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 right, nlines, i;
  58
  59     // clear window to print
  60     right = nc - HELP_RIGHT_MARGIN;
  61     nlines = nr - HELP_BODY_ROW - HELP_BOTTOM_MARGIN - 1;
  62
  63     f = findline(buf, from);
  64     if (!f)
  65         return;                 // nothing to print
  66     if (*f == '\n')
  67         f++;                    // start of from+1st line
  68     t = f;
  69     while (i < nlines) {
  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         i++;
  87     }
  88 }
  89
  90 void showhelp(const char *filename)
  91 {
  92     char ph;
  93     char *title, *text;
  94     union {
  95         char *buffer;
  96         void *vbuf;
  97     } buf;                      // This is to avoild type-punning issues
  98
  99     char line[512];
 100     size_t size;
 101     int scan;
 102     int rv, numlines, curr_line;
 103
 104     if (getscreensize(1, &nr, &nc)) {
 105         /* Unknown screen size? */
 106         nc = 80;
 107         nr = 24;
 108     }
 109     ph = nr - HELP_BODY_ROW;
 110     cls();
 111
 112     /* Turn autowrap off, to avoid scrolling the menu */
 113     printf(CSI "?7l");
 114
 115     if (filename == NULL) {     // print file contents
 116         strcpy(line, "Filename not given");
 117         goto puke;
 118     }
 119
 120     rv = loadfile(filename, (void **)&buf.vbuf, &size); // load entire file into memory
 121     if (rv < 0) {               // Error reading file or no such file
 122         sprintf(line, "Error reading file or file not found\n file=%s", filename);
 123         goto puke;
 124     }
 125
 126     title = buf.buffer;
 127     text = findline(title, 1);  // end of first line
 128     *text++ = '\0';             // end the title string and increment text
 129
 130     // Now we have a file just print it.
 131     numlines = countlines(text);
 132     curr_line = 0;
 133     scan = KEY_ESC + 1;         // anything except ESCAPE
 134
 135     /* top, left, bottom, right, attr */
 136     drawbox(0, 0, nr - 1, nc - 1, 0x07);
 137     while (scan != KEY_ESC) {
 138     /* Title */
 139     gotoxy(1, (nc - strlen(title)) / 2);
 140     fputs(title, stdout);
 141     drawhorizline(2, HELP_LEFT_MARGIN - 1, nc - HELP_RIGHT_MARGIN, 0x07, 0);    // dumb==0
 142     /* Text */
 143         printtext(text, curr_line);
 144     gotoxy(HELP_BODY_ROW - 1, nc - HELP_RIGHT_MARGIN);
 145         if (curr_line > 0)
 146             putchar(HELP_MORE_ABOVE);
 147         else
 148             putchar(' ');
 149         gotoxy(nr - HELP_BOTTOM_MARGIN - 1, nc - HELP_RIGHT_MARGIN);
 150         if (curr_line < numlines - ph)
 151             putchar(HELP_MORE_BELOW);
 152         else
 153             putchar(' ');
 154
 155     scan = get_key(stdout, 0); // wait for user keypress
 156
 157         switch (scan) {
 158         case KEY_HOME:
 159             curr_line = 0;
 160             break;
 161         case KEY_END:
 162             curr_line = numlines;
 163             break;
 164         case KEY_UP:
 165             curr_line--;
 166             break;
 167         case KEY_DOWN:
 168             curr_line++;
 169             break;
 170         case KEY_PGUP:
 171             curr_line -= ph;
 172             break;
 173         case KEY_PGDN:
 174             curr_line += ph;
 175             break;
 176         default:
 177             break;
 178         }
 179         if (curr_line > numlines - ph)
 180             curr_line = numlines - ph;
 181         if (curr_line < 0)
 182             curr_line = 0;
 183     }
 184 out:
 185     cls();
 186     return;
 187
 188 puke:
 189     gotoxy(HELP_BODY_ROW, HELP_LEFT_MARGIN);
 190     fputs(line, stdout);
 191     while (1) {
 192         scan = get_key(stdin, 0);
 193         if (scan == KEY_ESC)
 194             break;
 195     }
 196     goto out;
 197 }
 198
 199 void runhelp(const char *filename)
 200 {
 201     char fullname[HELPDIRLEN + 16];
 202
 203         cls();
 204     cursoroff();
 205     if (helpbasedir[0] != 0) {
 206         strcpy(fullname, helpbasedir);
 207         strcat(fullname, "/");
 208         strcat(fullname, filename);
 209         showhelp(fullname);
 210     } else
 211         showhelp(filename);     // Assume filename is absolute
 212 }
 213
 214 void runhelpsystem(unsigned int helpid)
 215 {
 216     char filename[15];
 217
 218     sprintf(filename, "hlp%05d.txt", helpid);
 219     runhelp(filename);
 220 }
 221
 222 void init_help(const char *helpdir)
 223 {
 224     if (helpdir != NULL)
 225         strcpy(helpbasedir, helpdir);
 226     else
 227         helpbasedir[0] = 0;
 228 }
 229
 230 void close_help(void)
 231 {
 232 }