com32/cmenu/libmenu/help.c

   1 /* -*- c -*- ------------------------------------------------------------- *
   2  *
   3  *   Copyright 2004-2005 Murali Krishnan Ganapathy - All Rights Reserved
   4  *
   5  *   This program is free software; you can redistribute it and/or modify
   6  *   it under the terms of the GNU General Public License as published by
   7  *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
   8  *   Boston MA 02111-1307, USA; either version 2 of the License, or
   9  *   (at your option) any later version; incorporated herein by reference.
  10  *
  11  * ----------------------------------------------------------------------- */
  12
  13 #include "help.h"
  14 #include <stdio.h>
  15 #include "string.h"
  16 #include "com32io.h"
  17 #include <syslinux/loadfile.h>  // to read entire file into memory
  18
  19 int nc, nr; // Number of columns/rows of the screen
  20 char helpbasedir[HELPDIRLEN];   // name of help directory limited to HELPDIRLEN
  21
  22 // Find the occurence of the count'th \n in buffer (or NULL) if not found
  23 static char *findline(char *buffer, int count)
  24 {
  25     int ctr;
  26     char *p = buffer - 1;
  27
  28     if (count < 1)
  29         return buffer;
  30     for (ctr = 0; ctr < count; ctr++) {
  31         p = strchr(p + 1, '\n');
  32         if (p == NULL)
  33             return NULL;
  34     }
  35     return p;
  36 }
  37
  38 // return the number of lines in buffer
  39 static int countlines(char *buffer)
  40 {
  41     int ans;
  42     const char *p;
  43
  44     p = buffer - 1;
  45     ans = 1;
  46     while (p) {
  47         p = strchr(p + 1, '\n');
  48         ans++;
  49     }
  50     return ans;
  51 }
  52
  53 // Print numlines of text starting from buf
  54 static void printtext(char *buf, int from)
  55 {
  56     char *f, *t;
  57     int nlines, i;
  58
  59     // clear window to print
  60     nlines = nr - HELP_BODY_ROW - HELP_BOTTOM_MARGIN - 1;
  61
  62     f = findline(buf, from);
  63     if (!f)
  64         return;                 // nothing to print
  65     if (*f == '\n')
  66         f++;                    // start of from+1st line
  67     t = f;
  68
  69     for (i = 0; i < nlines; i++) {
  70         gotoxy(HELP_BODY_ROW + i, HELP_LEFT_MARGIN);
  71         clear_end_of_line();
  72         putchar(SO);
  73         gotoxy(HELP_BODY_ROW + i, nc - 1);
  74         putch(LEFT_BORDER, 0x07);
  75         putchar(SI);
  76
  77         gotoxy(HELP_BODY_ROW + i, HELP_LEFT_MARGIN);
  78         while (*t != '\n') {
  79             if (*t == '\0')
  80                 return;
  81             putchar(*t);
  82             t++;
  83         }
  84         putchar('\n');
  85         t++;
  86     }
  87 }
  88
  89 void showhelp(const char *filename)
  90 {
  91     char ph;
  92     char *title, *text;
  93     union {
  94         char *buffer;
  95         void *vbuf;
  96     } buf;                      // This is to avoild type-punning issues
  97
  98     char line[512];
  99     size_t size;
 100     int scan;
 101     int rv, numlines, curr_line;
 102
 103     if (getscreensize(1, &nr, &nc)) {
 104         /* Unknown screen size? */
 105         nc = 80;
 106         nr = 24;
 107     }
 108     ph = nr - HELP_BODY_ROW;
 109     cls();
 110
 111     /* Turn autowrap off, to avoid scrolling the menu */
 112     printf(CSI "?7l");
 113
 114     if (filename == NULL) {     // print file contents
 115         strcpy(line, "Filename not given");
 116         goto puke;
 117     }
 118
 119     rv = loadfile(filename, (void **)&buf.vbuf, &size); // load entire file into memory
 120     if (rv < 0) {               // Error reading file or no such file
 121         sprintf(line, "Error reading file or file not found\n file=%s", filename);
 122         goto puke;
 123     }
 124
 125     title = buf.buffer;
 126     text = findline(title, 1);  // end of first line
 127     *text++ = '\0';             // end the title string and increment text
 128
 129     // Now we have a file just print it.
 130     numlines = countlines(text);
 131     curr_line = 0;
 132     scan = KEY_ESC + 1;         // anything except ESCAPE
 133
 134     /* top, left, bottom, right, attr */
 135     drawbox(0, 0, nr - 1, nc - 1, 0x07);
 136     while (scan != KEY_ESC) {
 137     /* Title */
 138     gotoxy(1, (nc - strlen(title)) / 2);
 139     fputs(title, stdout);
 140     drawhorizline(2, HELP_LEFT_MARGIN - 1, nc - HELP_RIGHT_MARGIN, 0x07, 0);    // dumb==0
 141     /* Text */
 142         printtext(text, curr_line);
 143     gotoxy(HELP_BODY_ROW - 1, nc - HELP_RIGHT_MARGIN);
 144         if (curr_line > 0)
 145             putchar(HELP_MORE_ABOVE);
 146         else
 147             putchar(' ');
 148         gotoxy(nr - HELP_BOTTOM_MARGIN - 1, nc - HELP_RIGHT_MARGIN);
 149         if (curr_line < numlines - ph)
 150             putchar(HELP_MORE_BELOW);
 151         else
 152             putchar(' ');
 153
 154     scan = get_key(stdout, 0); // wait for user keypress
 155
 156         switch (scan) {
 157         case KEY_HOME:
 158             curr_line = 0;
 159             break;
 160         case KEY_END:
 161             curr_line = numlines;
 162             break;
 163         case KEY_UP:
 164             curr_line--;
 165             break;
 166         case KEY_DOWN:
 167             curr_line++;
 168             break;
 169         case KEY_PGUP:
 170             curr_line -= ph;
 171             break;
 172         case KEY_PGDN:
 173             curr_line += ph;
 174             break;
 175         default:
 176             break;
 177         }
 178         if (curr_line > numlines - ph)
 179             curr_line = numlines - ph;
 180         if (curr_line < 0)
 181             curr_line = 0;
 182     }
 183 out:
 184     cls();
 185     return;
 186
 187 puke:
 188     gotoxy(HELP_BODY_ROW, HELP_LEFT_MARGIN);
 189     fputs(line, stdout);
 190     while (1) {
 191         scan = get_key(stdin, 0);
 192         if (scan == KEY_ESC)
 193             break;
 194     }
 195     goto out;
 196 }
 197
 198 void runhelp(const char *filename)
 199 {
 200     char fullname[HELPDIRLEN + 16];
 201
 202         cls();
 203     cursoroff();
 204     if (helpbasedir[0] != 0) {
 205         strcpy(fullname, helpbasedir);
 206         strcat(fullname, "/");
 207         strcat(fullname, filename);
 208         showhelp(fullname);
 209     } else
 210         showhelp(filename);     // Assume filename is absolute
 211 }
 212
 213 void runhelpsystem(unsigned int helpid)
 214 {
 215     char filename[15];
 216
 217     sprintf(filename, "hlp%05d.txt", helpid);
 218     runhelp(filename);
 219 }
 220
 221 void init_help(const char *helpdir)
 222 {
 223     if (helpdir != NULL)
 224         strcpy(helpbasedir, helpdir);
 225     else
 226         helpbasedir[0] = 0;
 227 }
 228
 229 void close_help(void)
 230 {
 231 }