From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-0.9 required=5.0 tests=BAYES_00,FORGED_GMAIL_RCVD, FREEMAIL_FROM autolearn=no autolearn_force=no version=3.4.4 X-Google-Thread: 103376,2aaba1527862ef22 X-Google-Attributes: gid103376,public X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news2.google.com!postnews.google.com!m58g2000cwm.googlegroups.com!not-for-mail From: "frikk" Newsgroups: comp.lang.ada Subject: Re: Reading Float Data from a binary file into ada Date: 30 Jan 2007 12:09:56 -0800 Organization: http://groups.google.com Message-ID: <1170187796.181930.11010@m58g2000cwm.googlegroups.com> References: <1170172307.292500.256090@m58g2000cwm.googlegroups.com> <2qKdna5hWvrXOSLYnZ2dnUVZ8sTinZ2d@bt.com> NNTP-Posting-Host: 12.129.98.129 Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" X-Trace: posting.google.com 1170187816 21522 127.0.0.1 (30 Jan 2007 20:10:16 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: Tue, 30 Jan 2007 20:10:16 +0000 (UTC) In-Reply-To: <2qKdna5hWvrXOSLYnZ2dnUVZ8sTinZ2d@bt.com> User-Agent: G2/1.0 X-HTTP-UserAgent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; InfoPath.1; .NET CLR 1.1.4322),gzip(gfe),gzip(gfe) X-HTTP-Via: 1.1 TRY0PX01 Complaints-To: groups-abuse@google.com Injection-Info: m58g2000cwm.googlegroups.com; posting-host=12.129.98.129; posting-account=192wHg0AAAAzciSzoZsEBI9bw5pVCopO Xref: g2news2.google.com comp.lang.ada:8734 Date: 2007-01-30T12:09:56-08:00 List-Id: On Jan 30, 3:02 pm, Martin Dowie wrote: > frikk wrote: > > Hello everyone! I am having a problem that I would love some help > > with. > > > Essentially I was given a Visual Basic program that dumps a binary > > configuration file with all of the variables in a set. The variables > > are each 32 bit floats, with the first 16 bits being the integer part > > and the second 16 bits being a representation of the fraction (I'm not > > sure if this is stanard - but its just how VB dumps the data). The > > binary dump is basically a copy of the way VB stores the data in > > memory. I need to be able to use this data in ada. There is a C > > counterpart to this that makes use of a 'union' to grab the data 1 > > byte (8 bits) at a time, put them into a char array of size 4, then > > use a 32 bit float to reference the data. Is there somehow I can do > > this in ada as well? > > > Basically I need to be able to read in the binary data byte by byte > > but store it into a 32 bit Float. The C union example above uses the > > same memory address for the Float as it does for the size 4 char > > array. I don't even know if the VB dump will correspond with the way > > ada handles floats or not, but I'll worry about that later. > > > I am also using Matlab/Simulink if that provides any additional tools > > to use for debugging. > > Here's a small example that I think shows what you need (doesn't deal > with any endian issues!) and goes the other way to what you need > (fixed-point -> unsigned 32-bit) but you'll get the idea. > > The one line I'm not sure about is if both 'Small and 'Size are needed - > I always use both but I think 'Size may not strictly be needed. > > Hope this helps! > Cheers > -- Martin > > -- File: fp_example.adb > with Ada.Text_IO; use Ada.Text_IO; > with Ada.Unchecked_Conversion; > > with Interfaces; use Interfaces; > > procedure FP_Example is > > -- Defines the LSB > FP_Delta : constant := 2.0**(-16); > > type FP is delta FP_Delta range -2.0**15 .. 2.0**15-FP_Delta; > for FP'Small use FP_Delta; > for FP'Size use 32; > > F1 : FP := FP'First; > F2 : FP := FP'Last; > > package FP_IO is > new Ada.Text_IO.Fixed_IO (FP); > use FP_IO; > > package Unsigned_32_IO is > new Ada.Text_IO.Modular_IO (Unsigned_32); > use Unsigned_32_IO; > > function To_Unsigned_32 is > new Ada.Unchecked_Conversion (Source => FP, > Target => Unsigned_32); > begin > Put (F1, Aft => 16); New_Line; > Put (F2, Aft => 16); New_Line; > Put (To_Unsigned_32 (F1), Base => 16); New_Line; > Put (To_Unsigned_32 (F2), Base => 16); New_Line; > end FP_Example; > > c:\ada\fp_example\fp_example.exe > -32768.0000000000000000 > 32767.9999847412109375 > 16#80000000# > 16#7FFFFFFF# > process terminated successfully- Hide quoted text - > > - Show quoted text - Niklas - I think this is exactly what I need to do. Martin - Thank you for the example. I will go through that and see what I can use - it looks very useful though. May I get some clarification on exactly what this line does: type FP is delta FP_Delta range -2.0**15 .. 2.0**15-FP_Delta; for FP'Small use FP_Delta; for FP'Size use 32; What is the delta used for? Thanks! Blaine