We have no floating point support in barebox and no strtod. Still some
user interaction could benefit from being able to supply command
arguments or device parameters in a format with decimal points.
This new simple_strtofract() function parses a fixed point format consisting
of a 32 bit integer and 32 bit fractional part and returns it multiplied
by a division argument. e.g.
simple_strtofract("1.02", NULL, 1000) == 1020
Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
---
include/linux/kernel.h | 1 +
lib/strtox.c | 57 ++++++++++++++++++++++++++++++++++++++++++
2 files changed, 58 insertions(+)
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index cd7dac73f93a..dd108ba0abf7 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -92,6 +92,7 @@ extern unsigned long simple_strtoul(const char *,char **,unsigned int);
extern long simple_strtol(const char *,char **,unsigned int);
extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
extern long long simple_strtoll(const char *,char **,unsigned int);
+extern s64 simple_strtofract(const char *cp, char **endp, u32 division);
/* The `const' in roundup() prevents gcc-3.3 from calling __divdi3 */
#define roundup(x, y) ( \
diff --git a/lib/strtox.c b/lib/strtox.c
index 76927743a72c..5ef0f0923a9e 100644
--- a/lib/strtox.c
+++ b/lib/strtox.c
@@ -78,3 +78,60 @@ long long simple_strtoll(const char *cp, char **endp, unsigned int base)
return simple_strtoull(cp, endp, base);
}
EXPORT_SYMBOL(simple_strtoll);
+
+static unsigned int simple_strtouint(const char *cp, char **endp, unsigned int base)
+{
+ unsigned int ret;
+
+ ret = simple_strtoull(cp, endp, base);
+ if (ret != (unsigned int)ret) {
+ if (endp)
+ *endp = (char *)cp;
+ return 0;
+ }
+
+ return ret;
+}
+
+s64 simple_strtofract(const char *cp, char **endp, u32 division)
+{
+ char *end = (char *)cp;
+ s64 integer, fract, scale, result = 0;
+ int fract_len = 0, sign = 1;
+
+ switch (*cp) {
+ case '-':
+ sign = -1;
+ fallthrough;
+ case '+':
+ cp++;
+ }
+
+ if (!isdigit(*cp))
+ goto out;
+
+ integer = simple_strtouint(cp, &end, 10);
+ if (end == cp)
+ goto out;
+
+ if (*end == '.' || *end == ',') {
+ cp = end + 1;
+ fract = simple_strtouint(cp, &end, 10);
+ fract_len = end - cp;
+ }
+
+ result = integer * division;
+
+ scale = 1;
+ for (int i = 0; i < fract_len; i++)
+ scale *= 10;
+ if (fract_len > 0)
+ result += (fract * division) / scale;
+
+out:
+ if (endp)
+ *endp = end;
+
+ return sign * result;
+}
+EXPORT_SYMBOL(simple_strtofract);
--
2.39.2
