help.c

三星公司的有线数字高频头资料及源代码

/****************************************************************
* File         : help.c
* Function     : On-line help for QAMLink Development software.
* Author       : P.J. Michalewicz
* History      :
****************************************************************/

/* include files */
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include <conio.h>
#include <fcntl.h>
#include <io.h>
#include <dos.h>
#include <alloc.h>
#include "qam3118.h"

#define HELP_FILE        "help.hlp"
#define TOPICS_PER_LINE  20
#define MAX_TITLE        132
#define MAX_TOPIC        8096
#define UP_ARROW         0x48
#define DOWN_ARROW       0x50
#define PAGE_UP          0x49
#define PAGE_DOWN        0x51
#define RETURN           0x0d
#define TOPIC_XSTART     4
#define TOPIC_YSTART     3
#define MAX_TOPICS       256

/******************************************************************
* draw_box - draws a box on screen while in test mode.
******************************************************************/
void draw_box(char *title,int xpos,int ypos,int xsiz, int ysiz,int color)
{
  int i,x;

  /* draw the box */
  textbackground(BLUE);
  textcolor(color);
  gotoxy(xpos,ypos);
  cprintf("%c",201);
  for (i=2; i<xsiz; i++) cprintf("%c",205);
  cprintf("%c",187);
  gotoxy(xpos,ypos+ysiz-1);
  cprintf("%c",200);
  for (i=2; i<xsiz; i++) cprintf("%c",205);
  cprintf("%c",188);

  for (i=1; i<ysiz-1; i++) {
    gotoxy(xpos,ypos+i);
    cprintf("%c",186);
    gotoxy(xpos+xsiz-1,ypos+i);
    cprintf("%c",186);
  }

  /* draw the title */
  x = strlen(title);
  if (x < xsiz) {
    x = xpos + (xsiz/2) - (x/2);
    gotoxy(x,ypos);
    cprintf(title);
  }
}




/******************************************************************
* help_code - this routine provides on_line help to the user. Help
* prints a list of available topics to the screen. The user selects
* topics using the arrow keys. Once a topic has been selected, the
* user hits a return.
******************************************************************/
int help_code(void)
{
  int  i,c,line,ntopics,cur_topic,handle;
  long *topic_ptr,done;
  int  title_length;
  int  topic_length;
  int  start,stop,tline,more,less,redraw,delta;
  char *title;
  char *topic;
  char *cp;

  /* allocate memory */
  title = (char *) malloc(MAX_TITLE * sizeof(char));
  topic = (char *) malloc(MAX_TOPIC * sizeof(char));
  
  /* open the help file and read in the topics pointers */
  if ((handle = open(HELP_FILE, O_RDONLY | O_BINARY)) < 0) return QAM_ERROR;
  read(handle,(char *) &ntopics, sizeof(int));
  if (ntopics > MAX_TOPICS) return QAM_ERROR;
  topic_ptr = (long *) malloc(ntopics * sizeof(long));
  read(handle,(char *) topic_ptr, ntopics * sizeof(long));


  /* setup current topic */
  cur_topic = start = 0;
  if (ntopics > TOPICS_PER_LINE) stop = TOPICS_PER_LINE-1;
    else                         stop = ntopics-1;

  redraw = 1;
  delta  = 0;
  while (1) {
    /* determine topics to be displayed */
    if (delta == 1 || delta == -1) {
      if (cur_topic < start) { 
				stop--;
				start--;
      } 
      else {
      	if (cur_topic > stop ) {
					stop++;
					start++;
        }
      }
    } else {
      start += delta;
      stop  += delta;
      if (start < 0) start = 0;
      if (stop  < 0) {
				stop = TOPICS_PER_LINE - 1;
				if (stop >= ntopics) stop = ntopics-1;
      }
      if (start >= ntopics) { 
				start = ntopics - TOPICS_PER_LINE; 
				if (start < 0) start = 0;
      }
      if (stop >= ntopics) stop = ntopics-1;
    }

    /* make sure screen is filled up */
    i = TOPICS_PER_LINE - (1 + stop - start);
    if (i > 0) {
      if (start > 0)        start -= i;
      if (stop < ntopics-1) stop  += i;
    }

    /* display the topics */
    if (redraw) {
      clrscr();
      draw_box(" QAMLink Help Menu ",1,1,79,24,WHITE);
      for (i=start; i <= stop; i++) {
        lseek(handle,topic_ptr[i],SEEK_SET);
        read(handle,(char *) &title_length, sizeof(int));
        read(handle,(char *) &topic_length, sizeof(int));
        if (topic_length > MAX_TOPIC) topic_length = MAX_TOPIC-4;
        read(handle,(char *) title, title_length);
        if (i == cur_topic) {
          textcolor(BLUE);
          textbackground(WHITE);
        } else {                
          textcolor(WHITE);
          textbackground(BLUE);
        }
        gotoxy(TOPIC_XSTART,TOPIC_YSTART + i - start);
        for (cp=title,c=0; *cp != '\0'; cp++,c++) {
          if (*cp == '\t') while (((++c) % 8) != 0) putch(' ');
          else putch(*cp);
        }
      }
      textcolor(WHITE);
      textbackground(BLUE);
      gotoxy(12,24); 
      printf("Hit <Up> <Down> to select topic. Hit <esc> to exit help");
    }

    /* display more prompts */
    if (stop  < (ntopics-1)) { gotoxy(35,23); cprintf("-- more --"); }
    if (start > 0)           { gotoxy(35,2);  cprintf("-- more --"); }

    /* wait for a key to be pressed */
    c = getch();
    if (c == 0) c = getch();
    done=0;
    while (!done) {
      switch (c) {
        case 0x1b: 
          done=1;
          break;

        case UP_ARROW: 
          if (cur_topic > 0) { 
            cur_topic--; 
            redraw = 1;
            delta = -1;
          }
          done = 1;
          break;

        case DOWN_ARROW: 
          if (cur_topic < ntopics-1) {
            cur_topic++; 
            redraw = 1;
            delta  = 1;
          }
          done=1;
          break;

        case PAGE_UP: 
          cur_topic -= TOPICS_PER_LINE;
          if (cur_topic < 0) cur_topic = 0;
          redraw = 1;
          delta  = -TOPICS_PER_LINE;
          done   = 1;
          break;

        case PAGE_DOWN: 
          cur_topic += TOPICS_PER_LINE;
          if (cur_topic >= ntopics) cur_topic = ntopics-1;
          redraw = 1;
          delta  = TOPICS_PER_LINE;
          done   = 1;
          break;
	
        case RETURN: /* display selected topic */
          redraw = 1;

          /* read in the topic */
          lseek(handle,topic_ptr[cur_topic],SEEK_SET);
          read(handle,(char *) &title_length, sizeof(int));
          read(handle,(char *) &topic_length, sizeof(int));
          if (title_length > MAX_TITLE || topic_length > MAX_TOPIC) goto help_exit;
          read(handle,(char *) title, title_length);
          read(handle,(char *) topic, topic_length);

          tline = 0;  /* starting line */
          while (1) {
            clrscr();
            draw_box(" QAMLink Help Menu ",1,1,79,24,WHITE);

            /* locate the requested tline */
            for (i=0,cp=topic; *cp != '\0' && i < tline; cp++) {
              if (*cp == 0x0a) i++;
            }
            if (*cp == 0x09) cp++;

            /* display the topic */
            gotoxy(TOPIC_XSTART,TOPIC_YSTART);
            for (i=c=0; i<TOPICS_PER_LINE && *cp != '\0'; cp++) {
              if (*cp == 0x0a) {
                gotoxy(TOPIC_XSTART,TOPIC_YSTART + i++);
                c = 0;

                /* nuke extra space after newlines */
                if (*(cp+1) == ' ') cp++;

              } else 
                if (*cp == 0x09) {
                  putch(' ');
                  c++;
                  while ((c++ % 8) != 0) putch(' ');
                } else {
                  putch(*cp);
                  c++;
                }
            }

            /* display more prompts */
            if (cp < (topic + topic_length - 1)) {
              gotoxy(35,23); cprintf("-- more --");
              more = 1;
            } else more = 0;
            if (tline > 0) {
              gotoxy(35,2); cprintf("-- more --");
              less = 1;
            } else less = 0;

            /* wait for input */
            if (more || less) {
              gotoxy(16,24); 
              printf("<Up><Down><PgUp><PgDn> to move, <esc> to exit");
            } else {
              gotoxy(32,24); 
              printf("<esc> to exit");
            }
            while (1) {
              c = getch();
              if (c == 0) c = getch();
              if (c == 0x1b) goto bail_topic;
              if (c == PAGE_UP) {
                tline -= (TOPICS_PER_LINE - 1);
                if (tline < 0) tline = 0;
                break;
              }
              if (more && c == PAGE_DOWN) {
                tline += (TOPICS_PER_LINE - 1);
                break;
              }
              if (more && c == DOWN_ARROW) {
                tline++;
                break;
              }
              if (less && c == UP_ARROW) {
                tline--;
                break;
              }
            }
          }
          bail_topic:  
          done=1;
          c = ' ';
          break;
      } /* end switch */

      if (!done) {
        c = getch();
        if (c == 0) c = getch();
      }
    }
	 	if (c == 0x1b) break;
  }
  help_exit:
  close(handle);
  free(title);
  free(topic);
  free(topic_ptr);
  return (QAM_OK);
}