log: Support for 256color terminals

And provide extended coloring capabilities for debugging.
The default colors do not change in 256 more to keep
supporting people using Black on White, White on Black and
Solarized terminals.

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>

doc/APIchanges

@@ -13,6 +13,9 @@ libavutil:     2013-12-xx
 
 API changes, most recent first:
 
+2014-04-xx - xxxxxxx - lavu 53.09.0 - log.h
+  Add AV_LOG(c) macro to have 256 color debug messages.
+
 2014-02-xx - xxxxxxx - lavu 53.08.0 - frame.h
   Add av_frame_remove_side_data() for removing a single side data
   instance from a frame.

libavutil/log.c

@@ -53,13 +53,13 @@ static HANDLE con;
 #else
 static const uint8_t color[] = { 0x41, 0x41, 0x11, 0x03, 9, 0x02, 0x06 };
 #define set_color(x)  fprintf(stderr, "\033[%d;3%dm", color[x] >> 4, color[x]&15)
+#define print_256color(x) fprintf(stderr, "\033[38;5;%dm", x)
 #define reset_color() fprintf(stderr, "\033[0m")
 #endif
 static int use_color = -1;
 
-static void colored_fputs(int level, const char *str)
+static void check_color_terminal(void)
 {
-    if (use_color < 0) {
 #if HAVE_SETCONSOLETEXTATTRIBUTE
     CONSOLE_SCREEN_BUFFER_INFO con_info;
     con = GetStdHandle(STD_ERROR_HANDLE);
@@ -71,17 +71,32 @@ static void colored_fputs(int level, const char *str)
         background = attr_orig & 0xF0;
     }
 #elif HAVE_ISATTY
+    char *term = getenv("TERM");
     use_color = !getenv("NO_COLOR") && !getenv("AV_LOG_FORCE_NOCOLOR") &&
-                    (getenv("TERM") && isatty(2) ||
-                     getenv("AV_LOG_FORCE_COLOR"));
+                (getenv("TERM") && isatty(2) || getenv("AV_LOG_FORCE_COLOR"));
+    use_color += !!strstr(term, "256color") ;
 #else
     use_color = getenv("AV_LOG_FORCE_COLOR") && !getenv("NO_COLOR") &&
                !getenv("AV_LOG_FORCE_NOCOLOR");
 #endif
-    }
+}
 
-    if (use_color) {
+static void colored_fputs(int level, int tint, const char *str)
+{
+    if (use_color < 0)
+        check_color_terminal();
+
+    switch (use_color) {
+    case 1:
+        set_color(level);
+        break;
+    case 2:
         set_color(level);
+        if (tint)
+            print_256color(tint);
+        break;
+    default:
+        break;
     }
     fputs(str, stderr);
     if (use_color) {
@@ -102,6 +117,10 @@ void av_log_default_callback(void *avcl, int level, const char *fmt, va_list vl)
     char line[1024];
     static int is_atty;
     AVClass* avc = avcl ? *(AVClass **) avcl : NULL;
+    int tint = av_clip(level >> 8, 0, 256);
+
+    level &= 0xff;
+
     if (level > av_log_level)
         return;
     line[0] = 0;
@@ -138,7 +157,7 @@ void av_log_default_callback(void *avcl, int level, const char *fmt, va_list vl)
         fprintf(stderr, "    Last message repeated %d times\n", count);
         count = 0;
     }
-    colored_fputs(av_clip(level >> 3, 0, 6), line);
+    colored_fputs(av_clip(level >> 3, 0, 6), tint, line);
     av_strlcpy(prev, line, sizeof line);
 }
 

libavutil/log.h

@@ -143,6 +143,14 @@ typedef struct AVClass {
  */
 #define AV_LOG_DEBUG    48
 
+/**
+ * Sets additional colors for extended debugging sessions.
+ * Requires 256color terminal support. Use outside debugging is not
+ * recommended.
+ */
+
+#define AV_LOG_C(x) (x << 8)
+
 /**
  * @}
  */

libavutil/version.h

@@ -54,7 +54,7 @@
  */
 
 #define LIBAVUTIL_VERSION_MAJOR 53
-#define LIBAVUTIL_VERSION_MINOR  8
+#define LIBAVUTIL_VERSION_MINOR  9
 #define LIBAVUTIL_VERSION_MICRO  0
 
 #define LIBAVUTIL_VERSION_INT   AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \