"The code is exactly
how I would like to write code and the algorithms used are very
efficient and well-documented."
Van T. Dinh, Microsoft MVP
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Class: CRLE
Class that implements run length encoding.
This Run Length Encoding algorithm reduces strings of recurring characters to a single character, followed by a count of how many times the character occurred.
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Procedure Name
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Type
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Description
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(Declarations)
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Declarations
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Declarations and private variables for the CRLE class
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InputFileName
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Property
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Sets the input file name
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OutputFileName
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Property
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Sets the output file name
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Compress
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Method
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Compresses the input file to the output file
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CompressString
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Method
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Compresses an input string
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dblToLong
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Private
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Performs an unsigned conversion from a Double value to a Long value.
This function correctly handles doubles greater than 2,147,483,647 and less than or equal to 4,294,967,295.
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Decompress
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Method
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Decompresses the input file to the output file
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DecompressString
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Method
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Decompresses a string that was previously compressed using the CompressString method of this class.
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ExpandBufferRun
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Private
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Writes a run of bytes to a buffer
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ExpandRun
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Private
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Writes a run of bytes to the file.
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HiByte
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Private
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Returns the high byte of the passed integer
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HiWord
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Private
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Returns the high integer of the passed long
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IntToLong
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Private
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Converts an Integer value to a Long value, treating the integer as unsigned.
For example, performing the following assignment
lngNumber = -1
assigns -1 to the variable lngNumber. However, This assignment
lngNumber = IntToLong(-1)
assigns 65,535 to lngNumber.
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LoByte
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Private
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Returns the low byte of the passed integer
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LongToInt
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Private
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Performs an unsigned conversion from a Long value to an integer value
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LoWord
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Private
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Returns the low integer of the passed long
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ReadFile
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Private
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Reads the specified number of bytes from the file.
Using this function significantly increases the speed of processing files. The alternative to using a file buffer is reading a byte at a time from the file
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Shll
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Private
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Shifts a numeric Value left the specified number of bits.
Left shifting can be defined as a multiplication operation. For the number of bits we want to shift a value to the left, we need to raise two to that power, then multiply the result by our original value.
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WriteBufferRun
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Private
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Writes a run of bytes to the output buffer
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WriteRun
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Private
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Writes a run of bytes to the file.
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