C/C++ Interactive Guide/c-cplusplus-interactive-guide.iso/c_ref/csource1/chint/useful23.hnt

Text File | 1993-09-20 | 5.7 KB | 162 lines

This useful hint outlines how to add an array to the standard report skeleton
so that it is possible to supress output in band(s) or parts thereof while
still having all the processing done.

1)  As usual the first step is to make a copy of the standard skeleton,
    DBCREP.SKL so that the original code remains intact, though the changes
    are made in such a way that this modified skeleton could be used as the
    standard skeleton.

2)  Add a new global variable, (after the existing declaration at the top of
    the code) :--

  bool supressband[MAX_BANDS][5];                                     /*MOD*/

3)  In the "addLine()" function test "supressband" to see if it is necessary
    to bypass putting backbgound characters and printer codes into the page
    buffer :--

void addLine(int band, int part, int line)
{
  if (!supressband[band][part]) {                                     /*MOD*/
...
  }                                                                   /*MOD*/
}

4)  In the "addMemos()" function test "supressband" to see if it is
    possible to bypass processing the memo :--

void addMemos(BOOL memofield, ...
{
  if (!supressband[band][part]) {                                     /*MOD*/
...
  }                                                                   /*MOD*/
}

5)  In the "addFields()" function test "supressband" to see if it is
    necessary to bypass putting the field characters into the page buffer:--

void addFields(strptr data, int band, int part, int line, int cond, ...
{
  ...
    if (*(trim(tempString1, strcopy(tempString2, tempString3, 0, TL))))  {
      if (!supressband[band][part]) {                                 /*MOD*/
        textadded = True;
        if (TL > 0) memmove(((*pagebuffer) + lineno)->line + pos - 1, tempString3, TL);
      }                                                               /*MOD*/
    }
  ...
}

6)  In the "fillDataLine" function test "supressband" to see if it is
    necessary to reset "textadded" to False.

void fillDataLine(int band, int part, int line)
{
  textadded = (part != _DATA) || (!(*(supressblanks + band)));
  textadded = textadded && !supressband[band][part];                  /*MOD*/
  switch (band) {
    ⁿFILLLINEⁿ
  }
  return;
}

7)  The "PrtBlanks" function needs to by modified so that it can tell if it
    is processing the Header, Data, Control Break or Footer.  Add a "part"
    parameter to the function header and then test "supressband" to see if
    "blank" lines should be added at the end of the area being processed.  If
    supression is True then set the "blanks" variable back to zero.

    Don't forget to update the function prototype at teh begining of the
    program to match the change to the function implementation.

void printBlankLines(int band, int part)                              /*MOD*/
{
  if (!supressband[band][part]) {                                     /*MOD*/
    textadded = True;
    while(blanks != 0) {
      blanks--;
      incrementLine(band);
    }
  }                                                                   /*MOD*/
  else blanks = 0;                                                    /*MOD*/
  return;
}

8)  In the four functions that place calls to "printBlanksLines()" add a
    second parameter, (either _HDR, _DATA, _BREAK, or _FOOTER depending on
    the part of the report being processed), to the call to
    "printBlanksLines()".

void printDataHeader(int band)
{
  ...
  printBlankLines(band,_HDR);                                         /*MOD*/
  ...
}

void printDataFooter(int band)
{
  ...
  printBlankLines(band,_FOOTER);                                      /*MOD*/
  ...
}

void printDataBand(int band)
{
  ...
  printBlankLines(band,_DATA);                                        /*MOD*/
  ...
}

void printControlBreak(int band)
{
  ...
  printBlankLines(band,_BREAK);                                       /*MOD*/
  ...
}


9)  In the "Initialize" procedure set all the "supressband" elements to
    false.  This means that, by default all the report will be printed as
    would normally be the case.

int initialize(void)
{
  int    counter, okStatus, stringLength;

  ...
  for (counter = 1; counter <= MAX_BANDS;  counter++) {
    *(break_ + counter)      = None;
    *(recordsread + counter) = *(recordsprinted + counter) = *(bandstartlno + counter) = 0;
    supressband[counter][_HDR] = False;                               /*MOD*/
    supressband[counter][_DATA] = False;                              /*MOD*/
    supressband[counter][_BREAK] = False;                             /*MOD*/
    supressband[counter][_FOOTER] = False;                            /*MOD*/
  }
  supressband[0][_HDR] = False;                                       /*MOD*/
  supressband[0][_DATA] = False;                                      /*MOD*/
  supressband[0][_BREAK] = False;                                     /*MOD*/
  supressband[0][_FOOTER] = False;                                    /*MOD*/
  ...
}


With the above modifications in place it is just a matter of re-setting some
or all of the "supressband" elements so that certain parts of the report
are processed but not actually printed to the output device.

This could be done by inserting compute fields into a filter associated with
a particular report, or by using the "Fields/Add/Statement" to insert some
code statements early in the report definition of the form :--

     supressband[2][_DATA] = True;  /* Stop Band 2 Data being printed */


Note the following constants are already defined :--

#define _HDR           1
#define _DATA          2
#define _BREAK         3
#define _FOOTER        4