font.c

   1 #include <fcntl.h>
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <sys/mman.h>
   5 #include <sys/stat.h>
   6 #include <unistd.h>
   7 #include <string.h>
   8 #include "config.h"
   9 #include "font.h"
  10 #include "util.h"
  11
  12 static int fd;
  13 static char *tf;
  14 static int rows;
  15 static int cols;
  16 static int n;
  17 static int *glyphs;
  18 static unsigned char *data;
  19
  20 static void xerror(char *msg)
  21 {
  22         perror(msg);
  23         exit(1);
  24 }
  25
  26 static size_t file_size(int fd)
  27 {
  28         struct stat st;
  29         if (!fstat(fd, &st))
  30                 return st.st_size;
  31         return 0;
  32 }
  33
  34 struct tf_header {
  35         char sig[8];
  36         int ver;
  37         int n;
  38         int rows, cols;
  39 };
  40
  41 void font_init(void)
  42 {
  43         struct tf_header *head;
  44         fd = open(TINYFONT, O_RDONLY);
  45         if (fd == -1)
  46                 xerror("can't open font");
  47         fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
  48         tf = mmap(NULL, file_size(fd), PROT_READ, MAP_SHARED, fd, 0);
  49         if (tf == MAP_FAILED)
  50                 xerror("can't mmap font file");
  51         head = (struct tf_header *) tf;
  52         n = head->n;
  53         rows = head->rows;
  54         cols = head->cols;
  55         glyphs = (int *) (tf + sizeof(*head));
  56         data = (unsigned char *) (glyphs + n);
  57 }
  58
  59 static int find_glyph(int c)
  60 {
  61         int l = 0;
  62         int h = n;
  63         while (l < h) {
  64                 int m = (l + h) / 2;
  65                 if (glyphs[m] == c)
  66                         return m;
  67                 if (c < glyphs[m])
  68                         h = m;
  69                 else
  70                         l = m + 1;
  71         }
  72         return -1;
  73 }
  74
  75 unsigned char *font_bitmap(int c)
  76 {
  77         int i = find_glyph(c);
  78         return i >= 0 ? &data[i * rows * cols] : NULL;
  79 }
  80
  81 void font_free(void)
  82 {
  83         munmap(tf, file_size(fd));
  84         close(fd);
  85 }
  86
  87 int font_rows(void)
  88 {
  89         return rows;
  90 }
  91
  92 int font_cols(void)
  93 {
  94         return cols;
  95 }