[PATCH v2 1/2] lib: add sputchar() helper
From: Yury Norov
Date: Sat Sep 04 2021 - 19:12:28 EST
There are 47 occurrences of the code snippet like this:
if (buf < end)
*buf = ' ';
++buf;
This patch adds a helper function sputchar() to replace opencoding.
It adds a lot to readability, and also saves 43 bytes of text on x86.
v2: cleanup cases discovered with coccinelle script.
Signed-off-by: Yury Norov <yury.norov@xxxxxxxxx>
---
include/linux/kernel.h | 8 ++
lib/string_helpers.c | 56 +++--------
lib/vsprintf.c | 222 +++++++++++++----------------------------
3 files changed, 90 insertions(+), 196 deletions(-)
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 1b2f0a7e00d6..01941ed2f5aa 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -283,6 +283,14 @@ extern char *bin2hex(char *dst, const void *src, size_t count);
bool mac_pton(const char *s, u8 *mac);
+static inline char *sputchar(char *buf, const char *end, char c)
+{
+ if (buf < end)
+ *buf = c;
+
+ return buf + 1;
+}
+
/*
* General tracing related utility functions - trace_printk(),
* tracing_on/tracing_off and tracing_start()/tracing_stop
diff --git a/lib/string_helpers.c b/lib/string_helpers.c
index 3806a52ce697..f4e0c719650d 100644
--- a/lib/string_helpers.c
+++ b/lib/string_helpers.c
@@ -335,12 +335,8 @@ static bool escape_space(unsigned char c, char **dst, char *end)
return false;
}
- if (out < end)
- *out = '\\';
- ++out;
- if (out < end)
- *out = to;
- ++out;
+ out = sputchar(out, end, '\\');
+ out = sputchar(out, end, to);
*dst = out;
return true;
@@ -368,12 +364,8 @@ static bool escape_special(unsigned char c, char **dst, char *end)
return false;
}
- if (out < end)
- *out = '\\';
- ++out;
- if (out < end)
- *out = to;
- ++out;
+ out = sputchar(out, end, '\\');
+ out = sputchar(out, end, to);
*dst = out;
return true;
@@ -386,12 +378,8 @@ static bool escape_null(unsigned char c, char **dst, char *end)
if (c)
return false;
- if (out < end)
- *out = '\\';
- ++out;
- if (out < end)
- *out = '0';
- ++out;
+ out = sputchar(out, end, '\\');
+ out = sputchar(out, end, '0');
*dst = out;
return true;
@@ -401,18 +389,10 @@ static bool escape_octal(unsigned char c, char **dst, char *end)
{
char *out = *dst;
- if (out < end)
- *out = '\\';
- ++out;
- if (out < end)
- *out = ((c >> 6) & 0x07) + '0';
- ++out;
- if (out < end)
- *out = ((c >> 3) & 0x07) + '0';
- ++out;
- if (out < end)
- *out = ((c >> 0) & 0x07) + '0';
- ++out;
+ out = sputchar(out, end, '\\');
+ out = sputchar(out, end, ((c >> 6) & 0x07) + '0');
+ out = sputchar(out, end, ((c >> 3) & 0x07) + '0');
+ out = sputchar(out, end, ((c >> 0) & 0x07) + '0');
*dst = out;
return true;
@@ -422,18 +402,10 @@ static bool escape_hex(unsigned char c, char **dst, char *end)
{
char *out = *dst;
- if (out < end)
- *out = '\\';
- ++out;
- if (out < end)
- *out = 'x';
- ++out;
- if (out < end)
- *out = hex_asc_hi(c);
- ++out;
- if (out < end)
- *out = hex_asc_lo(c);
- ++out;
+ out = sputchar(out, end, '\\');
+ out = sputchar(out, end, 'x');
+ out = sputchar(out, end, hex_asc_hi(c));
+ out = sputchar(out, end, hex_asc_lo(c));
*dst = out;
return true;
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 919b70d00855..9d4c9fd81845 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -509,59 +509,38 @@ char *number(char *buf, char *end, unsigned long long num,
/* leading space padding */
field_width -= precision;
if (!(spec.flags & (ZEROPAD | LEFT))) {
- while (--field_width >= 0) {
- if (buf < end)
- *buf = ' ';
- ++buf;
- }
+ while (--field_width >= 0)
+ buf = sputchar(buf, end, ' ');
}
/* sign */
- if (sign) {
- if (buf < end)
- *buf = sign;
- ++buf;
- }
+ if (sign)
+ buf = sputchar(buf, end, sign);
+
/* "0x" / "0" prefix */
if (need_pfx) {
- if (spec.base == 16 || !is_zero) {
- if (buf < end)
- *buf = '0';
- ++buf;
- }
- if (spec.base == 16) {
- if (buf < end)
- *buf = ('X' | locase);
- ++buf;
- }
+ if (spec.base == 16 || !is_zero)
+ buf = sputchar(buf, end, '0');
+ if (spec.base == 16)
+ buf = sputchar(buf, end, 'X' | locase);
}
/* zero or space padding */
if (!(spec.flags & LEFT)) {
char c = ' ' + (spec.flags & ZEROPAD);
- while (--field_width >= 0) {
- if (buf < end)
- *buf = c;
- ++buf;
- }
+ while (--field_width >= 0)
+ buf = sputchar(buf, end, c);
}
/* hmm even more zero padding? */
- while (i <= --precision) {
- if (buf < end)
- *buf = '0';
- ++buf;
- }
+ while (i <= --precision)
+ buf = sputchar(buf, end, '0');
+
/* actual digits of result */
- while (--i >= 0) {
- if (buf < end)
- *buf = tmp[i];
- ++buf;
- }
+ while (--i >= 0)
+ buf = sputchar(buf, end, tmp[i]);
+
/* trailing space padding */
- while (--field_width >= 0) {
- if (buf < end)
- *buf = ' ';
- ++buf;
- }
+ while (--field_width >= 0)
+ buf = sputchar(buf, end, ' ');
return buf;
}
@@ -619,11 +598,9 @@ char *widen_string(char *buf, int n, char *end, struct printf_spec spec)
move_right(buf - n, end, n, spaces);
return buf + spaces;
}
- while (spaces--) {
- if (buf < end)
- *buf = ' ';
- ++buf;
- }
+ while (spaces--)
+ buf = sputchar(buf, end, ' ');
+
return buf;
}
@@ -638,9 +615,7 @@ static char *string_nocheck(char *buf, char *end, const char *s,
char c = *s++;
if (!c)
break;
- if (buf < end)
- *buf = c;
- ++buf;
+ buf = sputchar(buf, end, c);
++len;
}
return widen_string(buf, len, end, spec);
@@ -931,7 +906,7 @@ char *dentry_name(char *buf, char *end, const struct dentry *d, struct printf_sp
}
}
s = array[--i];
- for (n = 0; n != spec.precision; n++, buf++) {
+ for (n = 0; n != spec.precision; n++) {
char c = *s++;
if (!c) {
if (!i)
@@ -939,8 +914,7 @@ char *dentry_name(char *buf, char *end, const struct dentry *d, struct printf_sp
c = '/';
s = array[--i];
}
- if (buf < end)
- *buf = c;
+ buf = sputchar(buf, end, c);
}
rcu_read_unlock();
return widen_string(buf, n, end, spec);
@@ -968,11 +942,9 @@ char *bdev_name(char *buf, char *end, struct block_device *bdev,
hd = bdev->bd_disk;
buf = string(buf, end, hd->disk_name, spec);
if (bdev->bd_partno) {
- if (isdigit(hd->disk_name[strlen(hd->disk_name)-1])) {
- if (buf < end)
- *buf = 'p';
- buf++;
- }
+ if (isdigit(hd->disk_name[strlen(hd->disk_name)-1]))
+ buf = sputchar(buf, end, 'p');
+
buf = number(buf, end, bdev->bd_partno, spec);
}
return buf;
@@ -1175,18 +1147,10 @@ char *hex_string(char *buf, char *end, u8 *addr, struct printf_spec spec,
len = min_t(int, spec.field_width, 64);
for (i = 0; i < len; ++i) {
- if (buf < end)
- *buf = hex_asc_hi(addr[i]);
- ++buf;
- if (buf < end)
- *buf = hex_asc_lo(addr[i]);
- ++buf;
-
- if (separator && i != len - 1) {
- if (buf < end)
- *buf = separator;
- ++buf;
- }
+ buf = sputchar(buf, end, hex_asc_hi(addr[i]));
+ buf = sputchar(buf, end, hex_asc_lo(addr[i]));
+ if (separator && i != len - 1)
+ buf = sputchar(buf, end, separator);
}
return buf;
@@ -1221,11 +1185,9 @@ char *bitmap_string(char *buf, char *end, unsigned long *bitmap,
bit = i % BITS_PER_LONG;
val = (bitmap[word] >> bit) & chunkmask;
- if (!first) {
- if (buf < end)
- *buf = ',';
- buf++;
- }
+ if (!first)
+ buf = sputchar(buf, end, ',');
+
first = false;
spec.field_width = DIV_ROUND_UP(chunksz, 4);
@@ -1248,20 +1210,17 @@ char *bitmap_list_string(char *buf, char *end, unsigned long *bitmap,
return buf;
for_each_set_bitrange(rbot, rtop, bitmap, nr_bits) {
- if (!first) {
- if (buf < end)
- *buf = ',';
- buf++;
- }
+ if (!first)
+ buf = sputchar(buf, end, ',');
+
first = false;
buf = number(buf, end, rbot, default_dec_spec);
if (rtop == rbot + 1)
continue;
- if (buf < end)
- *buf = '-';
- buf = number(buf + 1, end, rtop - 1, default_dec_spec);
+ buf = sputchar(buf, end, '-');
+ buf = number(buf, end, rtop - 1, default_dec_spec);
}
return buf;
}
@@ -1822,14 +1781,9 @@ char *date_str(char *buf, char *end, const struct rtc_time *tm, bool r)
int mon = tm->tm_mon + (r ? 0 : 1);
buf = number(buf, end, year, default_dec04_spec);
- if (buf < end)
- *buf = '-';
- buf++;
-
+ buf = sputchar(buf, end, '-');
buf = number(buf, end, mon, default_dec02_spec);
- if (buf < end)
- *buf = '-';
- buf++;
+ buf = sputchar(buf, end, '-');
return number(buf, end, tm->tm_mday, default_dec02_spec);
}
@@ -1838,14 +1792,9 @@ static noinline_for_stack
char *time_str(char *buf, char *end, const struct rtc_time *tm, bool r)
{
buf = number(buf, end, tm->tm_hour, default_dec02_spec);
- if (buf < end)
- *buf = ':';
- buf++;
-
+ buf = sputchar(buf, end, ':');
buf = number(buf, end, tm->tm_min, default_dec02_spec);
- if (buf < end)
- *buf = ':';
- buf++;
+ buf = sputchar(buf, end, ':');
return number(buf, end, tm->tm_sec, default_dec02_spec);
}
@@ -1889,11 +1838,8 @@ char *rtc_str(char *buf, char *end, const struct rtc_time *tm,
if (have_d)
buf = date_str(buf, end, tm, raw);
- if (have_d && have_t) {
- if (buf < end)
- *buf = iso8601_separator ? 'T' : ' ';
- buf++;
- }
+ if (have_d && have_t)
+ buf = sputchar(buf, end, iso8601_separator ? 'T' : ' ');
if (have_t)
buf = time_str(buf, end, tm, raw);
@@ -1972,11 +1918,8 @@ char *format_flags(char *buf, char *end, unsigned long flags,
buf = string(buf, end, names->name, default_str_spec);
flags &= ~mask;
- if (flags) {
- if (buf < end)
- *buf = '|';
- buf++;
- }
+ if (flags)
+ buf = sputchar(buf, end, '|');
}
if (flags)
@@ -2026,16 +1969,11 @@ char *format_page_flags(char *buf, char *end, unsigned long flags)
continue;
/* Format: Flag Name + '=' (equals sign) + Number + '|' (separator) */
- if (append) {
- if (buf < end)
- *buf = '|';
- buf++;
- }
+ if (append)
+ buf = sputchar(buf, end, '|');
buf = string(buf, end, pff[i].name, default_str_spec);
- if (buf < end)
- *buf = '=';
- buf++;
+ buf = sputchar(buf, end, '=');
buf = number(buf, end, (flags >> pff[i].shift) & pff[i].mask,
*pff[i].spec);
@@ -2125,11 +2063,8 @@ char *device_node_string(char *buf, char *end, struct device_node *dn,
for (pass = false; strspn(fmt,"fnpPFcC"); fmt++, pass = true) {
int precision;
- if (pass) {
- if (buf < end)
- *buf = ':';
- buf++;
- }
+ if (pass)
+ buf = sputchar(buf, end, ':');
switch (*fmt) {
case 'f': /* full_name */
@@ -2773,25 +2708,14 @@ int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
break;
case FORMAT_TYPE_CHAR: {
- char c;
-
if (!(spec.flags & LEFT)) {
- while (--spec.field_width > 0) {
- if (str < end)
- *str = ' ';
- ++str;
-
- }
- }
- c = (unsigned char) va_arg(args, int);
- if (str < end)
- *str = c;
- ++str;
- while (--spec.field_width > 0) {
- if (str < end)
- *str = ' ';
- ++str;
+ while (--spec.field_width > 0)
+ str = sputchar(str, end, ' ');
}
+ str = sputchar(str, end, (unsigned char) va_arg(args, int));
+
+ while (--spec.field_width > 0)
+ str = sputchar(str, end, ' ');
break;
}
@@ -2807,9 +2731,7 @@ int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
break;
case FORMAT_TYPE_PERCENT_CHAR:
- if (str < end)
- *str = '%';
- ++str;
+ str = sputchar(str, end, '%');
break;
case FORMAT_TYPE_INVALID:
@@ -3251,21 +3173,15 @@ int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf)
char c;
if (!(spec.flags & LEFT)) {
- while (--spec.field_width > 0) {
- if (str < end)
- *str = ' ';
- ++str;
- }
+ while (--spec.field_width > 0)
+ str = sputchar(str, end, ' ');
}
+
c = (unsigned char) get_arg(char);
- if (str < end)
- *str = c;
- ++str;
- while (--spec.field_width > 0) {
- if (str < end)
- *str = ' ';
- ++str;
- }
+ str = sputchar(str, end, c);
+
+ while (--spec.field_width > 0)
+ str = sputchar(str, end, ' ');
break;
}
@@ -3312,9 +3228,7 @@ int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf)
}
case FORMAT_TYPE_PERCENT_CHAR:
- if (str < end)
- *str = '%';
- ++str;
+ str = sputchar(str, end, '%');
break;
case FORMAT_TYPE_INVALID:
--
2.30.2