Tighten up Printer bootloader implementation; fold the IsHEX() function logic into...

[pub/USBasp.git] / Bootloaders / Printer / BootloaderPrinter.c

diff --git a/Bootloaders/Printer/BootloaderPrinter.c b/Bootloaders/Printer/BootloaderPrinter.c
index 023ec3e..b80c082 100644 (file)
--- a/Bootloaders/Printer/BootloaderPrinter.c
+++ b/Bootloaders/Printer/BootloaderPrinter.c
@@ -134,37 +134,23 @@ void Application_Jump_Check(void)
 }
 
 /**
- * Determines if a given input byte of data is an ASCII encoded HEX value.
- *
- * \note Input HEX bytes are expected to be in uppercase only.
- *
- * \param[in] Byte  ASCII byte of data to check
- *
- * \return Boolean \c true if the input data is ASCII encoded HEX, \c false otherwise.
- */
-static bool IsHex(const char Byte)
-{
-       return ((Byte >= 'A') && (Byte <= 'F')) ||
-              ((Byte >= '0') && (Byte <= '9'));
-}
-
-/**
  * Converts a given input byte of data from an ASCII encoded HEX value to an integer value.
  *
  * \note Input HEX bytes are expected to be in uppercase only.
  *
  * \param[in] Byte  ASCII byte of data to convert
  *
- * \return Integer converted value of the input ASCII encoded HEX byte of data.
+ * \return Integer converted value of the input ASCII encoded HEX byte of data, or -1 if the
+ *         input is not valid ASCII encoded HEX.
  */
-static uint8_t HexToDecimal(const char Byte)
+static int8_t HexToDecimal(const char Byte)
 {
        if ((Byte >= 'A') && (Byte <= 'F'))
          return (10 + (Byte - 'A'));
        else if ((Byte >= '0') && (Byte <= '9'))
          return (Byte - '0');
 
-       return 0;
+       return -1;
 }
 
 /**
@@ -180,7 +166,6 @@ static void ParseIntelHEXByte(const char ReadCharacter)
        {
                HEXParser.Checksum     = 0;
                HEXParser.CurrAddress  = HEXParser.CurrBaseAddress;
-               HEXParser.ParserState  = HEX_PARSE_STATE_WAIT_LINE;
                HEXParser.ReadMSB      = false;
 
                /* ASCII ':' indicates the start of a new HEX record */
@@ -191,11 +176,12 @@ static void ParseIntelHEXByte(const char ReadCharacter)
        }
 
        /* Only allow ASCII HEX encoded digits, ignore all other characters */
-       if (!IsHex(ReadCharacter))
+       int8_t ReadCharacterDec = HexToDecimal(ReadCharacter);
+       if (ReadCharacterDec < 0)
          return;
 
        /* Read and convert the next nibble of data from the current character */
-       HEXParser.Data    = (HEXParser.Data << 4) | HexToDecimal(ReadCharacter);
+       HEXParser.Data    = (HEXParser.Data << 4) | ReadCharacterDec;
        HEXParser.ReadMSB = !HEXParser.ReadMSB;
 
        /* Only process further when a full byte (two nibbles) have been read */