arch/common/grub2/font/manager.c

   1 /*
   2  *  GRUB  --  GRand Unified Bootloader
   3  *  Copyright (C) 2003,2005,2006,2007  Free Software Foundation, Inc.
   4  *
   5  *  GRUB 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, either version 3 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  GRUB is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include <grub/file.h>
  20 #include <grub/misc.h>
  21 #include <grub/dl.h>
  22 #include <grub/normal.h>
  23 #include <grub/types.h>
  24 #include <grub/mm.h>
  25 #include <grub/font.h>
  26
  27 struct entry
  28 {
  29   grub_uint32_t code;
  30   grub_uint32_t offset;
  31 };
  32
  33 struct font
  34 {
  35   struct font *next;
  36   grub_file_t file;
  37   grub_uint32_t num;
  38   struct entry table[0];
  39 };
  40
  41 static struct font *font_list;
  42
  43 static int
  44 add_font (const char *filename)
  45 {
  46   grub_file_t file = 0;
  47   char magic[4];
  48   grub_uint32_t num, i;
  49   struct font *font = 0;
  50
  51   file = grub_file_open (filename);
  52   if (! file)
  53     goto fail;
  54
  55   if (grub_file_read (file, magic, 4) != 4)
  56     goto fail;
  57
  58   if (grub_memcmp (magic, GRUB_FONT_MAGIC, 4) != 0)
  59     {
  60       grub_error (GRUB_ERR_BAD_FONT, "invalid font magic");
  61       goto fail;
  62     }
  63
  64   if (grub_file_read (file, (char *) &num, 4) != 4)
  65     goto fail;
  66
  67   num = grub_le_to_cpu32 (num);
  68   font = (struct font *) grub_malloc (sizeof (struct font)
  69                                       + sizeof (struct entry) * num);
  70   if (! font)
  71     goto fail;
  72
  73   font->file = file;
  74   font->num = num;
  75
  76   for (i = 0; i < num; i++)
  77     {
  78       grub_uint32_t code, offset;
  79
  80       if (grub_file_read (file, (char *) &code, 4) != 4)
  81         goto fail;
  82
  83       if (grub_file_read (file, (char *) &offset, 4) != 4)
  84         goto fail;
  85
  86       font->table[i].code = grub_le_to_cpu32 (code);
  87       font->table[i].offset = grub_le_to_cpu32 (offset);
  88     }
  89
  90   font->next = font_list;
  91   font_list = font;
  92
  93   return 1;
  94
  95  fail:
  96   if (font)
  97     grub_free (font);
  98
  99   if (file)
 100     grub_file_close (file);
 101
 102   return 0;
 103 }
 104
 105 static void
 106 remove_font (struct font *font)
 107 {
 108   struct font **p, *q;
 109
 110   for (p = &font_list, q = *p; q; p = &(q->next), q = q->next)
 111     if (q == font)
 112       {
 113         *p = q->next;
 114
 115         grub_file_close (font->file);
 116         grub_free (font);
 117
 118         break;
 119       }
 120 }
 121
 122 /* Return the offset of the glyph corresponding to the codepoint CODE
 123    in the font FONT.  If no found, return zero.  */
 124 static grub_uint32_t
 125 find_glyph (const struct font *font, grub_uint32_t code)
 126 {
 127   grub_uint32_t start = 0;
 128   grub_uint32_t end = font->num - 1;
 129   const struct entry *table = font->table;
 130
 131   /* This shouldn't happen.  */
 132   if (font->num == 0)
 133     return 0;
 134
 135   /* Do a binary search.  */
 136   while (start <= end)
 137     {
 138       grub_uint32_t i = (start + end) / 2;
 139
 140       if (table[i].code < code)
 141         start = i + 1;
 142       else if (table[i].code > code)
 143         end = i - 1;
 144       else
 145         return table[i].offset;
 146     }
 147
 148   return 0;
 149 }
 150
 151 /* Set the glyph to something stupid.  */
 152 static void
 153 fill_with_default_glyph (grub_font_glyph_t glyph)
 154 {
 155   unsigned i;
 156
 157   for (i = 0; i < 16; i++)
 158     glyph->bitmap[i] = (i & 1) ? 0x55 : 0xaa;
 159
 160   glyph->char_width = 1;
 161   glyph->width = glyph->char_width * 8;
 162   glyph->height = 16;
 163   glyph->baseline = (16 * 3) / 4;
 164 }
 165
 166 /* Get a glyph corresponding to the codepoint CODE.  Always fill glyph
 167    information with something, even if no glyph is found.  */
 168 int
 169 grub_font_get_glyph (grub_uint32_t code,
 170                      grub_font_glyph_t glyph)
 171 {
 172   struct font *font;
 173   grub_uint8_t bitmap[32];
 174
 175   /* FIXME: It is necessary to cache glyphs!  */
 176
 177  restart:
 178   for (font = font_list; font; font = font->next)
 179     {
 180       grub_uint32_t offset;
 181
 182       offset = find_glyph (font, code);
 183       if (offset)
 184         {
 185           grub_uint32_t w;
 186           int len;
 187
 188           /* Make sure we can find glyphs for error messages.  Push active
 189              error message to error stack and reset error message.  */
 190           grub_error_push ();
 191
 192           grub_file_seek (font->file, offset);
 193           if ((len = grub_file_read (font->file, (char *) &w, sizeof (w)))
 194               != sizeof (w))
 195             {
 196               remove_font (font);
 197               goto restart;
 198             }
 199
 200           w = grub_le_to_cpu32 (w);
 201           if (w != 1 && w != 2)
 202             {
 203               /* grub_error (GRUB_ERR_BAD_FONT, "invalid width"); */
 204               remove_font (font);
 205               goto restart;
 206             }
 207
 208           if (grub_file_read (font->file, (char *) bitmap, w * 16)
 209               != (grub_ssize_t) w * 16)
 210             {
 211               remove_font (font);
 212               goto restart;
 213             }
 214
 215           /* Fill glyph with information.  */
 216           grub_memcpy (glyph->bitmap, bitmap, w * 16);
 217
 218           glyph->char_width = w;
 219           glyph->width = glyph->char_width * 8;
 220           glyph->height = 16;
 221           glyph->baseline = (16 * 3) / 4;
 222
 223           /* Restore old error message.  */
 224           grub_error_pop ();
 225
 226           return 1;
 227         }
 228     }
 229
 230   /* Uggh...  No font was found.  */
 231   fill_with_default_glyph (glyph);
 232   return 0;
 233 }
 234
 235 static grub_err_t
 236 font_command (struct grub_arg_list *state __attribute__ ((unused)),
 237               int argc  __attribute__ ((unused)),
 238               char **args __attribute__ ((unused)))
 239 {
 240   if (argc == 0)
 241     return grub_error (GRUB_ERR_BAD_ARGUMENT, "no font specified");
 242
 243   while (argc--)
 244     if (! add_font (*args++))
 245       return 1;
 246
 247   return 0;
 248 }
 249
 250 GRUB_MOD_INIT(font_manager)
 251 {
 252   grub_register_command ("font", font_command, GRUB_COMMAND_FLAG_BOTH,
 253                          "font FILE...",
 254                          "Specify one or more font files to display.", 0);
 255 }
 256
 257 GRUB_MOD_FINI(font_manager)
 258 {
 259   grub_unregister_command ("font");
 260 }