font.c

   1 #include <fcntl.h>
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <unistd.h>
   5 #include <string.h>
   6 #include "fbpad.h"
   7
   8 struct font {
   9         int rows, cols; /* glyph bitmap rows and columns */
  10         int n;          /* number of font glyphs */
  11         int *glyphs;    /* glyph unicode character codes */
  12         char *data;     /* glyph bitmaps */
  13 };
  14
  15 /*
  16  * This tinyfont header is followed by:
  17  *
  18  * glyphs[n]    unicode character codes (int)
  19  * bitmaps[n]   character bitmaps (char[rows * cols])
  20  */
  21 struct tinyfont {
  22         char sig[8];    /* tinyfont signature; "tinyfont" */
  23         int ver;        /* version; 0 */
  24         int n;          /* number of glyphs */
  25         int rows, cols; /* glyph dimensions */
  26 };
  27
  28 static void *xread(int fd, int len)
  29 {
  30         void *buf = malloc(len);
  31         if (buf && read(fd, buf, len) == len)
  32                 return buf;
  33         free(buf);
  34         return NULL;
  35 }
  36
  37 struct font *font_open(char *path)
  38 {
  39         struct font *font;
  40         struct tinyfont head;
  41         int fd = open(path, O_RDONLY);
  42         if (fd < 0 || read(fd, &head, sizeof(head)) != sizeof(head)) {
  43                 close(fd);
  44                 return NULL;
  45         }
  46         font = malloc(sizeof(*font));
  47         font->n = head.n;
  48         font->rows = head.rows;
  49         font->cols = head.cols;
  50         font->glyphs = xread(fd, font->n * sizeof(int));
  51         font->data = xread(fd, font->n * font->rows * font->cols);
  52         close(fd);
  53         if (!font->glyphs || !font->data) {
  54                 font_free(font);
  55                 return NULL;
  56         }
  57         return font;
  58 }
  59
  60 static int find_glyph(struct font *font, int c)
  61 {
  62         int l = 0;
  63         int h = font->n;
  64         while (l < h) {
  65                 int m = (l + h) / 2;
  66                 if (font->glyphs[m] == c)
  67                         return m;
  68                 if (c < font->glyphs[m])
  69                         h = m;
  70                 else
  71                         l = m + 1;
  72         }
  73         return -1;
  74 }
  75
  76 int font_bitmap(struct font *font, void *dst, int c)
  77 {
  78         int i = find_glyph(font, c);
  79         int len = font->rows * font->cols;
  80         if (i < 0)
  81                 return 1;
  82         memcpy(dst, font->data + i * len, len);
  83         return 0;
  84 }
  85
  86 void font_free(struct font *font)
  87 {
  88         if (font && font->data)
  89                 free(font->data);
  90         if (font && font->glyphs)
  91                 free(font->glyphs);
  92         free(font);
  93 }
  94
  95 int font_rows(struct font *font)
  96 {
  97         return font->rows;
  98 }
  99
 100 int font_cols(struct font *font)
 101 {
 102         return font->cols;
 103 }