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;
  10         int cols;
  11         int n;
  12         int *glyphs;
  13         char *data;
  14 };
  15
  16 /*
  17  * tinyfont format:
  18  *
  19  * sig[8]       "tinyfont"
  20  * ver          0
  21  * n            number of glyphs
  22  * rows         glyph rows
  23  * cols         glyph cols
  24  *
  25  * glyphs[n]    unicode character numbers (int)
  26  * bitmaps[n]   character bitmaps (char[rows * cols])
  27  */
  28 struct tinyfont {
  29         char sig[8];
  30         int ver;
  31         int n;
  32         int rows, cols;
  33 };
  34
  35 static void *xread(int fd, int len)
  36 {
  37         void *buf = malloc(len);
  38         if (buf && read(fd, buf, len) == len)
  39                 return buf;
  40         free(buf);
  41         return NULL;
  42 }
  43
  44 struct font *font_open(char *path)
  45 {
  46         struct font *font;
  47         struct tinyfont head;
  48         int fd = open(path, O_RDONLY);
  49         if (fd < 0 || read(fd, &head, sizeof(head)) != sizeof(head)) {
  50                 close(fd);
  51                 return NULL;
  52         }
  53         font = malloc(sizeof(*font));
  54         font->n = head.n;
  55         font->rows = head.rows;
  56         font->cols = head.cols;
  57         font->glyphs = xread(fd, font->n * sizeof(int));
  58         font->data = xread(fd, font->n * font->rows * font->cols);
  59         close(fd);
  60         if (!font->glyphs || !font->data) {
  61                 font_free(font);
  62                 return NULL;
  63         }
  64         return font;
  65 }
  66
  67 static int find_glyph(struct font *font, int c)
  68 {
  69         int l = 0;
  70         int h = font->n;
  71         while (l < h) {
  72                 int m = (l + h) / 2;
  73                 if (font->glyphs[m] == c)
  74                         return m;
  75                 if (c < font->glyphs[m])
  76                         h = m;
  77                 else
  78                         l = m + 1;
  79         }
  80         return -1;
  81 }
  82
  83 int font_bitmap(struct font *font, void *dst, int c)
  84 {
  85         int i = find_glyph(font, c);
  86         int len = font->rows * font->cols;
  87         if (i < 0)
  88                 return 1;
  89         memcpy(dst, font->data + i * len, len);
  90         return 0;
  91 }
  92
  93 void font_free(struct font *font)
  94 {
  95         if (font->data)
  96                 free(font->data);
  97         if (font->glyphs)
  98                 free(font->glyphs);
  99         free(font);
 100 }
 101
 102 int font_rows(struct font *font)
 103 {
 104         return font->rows;
 105 }
 106
 107 int font_cols(struct font *font)
 108 {
 109         return font->cols;
 110 }