I need to copy an array of 8000 bytes to a structure of 8000 bytes.
Is it possible to do it with the function memcpy() ?
These are the two objects:
What kind of pointer should I pass to memcpy() in order to copyCode:char array[8000]; CHAR_INFO starget[2000];
the content of array[] into starget[] ?
Is it enough to do:
?Code:memcpy(starget, array, 8000);
Last edited by frktons; 07-30-2010 at 01:02 PM.
memcpy is the function you'd want to use if you want to avoid writing a loop, but it may be more complicated than just one function call. It depends on the specifics of the char info type.
The CHAR_INFO type is a standard Windows type defined in the include:Originally Posted by whiteflags
And well, the memcpy() works just fine, I tried it and it works.Code:typedef struct _CHAR_INFO { // chi union { /* Unicode or ANSI character */ WCHAR UnicodeChar; CHAR AsciiChar; } Char; WORD Attributes; // text and background colors } CHAR_INFO, *PCHAR_INFO;
I need to perform another operation on the structure, I need to
access the single bytes one at a time. Can I do it using a pointer?
Something like:
Code:char *ptr_starget = &starget[0]; char *ptr_array = &array[0]; for (x = 0; x <= 7999; x++) *ptr_starget++ = *ptr_array++;
Last edited by frktons; 07-30-2010 at 01:34 PM.
Yes you can access the structure one byte at a time; first you'll get an ansi character, or the first half of a unicode character, then eventually the bytes of the word.
This is another copy though... If that is what you're doing with CHAR_INFO arrays, then perhaps you can fill that array later, and work on character arrays first.Code:char *ptr_starget = &starget[0]; chat *ptr_array = &array[0]; for (x = 0; x <= 7999; x++) *ptr_starget++ = *ptr_array++;
This could be an alternative. Instead of filling array[] first and after copying it
into starget[], I could directly fill starget[] and not using array[] at all, bacause the
source info that I have to copy are inside another array that I manipulate a little
while copying into array[]. If accessing single bytes of a structure is possible, I can
copy data form source array after manipulating it, directly to starget[].
Something is wrong. The compiler complains about declaring a pointer to a structure
with the char type.
Being starget a structure, the pointer needs to be declared in a different way.
Anybody knows how?
Well if you're doing ugly things, be ready to use some ugly casting.
const int INFOSIZE= 2000;
CHAR_INFO starget[INFOSIZE];
unsigned char *p = (unsigned char*)starget; /** OK **/
No complaints. Now, as long as you know how to fill a CHAR_INFO array with a mess of bytes from god knows where, you're OK.
This means that if I want to access a structure of CHAR_INFO type byte by byte I have
to typecast the structure to unsigned char.
Well, thanks whiteflags, enlightning suggestion.
I'm going to give it a try. I'll let you know.
I don't mean to be too picky, especially if it's already making sense to you, but it would be more accurate to say that you're casting the -pointer- to the structure to a -pointer- to unsigned char. You're not changing anything about what you're looking at, but changing the way you talk about it is what allows you to access it byte-by-byte. It's a subtle difference, but I hope that helps you see why it works.This means that if I want to access a structure of CHAR_INFO type byte by byte I have
to typecast the structure to unsigned char.
Thanks sean, this is a more precise description of what the instruction does.
And well, the work is done, I attach the result. It is a program to display old DOS
screen format 25 x 80 chars, with colors, in a Win32 console. It works only for Windows
systems, because it calls Windows APIs.
If you want to see it or try it, change txt extension with scn, compile inside
a folder where the screen format is [scn], and you are done.
You have an handy Extended ASCII table with 255 displayable characters.
