Especially automated batch editing in order to avoid human error or repetitive tasks. Result.Append(buffer.Automated video editing with Xojo For years we use Xojo from time to time to write little apps to do video editing. Position = buffer.InStr(position, eol) If position > 0 Then Private Function GetNextObjects(t As TextInputStream) As String()ĭim buffer As String = rest + ConvertEncoding(t.Read(4096), Encodings.UTF8) How do I have to modify the code for BinaryStream? All three EndOfLine encodings have to be taken into account when reading the code. So what I need is a method that returns a Pair(start, length) as result:įunction GetNextObjects(bs As BinaryStream) As Pair() the offset (start position) and the size of the object (both logically as integer values). It is important that no TextEncoding is assigned, because I have to manipulate bytes later and therefore only need the object boundaries, i.e. Tim’s code has worked very well so far, but now I need a variant that works with a BinaryStream instead of TextInputStream. Here is a debugged version of the method: Function GetNextObject(infile as textinputstream) As String One problem was that I left out a bit of cleanup, where after the last object is found, we need to clear the lines() array. it doesn’t matter if the chunk contains an incomplete line, the rest of that line will be appended before it gets processed.instead of repeating the code that searches for the next object, this code could be made recursive, which would make it shorter as well as allow for objects that are longer than 1MB.for n = 1 to ubound(lines) will simply skip the loop if ubound(lines) is less than 1.STATIC allows the lines() array to survive between calls to the function.this is forum code, untested, and may require debugging.Instring = instring + infile.read(1000000) function GetNextObject(infile as textinputstream) as Stringĭim instring, theobject, remainder as string That will make it easier to adapt into your existing routines. Abstract your file reading routine into a function that returns a string containing a single object. Since memory is an issue, we’re going to trade memory for speed/complexity. You can just as easily use a string and split it into an array. I only used that as an example because you mentioned them in your post. Really, it doesn’t have to be a memoryblock. Return binaryTextData.stringValue( 0, binaryTextData.size)īy using Chunks, how could i show the parsing progress (each line) to with a Progressbar? How to use Chunks and MemoryBlocks, and how to design the program’s performance well? I am using the new Xojo Rowlands gave me this code:ĭim binaryTextData as new memoryblock( theFile.length)īinaryTextData.stringValue( position, chunkSize ) = ts.read( chunksize ) That’s why dividing up Chunks should be difficult, right? Because it could happen that the splitting happens in the middle of an object. Each object can contain any number of properties. The properties of the objects are then subordinate lines, each starting with a 1 (one). Objects, recognizable by the fact that the line begins with a 0 (zero). The structure of my files is schematic this: Dakin also writes this in his book “I Wish I Knew How To… Use MemoryBlocks with Xojo”. I have read about Chunks several times and that the use of MemoryBlocks is much better and faster. I can’t read them in this way, because then the RAM usage rises fast to 3-4 GByte. I also have files that are 669 MB (millions of lines) in size. The performance of the program then increases considerably (RAM utilization, etc.). This works wonderfully as long as the text files are smaller than 150 MB, with larger files it will be difficult. Then I pass through the array and can parse the contents of each line. So far, I’m reading text files via TextinputStream and then handing over their contents (lines) to a string array. I’m trying to understand how Chunks works.
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