nanosvg: Sync with upstream ccdb199

Includes fixes for a memory corruption bug (CVE-2019-1000032)
and possible division by zero.

(cherry picked from commit 05b28b66ea75a8f4b3158b0dfa7b6fae18eb2e3f)

thirdparty/README.md

@@ -374,7 +374,7 @@ Collection of single-file libraries used in Godot components.
 ## nanosvg
 
 - Upstream: https://github.com/memononen/nanosvg
-- Version: git (3e403ec72a9145cbbcc6c63d94a4caf079aafec2, 2020)
+- Version: git (ccdb1995134d340a93fb20e3a3d323ccb3838dd0, 2021)
 - License: zlib
 
 Files extracted from the upstream source:

thirdparty/nanosvg/nanosvg.h

@@ -1215,35 +1215,22 @@ static const char* nsvg__getNextPathItem(const char* s, char* it)
 
 static unsigned int nsvg__parseColorHex(const char* str)
 {
-	unsigned int c = 0, r = 0, g = 0, b = 0;
-	int n = 0;
-	str++; // skip #
-	// Calculate number of characters.
-	while(str[n] && !nsvg__isspace(str[n]))
-		n++;
-	if (n == 6) {
-		sscanf(str, "%x", &c);
-	} else if (n == 3) {
-		sscanf(str, "%x", &c);
-		c = (c&0xf) | ((c&0xf0) << 4) | ((c&0xf00) << 8);
-		c |= c<<4;
-	}
-	r = (c >> 16) & 0xff;
-	g = (c >> 8) & 0xff;
-	b = c & 0xff;
-	return NSVG_RGB(r,g,b);
+	unsigned int r=0, g=0, b=0;
+	if (sscanf(str, "#%2x%2x%2x", &r, &g, &b) == 3 )		// 2 digit hex
+		return NSVG_RGB(r, g, b);
+	if (sscanf(str, "#%1x%1x%1x", &r, &g, &b) == 3 )		// 1 digit hex, e.g. #abc -> 0xccbbaa
+		return NSVG_RGB(r*17, g*17, b*17);			// same effect as (r<<4|r), (g<<4|g), ..
+	return NSVG_RGB(128, 128, 128);
 }
 
 static unsigned int nsvg__parseColorRGB(const char* str)
 {
-	int r = -1, g = -1, b = -1;
-	char s1[32]="", s2[32]="";
-	sscanf(str + 4, "%d%[%%, \t]%d%[%%, \t]%d", &r, s1, &g, s2, &b);
-	if (strchr(s1, '%')) {
-		return NSVG_RGB((r*255)/100,(g*255)/100,(b*255)/100);
-	} else {
-		return NSVG_RGB(r,g,b);
-	}
+	unsigned int r=0, g=0, b=0;
+	if (sscanf(str, "rgb(%u, %u, %u)", &r, &g, &b) == 3)		// decimal integers
+		return NSVG_RGB(r, g, b);
+	if (sscanf(str, "rgb(%u%%, %u%%, %u%%)", &r, &g, &b) == 3)	// decimal integer percentage
+		return NSVG_RGB(r*255/100, g*255/100, b*255/100);
+	return NSVG_RGB(128, 128, 128);
 }
 
 typedef struct NSVGNamedColor {
@@ -2187,7 +2174,12 @@ static void nsvg__pathArcTo(NSVGparser* p, float* cpx, float* cpy, float* args,
 	// The loop assumes an iteration per end point (including start and end), this +1.
 	ndivs = (int)(fabsf(da) / (NSVG_PI*0.5f) + 1.0f);
 	hda = (da / (float)ndivs) / 2.0f;
-	kappa = fabsf(4.0f / 3.0f * (1.0f - cosf(hda)) / sinf(hda));
+	// Fix for ticket #179: division by 0: avoid cotangens around 0 (infinite)
+	if ((hda < 1e-3f) && (hda > -1e-3f))
+		hda *= 0.5f;
+	else
+		hda = (1.0f - cosf(hda)) / sinf(hda);
+	kappa = fabsf(4.0f / 3.0f * hda);
 	if (da < 0.0f)
 		kappa = -kappa;