| Re: Is there a way to use C++ code in IDL [message #34194 is a reply to message #34193] |
Thu, 20 February 2003 11:55   |
CelticBlues
Messages: 10
Registered: February 2003
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Junior Member |
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Good stuff... thanks for the info on structs...
Ed
"Paul van Delst" <paul.vandelst@noaa.gov> wrote in message
news:3E552C46.ECC98EAB@noaa.gov...
> CelticBlues wrote:
>>
>> The file is a home grown tagged file format containing a type of image
data
>> and additional information about the conditions at the time the image
was
>> taken etc. Here is an example of what a simple file may look like:
>> ---------------------------------------------------------
>> [System]
>> Name = 1
>> [End]
>> [Data Sets] // will be at least one data set, could be as many as 3
>> DataSet1
>> [End]
>> [Files Attributes]
>> [Conditions File]
>> [Properties]
>> Name = 97918.10
>> CreateTime = Thu Sept 18 1997 at 11:21:36
>> LastAccessTime = Mon Jan 01 1601
>> LastModifiedTime = Thu Sept 18 1997 at 11:21:36
>> Size = 16882000 // bytes
>> [End]
>> [Frame information]
>> Width = 133
>> Height = 148
>> [End]
>> [End] // end [Telemetry File]
>>
>> [Saved File]
>> CreateDate = Tue Feb 11 2003 at 16:08:54
>> Width = 133
>> Height = 148
>> FrameNumber = 1
>> DataUnits = meters
>> Comment =
>> CoordinateSystem = UTM // Latlong or UTM
>> [End]
>>
>> [End] // end [Files Attributes]
>>
>> [DataBlock:DataSet1]
>> R1P1 R1P2...R1P148
>> R2P1 R2P2...R2P148
>> .
>> .
>> .
>> R133P1 R133P2...R133P148
>> [End]
>>
>> ---------------------------------------------------------
>>
>> R1P1 = Row 1 Pixel 1, R2P1 = Row 2, Pixel 2 etc.
>>
>> One additional bit of info... the datablock may not actually have CR/NL
>> after each row, i.e. it may be
>>
>> [DataBlock:DataSet1]
>> R1P1 R1P2...R1P148 R2P1 R2P2...R2P148 ... R133P1 R133P2...R133P148
>> [End]
>>
>> Ok, assume that I want to rewrite the parser in IDL... From what I
>> understand it is simple enough to read an ascii table from a file, but
what
>> about reading this type of format?
>
> The reading isn't the problem - it's the sorting of the read-in bits. :o)
>
> But, it doesn't look too difficult. Given what you know about the
allowable syntax in your
> ASCII file, you can create the structures up front, e.g.
>
> Properties = { Name: 0.0, $
> CreateTime: ' ', $
> LastAccessTime: ' ', $
> LastModifiedTime: ' ', $
> Size: 0L }
>
> FrameInformation = { Width: 0L, $
> Height: 0L }
>
> ConditionsFile = { Properties: Properties, $
> Frame_Information: FrameInformation }
>
> SavedFile = { ...etc }
>
>
> FilesAttributes = { ConditionsFile: ConditionsFile, $
> SavedFile: SavedFile }
>
> etc..etc.
>
> although your lines may get a bit long, e.g.
>
> print, FilesAttributes.ConditionsFiles.Properties.LastModifiedTime
>
> ...phew!
>
> I would use structure contructor functions (search for "Automatic
Structure Definition" in
> the IDL help) to do it, so you can automatically define a valid structure
containing all
> the allowed bits. You could also approach this in an OO way (search for
"IDL Object
> Overview"). I'm not an IDL OO feller, so others will have more to say
about that aspect.
>
> All the data stuff would be stored in a pointer array structure element
that you can
> allocate when you determine what the required dimensions are.
>
> Actually it sounds like a neato little project to do this. you'll learn
everything you
> ever wanted to know about IDL structures, and if you're keen, about the OO
capabilities
> also.
>
> paulv
>
> --
> Paul van Delst
> CIMSS @ NOAA/NCEP/EMC
> Ph: (301)763-8000 x7274
> Fax:(301)763-8545
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