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Error reading in file in binary mode
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Join Date: Feb 2005
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That works nicely - I guess rdbuf reads the entire contents in one shot? (If so, it's nice to not to have to do the size calculation and to just use string's dynamic allocation)... How big a file you think I need to try this with to really test it out?
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Join Date: Apr 2004
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This took about 30 seconds for the 1 Meg file. (Made a little change, too.)
#include <iostream>
#include <fstream>
#include <sstream>
int main ()
{
static const char filename[] = "file.txt";
std::ifstream file(filename, std::ios::binary);
std::ostringstream text;
text << file.rdbuf(); // slurp
std::cout << "okay" << std::endl;
return 0;
}
/* my output
C:\Test>"TestPP.exe"
okay
C:\Test>dir file.txt
Volume in drive C has no label.
Volume Serial Number is 3BA1-7549
Directory of C:\Test
07/14/2005 01:08p 1,179,648 file.txt
1 File(s) 1,179,648 bytes
0 Dir(s) 7,913,684,992 bytes free
*/ "One of the methods used by statists to destroy capitalism consists in establishing controls that tie a given industry hand and foot, making it unable to solve its problems, then declaring that freedom has failed and stronger controls are necessary." --Ayn Rand
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Dave,
I ran it on a SUN box (4 cpu machine), a 1 mb file took 7 seconds in your new way (with the stringstream) and basically 0 seconds in the 'C' way you provided earlier... Guess which one I'm going to stick with ...
14-JUL-05 14:30:47->Program Start, HoffLib version: 2.3.5 JULY 14, 2005
14-JUL-05 14:30:47->STARTING stringstream WAY
14-JUL-05 14:30:54->ENDING 1229678
14-JUL-05 14:30:54->STARTING C/FILE * WAY
14-JUL-05 14:30:54->ENDING 1229678
(1229678 was the size read, just to confirm I'm getting the same data)
I ran it on a SUN box (4 cpu machine), a 1 mb file took 7 seconds in your new way (with the stringstream) and basically 0 seconds in the 'C' way you provided earlier... Guess which one I'm going to stick with ...
14-JUL-05 14:30:47->Program Start, HoffLib version: 2.3.5 JULY 14, 2005
14-JUL-05 14:30:47->STARTING stringstream WAY
14-JUL-05 14:30:54->ENDING 1229678
14-JUL-05 14:30:54->STARTING C/FILE * WAY
14-JUL-05 14:30:54->ENDING 1229678
(1229678 was the size read, just to confirm I'm getting the same data)
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Yay C! :p
I'm not sure if it would make any noticeable difference, but sometimes the platform-specific functions can be quicker, too. Such as maybe using stat. But maybe even the platform's read may be speedier too. (I remember a contest on another forum a while back.) If speed is a real issue.
I'm not sure if it would make any noticeable difference, but sometimes the platform-specific functions can be quicker, too. Such as maybe using stat. But maybe even the platform's read may be speedier too. (I remember a contest on another forum a while back.) If speed is a real issue.
"One of the methods used by statists to destroy capitalism consists in establishing controls that tie a given industry hand and foot, making it unable to solve its problems, then declaring that freedom has failed and stronger controls are necessary." --Ayn Rand
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Speed is definitely an issue as this function is part of my new 'library' that I'm building. The performance difference is HUGE with 3.8 MB...
14-JUL-05 14:41:58->Program Start, HoffLib version: 2.3.5 JULY 14, 2005
14-JUL-05 14:41:58->STARTING stringstream WAY
14-JUL-05 14:42:56->ENDING 3807956
14-JUL-05 14:42:56->STARTING C/FILE * WAY
14-JUL-05 14:42:57->ENDING 3807956
14-JUL-05 14:42:57->SAME
14-JUL-05 14:42:57->Program Completion, Total Runtime: 59 SECOND(S). Return Code: [0]
By the way (somewhat unrelated), is there any way in C/C++ to keep track of milliseconds? the time_t structure only seems to go up to seconds. (Since java has milliseconds, I was hoping there would be a way in C++, but I suspect no..)
14-JUL-05 14:41:58->Program Start, HoffLib version: 2.3.5 JULY 14, 2005
14-JUL-05 14:41:58->STARTING stringstream WAY
14-JUL-05 14:42:56->ENDING 3807956
14-JUL-05 14:42:56->STARTING C/FILE * WAY
14-JUL-05 14:42:57->ENDING 3807956
14-JUL-05 14:42:57->SAME
14-JUL-05 14:42:57->Program Completion, Total Runtime: 59 SECOND(S). Return Code: [0]
By the way (somewhat unrelated), is there any way in C/C++ to keep track of milliseconds? the time_t structure only seems to go up to seconds. (Since java has milliseconds, I was hoping there would be a way in C++, but I suspect no..)
>is there any way in C/C++ to keep track of milliseconds?
No, the smallest portable measurement is a second. However, most systems provide a way to have sub-second measurements. Check your man pages.
No, the smallest portable measurement is a second. However, most systems provide a way to have sub-second measurements. Check your man pages.
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I primarily use Sun solaris. I'm not even sure what to search for in the man pages...
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man -k second
/usr/dt/man/windex: No such file or directory
/usr/man/windex: No such file or directory
/usr/openwin/share/man/windex: No such file or directory
whereas any other command like ,
man whodo
Reformatting page. Please Wait... done
System Administration Commands whodo(1M)
NAME
whodo - who is doing what
SYNOPSIS
/usr/sbin/whodo [-h] [-l] [user]
DESCRIPTION
The whodo command produces formatted and dated output ...etc..
/usr/dt/man/windex: No such file or directory
/usr/man/windex: No such file or directory
/usr/openwin/share/man/windex: No such file or directory
whereas any other command like ,
man whodo
Reformatting page. Please Wait... done
System Administration Commands whodo(1M)
NAME
whodo - who is doing what
SYNOPSIS
/usr/sbin/whodo [-h] [-l] [user]
DESCRIPTION
The whodo command produces formatted and dated output ...etc..
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