Graphics Programs Reference
In-Depth Information
#define FILENAME "/var/notes"
int print_notes(int, int, char *); // Note printing function.
int find_user_note(int, int); // Seek in file for a note for user.
int search_note(char *, char *); // Search for keyword function.
void fatal(char *); // Fatal error handler
int main(int argc, char *argv[]) {
int userid, printing=1, fd; // File descriptor
char searchstring[100];
if(argc > 1) // If there is an arg,
strcpy(searchstring, argv[1]); // that is the search string;
else // otherwise,
searchstring[0] = 0; // search string is empty.
userid = getuid();
fd = open(FILENAME, O_RDONLY); // Open the file for read-only access.
if(fd == -1)
fatal("in main() while opening file for reading");
while(printing)
printing = print_notes(fd, userid, searchstring);
printf("-------[ end of note data ]-------\n");
close(fd);
}
// A function to print the notes for a given uid that match
// an optional search string;
// returns 0 at end of file, 1 if there are still more notes.
int print_notes(int fd, int uid, char *searchstring) {
int note_length;
char byte=0, note_buffer[100];
note_length = find_user_note(fd, uid);
if(note_length == -1) // If end of file reached,
return 0; // return 0.
read(fd, note_buffer, note_length); // Read note data.
note_buffer[note_length] = 0; // Terminate the string.
if(search_note(note_buffer, searchstring)) // If searchstring found,
printf(note_buffer); // print the note.
return 1;
}
// A function to find the next note for a given userID;
// returns -1 if the end of the file is reached;
// otherwise, it returns the length of the found note.
int find_user_note(int fd, int user_uid) {
int note_uid=-1;
unsigned char byte;
int length;
while(note_uid != user_uid) { // Loop until a note for user_uid is found.
