I want to read a single byte from a wifstream. With an ifstream I would use read(), but given that the char type for an wifstream is wchar_t (2 bytes), this is also being used by read(), so how can I read a single byte from such a stream?
View 3 Repliesand see if the first three match a list then read in three more behind those that were left and perform a similar test on them and keep going?
View 8 Replies View RelatedI am a member of a group still developing the Microprose European Air War game. We have the source code and permission to do this. As the code dates back to 1998 I use Visual Studio 2006.
I have written many programs in Visual basic, and have the following one to read the airbase value in the "targets.dat" file. The file has a four byte header containing the number of tatgets, and a 32 byte data block containing the data for each target.
Private Sub Command1_Click()
List1.Clear
Dim nt As Long
Dim a4() As Long
Open App.Path & " argets.dat" For Binary Access Read As 1
'read and display the number of targets
[Code] ....
Despite many attempts I cannot write the C equivalent of this code into the eaw.exe source. All I really need to know is how to open the 'targets.dat' file and how to get the value of a byte (or integer, or long) at a given position as in the "Get #1, k, a4(n)" line.
How to read a line with maximum of 8 bytes from a line in a file.
Let say line has 10248 bytes in one single line and same repeats for remaining lines in the file.
I need to read the first 8 bytes of a line and go on read the last 2 bytes of the line and repeat the till end of file.
My question is on c++ strings. At the moment my program is reading input in one line at a time after the user presses enter.
I want to read multiple values in on a single line. Example: "apple banana orange end" ... How would I do this?
MAIN Code:
#include "Header.h"
#include "Orange.h"
#include <iostream>
#include <string>
#include <cctype>
using namespace std;
[Code] ......
how to accommodate double-size:8 bytes in 4 bytes pointer in 32bit system.
View 1 Replies View RelatedCode:
int i12 = 1001;
cout << i12 << " " << &i12 << endl;
gives the result: 0x7fff0d065098
It's 6 bytes, but I'd expect the address to be 8 bytes on my 64 bit machine. I am using Ubuntu 12.04, GNU compiler.
So, why the address is 6 bytes and not 8 bytes?
Im using some motors which run off PWM pins.Theres a High byte and Loq byte register (PWMH,PWML).I have an int which i need to put into these registers but i dont know how???so for example
int:84 -> PWMH=0x00 , PWML=0x54
int:310 -> PWMH=0x01 , PWML=0x36
int:11588 -> PWMH=0x2D , PWML=0x44
How many bytes in a string ....
How many bit in a string ...
I'm confused about the actual value of 8 bytes for unsigned integers.
The below code suggests the value is 13217906525252912201:
#include <stdio.h>
#include <inttypes.h>
typedef uint64_t byte_int_t;
int main(void){
byte_int_t t;
printf("%" PRIu64 "
", t);
}
./runprogram
13217906525252912201
However, when I use a calculator, I get a different value: 2^64= 1.8446744e+19
So I was wondering is this really 8 bytes? So I try below test and it produces 8, as expected:
#include <stdio.h>
#include <inttypes.h>
typedef uint64_t byte_int_t;
int main(void) {
byte_int_t t;
printf("%u
", sizeof(t));
return 0;
}
So why does C and my calculator provide two different results?
I need to read repeatedly data from a MPEG2 file to the buffer of 188 bytes and analyse data bit by bit.
I have the problem with correct bytes reading from file. In my code listed below I have two methods for that.
First one is lossing this bytes which in hex_base mode have 0 at the begining, eg: 03, 0F, etc.
The second method based on read function which need to have buffer as a char (lenght > 1 byte). Because of that I receive different values from that from file in some cases.
How can I properly read such file?
Code:
#include <iostream>
#include <fstream>
#include <stdlib.h>
#include <windows.h>
using namespace std;
int main() {
fstream plik_in;
[Code] .....
I am encoding some information in a binary file, and I want to check what I am doing by printing out all the bytes that represent the file.
This is being done by opening a pointer to the file with fopen, reading in each byte of data as a char, and then writing this char to the screen.
I have some image files (e.g. "image.jpg"), whose structure I know, so that I can test my program.
When I print out the chars, they are initially correct, and follow the structure of the file as expected.
However, after about 40 bytes, I find that every subsequent character is ' ' i.e. a blank character.
I then created a CharToBin function, which allows me to print out the actual bits in the char. When doing this, it shows that all the bits are 1 for the characters. i.e. most of the file is represented by 1's, which is clearly not correct.
This happens on all the image files I have tested, and furthermore, on several other non-image files. They all start printing out ' ' after a while. However, all these files are fine and not corrupted, e.g. the image files display correctly.
Code:
#include <fstream>
#include <iostream>
#include <sstring>
#include <string>
#include <stdio.h>
using namespace std;
string CharToBin(char ch) {
bool bits[8];
for (int i = 0; i < 8; i++)
[Code] ....
I have a FILE stream, and I want to create a function that streams a specified number of bytes (up to four bytes) and returns the value of this, as an integar.
For example, supposing that my FILE has the following data, in hex: 74 C8 02 33 F2 7B....... I then want to stream three bytes and store this as an integar. So, I want to stream "04 08 02". The data stored in the integar should then be "00 74 C8 02", because I have not streamed anything into the first byte. By converting the hex to dec, the integar should then be of the value 7653378 (if it is unsigned).
To try to achieve this, I have written the following function. I create an integar and initialise it to zero, then take each byte from the stream, and OR it with my integar. Then, I shift the integar left by 8, and read the next byte, and so on.
The problem is, when I convert "c" to "c_int", it adds on a load of 1's to the left of the "c" data. This then means that the OR comparison changes all those bits in my integar to 1.
How to solve this? I am also wondering whether there is a much more simple way of doing this, rather than having to write my own function....
Code:
int StreamFileToInt(FILE *fp, int num_bytes) {
char c;
int c_int;
int x = 0x0000;
for (int i = 0; i < num_bytes; i++) {
[Code] ....
How can I convert bytes to ASCII?, I read wikipedia about UTF-8 and I understood a little bit about add or split bytes to change the value.
Now I have those bytes
0xC7 0xE6 0xC2 0x91 0x93 0x7B 0xCE 0x01
And I found a program (DCode) that convert to 64 bits little-endian, supposedly those bytes in ASCII is this.
lun, 08 julio 2013 04:28:17 UTC <---
while bytesremaining >=8 do something;
if bytesremaing <8 then something else .
I am new and don't know how to code for this.
I made this program to convert bits to bytes, because I'm so sick of seeing ISP's advertise speeds in megabits, which I consider an intentional attempt to decieve :P And I think I've finally understood how the return value of scanf works since the last time I posted here, so my program can check to see if an integer was entered before processing the input, but I'm stuck on how to make the whole program start over if an integer is not entered. I have a hunch it would involve a loop, but I can't figure out how to make the program start over at "How many mb do you need converted?" if an integer is not entered into scanf..Here is the code I have so far:
Code:
#include <stdio.h>
int main () {
int b, mb, kb, Byte, kB, mB, gB;
char term;
}
[code]....
and my program makes the assumption for now at least, that mb will be inputted because that's the unit of measurement that i usually see advertised, and i didn't bother making an if statement to print a conversion in terms of gigabytes because i've never heard of a connection that fast :P
I'd like to know how I could break a float into individual bytes for binary use.
Sounds simple, but it seems as though the compiler doesn't realize everything is just a series of bytes.
m_sName-- character array shall be 128 bytes
How do i create a character array that has 128 bytes?
How to delete certain bytes from middle of a binary file?
Those bytes are in fact of a struct.
One approach I found was to re-write the whole data except the struct I want to delete. But may be its not good one if file size is in gb and I will have to write complete data again.
how to combine two bytes (each byte is 8 bits wide) in order to get the original value. I am displaying values(from 0 to 500)sent from my microcontroller on the GUI.I can successfully display values from 0 to 255 as this requires just sending a byte. However sending values from 256 to 500 requires sending two bytes. The problem I am having is that I was unable to re-combine the received two bytes in order to get the original value. Below are my lines of code:
int main( void ) // this is the main function inside the microcontroller {
sei();
USI_TWI_Master_Initialise();
Spi_Master_Init();
while(1) // I am using this loop to send 500(111110100) {
Transmitt_Receive(244);//this function sends LOW BYTE of 500(11110100)
_delay_ms(1000);
[code]....
When I combined the two bytes using the above arrangements, instead of getting 500 my GUI displayed 62708.I got the same result when I used BitConverter.
value3 = BitConverter.ToInt32(val,0);
Writing bytes to external process to remove a detour that the program does
this is what im trying it fails
HANDLE Handle = OpenProcess(PROCESS_ALL_ACCESS, false, ProcessId);
BYTE btLdrLoadDll[] = { 0x8B, 0xFF, 0x55, 0x8B, 0xEC };
if (!WriteProcessMemory(Handle, (BYTE*)((DWORD)GetProcAddress(GetModuleHandle("ntdll.dll"), "LdrLoadDll")), &btLdrLoadDll, sizeof(btLdrLoadDll), NULL)) {
CloseHandle(Handle);
std::cout << "
Failed to write Bytes to memory. Press enter to exit.";
[Code] ....
an also using the right address like this fails
WriteProcessMemory(Handle, (BYTE*)0x77C64F9F, &btLdrLoadDll, sizeof(btLdrLoadDll), NULL)
#include <stdio.h>
#include <stdlib.h>
int main(int argc, int * argv) {
char buffer[16];
FILE *fp;
unsigned long long test;
unsigned char key[16];
fp = fopen("D:key.txt","r");
[code].....
i searched for a code for reading bytes from a file and i found this one but when i run the program, it doesn't return the bytes written in the file, it returns another bytes / what is the problem?
How to convert bytes of data to string using c programming , I searched but i didnt get appropriate one .
Example : 112131(bytes) to string ("some sample")
Using a table with the 256 bytes as strings, said table is used as a reference in the 2 functions of this code. Functions who make the conversion such as the title establishes, and in the inverse way too.
The main advantage is that you don't need any knowledge about managing bytes with c++..
Code:
#include <windows.h>
#include <stdlib.h>
#include <stdio.h>
char* hextabla[] = { //256 BYTES
"00","01","02","03","04","05","06","07","08","09",
"0A","0B","0C","0D","0E","0F","10","11","12","13",
[Code] ....
I leave the project in MSVCPP 6, see attachment...
It's ready to compile in 'Release' mode.
I am using atomic instructions on x64 and variables so used must be 16 byte aligned.
I use a number of structures where their members are so operated upon.
The structures accordingly needs must be 16 byte aligned and padded - their internal members must be on 16 byte boundaries and, crucially, there must be tail padding to a 16 byte boundary, so I can allocate arrays of these structures and use pointer math to iterate. (I am naturally using aligned malloc).
The problem I am finding is that it is not apparent to me how to achieve this end. Here below we have a test structure (currently I'm working with the latest Amazon Linux GCC, 4.6.3, on x64);
Code:
#define LFDS700_ALIGN_DOUBLE_POINTER 16
#define LFDS700_ALIGN(alignment) __attribute__( (aligned(alignment)) )
LFDS700_ALIGN(LFDS700_ALIGN_DOUBLE_POINTER) struct test_element
{
struct lfds700_freelist_element
[Code] ....
I allocate an array of test elements, thus;
Code:
te_array = abstraction_aligned_malloc( sizeof(struct test_element) * 100000, LFDS700_ALIGN_DOUBLE_POINTER );
The problem manifest is that sizeof(struct test_element) is 40 bytes! So the second element does not begin on a 16 byte boundary and we all fall down. Printing the addresses of the first element in the test element array, I see the following;
Code:
(gdb) print *ts->te_array
$2 = {fe = {next = {0x7fffec0008d0, 0x2}, user_data = 0x7fffdc0008d0}, thread_number = 3, datum = 0}
(gdb) print sizeof(struct test_element)
$3 = 40
(gdb) print &ts->te_array->fe.next
[Code] ....
So we see fe->next is the first element and so is correctly aligned curtsey of aligned malloc, where fe->next is 16 bytes, fe->user_data is correctly aligned, but then te->thread_number is misaligned and te->datum is given eight bytes rather than four, leaving us in the end without correct tail padding to a 16 byte boundary.
So, what gives? how *am* I supposed to indicate to the compiler it must pad structures to 16 byte boundaries?
I'll process the raw content of a stream which obviously will be loaded one chunk at a time into an buffer.I need to check if every chunk content is x00 filled. If it is, I'll increase the blank chunks counter of 1.On your personal opinion, which is the fastest an less cycles consuming manner to achieve such result?
I was wondering this: is it possible to make an instant XOR of all the buffer content to check if it does return 0 ?the only way is it to cycle through all the bytes and compare each one of them with 0?