#include <stdio.h>
#include <tapi.h>

// Assuming a call is already active and the message LINE_CALLINFO was
// received with dwParam1 set to LINECALLINFOSTATE_CALLERID, the 
// following code will obtain and print out the CallerID information.

// The code actively demonstrates the use of the dwTotalSize field
// in the variable sized structure LINECALLINFO by initially setting
// the size of the structure to simply sizeof(LINECALLINFO)

void PrintCallerID(HCALL hCall)
{
LINECALLINFO *ci;
size_t ci_size = sizeof(LINECALLINFO);
DWORD result;
BOOL done = FALSE;
char *p;
char szData[80];

  // Call lineGetCallInfo to obtain the CallerID information.  If TAPI
  // tells us that the structure is too small, either via the 
  // LINEERR_STRUCTURETOOSMALL error or by indicating that the needed
  // size of the structure is larger than the total size of the
  // structure then allocate a new structure and call lineGetCallInfo
  // again.
  while (!done) {
  
    ci = (LINECALLINFO *)calloc(ci_size, 1);
    if (ci == NULL) {
      printf("out of memory\n");
      return;
    }

    ci->dwTotalSize = ci_size;

    result = lineGetCallInfo(hCall, ci);
   
    if ((result < 0) && (result != LINEERR_STRUCTURETOOSMALL)) {
      printf("TAPI error 0x%08lx calling lineGetCallInfo\n");
      free(ci);
      return;
      }
  
    done = ((result == 0) && (ci->dwNeededSize <= ci->dwTotalSize));
  
    if (!done) {
      ci_size = ci->dwNeededSize;
      free (ci);
    }
  
  }; // while (!done)

  // Now that we have a full LINECALLINFO structure, obtain the 
  // CallerID information.  This is done in multiple steps here 
  // in order to make it simple to understand.  This code could
  // easily be compacted to make it more efficient.
  // Rather than use a switch statement, check to see if each
  // individual flag is set.  Most of the time only one flag 
  // should be set, but you never know what a TSP might send up.

  if (ci->dwCallerIDFlags & LINECALLPARTYID_BLOCKED)
    printf("CallerID is Blocked\n");

  if (ci->dwCallerIDFlags & LINECALLPARTYID_UNKNOWN)
    printf("CallerID is Unknown\n");
 
  if (ci->dwCallerIDFlags & LINECALLPARTYID_UNAVAIL)
    printf("CallerID is Unavailable\n");
 
  if (ci->dwCallerIDFlags & LINECALLPARTYID_NAME) {
    p = (char *)ci + ci->dwCallerIDNameOffset;

    // For string data TAPI will nul-terminate the string, 
    // so technically all this isn't necessary, a simple
    // strcpy will actually do.  But this way shows the use
    // of the Size field as well as the Offset field.
    memset(szData, 0, sizeof(szData));
    strncpy(szData, p, ci->dwCallerIDNameSize);

    printf("CallerID Name: %s\n", szData);
  }

  if (ci->dwCallerIDFlags & 
  (LINECALLPARTYID_ADDRESS | LINECALLPARTYID_PARTIAL)) {
    p = (char *)ci + ci->dwCallerIDOffset;

    memset(szData, 0, sizeof(szData));
    strncpy(szData, p, ci->dwCallerIDSize);

    printf("CallerID : %s\n", szData);
  }

  free (ci);
}