C++ :: Reading Large Number Of Binary Files
Apr 14, 2014
Windows 7, 64 bits, Visual Studio 10.
I have a problem to read a large number of binary files, process them and store them under a new name. The program and routines go very well for 505 files. After reading 506 files, the program now refuses to read the next file. I have 16 Gb of memory and tried to close all other programs and restart the PC. it always stops after 506 files (512 files would be more understanding in a way...).
Here is my code. I have tried many things without success. This is only part of the loop that stops. The if test if (myfile.is_open() returns false by some reason. I can start the process again starting with the file that does not open and then it stops again after 506 files.
char * tfiBlock;
ifstream myfile (OrigFilename, ios::in|ios::binary|ios::ate);
if (myfile.is_open()) {
int lengde = myfile.tellg();
tfiBlock = new char [lengde];
//static char memblock [size];
[Code] .....
Clean up procedure:
delete[] tfiBlock;
Are there any limits to how many files that can be opened, or is it maybe someting to be set in the compiler?
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May 21, 2014
I want to read a folder that contains large number of tif files. (say 1000 tif images) requirement is to read all files and store in a array/array pointer.
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Jan 14, 2014
We have a program that sequentially processes a large number of files (currently about 700 expected to increase to about 1500). The program performs the same processing on each file (and doesn't involve any other file) which is io-bound and not cpu-bound. This process takes several hours and it is normally performed overnight.
I've refactored the program so that the processing for each file is done within its own thread (ie one thread created for the processing of one file). This gives rise to many hundreds of io-bound threads. This refactored program is working with no errors reported and has reduced the total processing time down to about 10 minutes.
Any problems that might arise having this number of threads (700 to 1500) created/running?
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Jun 5, 2014
why I'm giving "Access violation reading location 0x336827B8" and also I was able to read my data but it's giving me weird stuff. I want to write the sorted grades and the average in a new disk file. so here's my code so far here's my code
#include "stdafx.h"
#include <iostream>
#include <fstream>
#include <string>
#include <iomanip>
using namespace std;
int avg(int sum, int size);
void swap(int *, int *);
[code]....
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Dec 11, 2014
I have written in a binary file using fstream an using sort value.
unsigned shortwidth=50,height=50;
file.write((char*)&width,sizeof(width));
file.write((char*)&height,sizeof(height));
When i try to read it back from fstream again there are some symbols (binary obviously). How can i get my values back? I want to read those symbols and in a way to convert them to my old width and height values.
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Apr 18, 2013
I have managed to make a program that permutates a string with repetition.
I ran it to permutate "abcdefghijklmnopqrstuvwxyz1234567890" with a limit of 5 characters.
This took a little over 5 hours for my pc to process this and I ended up with a .txt 403MB in size. Needless to say I am unable to open this .txt in notepad without Notepad.exe not responding and me having to end the process.
So what I want to do is modify my code to break up the output in to several files rather than one. Possibly all permutations starting with a in one file, b in another, etc.
Here is my current code:
#include <iostream>
#include <string>
#include <sstream>
[Code]....
As you can see it currently appends permutation.txt with all output. I would like it to make files like this permut_5char_a.txt, permut_5char_b.txt, etc.
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Jul 5, 2012
I am reading in some large files to process. The files need to be parsed into multi-line sub units for processing (by a different physical process). My current setup is crude and parses the entire file into memory before beginning to process the sub units. This is fine as long as the file fits, so I get into trouble > 2GB or so when my machine flat runs out of memory. The simple thing to do is to only read in some of the file, process what was read in, and then read in more. I more or less know how to stop reading at some point in the file, but I'm not sure how to resume from that point later when I need more data. Is there a way to count lines and then getline() starting from a specific point in the file? From reading the getline() doc, it doesn't look like there is.
This is my current function,
Code:
void ParseFile(char *path, char type) {
// open input file
ifstream input_file(path);
if( !input_file.good() ) { cerr << "Failed to open " << path << endl; exit(ERRCODE_ERROR); }
int pos = 1;
[Code] ....
I need to remove the code to open the file from this function and open it elsewhere. I would like to call this every time I run out of data, if( tasks.empty() ), and get more data from the input file, but I don't know how to resume reading the input file from where I left off.
If this is not possible, I guess I would have to place a function call in while( input_file.good() ) to call out and process the data I have. When the current tasks list is finished, the list could be cleared and control returned into the while loop to continue reading input and start re-populating the list.
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Mar 31, 2014
I am creating a simple log parser (loads a text file and filters out unnecessary information, but has the option to show the full log) and I'm running into an issue with fairly large log sizes (50+mgs). I have seen a few recommendations from a stream to memory manged files and even alternate 3rd party controls.
I foresee a few issues with any of the non-third party solutions (which I would prefer to avoid third-party add-ins) such as the scroll bar not correctly reporting the relative length or position of the complete text in the box (when displaying only a portion of the file at a time) and in the stream solution where you read on scroll (as necessary) have not only the same issues, but how do you resume reading in the middle of the file? This also all assumes I would be periodically clearing the RichTextBox to keep the memory usage down to avoid an OutOfMemoryException (which I have been running into.)
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Feb 9, 2015
I'm trying to make sure my code is written in smaller modules, so my first step is to create my initialization process in and external file to load the necessary data from external sources and set up things like the content of drop down list boxes.
My first attempt failed to give me access to the combobox items add function so I moved that code back into the form1.h file:
Code:
public:
Form1(void) {
InitializeComponent();
//
//TODO: Add the constructor code here
//
}
void AddDate(char *date, int ID)
{
this->comboBox1->Items->Add("line 1");
}
It compiles fine, but the call to it in my Initialize.cpp file
Code:
MarketView::Form1::AddDate("abs",1);
Gives error C2352: 'MarketView::Form1::AddDate' : illegal call of non-static member function
OK, so I change "void AddDate" to "static void AddDate" and now get the error that "static member functions do not have 'this' pointers" so I go back to the "MarketView::Form1::comboBox1" situation where there is no legal syntax after "Box1 to get me to Items->Add
I've been an old fashion programmer for over 47 years. It seems as is the concept of programming computers has changed from the concepts of logic to memorization of complex syntax.
There has to be a simple answer to do this other than to write thousands of lines of code in one Form1.h file. I refuse to believe that the new programming concepts will not allow you to write code in smaller more manageable modules.
What is the proper syntax for breaking up the larger file into more manageable chucks?
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Jan 15, 2013
Opening large files in c++. In my application, i am trying to save video as long as users have space in harddisk. What I am trying to do is when user is recording video i am trying to append the video data in to the file. The problem is that every time file size reach over 2GB my software crashes.
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Jan 22, 2015
storing int=9000000000; gives me another number. how can i store the value?my bad int number=9000000000;
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Jan 20, 2013
I am trying to run a simulation with a large number of objects (mainly arrays and vectors). I am not sure where shall I define my objects: inside or outside of the main() function, like the following two structures:
(1) ---------------
//main.cpp
int main(){
array<double, 1000> a_1 = {};
array<double, 1000> a_2 = {};
......
func_1(a_1, a_2, ..., a_100);
return 0;
}
[Code]...
I know there is a question about scope. But besides this question (which seems have no difference between these two structures here), is there any difference in terms of execution performance or security issue?
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Sep 15, 2013
I have a very large number in word ~6million digits long
I wish to make a program to check if it is prime.
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Feb 16, 2014
Suppose i have a very large number stored as a string, say
std::string str = "1000000000000000000000000000000000001";
And i use std::stringstream to convert it to int like this
std::stringstream ss(str);
uint64_t i;
ss >> i;
Then I would be maxed out right. so how would one practically handle things like comparison of two such numbers.
I could think of 2 approaches :
1) I can compare the numbers character by character.
2) I can put the results of ss >> i; into an array then compare each element of array
would there be any other methods??
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Sep 20, 2014
I'm trying read a binary file. A binary files is continued with bytes(ascci characters). and the 1st position is the position 0(zero).
I'm trying read just some values from ICO file:
- the 3rd value is in 4th-1 position(number of icons); (See the table: [URL] .... )
- the with is the (numberoficons*16) + 4 (the 16 is the Entries structure size) position;
- the height is the (numberoficons*16) + 4 + 4 (the 16 is the Entries structure size) position.
now see the code:
int iconwidth;
int iconheight;
int iconcount;
FILE *iconfile = fopen(filename.c_str(), "rb");//open the file
fseek(iconfile,4-1,SEEK_SET); //put the file in position 6(the position starts from 0)
fread(&iconcount,sizeof(char),2,iconfile);//get 2 blocks with char size(2 bytes).. i'm getting the number of icons
[Code] ....
so what i'm doing wrong with block positions?
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Jan 5, 2013
I am attempting to merge binary files. However, this is to no avail. The program keeps segfaulting. I want to merge the buffers the files are stored in and then write the new one to disk. Anyway, here is my code.
Main.cpp:
#include "getsize.h"
long lSize;
char * buffer;
size_t result;
FILE * pFile;
FILE * pFile2;
FILE * pFile3;
void read1() {
pFile = fopen ( "uTorrent.exe", "rb");
[Code] ....
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Feb 26, 2013
How do I read a .pdf file using C++? When I try to open it using myfile.open ("example.pdf"); but all I see is some Crazy Symbols. Is there any way to open ?
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Jul 6, 2013
Code: Complete the program below which converts a binary number into a decimal number. Sample outputs are shown belowComplete the program below which converts a binary number into a decimal number. Sample outputs are shown below.
Sample Output 1:
8-bit Binary Number => 11111111
Decimal Number = 255
Sample Output 2:
8-bit Binary Number => 10101010
Decimal Number = 170
Sample Output 3:
8-bit Binary Number => 101010102
Number entered is not a binary number
#include <iostream>
using namespace std;
int main()
{
int num;
[code]....
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Sep 6, 2013
I have a structure stored in a binary file, now I want to read each string from it (or line), can I do that using fgets?
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Dec 22, 2014
I cant seem to read stuff in from my students.txt file which contains this
19992195 John Smith 20 05 1995 09 09 2011 15 05 2014 55 65 72 58 80 45 40 45 66 78 88 81
20051195 Mark Dobson 20 05 1995 09 09 2011 15 05 2014 55 65 72 58 80 45 40 45 66 78 88 81
20063196 Paula O'Reilly 20 05 1995 09 09 2011 15 05 2014 55 65 72 58 80 45 40 45 66 78 88 81
20053344 Aoife Cleary 20 05 1995 09 09 2011 15 05 2014 55 65 72 58 80 45 40 45 66 78 88 81
It has something to do with the lines at the bottom of the code. It doesnt cout anything. The program just crashes upon execution. First, it asks me the amount of students i want to handle. I enter '1'. Then it asks me if i want to read in from external file and i enter 'Y'. then the exe just crashes
#include <iostream>
#include <cstddef>
#include <cstdlib>
[Code]......
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Feb 20, 2015
I have to write a program that sorts names and grades from a file and output them to another.
For example:
Name: Peter Parker
Exam 1: 95
Exam 2: 90.625
Exam 3: 91.20
Name: Mary Smith
Exam 1: 65
Exam 2: 79.1234
Exam 3: 70.24
Becomes something like this in the output file:
Name: Parker, Peter
Average Score: 92.28
Grade: A
Name: Smith, Mary
Average Score: 71.45
Grade: C
I know I'm supposed to read the whole file, but I'm getting really confused on how to take the name of each student separately without recording Exam 1, 2, and 3. I'll be able to do the average score and grade on my own.
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Jan 28, 2014
Is there a way to indicate how many records exist in a given file? For example, vectors have the vector.size() command to show the number of given elements. Is there a such command for files and records?
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Oct 3, 2014
The directions are to write a program that reads sorted integers from two separate files and merge the contents of the file to an output file (third file). The only standard output will be any errors to be reported and a “FINISHED” statement after all items have been processed.
file1.txt
2
4
6
8
10
file2.txt
1
5
11
12
15
Output.txt
1
2
4
5
6
8
10
11
12
15
This is the code I have so far, but it is not working, and I have put the two txt files in the same directory as my .cpp file. It is not working though still. What have I done wrong and how can I fix it to read these integers from the two numbers and merge the contents into a third file?
#include <iostream>
#include <fstream>
using namespace std;
int main() {
int num1;
int num2;
ifstream inputFile;
[Code] ....
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Mar 24, 2014
My question portion is attached. The code I have written is below.
#define _USE_MATH_DEFINES // for C++
#include <cmath>
#include <iostream>
#include <iomanip>
[Code].....
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Jan 16, 2015
I'm messing around with reading and writing files. The first file creates a small txt file. Simple enough
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
int main(){
string name;
string desc;
[Code] ....
It does what it should. It creates a text file "items.txt" .... It reads as such:
dagger,a dagger,15,10,0,1,3,1,0,0,0,1,0,0,0,0,0,1
The second file is meant to read the file and place the data back into the variables. This happens, but the data crams itself into the first variable, and the rest of them collect the trash that's in memory.
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
int main() {
string name,desc;
[Code ....
I need to get "dagger" into name, "a dagger" into description, and each value with their perspective variable. I'm sure I need some type of "separator". Hopefully I can use the comma. Before it's over, I will have about a hundred items that will need to be read into a class of items.
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Jun 11, 2014
My assignment was to take numbers from two different files, and merge them into a third file in numerical order. I have everything working well, but the output shows the lowest number everytime and i'm not sure why. logical error ....
Sample:
File1 File2 File3
10 12 10
20 25 12
30 37 10
40 49 25
10
37
10
49
Here is my code as well
#include <iostream>
#include <fstream>
#include <cstdlib>
using namespace std;
int main() {
ifstream File1, File2;
ofstream Output;
[Code] ....
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