On Fri, Dec 13, 2013 at 11:58:04AM +0100, Andrew Jones wrote:
> Support format flags for field padding, such as "%08x", allowing
> register dumps to be easier on the eyes.
>
> Signed-off-by: Andrew Jones <drjones@xxxxxxxxxx>
> ---
> lib/printf.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++++++----------
> 1 file changed, 70 insertions(+), 14 deletions(-)
>
> diff --git a/lib/printf.c b/lib/printf.c
> index 867eb1926f742..dd20f755c01a0 100644
> --- a/lib/printf.c
> +++ b/lib/printf.c
> @@ -6,6 +6,11 @@ typedef struct pstream {
> int added;
> } pstream_t;
>
> +typedef struct strprops {
> + char pad;
> + int npad;
> +} strprops_t;
> +
> static void addchar(pstream_t *p, char c)
> {
> if (p->remain) {
> @@ -15,15 +20,37 @@ static void addchar(pstream_t *p, char c)
> ++p->added;
> }
>
> -void print_str(pstream_t *p, const char *s)
> +void print_str(pstream_t *p, const char *s, strprops_t props)
> {
> + const char *s_orig = s;
> + int npad = props.npad;
> +
> + if (npad > 0) {
> + npad -= strlen(s_orig);
> + while (npad > 0) {
> + addchar(p, props.pad);
> + --npad;
> + }
> + }
> +
> while (*s)
> addchar(p, *s++);
> +
> + if (npad < 0) {
> + char pad = props.pad;
> + if (pad == '0') /* ignore '0' flag with '-' flag */
> + pad = ' ';
there are only the two options, so you can drop the check if
you like.
> + npad += strlen(s_orig);
> + while (npad < 0) {
> + addchar(p, pad);
> + ++npad;
> + }
> + }
> }
>
> static char digits[16] = "0123456789abcdef";
>
> -void print_int(pstream_t *ps, long long n, int base)
> +void print_int(pstream_t *ps, long long n, int base, strprops_t props)
> {
> char buf[sizeof(long) * 3 + 2], *p = buf;
> int s = 0, i;
> @@ -54,10 +81,11 @@ void print_int(pstream_t *ps, long long n, int base)
>
> *p = 0;
>
> - print_str(ps, buf);
> + print_str(ps, buf, props);
> }
>
> -void print_unsigned(pstream_t *ps, unsigned long long n, int base)
> +void print_unsigned(pstream_t *ps, unsigned long long n, int base,
> + strprops_t props)
> {
> char buf[sizeof(long) * 3 + 1], *p = buf;
> int i;
> @@ -80,7 +108,23 @@ void print_unsigned(pstream_t *ps, unsigned long long n, int base)
>
> *p = 0;
>
> - print_str(ps, buf);
> + print_str(ps, buf, props);
> +}
> +
> +static int fmtnum(const char **fmt)
> +{
> + const char *f = *fmt;
> + int len = 0, num;
> +
> + if (*f == '-')
> + ++f, ++len;
oh wow, this deserves a small comment saying that negative values are
used to add trailing padding instead of leading.
> +
> + while (*f >= '0' && *f <= '9')
> + ++f, ++len;
> +
> + num = atol(*fmt);
> + *fmt += len;
> + return num;
> }
some funny indentation is back here... Better check your entire patch
for that.
>
> int vsnprintf(char *buf, int size, const char *fmt, va_list va)
> @@ -93,6 +137,9 @@ int vsnprintf(char *buf, int size, const char *fmt, va_list va)
> while (*fmt) {
> char f = *fmt++;
> int nlong = 0;
> + strprops_t props;
> + memset(&props, 0, sizeof(props));
> + props.pad = ' ';
>
> if (f != '%') {
> addchar(&s, f);
> @@ -110,41 +157,50 @@ int vsnprintf(char *buf, int size, const char *fmt, va_list va)
> case '\0':
> --fmt;
> break;
> + case '0':
> + props.pad = '0';
> + ++fmt;
> + /* fall through */
> + case '1'...'9':
> + case '-':
> + --fmt;
> + props.npad = fmtnum(&fmt);
> + goto morefmt;
> case 'l':
> ++nlong;
> goto morefmt;
> case 'd':
> switch (nlong) {
> case 0:
> - print_int(&s, va_arg(va, int), 10);
> + print_int(&s, va_arg(va, int), 10, props);
> break;
> case 1:
> - print_int(&s, va_arg(va, long), 10);
> + print_int(&s, va_arg(va, long), 10, props);
> break;
> default:
> - print_int(&s, va_arg(va, long long), 10);
> + print_int(&s, va_arg(va, long long), 10, props);
> break;
> }
> break;
> case 'x':
> switch (nlong) {
> case 0:
> - print_unsigned(&s, va_arg(va, unsigned), 16);
> + print_unsigned(&s, va_arg(va, unsigned), 16, props);
> break;
> case 1:
> - print_unsigned(&s, va_arg(va, unsigned long), 16);
> + print_unsigned(&s, va_arg(va, unsigned long), 16, props);
> break;
> default:
> - print_unsigned(&s, va_arg(va, unsigned long long), 16);
> + print_unsigned(&s, va_arg(va, unsigned long long), 16, props);
> break;
> }
> break;
> case 'p':
> - print_str(&s, "0x");
> - print_unsigned(&s, (unsigned long)va_arg(va, void *), 16);
> + print_str(&s, "0x", props);
> + print_unsigned(&s, (unsigned long)va_arg(va, void *), 16, props);
> break;
> case 's':
> - print_str(&s, va_arg(va, const char *));
> + print_str(&s, va_arg(va, const char *), props);
> break;
> default:
> addchar(&s, f);
> --
> 1.8.1.4
>
Besides the formatting stuff:
Reviewed-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
