Platinum Edition Using HTML 4, XML, and Java 1.2
(Publisher: Macmillan Computer Publishing)
Author(s): Eric Ladd
ISBN: 078971759x
Publication Date: 11/01/98

Listing 32.3 rq.c—A Simple Random Quotation Script Used as an SSI

// RQ.C
// This program reads a text file and extracts a random
// quotation from it. If a citation line is found, it
// treats it as a citation; otherwise, all text is treated
// the same.  HTML tags may be embedded in the text.

// RQ is mostly platform-independent.  You’ll have to change
// path element separators to the correct slash if you
// compile for UNIX.  There are no platform-specific system
// calls, though, so a little bit of customization should
// enable the code to run on any platform.

#include <windows.h>  // only required for Windows
#include <stdio.h>
#include <stdlib.h>
#include <io.h>

char     buffer[16000];     // temp holding buffer

void main(int argc, char * argv[]) {
     FILE          *f;          // file-info structure
     fpos_t        fpos;        // file-pos structure
     long          flen;        // length of the file
     char          fname[80];   // the file name
     long          lrand;       // a long random number
     BOOL          goodpos;     // switch
     char          *p;          // generic pointer
     char          *soq;        // start-of-quote pointer
     char          *eoq;        // end-of-quote pointer

     // Seed the random number generator

     srand(GetTickCount());

     // Set all I/O streams to unbuffered

     setvbuf(stdin,NULL,_IONBF,0);
     setvbuf(stdout,NULL,_IONBF,0);

     // Open the quote file

     // If a command-line argument is present, treat it as
     // the file name.  But first check it for validity!

     if (argc > 1) {
          p = strstr(argv[1],“..”);
          if (p==NULL) p = strstr(argv[1],“\\\\”);
          if (p==NULL) p = strchr(argv[1],‘:’);

          // If .., \\, or : found, reject the filename
          if (p) {
               printf(“Invalid relative path ”
                      “specified: %s”,argv[1]);
               return;
          }

          // Otherwise append it to our own path
          strcpy(fname,argv[0]);
          p = strrchr(fname,‘\\’);
          if (p) *p = ‘\0’;
          strcat(fname,“\\”);
          strcat(fname,argv[1]);

     } else {

          // No command-line parm found, so use our
          // executable name, minus our extension, plus
          // .txt as the filename

          strcpy(fname,_pgmptr);
          p = strrchr(fname,‘.’);
          if (p) strcpy(p,“.txt”);
     }

     // We have a filename, so try to open the file

     f = fopen(fname,“r”);

     // If open failed, die right here

     if (f==NULL) {
          printf(“Could not open ‘%s’ for read.”,fname);
          return;
     }

     // Get total length of file in bytes.
     // We do this by seeking to the end and then
     // reading the offset of our current position.
     // There are other ways of getting this
     // information, but this way works almost
     // everywhere, whereas the other ways are
     // platform-dependent.

     fseek(f,0,SEEK_END);
     fgetpos(f,&fpos);
     flen = (long) fpos;

     // Seek to a random point in the file.  Loop through
     // the following section until we find a block of text
     // we can use.

     goodpos = FALSE;          // goes TRUE when we’re done

     while (!goodpos) {

          // Make a random offset into the file.  Generate
          // the number based on the file’s length.

          if (flen > 65535) {
               lrand = MAKELONG(rand(),rand());
          } else {
               lrand = MAKELONG(rand(),0);
          }

          // If our random number is less than the length
          // of the file, use it as an offset.  Seek there
          // and read whatever we find.

          if (lrand < flen) {
               fpos = lrand;
               fsetpos(f,&fpos);
               if (fread(buffer, sizeof(char),
                    sizeof(buffer),f) !=0 ) {
                    soq=NULL;
                    eoq=NULL;
                    soq = strstr(buffer,“\n\n”);
                    if (soq) eoq = strstr(soq+2,“\n\n”);
                    if (eoq) {
                         // skip the first CR
                         soq++;
                         // and the one for the blank line
                         soq++;
                         // mark end of string
                         *eoq=’\0';
                         // look for citation marker
                         p = strstr(soq,“\n--”);
                         // if found, exempt it & remember
                         if (p) {
                              *p=’\0';
                              p++;
                         }
                         // print the quotation
                         printf(soq);
                         if (p)
                         // and citation if any
                         printf(“<br><cite>%s</cite>”,p);
                         // exit the loop
                         goodpos=TRUE;
                    }
               }
          }
     }

     fclose(f);
     fflush(stdout);
        return;
}

XMAS

The XMAS program prints out the number of days remaining until Christmas. It recognizes Christmas Day and Christmas Eve as special cases, and solves the general case problem through brute force. You can certainly find more elegant and efficient ways to calculate elapsed time, but this method doesn’t rely on any platform-specific date/time routines.

The code in Listing 32.4 is short enough and uncomplicated enough that it needs no further explanation.

Listing 32.4 xmas.c—A Simple SSI Script that Counts Down the Days Until Christmas

// CHRISTMAS.C
// This program calculates the number of days between
// the time of invocation and the nearest upcoming 25
// December.  It reports the result as a complete sentence.
// The code is platform-independent.


#include <windows.h>     // only required for Windows
#include <stdio.h>
#include <time.h>

void main() {

     // Some variables, all self-explanatory

     struct tm     today;
     time_t        now;
     int           days;

     // Get the current date, first retrieving the
     // Universal Coordinated Time, then converting it
     // to local time, stored in the today tm structure.

     time(&now);
     today = *localtime(&now);
     mktime(&today);

     // month is zero-based (0=jan, 1=feb, etc);
     // day is one-based
     // year is one-based
     // so Christmas Eve is 11/24

     // Is it Christmas Eve?

     if ((today.tm_mon == 11) && (today.tm_mday==24)) {
          printf(“Today is Christmas Eve!”);

     } else {

          // Is it Christmas Day?

          if ((today.tm_mon == 11) && (today.tm_mday==25)) {
               printf(“Today is Christmas Day!”);
          } else {

               // Calculate days by adding one and comparing
               // for 11/25 repeatedly

               days =0;
               while ( (today.tm_mon  != 11) |
                       (today.tm_mday != 25) )
               {
                    days++;
                    today.tm_mday = today.tm_mday + 1;
                    mktime(&today);
               }

               // Print the result using the customary
               // static verb formation

               printf(“There are %i days until Christmas.”
                      ,days);
          }
     }

     // Flush the output and we’re done

     fflush(stdout);
     return;
}