From 050e0bef8e571a571684a12c4c86364c637c12d7 Mon Sep 17 00:00:00 2001
From: Marcelo Lira <setanta@gmail.com>
Date: Sun, 2 Mar 2025 03:00:07 -0300
Subject: Undercurl patch

https://st.suckless.org/patches/undercurl/
---
 st.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 50 insertions(+), 1 deletion(-)

(limited to 'st.c')

diff --git a/st.c b/st.c
index ef8a793..6351657 100644
--- a/st.c
+++ b/st.c
@@ -33,6 +33,7 @@
 #define UTF_SIZ       4
 #define ESC_BUF_SIZ   (128*UTF_SIZ)
 #define ESC_ARG_SIZ   16
+#define CAR_PER_ARG   4
 #define STR_BUF_SIZ   ESC_BUF_SIZ
 #define STR_ARG_SIZ   ESC_ARG_SIZ
 
@@ -139,6 +140,7 @@ typedef struct {
 	int arg[ESC_ARG_SIZ];
 	int narg;              /* nb of args */
 	char mode[2];
+	int carg[ESC_ARG_SIZ][CAR_PER_ARG]; /* colon args */
 } CSIEscape;
 
 /* STR Escape sequence structs */
@@ -159,6 +161,7 @@ static void ttywriteraw(const char *, size_t);
 
 static void csidump(void);
 static void csihandle(void);
+static void readcolonargs(char **, int, int[][CAR_PER_ARG]);
 static void csiparse(void);
 static void csireset(void);
 static void osc_color_response(int, int, int);
@@ -1127,6 +1130,28 @@ tnewline(int first_col)
 	tmoveto(first_col ? 0 : term.c.x, y);
 }
 
+void
+readcolonargs(char **p, int cursor, int params[][CAR_PER_ARG])
+{
+	int i = 0;
+	for (; i < CAR_PER_ARG; i++)
+		params[cursor][i] = -1;
+
+	if (**p != ':')
+		return;
+
+	char *np = NULL;
+	i = 0;
+
+	while (**p == ':' && i < CAR_PER_ARG) {
+		while (**p == ':')
+			(*p)++;
+		params[cursor][i] = strtol(*p, &np, 10);
+		*p = np;
+		i++;
+	}
+}
+
 void
 csiparse(void)
 {
@@ -1150,6 +1175,7 @@ csiparse(void)
 			v = -1;
 		csiescseq.arg[csiescseq.narg++] = v;
 		p = np;
+		readcolonargs(&p, csiescseq.narg-1, csiescseq.carg);
 		if (sep == ';' && *p == ':')
 			sep = ':'; /* allow override to colon once */
 		if (*p != sep || csiescseq.narg == ESC_ARG_SIZ)
@@ -1368,6 +1394,10 @@ tsetattr(const int *attr, int l)
 				ATTR_STRUCK     );
 			term.c.attr.fg = defaultfg;
 			term.c.attr.bg = defaultbg;
+			term.c.attr.ustyle = -1;
+			term.c.attr.ucolor[0] = -1;
+			term.c.attr.ucolor[1] = -1;
+			term.c.attr.ucolor[2] = -1;
 			break;
 		case 1:
 			term.c.attr.mode |= ATTR_BOLD;
@@ -1379,7 +1409,14 @@ tsetattr(const int *attr, int l)
 			term.c.attr.mode |= ATTR_ITALIC;
 			break;
 		case 4:
-			term.c.attr.mode |= ATTR_UNDERLINE;
+			term.c.attr.ustyle = csiescseq.carg[i][0];
+
+			if (term.c.attr.ustyle != 0)
+				term.c.attr.mode |= ATTR_UNDERLINE;
+			else
+				term.c.attr.mode &= ~ATTR_UNDERLINE;
+
+			term.c.attr.mode ^= ATTR_DIRTYUNDERLINE;
 			break;
 		case 5: /* slow blink */
 			/* FALLTHROUGH */
@@ -1430,6 +1467,18 @@ tsetattr(const int *attr, int l)
 		case 49:
 			term.c.attr.bg = defaultbg;
 			break;
+		case 58:
+			term.c.attr.ucolor[0] = csiescseq.carg[i][1];
+			term.c.attr.ucolor[1] = csiescseq.carg[i][2];
+			term.c.attr.ucolor[2] = csiescseq.carg[i][3];
+			term.c.attr.mode ^= ATTR_DIRTYUNDERLINE;
+			break;
+		case 59:
+			term.c.attr.ucolor[0] = -1;
+			term.c.attr.ucolor[1] = -1;
+			term.c.attr.ucolor[2] = -1;
+			term.c.attr.mode ^= ATTR_DIRTYUNDERLINE;
+			break;
 		default:
 			if (BETWEEN(attr[i], 30, 37)) {
 				term.c.attr.fg = attr[i] - 30;
-- 
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