How to convert to ESRI ASCII to geotiff and vice versa?

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How to convert to ESRI ASCII to geotiff and vice versa?

Soon Hui Ngu
My problem statement:

  1. Given the geotiff file, how to convert it to ESRI ASCII file?
  2. And given the ESRI ASCII file, how to convert it to geotiff?
This is how my file information looks like in ESRI ASCII:

ncols         5 
nrows         4 
xllcorner     0 
yllcorner     0 
cellsize      10 
NODATA_value  -9999 
25.4 26.1 27 28.6 27.7
25 26 26.4 27.9 27.4
25.1 25.8 26.8 28.6 27.6
27.5 28 27.7 30.6 28.3

No georeferencing data, no metadata, just grid information with the z value-- with z value being the drain number where the cell is draining to.

How can I use the libgeotiff library to do this conversion?

Motivation:

I use TauDEM in my application for catchment delineation, and TauDEM uses raster file ( in the form of geotiff/ASCII) as input, and outputs the catchment delineation result in geotiff format. 

I have my mesh from analysis, that I will need to convert to geotiff file for TauDEM for processing. When TauDEM finishes the work and outputs the result in geotiff format, I would need to read it into the memory in my code and render it using my own rendering engine-- vdraw. If I know how to convert between geotiff and ASCII file, I can immediately go from mesh to geotiff file without the intermediate ASCII ( which is very wasteful); likewise, if I know how to take the output geotiff and convert it to ASCII, I can process the geotiff file in memory and render it much faster without convert it to file in ASCII format. 

This is why I need to know how to use libgeotiff ( or any other library) to do the conversion-- because my ESRI ASCII "file" lives in the memory and not hard disk.  Even though GDAL contains such a conversion utility method, I couldn't use GDAL because using it will then require the actual ASCII file for conversion.

Any ideas?

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