Messages in this thread Patch in this message | | | Subject | [PATCH] vsprintf.c: Reduce sizeof struct printf_spec from 24 to 8 bytes | From | Joe Perches <> | Date | Sat, 06 Mar 2010 17:10:14 -0800 |
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On Sat, 2010-03-06 at 15:58 -0800, Linus Torvalds wrote: > And no, I guess we don't really need to make it 32-bit. Fitting in 64 bits > would already be a big improvement over what we have now.
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> --- lib/vsprintf.c | 22 ++++++++++++---------- 1 files changed, 12 insertions(+), 10 deletions(-)
diff --git a/lib/vsprintf.c b/lib/vsprintf.c index af4aaa6..fdee7f7 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -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);
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