diff options
| -rw-r--r-- | lexers/LexHex.cxx | 95 |
1 files changed, 60 insertions, 35 deletions
diff --git a/lexers/LexHex.cxx b/lexers/LexHex.cxx index 21ce8790e..231142a1c 100644 --- a/lexers/LexHex.cxx +++ b/lexers/LexHex.cxx @@ -57,6 +57,8 @@ static inline bool IsNewline(const int ch); static int GetHexaChar(char hd1, char hd2); static int GetHexaChar(unsigned int pos, Accessor &styler); static bool ForwardWithinLine(StyleContext &sc, int nb = 1); +static int CountByteCount(unsigned int startPos, int uncountedDigits, Accessor &styler); +static int CalcChecksum(unsigned int startPos, int cnt, bool twosCompl, Accessor &styler); // prototypes for file format specific helper functions static unsigned int GetSrecRecStartPosition(unsigned int pos, Accessor &styler); @@ -129,6 +131,62 @@ static bool ForwardWithinLine(StyleContext &sc, int nb) return true; } +// Count the number of digit pairs from <startPos> till end of record, ignoring +// <uncountedDigits> digits. +// If the record is too short, a negative count may be returned. +static int CountByteCount(unsigned int startPos, int uncountedDigits, Accessor &styler) +{ + int cnt; + unsigned int pos; + + pos = startPos; + + while (!IsNewline(styler.SafeGetCharAt(pos, '\n'))) { + pos++; + } + + // number of digits in this line minus number of digits of uncounted fields + cnt = static_cast<int>(pos - startPos) - uncountedDigits; + + // Prepare round up if odd (digit pair incomplete), this way the byte + // count is considered to be valid if the checksum is incomplete. + if (cnt >= 0) { + cnt++; + } + + // digit pairs + cnt /= 2; + + return cnt; +} + +// Calculate the checksum of the record. +// <startPos> is the position of the first character of the starting digit +// pair, <cnt> is the number of digit pairs. +static int CalcChecksum(unsigned int startPos, int cnt, bool twosCompl, Accessor &styler) +{ + int cs = 0; + + for (unsigned int pos = startPos; pos < startPos + cnt; pos += 2) { + int val = GetHexaChar(pos, styler); + + if (val < 0) { + return val; + } + + // overflow does not matter + cs += val; + } + + if (twosCompl) { + // low byte of two's complement + return -cs & 0xFF; + } else { + // low byte of one's complement + return ~cs & 0xFF; + } +} + // Get the position of the record "start" field (first character in line) in // the record around position <pos>. static unsigned int GetSrecRecStartPosition(unsigned int pos, Accessor &styler) @@ -159,28 +217,7 @@ static int GetSrecByteCount(unsigned int recStartPos, Accessor &styler) // If the record is too short, a negative count may be returned. static int CountSrecByteCount(unsigned int recStartPos, Accessor &styler) { - int cnt; - unsigned int pos; - - pos = recStartPos; - - while (!IsNewline(styler.SafeGetCharAt(pos, '\n'))) { - pos++; - } - - // number of digits in this line minus number of digits of uncounted fields - cnt = static_cast<int>(pos - recStartPos) - 4; - - // Prepare round up if odd (digit pair incomplete), this way the byte - // count is considered to be valid if the checksum is incomplete. - if (cnt >= 0) { - cnt++; - } - - // digit pairs - cnt /= 2; - - return cnt; + return CountByteCount(recStartPos, 4, styler); } // Get the size of the "address" field. @@ -247,23 +284,11 @@ static int GetSrecChecksum(unsigned int recStartPos, Accessor &styler) static int CalcSrecChecksum(unsigned int recStartPos, Accessor &styler) { int byteCount; - unsigned int cs = 0; byteCount = GetSrecByteCount(recStartPos, styler); // sum over "byte count", "address" and "data" fields (6..510 digits) - for (unsigned int pos = recStartPos + 2; pos < recStartPos + 2 + byteCount * 2; pos += 2) { - int val = GetHexaChar(pos, styler); - - if (val < 0) { - return val; - } - - cs += val; - } - - // low byte of one's complement - return (~cs) & 0xFF; + return CalcChecksum(recStartPos + 2, byteCount * 2, false, styler); } static void ColouriseSrecDoc(unsigned int startPos, int length, int initStyle, WordList *[], Accessor &styler) |