vsprintf.c: Reduce sizeof struct printf_spec from 24 to 8 bytes
Joe Perches [Sun, 7 Mar 2010 01:10:14 +0000 (17:10 -0800)]
Reducing the size of struct printf_spec is a good thing because multiple
instances are commonly passed on stack.

It's possible for type to be u8 and field_width to be s8, but this is
likely small enough for now.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/vsprintf.c

index af4aaa6..e994cea 100644 (file)
@@ -408,12 +408,12 @@ enum format_type {
 };
 
 struct printf_spec {
-       enum format_type        type;
-       int                     flags;          /* flags to number() */
-       int                     field_width;    /* width of output field */
-       int                     base;
-       int                     precision;      /* # of digits/chars */
-       int                     qualifier;
+       u16     type;
+       s16     field_width;    /* width of output field */
+       u8      flags;          /* flags to number() */
+       u8      base;
+       s8      precision;      /* # of digits/chars */
+       u8      qualifier;
 };
 
 static char *number(char *buf, char *end, unsigned long long num,
@@ -1333,7 +1333,7 @@ int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
                        break;
 
                case FORMAT_TYPE_NRCHARS: {
-                       int qualifier = spec.qualifier;
+                       u8 qualifier = spec.qualifier;
 
                        if (qualifier == 'l') {
                                long *ip = va_arg(args, long *);
@@ -1619,7 +1619,7 @@ do {                                                                      \
 
                case FORMAT_TYPE_NRCHARS: {
                        /* skip %n 's argument */
-                       int qualifier = spec.qualifier;
+                       u8 qualifier = spec.qualifier;
                        void *skip_arg;
                        if (qualifier == 'l')
                                skip_arg = va_arg(args, long *);
@@ -1885,7 +1885,9 @@ int vsscanf(const char *buf, const char *fmt, va_list args)
        char *next;
        char digit;
        int num = 0;
-       int qualifier, base, field_width;
+       u8 qualifier;
+       u8 base;
+       s16 field_width;
        bool is_sign;
 
        while (*fmt && *str) {
@@ -1963,7 +1965,7 @@ int vsscanf(const char *buf, const char *fmt, va_list args)
                {
                        char *s = (char *)va_arg(args, char *);
                        if (field_width == -1)
-                               field_width = INT_MAX;
+                               field_width = SHORT_MAX;
                        /* first, skip leading white space in buffer */
                        str = skip_spaces(str);