1 files changed, 122 insertions, 0 deletions
diff --git a/src/utils/utils.c b/src/utils/utils.c
new file mode 100644
index 0000000..a8d0cb5
--- /dev/null
+++ b/src/utils/utils.c
@@ -0,0 +1,122 @@
+/*
+ * This file is part of LibCSS.
+ * Licensed under the MIT License,
+ *                http://www.opensource.org/licenses/mit-license.php
+ * Copyright 2007-9 John-Mark Bell <jmb@netsurf-browser.org>
+ */
+
+#include "utils/utils.h"
+
+css_fixed number_from_css_string(const css_string *string,
+		bool int_only, size_t *consumed)
+{
+	size_t len;
+	const uint8_t *ptr;
+	int sign = 1;
+	int32_t intpart = 0;
+	int32_t fracpart = 0;
+	int32_t pwr = 1;
+
+	if (string == NULL || string->len == 0 || consumed == NULL)
+		return 0;
+
+	len = string->len;
+	ptr = string->data;
+
+	/* number = [+-]? ([0-9]+ | [0-9]* '.' [0-9]+) */
+
+	/* Extract sign, if any */
+	if (ptr[0] == '-') {
+		sign = -1;
+		len--;
+		ptr++;
+	} else if (ptr[0] == '+') {
+		len--;
+		ptr++;
+	}
+
+	/* Ensure we have either a digit or a '.' followed by a digit */
+	if (len == 0) {
+		*consumed = 0;
+		return 0;
+	} else {
+		if (ptr[0] == '.') {
+			if (len == 1 || ptr[1] < '0' || '9' < ptr[1]) {
+				*consumed = 0;
+				return 0;
+			}
+		} else if (ptr[0] < '0' || '9' < ptr[0]) {
+			*consumed = 0;
+			return 0;
+		}
+	}
+
+	/* Now extract intpart, assuming base 10 */
+	while (len > 0) {
+		/* Stop on first non-digit */
+		if (ptr[0] < '0' || '9' < ptr[0])
+			break;
+
+		/* Prevent overflow of 'intpart'; proper clamping below */
+		if (intpart < (1 << 22)) {
+			intpart *= 10;
+			intpart += ptr[0] - '0';
+		}
+		ptr++;
+		len--;
+	}
+
+	/* And fracpart, again, assuming base 10 */
+	if (int_only == false && len > 1 && ptr[0] == '.' && 
+			('0' <= ptr[1] && ptr[1] <= '9')) {
+		ptr++;
+		len--;
+
+		while (len > 0) {
+			if (ptr[0] < '0' || '9' < ptr[0])
+				break;
+
+			if (pwr < 1000000) {
+				pwr *= 10;
+				fracpart *= 10;
+				fracpart += ptr[0] - '0';
+			}
+			ptr++;
+			len--;
+		}
+		fracpart = ((1 << 10) * fracpart + pwr/2) / pwr;
+		if (fracpart >= (1 << 10)) {
+			intpart++;
+			fracpart &= (1 << 10) - 1;
+		}
+	}
+
+	*consumed = ptr - string->data;
+
+	if (sign > 0) {
+		/* If the result is larger than we can represent,
+		 * then clamp to the maximum value we can store. */
+		if (intpart >= (1 << 21)) {
+			intpart = (1 << 21) - 1;
+			fracpart = (1 << 10) - 1;
+		}
+	}
+	else {
+		/* If the negated result is smaller than we can represent
+		 * then clamp to the minimum value we can store. */
+		if (intpart >= (1 << 21)) {
+			intpart = -(1 << 21);
+			fracpart = 0;
+		}
+		else {
+			intpart = -intpart;
+			if (fracpart) {
+				fracpart = (1 << 10) - fracpart;
+				intpart--;
+			}
+		}
+	}
+
+	return (intpart << 10) | fracpart;
+}
+