Optimize fb_print()

2 files changed, 45 insertions, 10 deletions

diff --git a/framebuffer.c b/framebuffer.c
index 36969e0..b4c2f6e 100644
--- a/framebuffer.c
+++ b/framebuffer.c
@@ -3,8 +3,10 @@
 #include <termios.h>
 #include <unistd.h>
 #include <sys/ioctl.h>
+#include <string.h>
 
 #include "framebuffer.h"
+#include "uint8toa.h"
 
 size_t term_width = 0,
        term_height = 0;
@@ -29,20 +31,29 @@ Framebuffer fb_new(size_t width, size_t height) {
         }
     }
 
+    fb.print_buf = malloc(42 * width * height);
+    if (fb.print_buf == NULL) {
+        /* FIXME: see above */
+        fb.fb = NULL;
+        return fb;
+    }
+
     fb.width = width;
     fb.height = height;
     return fb;
 }
 
 void fb_free(Framebuffer *fb) {
-    if (fb->fb == NULL) goto ret;
-
-    for (size_t i = 0; i < fb->height; i++) {
-        free(fb->fb[i]);
+    if (fb->fb != NULL) {
+        for (size_t i = 0; i < fb->height; i++) {
+            free(fb->fb[i]);
+        }
+        free(fb->fb);
     }
-    free(fb->fb);
 
-ret:
+    if (fb->print_buf != NULL)
+        free(fb->print_buf);
+
     fb->width = 0;
     fb->height = 0;
     return;
@@ -108,24 +119,46 @@ void term_update_size(void) {
 #endif
 }
 
+/* Converts pixel to ascii and puts it in buf, used in fb_print().
+ * This is faster than sprinf().
+ * TODO: maybe less memcpy()s will be better? */
+static inline void pixel_to_ascii(char *buf, Pixel p) {
+    memcpy(buf, "\x1b[38;2;XXX;XXX;XXXm\x1b[48;2;XXX;XXX;XXXmXXXX", 42);
+    memcpy(buf + 7, uint8toa[p.fg.r], 3);
+    memcpy(buf + 11, uint8toa[p.fg.g], 3);
+    memcpy(buf + 15, uint8toa[p.fg.b], 3);
+    memcpy(buf + 26, uint8toa[p.bg.r], 3);
+    memcpy(buf + 30, uint8toa[p.bg.g], 3);
+    memcpy(buf + 34, uint8toa[p.bg.b], 3);
+    memcpy(buf + 38, &p.ch, 4);
+}
+
 void fb_print(Framebuffer fb) {
+    /* TODO: move this to buffer, maybe? to avoid an extra write every 'frame' */
     write(STDOUT_FILENO, "\x1b[H", 3); /* Move cursor to top-left */
 
+    /* 'cursor' of print_buf, used to build it */
+    char *cur = fb.print_buf;
+
+    /* build the buffer */
     for (size_t row = 0; row < fb.height; row++) {
         for (size_t col = 0; col < fb.width; col++) {
-            set_fg(fb.fb[row][col].fg);
-            set_bg(fb.fb[row][col].bg);
-            write(STDOUT_FILENO, &(fb.fb[row][col].ch), sizeof(wchar_t));
+            pixel_to_ascii(cur, fb.fb[row][col]);
+            cur += 42;
         }
     }
-    fflush(stdout);
+
+    /* flush the buffer */
+    write(STDOUT_FILENO, fb.print_buf, 42 * fb.width * fb.height);
 }
 
+__attribute__((unused))
 static inline void set_fg(Colour col) {
     fprintf(stdout, "\x1b[38;2;%u;%u;%um", col.r, col.g, col.g);
     fflush(stdout);
 }
 
+__attribute__((unused))
 static inline void set_bg(Colour col) {
     fprintf(stdout, "\x1b[48;2;%u;%u;%um", col.r, col.g, col.g);
     fflush(stdout);
diff --git a/framebuffer.h b/framebuffer.h
index cadcb00..2a26454 100644
--- a/framebuffer.h
+++ b/framebuffer.h
@@ -44,6 +44,8 @@ typedef struct Pixel_s {
 typedef struct Framebuffer_s {
     Pixel **fb; /* Adressed as fb[row][col] or fb[x][y] */
     size_t width, height;
+    char *print_buf; /* is of size (42 * width * height)
+                      * 42 is ANSI 24-bit fg and bg + one wchar_t */
 } Framebuffer;
 
 /* Check if fb == NULL in case malloc() fails */