matlab-grid-generator/bin/rdslice.m

% rdslice(filename,[nx ny ...],k) returns an array of shape [nx,ny,...]
% read from a direct access binary file (float or double precisision) named
% by the string 'filename'. The file may contain multi-dimensional
% data. Note that cumsum([nx ny ...]*k) <= length of file.
%
% eg.   temp=rdslice('t.xyt',[160 120],4);
%
% rdsclice(filename,[nx ny ...],k,type) returns an array of type 'type'.
% where type can be one of 'real*4' or 'real*8'. The default is 'real*8'.
function [arr] = rdslice(file,N,k,varargin)

% Default word-length
WORDLENGTH=8;
rtype='real*8';
ieee='b';

% Check optional arguments
args=char(varargin);
while (size(args,1) > 0)
 if deblank(args(1,:)) == 'real*4'
  WORDLENGTH=4;
  rtype='real*4';
 elseif deblank(args(1,:)) == 'real*8'
  WORDLENGTH=8;
  rtype='real*8';
 elseif deblank(args(1,:)) == 'n' | deblank(args(1,:)) == 'native'
  ieee='n';
 elseif deblank(args(1,:)) == 'l' | deblank(args(1,:)) == 'ieee-le'
  ieee='l';
 elseif deblank(args(1,:)) == 'b' | deblank(args(1,:)) == 'ieee-be'
  ieee='b';
 elseif deblank(args(1,:)) == 'c' | deblank(args(1,:)) == 'cray'
  ieee='c';
 elseif deblank(args(1,:)) == 'a' | deblank(args(1,:)) == 'ieee-le.l64'
  ieee='a';
 elseif deblank(args(1,:)) == 's' | deblank(args(1,:)) == 'ieee-be.l64'
  ieee='s';
 else
  sprintf(['Optional argument ' args(1,:) ' is unknown'])
  return
 end
 args=args(2:end,:);
end

nnn=prod(N);

[fid mess]=fopen(file,'r',ieee);
if fid == -1
 sprintf('Error while opening file:\n%s',mess)
 arr=0;
 return
end
st=fseek(fid,nnn*(k-1)*WORDLENGTH,'bof');
if st ~= 0
 mess=ferror(fid);
 sprintf('There was an error while positioning the file pointer:\n%s',mess)
 arr=0;
 return
end
[arr count]=fread(fid,nnn,rtype);
if count ~= nnn
 sprintf('Not enough data was available to be read: off EOF?')
 arr=0;
 return
end
st=fclose(fid);
arr=reshape(arr,N);
1	% rdslice(filename,[nx ny ...],k) returns an array of shape [nx,ny,...]
2	% read from a direct access binary file (float or double precisision) named
3	% by the string 'filename'. The file may contain multi-dimensional
4	% data. Note that cumsum([nx ny ...]*k) <= length of file.
5	%
6	% eg. temp=rdslice('t.xyt',[160 120],4);
7	%
8	% rdsclice(filename,[nx ny ...],k,type) returns an array of type 'type'.
9	% where type can be one of 'real4' or 'real8'. The default is 'real*8'.
10	function [arr] = rdslice(file,N,k,varargin)
11
12	% Default word-length
13	WORDLENGTH=8;
14	rtype='real*8';
15	ieee='b';
16
17	% Check optional arguments
18	args=char(varargin);
19	while (size(args,1) > 0)
20	if deblank(args(1,:)) == 'real*4'
21	WORDLENGTH=4;
22	rtype='real*4';
23	elseif deblank(args(1,:)) == 'real*8'
24	WORDLENGTH=8;
25	rtype='real*8';
26	elseif deblank(args(1,:)) == 'n' \| deblank(args(1,:)) == 'native'
27	ieee='n';
28	elseif deblank(args(1,:)) == 'l' \| deblank(args(1,:)) == 'ieee-le'
29	ieee='l';
30	elseif deblank(args(1,:)) == 'b' \| deblank(args(1,:)) == 'ieee-be'
31	ieee='b';
32	elseif deblank(args(1,:)) == 'c' \| deblank(args(1,:)) == 'cray'
33	ieee='c';
34	elseif deblank(args(1,:)) == 'a' \| deblank(args(1,:)) == 'ieee-le.l64'
35	ieee='a';
36	elseif deblank(args(1,:)) == 's' \| deblank(args(1,:)) == 'ieee-be.l64'
37	ieee='s';
38	else
39	sprintf(['Optional argument ' args(1,:) ' is unknown'])
40	return
41	end
42	args=args(2:end,:);
43	end
44
45	nnn=prod(N);
46
47	[fid mess]=fopen(file,'r',ieee);
48	if fid == -1
49	sprintf('Error while opening file:\n%s',mess)
50	arr=0;
51	return
52	end
53	st=fseek(fid,nnn(k-1)WORDLENGTH,'bof');
54	if st ~= 0
55	mess=ferror(fid);
56	sprintf('There was an error while positioning the file pointer:\n%s',mess)
57	arr=0;
58	return
59	end
60	[arr count]=fread(fid,nnn,rtype);
61	if count ~= nnn
62	sprintf('Not enough data was available to be read: off EOF?')
63	arr=0;
64	return
65	end
66	st=fclose(fid);
67	arr=reshape(arr,N);