, then this value will be changed to reflect it</param>
+        /// <returns>An array of integers representing the codes that need to be output to produce the 
+        /// given character</returns>
+        public static int[] CodesForChar(int charAscii, int lookAheadAscii, ref CodeSet currentCodeSet)
+        {
+            int[] result;
+            var shifter = -1;
+
+            if (!CharCompatibleWithCodeset(charAscii, currentCodeSet))
+            {
+                // if we have a lookahead character AND if the next character is ALSO not compatible
+                if ((lookAheadAscii != -1) && !CharCompatibleWithCodeset(lookAheadAscii, currentCodeSet))
+                {
+                    // we need to switch code sets
+                    switch (currentCodeSet)
+                    {
+                        case CodeSet.CodeA:
+                            shifter = CCodeB;
+                            currentCodeSet = CodeSet.CodeB;
+                            break;
+                        case CodeSet.CodeB:
+                            shifter = CCodeA;
+                            currentCodeSet = CodeSet.CodeA;
+                            break;
+                    }
+                }
+                else
+                {
+                    // no need to switch code sets, a temporary SHIFT will suffice
+                    shifter = CShift;
+                }
+            }
+
+            if (shifter != -1)
+            {
+                result = new int[2];
+                result[0] = shifter;
+                result[1] = CodeValueForChar(charAscii);
+            }
+            else
+            {
+                result = new int[1];
+                result[0] = CodeValueForChar(charAscii);
+            }
+
+            return result;
+        }
+
+        /// <summary>
+        /// Tells us which codesets a given character value is allowed in
+        /// </summary>
+        /// <param name="charAscii">ASCII value of character to look at</param>
+        /// <returns>Which codeset(s) can be used to represent this character</returns>
+        public static CodeSetAllowed CodesetAllowedForChar(int charAscii)
+        {
+            if (charAscii >= 32 && charAscii <= 95)
+            {
+                return CodeSetAllowed.CodeAorB;
+            }
+            else
+            {
+                return charAscii < 32 ? CodeSetAllowed.CodeA : CodeSetAllowed.CodeB;
+            }
+        }
+
+        /// <summary>
+        /// Determine if a character can be represented in a given codeset
+        /// </summary>
+        /// <param name="charAscii">character to check for</param>
+        /// <param name="currentCodeSet">codeset context to test</param>
+        /// <returns>true if the codeset contains a representation for the ASCII character</returns>
+        public static bool CharCompatibleWithCodeset(int charAscii, CodeSet currentCodeSet)
+        {
+            var csa = CodesetAllowedForChar(charAscii);
+            return csa == CodeSetAllowed.CodeAorB || (csa == CodeSetAllowed.CodeA && currentCodeSet == CodeSet.CodeA)
+                   || (csa == CodeSetAllowed.CodeB && currentCodeSet == CodeSet.CodeB);
+        }
+
+        /// <summary>
+        /// Gets the integer code128 code value for a character (assuming the appropriate code set)
+        /// </summary>
+        /// <param name="charAscii">character to convert</param>
+        /// <returns>code128 symbol value for the character</returns>
+        public static int CodeValueForChar(int charAscii)
+        {
+            return charAscii >= 32 ? charAscii - 32 : charAscii + 64;
+        }
+
+        /// <summary>
+        /// Return the appropriate START code depending on the codeset we want to be in
+        /// </summary>
+        /// <param name="cs">The codeset you want to start in</param>
+        /// <returns>The code128 code to start a barcode in that codeset</returns>
+        public static int StartCodeForCodeSet(CodeSet cs)
+        {
+            return cs == CodeSet.CodeA ? CStartA : CStartB;
+        }
+
+        /// <summary>
+        /// Return the Code128 stop code
+        /// </summary>
+        /// <returns>the stop code</returns>
+        public static int StopCode()
+        {
+            return CStop;
+        }
+    }
+}