lib/kstrtox: common code between kstrto*() and simple_strto*() functions

Currently termination logic (\0 or \n\0) is hardcoded in _kstrtoull(), avoid that for code reuse between kstrto*() and simple_strtoull(). Essentially, make them different only in termination logic. simple_strtoull() (and scanf(), BTW) ignores integer overflow, that's a bug we currently don't have guts to fix, making KSTRTOX_OVERFLOW hack necessary. Almost forgot: patch shrinks code size by about ~80 bytes on x86_64. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/kstrtox: common code between kstrto() and simple_strto() functions
Currently termination logic (\0 or \n\0) is hardcoded in _kstrtoull(), avoid that for code reuse between kstrto*() and simple_strtoull(). Essentially, make them different only in termination logic. simple_strtoull() (and scanf(), BTW) ignores integer overflow, that's a bug we currently don't have guts to fix, making KSTRTOX_OVERFLOW hack necessary. Almost forgot: patch shrinks code size by about ~80 bytes on x86_64. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alexey Dobriyan · Linus Torvalds
1 parent b3c49c05b7
Showing 3 changed files with 68 additions and 48 deletions Side-by-side Diff
lib/kstrtox.c
lib/kstrtox.h
lib/vsprintf.c
@@ -18,26 +18,40 @@
 #include <linux/module.h>
 #include <linux/types.h>
 #include <asm/uaccess.h>
+#include "kstrtox.h"
  
-static int _kstrtoull(const char *s, unsigned int base, unsigned long long *res)
+const char *_parse_integer_fixup_radix(const char *s, unsigned int *base)
 {
-	unsigned long long acc;
-	int ok;
-
-	if (base == 0) {
+	if (*base == 0) {
 		if (s[0] == '0') {
 			if (_tolower(s[1]) == 'x' && isxdigit(s[2]))
-				base = 16;
+				*base = 16;
 			else
-				base = 8;
+				*base = 8;
 		} else
-			base = 10;
+			*base = 10;
 	}
-	if (base == 16 && s[0] == '0' && _tolower(s[1]) == 'x')
+	if (*base == 16 && s[0] == '0' && _tolower(s[1]) == 'x')
 		s += 2;
+	return s;
+}
  
-	acc = 0;
-	ok = 0;
+/*
+ * Convert non-negative integer string representation in explicitly given radix
+ * to an integer.
+ * Return number of characters consumed maybe or-ed with overflow bit.
+ * If overflow occurs, result integer (incorrect) is still returned.
+ *
+ * Don't you dare use this function.
+ */
+unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *res)
+{
+	unsigned int rv;
+	int overflow;
+
+	*res = 0;
+	rv = 0;
+	overflow = 0;
 	while (*s) {
 		unsigned int val;
  
  
  
  
  
@@ -45,23 +59,40 @@
 			val = *s - '0';
 		else if ('a' <= _tolower(*s) && _tolower(*s) <= 'f')
 			val = _tolower(*s) - 'a' + 10;
-		else if (*s == '\n' && *(s + 1) == '\0')
-			break;
 		else
-			return -EINVAL;
+			break;
  
 		if (val >= base)
-			return -EINVAL;
-		if (acc > div_u64(ULLONG_MAX - val, base))
-			return -ERANGE;
-		acc = acc * base + val;
-		ok = 1;
-
+			break;
+		if (*res > div_u64(ULLONG_MAX - val, base))
+			overflow = 1;
+		*res = *res * base + val;
+		rv++;
 		s++;
 	}
-	if (!ok)
+	if (overflow)
+		rv |= KSTRTOX_OVERFLOW;
+	return rv;
+}
+
+static int _kstrtoull(const char *s, unsigned int base, unsigned long long *res)
+{
+	unsigned long long _res;
+	unsigned int rv;
+
+	s = _parse_integer_fixup_radix(s, &base);
+	rv = _parse_integer(s, base, &_res);
+	if (rv & KSTRTOX_OVERFLOW)
+		return -ERANGE;
+	rv &= ~KSTRTOX_OVERFLOW;
+	if (rv == 0)
 		return -EINVAL;
-	*res = acc;
+	s += rv;
+	if (*s == '\n')
+		s++;
+	if (*s)
+		return -EINVAL;
+	*res = _res;
 	return 0;
 }
  
+#ifndef _LIB_KSTRTOX_H
+#define _LIB_KSTRTOX_H
+
+#define KSTRTOX_OVERFLOW	(1U << 31)
+const char *_parse_integer_fixup_radix(const char *s, unsigned int *base);
+unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *res);
+
+#endif
@@ -31,17 +31,7 @@
 #include <asm/div64.h>
 #include <asm/sections.h>	/* for dereference_function_descriptor() */
  
-static unsigned int simple_guess_base(const char *cp)
-{
-	if (cp[0] == '0') {
-		if (_tolower(cp[1]) == 'x' && isxdigit(cp[2]))
-			return 16;
-		else
-			return 8;
-	} else {
-		return 10;
-	}
-}
+#include "kstrtox.h"
  
 /**
  * simple_strtoull - convert a string to an unsigned long long
  
  
@@ -51,23 +41,14 @@
  */
 unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base)
 {
-	unsigned long long result = 0;
+	unsigned long long result;
+	unsigned int rv;
  
-	if (!base)
-		base = simple_guess_base(cp);
+	cp = _parse_integer_fixup_radix(cp, &base);
+	rv = _parse_integer(cp, base, &result);
+	/* FIXME */
+	cp += (rv & ~KSTRTOX_OVERFLOW);
  
-	if (base == 16 && cp[0] == '0' && _tolower(cp[1]) == 'x')
-		cp += 2;
-
-	while (isxdigit(*cp)) {
-		unsigned int value;
-
-		value = isdigit(*cp) ? *cp - '0' : _tolower(*cp) - 'a' + 10;
-		if (value >= base)
-			break;
-		result = result * base + value;
-		cp++;
-	}
 	if (endp)
 		*endp = (char *)cp;
...	...	@@ -18,26 +18,40 @@
18	18	#include <linux/module.h>
19	19	#include <linux/types.h>
20	20	#include <asm/uaccess.h>
	21	+#include "kstrtox.h"
21	22
22		-static int _kstrtoull(const char s, unsigned int base, unsigned long long res)
	23	+const char _parse_integer_fixup_radix(const char s, unsigned int *base)
23	24	{
24		- unsigned long long acc;
25		- int ok;
26		-
27		- if (base == 0) {
	25	+ if (*base == 0) {
28	26	if (s[0] == '0') {
29	27	if (_tolower(s[1]) == 'x' && isxdigit(s[2]))
30		- base = 16;
	28	+ *base = 16;
31	29	else
32		- base = 8;
	30	+ *base = 8;
33	31	} else
34		- base = 10;
	32	+ *base = 10;
35	33	}
36		- if (base == 16 && s[0] == '0' && _tolower(s[1]) == 'x')
	34	+ if (*base == 16 && s[0] == '0' && _tolower(s[1]) == 'x')
37	35	s += 2;
	36	+ return s;
	37	+}
38	38
39		- acc = 0;
40		- ok = 0;
	39	+/*
	40	+ * Convert non-negative integer string representation in explicitly given radix
	41	+ * to an integer.
	42	+ * Return number of characters consumed maybe or-ed with overflow bit.
	43	+ * If overflow occurs, result integer (incorrect) is still returned.
	44	+ *
	45	+ * Don't you dare use this function.
	46	+ */
	47	+unsigned int _parse_integer(const char s, unsigned int base, unsigned long long res)
	48	+{
	49	+ unsigned int rv;
	50	+ int overflow;
	51	+
	52	+ *res = 0;
	53	+ rv = 0;
	54	+ overflow = 0;
41	55	while (*s) {
42	56	unsigned int val;
43	57
44	58
45	59
46	60
47	61
...	...	@@ -45,23 +59,40 @@
45	59	val = *s - '0';
46	60	else if ('a' <= _tolower(s) && _tolower(s) <= 'f')
47	61	val = _tolower(*s) - 'a' + 10;
48		- else if (s == '\n' && (s + 1) == '\0')
49		- break;
50	62	else
51		- return -EINVAL;
	63	+ break;
52	64
53	65	if (val >= base)
54		- return -EINVAL;
55		- if (acc > div_u64(ULLONG_MAX - val, base))
56		- return -ERANGE;
57		- acc = acc * base + val;
58		- ok = 1;
59		-
	66	+ break;
	67	+ if (*res > div_u64(ULLONG_MAX - val, base))
	68	+ overflow = 1;
	69	+ res = res * base + val;
	70	+ rv++;
60	71	s++;
61	72	}
62		- if (!ok)
	73	+ if (overflow)
	74	+ rv \|= KSTRTOX_OVERFLOW;
	75	+ return rv;
	76	+}
	77	+
	78	+static int _kstrtoull(const char s, unsigned int base, unsigned long long res)
	79	+{
	80	+ unsigned long long _res;
	81	+ unsigned int rv;
	82	+
	83	+ s = _parse_integer_fixup_radix(s, &base);
	84	+ rv = _parse_integer(s, base, &_res);
	85	+ if (rv & KSTRTOX_OVERFLOW)
	86	+ return -ERANGE;
	87	+ rv &= ~KSTRTOX_OVERFLOW;
	88	+ if (rv == 0)
63	89	return -EINVAL;
64		- *res = acc;
	90	+ s += rv;
	91	+ if (*s == '\n')
	92	+ s++;
	93	+ if (*s)
	94	+ return -EINVAL;
	95	+ *res = _res;
65	96	return 0;
66	97	}
67	98
	1	+#ifndef _LIB_KSTRTOX_H
	2	+#define _LIB_KSTRTOX_H
	3	+
	4	+#define KSTRTOX_OVERFLOW (1U << 31)
	5	+const char _parse_integer_fixup_radix(const char s, unsigned int *base);
	6	+unsigned int _parse_integer(const char s, unsigned int base, unsigned long long res);
	7	+
	8	+#endif
...	...	@@ -31,17 +31,7 @@
31	31	#include <asm/div64.h>
32	32	#include <asm/sections.h> /* for dereference_function_descriptor() */
33	33
34		-static unsigned int simple_guess_base(const char *cp)
35		-{
36		- if (cp[0] == '0') {
37		- if (_tolower(cp[1]) == 'x' && isxdigit(cp[2]))
38		- return 16;
39		- else
40		- return 8;
41		- } else {
42		- return 10;
43		- }
44		-}
	34	+#include "kstrtox.h"
45	35
46	36	/**
47	37	* simple_strtoull - convert a string to an unsigned long long
48	38
49	39
...	...	@@ -51,23 +41,14 @@
51	41	*/
52	42	unsigned long long simple_strtoull(const char cp, char *endp, unsigned int base)
53	43	{
54		- unsigned long long result = 0;
	44	+ unsigned long long result;
	45	+ unsigned int rv;
55	46
56		- if (!base)
57		- base = simple_guess_base(cp);
	47	+ cp = _parse_integer_fixup_radix(cp, &base);
	48	+ rv = _parse_integer(cp, base, &result);
	49	+ /* FIXME */
	50	+ cp += (rv & ~KSTRTOX_OVERFLOW);
58	51
59		- if (base == 16 && cp[0] == '0' && _tolower(cp[1]) == 'x')
60		- cp += 2;
61		-
62		- while (isxdigit(*cp)) {
63		- unsigned int value;
64		-
65		- value = isdigit(cp) ? cp - '0' : _tolower(*cp) - 'a' + 10;
66		- if (value >= base)
67		- break;
68		- result = result * base + value;
69		- cp++;
70		- }
71	52	if (endp)
72	53	endp = (char )cp;
73	54