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struct_read/struct_write

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struct_read/struct_write

by Val Schmidt

 

24 Jun 2009

Functions to ease the reading and writing of C data structures from and to binary files.

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Description

struct_read simplifies the reading of a C structure from a binary file by providing a functionality similar to the Python 'struct' module. The elements of the structure are specified as a series of characters (and optional multipliers) in a format string. struct_read then reads these binary values returning a cell array of the results. Results are returned either as character arrays or doubles since these are the default MATLAB types.

struct_write similarly takes a file handle, a format string and a cell array of data. Each item in the cell array is converted to the specified format in the string and written to the file handle.

The following list of format specifiers is generally supported.
% FORMAT SPECIFIERS:
%
% Specifier Bytes: Notes
% c 2 char returned as a string character
% C 2 char returned as a number (double)
% b 2 signed char
% B 2 unsigned char
% h 2 short
% H 4 unsigned short
% i 4 int
% I 4 unsigned int
% l 4 long
% L 4 unsigned long
% f 4 float
% d 8 double
% s char[] char[] returns character string

% EXAMPLE:
%
% Given the following C structure definition for a depth measurement from an
% echo-sounder:
%
% typedef struct
% {
% float depth1; //Depth1
% char units; // m for meters, f for feet
% double time_stamp; //Time stamp, number of seconds elapsed since midnight (00:00:00), January 1, 1970
% char[256] navstring; // GPS Position String
% } ECHO;
%
% fid = fopen('mybinaryfile','r');
% D = struct_read(fid,'fcd256c')
%
% D:
% { [23.456],'m',[1242238192.870432012], ...
% '$GPGGA,182503.00,7121.11801,N,15651.53926,W,1,12,0.8,20.49,M,-048,M,,*57' }

NOTE:
Reading and properly interpreting C-pointers is not generally supported.

MATLAB release MATLAB 7.6 (R2008a)
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Tag Activity for this File
Tag Applied By Date/Time
c Val Schmidt 24 Jun 2009 09:31:25
structure Val Schmidt 24 Jun 2009 09:31:25
binary Val Schmidt 24 Jun 2009 09:31:25
writing Val Schmidt 24 Jun 2009 09:31:25
reading Val Schmidt 24 Jun 2009 09:31:25
file Val Schmidt 24 Jun 2009 09:31:25
gps kuoping 29 Jun 2010 07:15:50

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