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Subject[PATCH v4 12/34] vsprintf: prt_u64_minwidth(), prt_u64()
Date
This adds two new-style printbuf helpers for printing simple u64s, and
converts num_to_str() to be a simple wrapper around prt_u64_minwidth().

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
---
include/linux/kernel.h | 4 +-
lib/vsprintf.c | 94 ++++++++++++++++++++----------------------
2 files changed, 48 insertions(+), 50 deletions(-)

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 1906861ece..9ba5a53c6a 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -202,12 +202,14 @@ static inline void might_fault(void) { }

void do_exit(long error_code) __noreturn;

+struct printbuf;
+extern void prt_u64_minwidth(struct printbuf *out, u64 num, unsigned width);
+extern void prt_u64(struct printbuf *out, u64 num);
extern int num_to_str(char *buf, int size,
unsigned long long num, unsigned int width);

/* lib/printf utilities */

-struct printbuf;
extern __printf(2, 3) void prt_printf(struct printbuf *out, const char *fmt, ...);
extern __printf(2, 0) void prt_vprintf(struct printbuf *out, const char *fmt, va_list);

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 7d20406deb..e65115f90f 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -368,41 +368,51 @@ char *put_dec(char *buf, unsigned long long n)

#endif

-/*
- * Convert passed number to decimal string.
- * Returns the length of string. On buffer overflow, returns 0.
- *
- * If speed is not important, use snprintf(). It's easy to read the code.
+/**
+ * prt_u64_minwidth - print a u64, in decimal, with zero padding
+ * @out: printbuf to output to
+ * @num: u64 to print
+ * @width: minimum width
*/
-int num_to_str(char *buf, int size, unsigned long long num, unsigned int width)
+void prt_u64_minwidth(struct printbuf *out, u64 num, unsigned width)
{
/* put_dec requires 2-byte alignment of the buffer. */
char tmp[sizeof(num) * 3] __aligned(2);
- int idx, len;
+ unsigned len = put_dec(tmp, num) - tmp;

- /* put_dec() may work incorrectly for num = 0 (generate "", not "0") */
- if (num <= 9) {
- tmp[0] = '0' + num;
- len = 1;
- } else {
- len = put_dec(tmp, num) - tmp;
- }
+ printbuf_make_room(out, max(len, width));

- if (len > size || width > size)
- return 0;
+ if (width > len)
+ __prt_chars_reserved(out, '0', width - len);

- if (width > len) {
- width = width - len;
- for (idx = 0; idx < width; idx++)
- buf[idx] = ' ';
- } else {
- width = 0;
- }
+ while (len)
+ __prt_char_reserved(out, tmp[--len]);
+ printbuf_nul_terminate(out);
+}

- for (idx = 0; idx < len; ++idx)
- buf[idx + width] = tmp[len - idx - 1];
+/**
+ * prt_u64 - print a simple u64, in decimal
+ * @out: printbuf to output to
+ * @num: u64 to print
+ */
+void prt_u64(struct printbuf *out, u64 num)
+{
+ prt_u64_minwidth(out, num, 0);
+}

- return len + width;
+/*
+ * Convert passed number to decimal string.
+ * Returns the length of string. On buffer overflow, returns 0.
+ *
+ * Consider switching to printbufs and using prt_u64() or prt_u64_minwith()
+ * instead.
+ */
+int num_to_str(char *buf, int size, unsigned long long num, unsigned int width)
+{
+ struct printbuf out = PRINTBUF_EXTERN(buf, size);
+
+ prt_u64_minwidth(&out, num, width);
+ return out.pos;
}

#define SIGN 1 /* unsigned/signed, must be 1 */
@@ -1018,20 +1028,6 @@ static const struct printf_spec default_dec_spec = {
.precision = -1,
};

-static const struct printf_spec default_dec02_spec = {
- .base = 10,
- .field_width = 2,
- .precision = -1,
- .flags = ZEROPAD,
-};
-
-static const struct printf_spec default_dec04_spec = {
- .base = 10,
- .field_width = 4,
- .precision = -1,
- .flags = ZEROPAD,
-};
-
static noinline_for_stack
void resource_string(struct printbuf *out, struct resource *res,
struct printf_spec spec, const char *fmt)
@@ -1231,12 +1227,12 @@ void bitmap_list_string(struct printbuf *out, unsigned long *bitmap,
prt_char(out, ',');
first = false;

- number(out, rbot, default_dec_spec);
+ prt_u64(out, rbot);
if (rtop == rbot + 1)
continue;

prt_char(out, '-');
- number(out, rtop - 1, default_dec_spec);
+ prt_u64(out, rtop - 1);
}
}

@@ -1778,21 +1774,21 @@ void date_str(struct printbuf *out,
int year = tm->tm_year + (r ? 0 : 1900);
int mon = tm->tm_mon + (r ? 0 : 1);

- number(out, year, default_dec04_spec);
+ prt_u64_minwidth(out, year, 4);
prt_char(out, '-');
- number(out, mon, default_dec02_spec);
+ prt_u64_minwidth(out, mon, 2);
prt_char(out, '-');
- number(out, tm->tm_mday, default_dec02_spec);
+ prt_u64_minwidth(out, tm->tm_mday, 2);
}

static noinline_for_stack
void time_str(struct printbuf *out, const struct rtc_time *tm, bool r)
{
- number(out, tm->tm_hour, default_dec02_spec);
+ prt_u64_minwidth(out, tm->tm_hour, 2);
prt_char(out, ':');
- number(out, tm->tm_min, default_dec02_spec);
+ prt_u64_minwidth(out, tm->tm_min, 2);
prt_char(out, ':');
- number(out, tm->tm_sec, default_dec02_spec);
+ prt_u64_minwidth(out, tm->tm_sec, 2);
}

static noinline_for_stack
@@ -2070,7 +2066,7 @@ void device_node_string(struct printbuf *out, struct device_node *dn,
str_spec.precision = precision;
break;
case 'p': /* phandle */
- number(out, (unsigned int)dn->phandle, default_dec_spec);
+ prt_u64(out, (unsigned int)dn->phandle);
break;
case 'P': /* path-spec */
p = fwnode_get_name(of_fwnode_handle(dn));
--
2.36.1
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