abiview bug

[James Bonfield]

Hello all,

I've now identified the problem in the abiview program.
The program was assuming that the position of the PLOC block immediately
follows the PBAS block, which is not always true. All blocks should be
considered as files in a directory - they can physically be stored in any
order. Hence you have to query the directory in order to find the file
location. Fortunately the patch is simple:

*** abiview.c~  Wed Feb 14 09:48:07 2001
--- abiview.c   Wed Feb 14 10:05:59 2001
***************
*** 71,76 ****
--- 71,77 ----
      int i;
      int base;
      long int baseO;
+     long int basePosO;
      long int numBases;
      long int numPoints;
      long int dataOffset[4];
***************
*** 121,126 ****
--- 122,129 ----
      res4 = (char)(fwo_&BYTE[0]);
  
      ajSeqABIReadSeq(fp,baseO,numBases,&nseq);
+     basePosO = ajSeqABIGetBasePosOffset(fp); /* find PLOC tag & get offset */
+     ajFileSeek(fp, basePosO, SEEK_SET);
      ajSeqABIGetBasePosition(fp,numBases,&basePositions);

On a more general note, most people do not keep ABI files on disk as they are
simply too large. They typically convert them to SCF instead. (Indeed some
machines, eg Licor, write SCF as their native format.) We maintain a freely
available library (io_lib) of routines for reading and writing ABI, ALF, SCF,
CTF (Jean Thierry-mieg's compressed format) and ZTR (my own compressed
format). All of ABI->* filters are lossy as there's lots of other bits in the
ABI files which no one quite knows what to do with, however the SCF->CTF and
SCF->ZTR are lossless (and SCF->ZTR is typically slightly smaller than bzipped
SCF). Maybe it makes sense not to duplicate work. 

io_lib is free although it isn't yet GPLed. That shouldn't be a problem, but
if it is I cannot see an issue with GPLing io_lib. Indeed it already looks
like parts of io_lib (or at least "ted" which much of it came from) are in
emboss; there's a striking similarities in the seqABIGetFlag and
getABIIndexEntryLW functions (eg the same bizarre flow controls, identical
code layout, and some identical variable names).

James

-- 
James Bonfield (jkb at mrc-lmb.cam.ac.uk)   Tel: 01223 402499   Fax: 01223 213556
Medical Research Council - Laboratory of Molecular Biology,
Hills Road, Cambridge, CB2 2QH, England.
Also see Staden Package WWW site at http://www.mrc-lmb.cam.ac.uk/pubseq/