From 9b5168981221c515fb9c5ed6d0a1733ba4821b67 Mon Sep 17 00:00:00 2001
From: Mikko Mononen <memononen@gmail.com>
Date: Fri, 30 Jun 2017 18:16:26 +0300
Subject: [PATCH] Fix for issue #90 - use custom strong to float conversion

Use custom strong to float conversion instead of the one from std
library to fix parsing floats with locales which use different number
format than specified by SVG.
---
 src/nanosvg.h | 70 +++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 65 insertions(+), 5 deletions(-)

diff --git a/src/nanosvg.h b/src/nanosvg.h
index e5e8039..8e12904 100644
--- a/src/nanosvg.h
+++ b/src/nanosvg.h
@@ -215,7 +215,7 @@ static int nsvg__isspace(char c)
 
 static int nsvg__isdigit(char c)
 {
-	return strchr("0123456789", c) != 0;
+	return c >= '0' && c <= '9';
 }
 
 static int nsvg__isnum(char c)
@@ -1075,6 +1075,66 @@ error:
 	}
 }
 
+// We roll our own string to float because the std library one uses locale and messes things up.
+static double nsvg__atof(const char* s)
+{
+	char* cur = (char*)s;
+	char* end = NULL;
+	double res = 0.0, sign = 1.0;
+	long long intPart = 0, fracPart = 0;
+	char hasIntPart = 0, hasFracPart = 0;
+
+	// Parse optional sign
+	if (*cur == '+') {
+		cur++;
+	} else if (*cur == '-') {
+		sign = -1;
+		cur++;
+	}
+
+	// Parse integer part
+	if (nsvg__isdigit(*cur)) {
+		// Parse digit sequence
+		intPart = (double)strtoll(cur, &end, 10);
+		if (cur != end) {
+			res = (double)intPart;
+			hasIntPart = 1;
+			cur = end;
+		}
+	}
+
+	// Parse fractional part.
+	if (*cur == '.') {
+		cur++; // Skip '.'
+		if (nsvg__isdigit(*cur)) {
+			// Parse digit sequence
+			fracPart = strtoll(cur, &end, 10);
+			if (cur != end) {
+				res += (double)fracPart / pow(10.0, (double)(end - cur)) * sign;
+				hasFracPart = 1;
+				cur = end;
+			}
+		}
+	}
+
+	// A valid number should have integer or fractional part.
+	if (!hasIntPart && !hasFracPart)
+		return 0.0;
+
+	// Parse optional exponent
+	if (*cur == 'e' || *cur == 'E') {
+		int expPart = 0;
+		cur++; // skip 'E'
+		expPart = strtol(cur, &end, 10); // Parse digit sequence with sign
+		if (cur != end) {
+			res *= pow(10.0, (double)expPart);
+		}
+	}
+
+	return res * sign;
+}
+
+
 static const char* nsvg__parseNumber(const char* s, char* it, const int size)
 {
 	const int last = size-1;
@@ -1434,7 +1494,7 @@ static int nsvg__parseTransformArgs(const char* str, float* args, int maxNa, int
 		if (*ptr == '-' || *ptr == '+' || *ptr == '.' || nsvg__isdigit(*ptr)) {
 			if (*na >= maxNa) return 0;
 			ptr = nsvg__parseNumber(ptr, it, 64);
-			args[(*na)++] = (float)atof(it);
+			args[(*na)++] = (float)nsvg__atof(it);
 		} else {
 			++ptr;
 		}
@@ -2079,7 +2139,7 @@ static void nsvg__pathArcTo(NSVGparser* p, float* cpx, float* cpy, float* args,
 //	if (vecrat(ux,uy,vx,vy) <= -1.0f) da = NSVG_PI;
 //	if (vecrat(ux,uy,vx,vy) >= 1.0f) da = 0;
 
-	if (fs == 0 && da > 0) 
+	if (fs == 0 && da > 0)
 		da -= 2 * NSVG_PI;
 	else if (fs == 1 && da < 0)
 		da += 2 * NSVG_PI;
@@ -2152,7 +2212,7 @@ static void nsvg__parsePath(NSVGparser* p, const char** attr)
 			if (!*item) break;
 			if (nsvg__isnum(item[0])) {
 				if (nargs < 10)
-					args[nargs++] = (float)atof(item);
+					args[nargs++] = (float)nsvg__atof(item);
 				if (nargs >= rargs) {
 					switch (cmd) {
 						case 'm':
@@ -2409,7 +2469,7 @@ static void nsvg__parsePoly(NSVGparser* p, const char** attr, int closeFlag)
 				nargs = 0;
 				while (*s) {
 					s = nsvg__getNextPathItem(s, item);
-					args[nargs++] = (float)atof(item);
+					args[nargs++] = (float)nsvg__atof(item);
 					if (nargs >= 2) {
 						if (npts == 0)
 							nsvg__moveTo(p, args[0], args[1]);