Re: [c++] get() and read() functions.
ZikO wrote:
Im using C++ Compiler as below:
g++ (GCC) 4.3.0 20080305 (alpha-testing) mingw-20080502
Copyright (C) 2008 Free Software Foundation, Inc.
That's not necessarily important here. Unless you suspect it's a bug in
the compiler or the standard library that comes with it, they all should
be essentially the same.
Im writing the simple program which is supposed to give info about sound
wave file. It checks whether a file is a wave format (4 ASCII bytes
should be like {'R','I','F','F'}) and then it reads what the size of the
file is (another 4 bytes). However, I found difficult to understand how
to use both get() and read() functions properly which are in <fstream>
library.
there is the code below in which I check if file starts with "RIFF". I
have used waveFile.get() function to obtain 4 bytes from the input
stream, although I wanted read() before. I had to use get() because if I
used read() instead the program would go straight to else branch and
display "This is not a wave file", even if it is.
Any suggestions why read() does not work here?
Why are you sure that it "does not work"?
Thanks.
PS. The test file can be found here:
http://rapidshare.de/files/44749739/test.wav.html
[code]
.ifstream waveFile("test.txt");
.int filePointer = 0;
. char temp[5] = {0,0,0,0};
. if(waveFile.get(temp,4)) {
Try looking at the 'temp' buffer. Print it out, char by char. Are you
sure you get 'R', 'I', 'F', 'F' in it? Could it be 'F', 'F', 'I', 'R'?
Anyway, what does your favourite C++ book say about the behaviour of
this particular 'get'? What if you fill your array char by char, as in
temp[0] = waveFile.get();
temp[1] = waveFile.get();
temp[2] = waveFile.get();
temp[3] = waveFile.get();
?
. // cout << "stream pointer = " << waveFile.tellg() << endl;
. filePointer += 4;
. char waveChunk[] = {"RIFF"};
. if(strcmp(temp, waveChunk)) {
. cout << "This is a wave file." << endl;
. }
. else {
. cout << "This is not a wave file" << endl;
. return 0;
. }
. }
. else
. checkStream(waveFile);
.
. int roz;
. waveFile.seekg(filePointer);
. if(waveFile.read(reinterpret_cast<char*>(&roz), 4)) {
. filePointer += 4;
. roz += 8;
. cout << "The size is: " << roz << endl;
. }
. else
. checkStream(waveFile);
[/code]
V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask