I have got some data in a buffer and want to put those data in an array.
typedef struct chunk
{
char data[300]; /* the bufferr. */
} CHUNK;
char *buffer, CHUNK c [100];
Assuming I have got data into the buffer, how can I put 300 char per chunk? I'm new to C so please explain me with simple example.
Thanks, Kevin
The declaration is invalid, but I think you mean:
typedef struct chunk
{
char data[300]; /* the bufferr. */
} CHUNK;
char *buffer;
CHUNK c [100];
If I understand your question correctly (which I'm far from certain that I do), the code would be something like:
int j = 0;
char *bp = buffer;
while (*bp)
{
strncpy (c [j] .data, bp, 300); // copy data into next item
bp += strlen (bp);
++ j;
}
In C, you can copy memory from one area to another using memcpy(). The prototype for memcpy() is:
void *memcpy(void *dst, const void *src, size_t n);
and the description is that it copies n bytes from src to dst, and returns dst.
So, to copy 300 bytes from b to a where both a and b point to something useful, b has at least 300 bytes of data, and a points to at least 300 bytes of space you can write to, you would do:
memcpy(a, b, 300);
Now your task should be something along the lines of:
typedef struct chunk
{
char data[300];
} CHUNK;
char *buffer;
CHUNK c[100];
size_t i;
/* make buffer point to useful data, and then: */
for (i=0; i < 300; ++i)
memcpy(c[i].data, buffer+i*300, 300);
You can use strncpy.
strncpy( data, buffer, 299 ) ;
Leaving the last index for the termination character '\0'. Or make the array size 301 and then use strncpy for 300 elements.
strncpy will always start from the starting of the index of the array by default. If needed to started from a different index, give data+i where i is the position to start from. So if previously copied with any values in data will get over written with new values.toBeReadLength = strlen(buffer); while( toBeReadLength) { strncpy( data, buffer, toBeReadLength ); toBeReadLength = strlen(buffer); }. But this kind code has a red flag since there is no check for buffer overflows. It works fine as along as the toBeReadLength is less than 300.