C / C++ / MFC

// returns 0 on success
// returns -1 on failure
// returns >0 if buffer isn't big enough

int getpartname(char *filename, char *partname, size_t partnamesize)
{
  int dot = -1;
  int filenamelen = strlen(filename);
  int pos;
  for(pos = filenamelen; pos >= 0; pos--)
  {
    if(filename[pos] == '.')
    {
      dot = pos;
      break;
    }
  }

  if(dot == -1) return -1;
  if(partname == 0 || partnamesize < dot + 4 + 1)
  {
    if(partnamesize != 0) partname[0] = '\0';
    return dot + 4 + 1;
  }

  strncpy(partname, filename, dot);
  partname[dot] = '\0';
  strcat(partname, ".000");

  return 0;
}

// use an array on the stack that has more than enough buffer to store the partname
char partname[80];
getpartname("is730enu.exe.mtx", partname, sizeof(partname));

// or
char *partname;
int len = getpartname("is730enu.exe.mtx", 0, 0);
partname = (char*) malloc(len);
getpartname("is730enu.exe.mtx", partname, len);

// use partname
    :     :

free(partname); // free the memory allocated on the heap

Zac Howland wrote:

not sure how it will handle the double extensions...

"The largest fire starts but with the smallest spark." - David Crow

"Judge not by the eye but by the heart." - Native American Proverb

<br />
strncpy(unexName,filename,strlen(filename)-4);<br />
unexName[strlen(filename)-4]='\0';<br />
strcpy(partName,unexName);<br />
strcat(partName,".000");<br />
printf("\n%s",partName);<br />

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<marquee scrollamount="1" scrolldelay="1" direction="up" height="10" step="1">--[ ]--

[My Current Status]

I try to add something that's larger than that, why does it add it anyways without crashing

hfry wrote:

The point is you shouldn't pass the pointer out, instead the caller should pass a buffer in. The caller has an option of creating a buffer on the heap or on the stack. If the caller creates the buffer on the heap using malloc, then he would also know that he has to free it.

hfry wrote:

Extensions are not always 3 characters.

Cyber Friend wrote:

At most how many timers can I use in an application as in future I will update my application for 32 threads?

"The largest fire starts but with the smallest spark." - David Crow

"Judge not by the eye but by the heart." - Native American Proverb

Jun Du wrote:

Whenever that program is run, it used up all 100% CPU. Of ocourse, the 20 timers have been later combined to one centralized, high-resolution timer.