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Groups > comp.lang.c++ > #10867
| From | Richard Damon <news.x.richarddamon@xoxy.net> |
|---|---|
| Newsgroups | comp.lang.c++ |
| Subject | Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) |
| Date | 2011-10-15 17:35 -0400 |
| Organization | A noiseless patient Spider |
| Message-ID | <j7cub0$v2d$1@dont-email.me> (permalink) |
| References | <2508ba10-93ae-4864-bb07-dc418eae066b@g16g2000yqi.googlegroups.com> |
On 10/15/11 3:00 PM, someone wrote: > Hi, > > Here's my program: ... > int R1_begin; > R1_begin = static_cast<typeof R1_begin> (memblock[0]);//, 1, > 'uint32',endianNess); > cout<< "Value = "<< R1_begin<< endl; > > delete[] memblock; > return 0; > } > ========================== > > Problem: > > R1_begin is the first value read from a binary file. But it's wrong! > It should be 72 but the program prints 49 out to the screen. So I > cannot continue before I get this right. The first few bytes I'm going > to read is: > > R1begin = 1 byte times sizeof 'uint32' = 4 bytes > I1_I6 = 6 bytes times sizeof 'uint32' = 6x4 = 24 bytes > TEXT = 40 ASCII characters of type 'char' = 40 bytes > R1end = 1 byte times sizeof 'uint32' = 4 bytes > > Total bytes read = 4+24+40+4 = 72 bytes. That's why I must read 72 > bytes from the very first byte in the binary file... And I cannot > solve this! :-( > > Please help (and please provide hints for reading the next few bytes > and how I should convert from data in memory into different data > types). Later I also need to convert some bytes from memblock[ ] into > floats and doubles... > > I'm stuck... > > And what about big endian / little endian? I'm confused. Looking > forward to hear from you! > > First, what is the first byte in the file? you are saying that you are expecting it to be 72 but you are getting 49. Have you looked at the file. Next you talk about getting R1begin which should be 4 bytes, but you are setting it to the value of the first byte of the file (memblock[0] is the first byte of the file) the static_cast to int is unneeded, as char will convert to int implicitly. Lastly, you are saying that you are expecting to read 72 bytes at the beginning of the file, and also that you are expecting to get the value 72 from the beginning of the file, implying that R1begin is a byte count for the record, but then don't describe the record format depending on that value at all, and then only look at 1 byte for that info, when you describe it as a 4 byte number. If R1_begin ins't a data length field, why are you expecting it to have the value 72?
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reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) someone <newsboost@gmail.com> - 2011-10-15 12:00 -0700
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Ian Collins <ian-news@hotmail.com> - 2011-10-16 09:29 +1300
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) someone <newsboost@gmail.com> - 2011-10-15 14:17 -0700
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Ebenezer <woodbrian77@gmail.com> - 2011-10-15 14:41 -0700
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Ian Collins <ian-news@hotmail.com> - 2011-10-16 10:45 +1300
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Martin Jørgensen <mjoerg@gmail.com> - 2011-10-15 15:43 -0700
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Richard Damon <news.x.richarddamon@xoxy.net> - 2011-10-15 21:37 -0400
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) someone <newsboost@gmail.com> - 2011-10-15 23:23 -0700
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Ian Collins <ian-news@hotmail.com> - 2011-10-16 20:53 +1300
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Paavo Helde <myfirstname@osa.pri.ee> - 2011-10-16 03:04 -0500
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Ian Collins <ian-news@hotmail.com> - 2011-10-16 21:52 +1300
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Jorgen Grahn <grahn+nntp@snipabacken.se> - 2011-10-16 18:21 +0000
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Richard Damon <news.x.richarddamon@xoxy.net> - 2011-10-16 16:40 -0400
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Ian Collins <ian-news@hotmail.com> - 2011-10-17 10:00 +1300
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) someone <newsboost@gmail.com> - 2011-10-16 15:19 -0700
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Richard Damon <news.x.richarddamon@xoxy.net> - 2011-10-16 20:03 -0400
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) someone <newsboost@gmail.com> - 2011-10-16 17:49 -0700
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Richard Damon <news.x.richarddamon@xoxy.net> - 2011-10-16 21:29 -0400
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Jorgen Grahn <grahn+nntp@snipabacken.se> - 2011-10-17 09:10 +0000
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Richard Damon <news.x.richarddamon@xoxy.net> - 2011-10-15 17:35 -0400
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Martin Jørgensen <mjoerg@gmail.com> - 2011-10-15 15:39 -0700
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) someone <newsboost@gmail.com> - 2011-10-15 16:12 -0700
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) someone <newsboost@gmail.com> - 2011-10-15 16:32 -0700
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Richard Damon <news.x.richarddamon@xoxy.net> - 2011-10-15 19:41 -0400
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) someone <newsboost@gmail.com> - 2011-10-16 11:33 -0700
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Paavo Helde <myfirstname@osa.pri.ee> - 2011-10-16 13:54 -0500
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Paavo Helde <myfirstname@osa.pri.ee> - 2011-10-16 14:01 -0500
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) someone <newsboost@gmail.com> - 2011-10-16 15:12 -0700
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Richard Damon <news.x.richarddamon@xoxy.net> - 2011-10-16 20:14 -0400
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) someone <newsboost@gmail.com> - 2011-10-16 17:56 -0700
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Ian Collins <ian-news@hotmail.com> - 2011-10-16 12:33 +1300
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) someone <newsboost@gmail.com> - 2011-10-15 16:37 -0700
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Leigh Johnston <leigh@i42.co.uk> - 2011-10-16 19:59 +0100
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Leigh Johnston <leigh@i42.co.uk> - 2011-10-16 20:13 +0100
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Joshua Maurice <joshuamaurice@gmail.com> - 2011-10-17 18:17 -0700
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Joshua Maurice <joshuamaurice@gmail.com> - 2011-10-17 18:32 -0700
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Pavel <pauldontspamtolk@removeyourself.dontspam.yahoo> - 2011-10-15 19:56 -0400
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) someone <newsboost@gmail.com> - 2011-10-15 23:27 -0700
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Paavo Helde <myfirstname@osa.pri.ee> - 2011-10-16 02:48 -0500
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) someone <newsboost@gmail.com> - 2011-10-16 10:57 -0700
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Paavo Helde <myfirstname@osa.pri.ee> - 2011-10-16 13:18 -0500
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) someone <newsboost@gmail.com> - 2011-10-16 12:52 -0700
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) someone <newsboost@gmail.com> - 2011-10-16 10:58 -0700
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Paavo Helde <myfirstname@osa.pri.ee> - 2011-10-16 13:37 -0500
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) someone <newsboost@gmail.com> - 2011-10-16 14:37 -0700
Re: reading binary file into memory. Converting from char to uint32, float, double, ASCII strings etc (static_cast< > ?) Paavo Helde <myfirstname@osa.pri.ee> - 2011-10-17 01:21 -0500
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