[PATCH weston 1/2] config-parser: add support for more color formats

[Eric Engestrom]

Valid colours start with an optional '0x' or '#', followed by:
- AARRGGBB
-   RRGGBB
-  A R G B
-    R G B
-   XYXYXY
-   XXXXXX

Signed-off-by: Eric Engestrom <eric at engestrom.ch>
---

I just stumbled back on this discussion from a few months ago, and
decided to give it a go.

Once again, I apologise for length of the lines in the switch, but
I believe they are much less readable when folded.

I feel like there should be a place where the supported colour formats$
are documented, but I couldn't find it?

---
 shared/config-parser.c | 39 +++++++++++++++++++++++++++++++--------
 1 file changed, 31 insertions(+), 8 deletions(-)

diff --git a/shared/config-parser.c b/shared/config-parser.c
index e2b5fa2..a00b2d6 100644
--- a/shared/config-parser.c
+++ b/shared/config-parser.c
@@ -224,6 +224,9 @@ weston_config_section_get_color(struct weston_config_section *section,
 	struct weston_config_entry *entry;
 	int len;
 	char *end;
+	const char alpha[] = "FF"; /* Default alpha when unspecified */
+	const char *val;
+	const char *color_string;
 
 	entry = config_section_get_entry(section, key);
 	if (entry == NULL) {
@@ -232,19 +235,39 @@ weston_config_section_get_color(struct weston_config_section *section,
 		return -1;
 	}
 
+	val = entry->value;
-	len = strlen(entry->value);
+	len = strlen(val);
+
-	if (len == 1 && entry->value[0] == '0') {
+	if (len == 1 && val[0] == '0') {
 		*color = 0;
 		return 0;
+	}
-	} else if (len != 8 && len != 10) {
-		*color = default_color;
-		errno = EINVAL;
-		return -1;
+
+	if (len > 2 && val[0] == '0' && val[1] == 'x')
+	{
+		val += 2;
+		len -= 2;
+	}
+	else if (len > 1 && val[0] == '#')
+	{
+		val += 1;
+		len -= 1;
+	}
+
+	switch (len) {
+	case 8: color_string = (char[]){   val[0],   val[1], val[2], val[3], val[4], val[5], val[6], val[7], '\0' }; break; /* AARRGGBB */
+	case 6: color_string = (char[]){ alpha[0], alpha[1], val[0], val[1], val[2], val[3], val[4], val[5], '\0' }; break; /*   RRGGBB */
+	case 4: color_string = (char[]){   val[0],   val[0], val[1], val[1], val[2], val[2], val[3], val[3], '\0' }; break; /*  A R G B */
+	case 3: color_string = (char[]){ alpha[0], alpha[1], val[0], val[0], val[1], val[1], val[2], val[2], '\0' }; break; /*    R G B */
+	case 2: color_string = (char[]){ alpha[0], alpha[1], val[0], val[1], val[0], val[1], val[0], val[1], '\0' }; break; /*   XYXYXY */
+	case 1: color_string = (char[]){ alpha[0], alpha[1], val[0], val[0], val[0], val[0], val[0], val[0], '\0' }; break; /*   XXXXXX */
+	default: goto invalid;
 	}
 
 	errno = 0;
-	*color = strtoul(entry->value, &end, 16);
+	*color = strtoul(color_string, &end, 16);
-	if (errno != 0 || end == entry->value || *end != '\0') {
+	if (errno != 0 || end == color_string || *end != '\0') {
+invalid:
 		*color = default_color;
 		errno = EINVAL;
 		return -1;
-- 
Cheers,
  Eric