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authorJason Hobbs <jason.hobbs@calxeda.com>2011-08-31 10:37:25 -0500
committerJohn Rigby <john.rigby@linaro.org>2011-09-23 07:10:37 -0600
commit01b5cfa995d9f618fd6b2318cef55e8e82c3720e (patch)
parent74a57989d97862da6ee587e32bea78385c5514d7 (diff)
Add isblank
Existing ctype checks are implemented using a 256 byte lookup table, allowing each character to be in any of 8 character classes. Since there are 8 existing character classes without the blank class, I implemented isblank without using the lookup table. Since there are only two blank characters - tab and space - this is a more reasonable approach than doubling the size of the lookup table to accommodate one more class. Signed-off-by: Jason Hobbs <jason.hobbs@calxeda.com>
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/ctype.h b/include/linux/ctype.h
index 6dec944a3..42f9305a0 100644
--- a/include/linux/ctype.h
+++ b/include/linux/ctype.h
@@ -31,6 +31,12 @@ extern const unsigned char _ctype[];
#define isupper(c) ((__ismask(c)&(_U)) != 0)
#define isxdigit(c) ((__ismask(c)&(_D|_X)) != 0)
+ * Rather than doubling the size of the _ctype lookup table to hold a 'blank'
+ * flag, just check for space or tab.
+ */
+#define isblank(c) (c == ' ' || c == '\t')
#define isascii(c) (((unsigned char)(c))<=0x7f)
#define toascii(c) (((unsigned char)(c))&0x7f)