#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

/* ...	'InputFile' is site dependent */

#define INPUTFILE  "/home/leslim/WWW/C/FUNCTIONS/function.ref.html"
#define LINELENGTH 1024
 
void TopBit(FILE *fp);
void GetString(char **String);
void SelectBit(FILE *fp, char *String);
void BottomBit(FILE *fp);
void UpperCase(char *String);

/************************************************************************/

main()
{

  FILE *fp;

  char *String;

  /* ... Open the file */

  fp = fopen(INPUTFILE, "r");

  if (!fp)
  {
    printf(" Open if %s failed.", INPUTFILE);
    exit(0);
  }

  TopBit(fp);

  GetString(&String);

  /* ... Now filter using the supplied information. */

  SelectBit(fp, String);

  BottomBit(fp);

  fclose(fp);
}

/************************************************************************/

void TopBit(FILE *fp)
{
   char Line[LINELENGTH];

   puts("Content-type: text/html");
   puts("");                            /* BLANK LINE IS REQUIRED       */

  /* ... Read the heading */

  do 
  {
    fgets(Line, LINELENGTH, fp);
    printf("%s", Line);
  } while (!strstr(Line, "<!-- End of heading area -->"));
}

/************************************************************************/

void GetString(char **String)
{
  char *TmpPtr;
  char *Ptr;
  
  TmpPtr = getenv("QUERY_STRING");
 
  Ptr = (char *) malloc(strlen(TmpPtr)+1);
  strcpy(Ptr, TmpPtr);
  TmpPtr = Ptr;

  /* 	QUERY_STRING will look like.
   * 
   *    String=Text
   *
   */

  if (TmpPtr)
  { 
    *String = strtok(TmpPtr, "=");
    *String = strtok(NULL,   "=");
  }
  else
  {
    *String = NULL;
  }

  /* Convert to uppercase */

  UpperCase(*String);
}

/************************************************************************/

void SelectBit(FILE *fp, char *String)
{
  char Line[LINELENGTH];
  char UpperLine[LINELENGTH];

  do 
  {
    fgets(Line, LINELENGTH, fp);

    strcpy(UpperLine, Line);
    UpperCase(UpperLine);

    if (strstr(UpperLine, String))
    {
      printf("%s", Line);
    }

  } while (!strstr(Line, "<!-- Start of footer. -->"));

}

/************************************************************************/

void BottomBit(FILE *fp)
{
  char Line[LINELENGTH];

  while(fgets(Line, LINELENGTH, fp) != NULL)
  {
    printf("%s", Line);
  }
}

/************************************************************************/

void UpperCase(char *String)
{
  int Pos;

  for (Pos = 0; Pos < strlen(String); Pos++)
  {
    String[Pos] = toupper(String[Pos]);
  } 
}