[PATCH weston v2 1/2] config-parser: add support for more color formats

[Eric Engestrom]

Supported colour formats are:
- (0x)(AA)RRGGBB
- #RGB(A)
- #RRGGBB(AA)

Cc: Bryce Harrington <bryce at osg.samsung.com>
Cc: Quentin Glidic <sardemff7+wayland at sardemff7.net>
Signed-off-by: Eric Engestrom <eric at engestrom.ch>
---
v2: reduce the number of formats supported
    read #-prefixed values the same way CSS would
---
 shared/config-parser.c | 54 ++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 46 insertions(+), 8 deletions(-)

diff --git a/shared/config-parser.c b/shared/config-parser.c
index e2b5fa2..b3848a2 100644
--- a/shared/config-parser.c
+++ b/shared/config-parser.c
@@ -215,6 +215,12 @@ weston_config_section_get_uint(struct weston_config_section *section,
 	return 0;
 }
 
+/*
+ * Supported colour formats:
+ * - (0x)(AA)RRGGBB
+ * - #RGB(A)
+ * - #RRGGBB(AA)
+ */
 WL_EXPORT
 int
 weston_config_section_get_color(struct weston_config_section *section,
@@ -224,6 +230,10 @@ 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;
+	enum { hex, css } colour_type;
 
 	entry = config_section_get_entry(section, key);
 	if (entry == NULL) {
@@ -232,19 +242,47 @@ weston_config_section_get_color(struct weston_config_section *section,
 		return -1;
 	}
 
+	val = entry->value;
+	len = strlen(val);
-	len = strlen(entry->value);
+
-	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;
+		colour_type = hex;
+	}
+	else if (len > 1 && val[0] == '#') {
+		val += 1;
+		len -= 1;
+		colour_type = css;
+	}
+	else
+		colour_type = hex;
+
+	if (colour_type == hex)
+		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; /* (0x)AARRGGBB */
+		case 6: color_string = (char[]){ alpha[0], alpha[1], val[0], val[1], val[2], val[3], val[4], val[5], '\0' }; break; /*   (0x)RRGGBB */
+		default: goto invalid;
+		}
+
+	if (colour_type == css)
+		switch (len) {
+		case 8: color_string = (char[]){   val[6],   val[7], val[0], val[1], val[2], val[3], val[4], val[5], '\0' }; break; /* #RRGGBBAA */
+		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[3],   val[3], val[0], val[0], val[1], val[1], val[2], val[2], '\0' }; break; /* # R G B A */
+		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   */
+		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