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-rw-r--r--lib/vsprintf.c139
1 files changed, 67 insertions, 72 deletions
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 0e337541f00..39c99fea7c0 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -174,35 +174,25 @@ char *put_dec_trunc8(char *buf, unsigned r)
unsigned q;
/* Copy of previous function's body with added early returns */
- q = (r * (uint64_t)0x1999999a) >> 32;
- *buf++ = (r - 10 * q) + '0'; /* 2 */
- if (q == 0)
- return buf;
- r = (q * (uint64_t)0x1999999a) >> 32;
- *buf++ = (q - 10 * r) + '0'; /* 3 */
- if (r == 0)
- return buf;
- q = (r * (uint64_t)0x1999999a) >> 32;
- *buf++ = (r - 10 * q) + '0'; /* 4 */
- if (q == 0)
- return buf;
- r = (q * (uint64_t)0x1999999a) >> 32;
- *buf++ = (q - 10 * r) + '0'; /* 5 */
- if (r == 0)
- return buf;
- q = (r * 0x199a) >> 16;
- *buf++ = (r - 10 * q) + '0'; /* 6 */
+ while (r >= 10000) {
+ q = r + '0';
+ r = (r * (uint64_t)0x1999999a) >> 32;
+ *buf++ = q - 10*r;
+ }
+
+ q = (r * 0x199a) >> 16; /* r <= 9999 */
+ *buf++ = (r - 10 * q) + '0';
if (q == 0)
return buf;
- r = (q * 0xcd) >> 11;
- *buf++ = (q - 10 * r) + '0'; /* 7 */
+ r = (q * 0xcd) >> 11; /* q <= 999 */
+ *buf++ = (q - 10 * r) + '0';
if (r == 0)
return buf;
- q = (r * 0xcd) >> 11;
- *buf++ = (r - 10 * q) + '0'; /* 8 */
+ q = (r * 0xcd) >> 11; /* r <= 99 */
+ *buf++ = (r - 10 * q) + '0';
if (q == 0)
return buf;
- *buf++ = q + '0'; /* 9 */
+ *buf++ = q + '0'; /* q <= 9 */
return buf;
}
@@ -243,18 +233,34 @@ char *put_dec(char *buf, unsigned long long n)
/* Second algorithm: valid only for 64-bit long longs */
+/* See comment in put_dec_full9 for choice of constants */
static noinline_for_stack
-char *put_dec_full4(char *buf, unsigned q)
+void put_dec_full4(char *buf, unsigned q)
{
unsigned r;
- r = (q * 0xcccd) >> 19;
- *buf++ = (q - 10 * r) + '0';
- q = (r * 0x199a) >> 16;
- *buf++ = (r - 10 * q) + '0';
+ r = (q * 0xccd) >> 15;
+ buf[0] = (q - 10 * r) + '0';
+ q = (r * 0xcd) >> 11;
+ buf[1] = (r - 10 * q) + '0';
r = (q * 0xcd) >> 11;
- *buf++ = (q - 10 * r) + '0';
- *buf++ = r + '0';
- return buf;
+ buf[2] = (q - 10 * r) + '0';
+ buf[3] = r + '0';
+}
+
+/*
+ * Call put_dec_full4 on x % 10000, return x / 10000.
+ * The approximation x/10000 == (x * 0x346DC5D7) >> 43
+ * holds for all x < 1,128,869,999. The largest value this
+ * helper will ever be asked to convert is 1,125,520,955.
+ * (d1 in the put_dec code, assuming n is all-ones).
+ */
+static
+unsigned put_dec_helper4(char *buf, unsigned x)
+{
+ uint32_t q = (x * (uint64_t)0x346DC5D7) >> 43;
+
+ put_dec_full4(buf, x - q * 10000);
+ return q;
}
/* Based on code by Douglas W. Jones found at
@@ -276,28 +282,19 @@ char *put_dec(char *buf, unsigned long long n)
d3 = (h >> 16); /* implicit "& 0xffff" */
q = 656 * d3 + 7296 * d2 + 5536 * d1 + ((uint32_t)n & 0xffff);
+ q = put_dec_helper4(buf, q);
+
+ q += 7671 * d3 + 9496 * d2 + 6 * d1;
+ q = put_dec_helper4(buf+4, q);
+
+ q += 4749 * d3 + 42 * d2;
+ q = put_dec_helper4(buf+8, q);
- buf = put_dec_full4(buf, q % 10000);
- q = q / 10000;
-
- d1 = q + 7671 * d3 + 9496 * d2 + 6 * d1;
- buf = put_dec_full4(buf, d1 % 10000);
- q = d1 / 10000;
-
- d2 = q + 4749 * d3 + 42 * d2;
- buf = put_dec_full4(buf, d2 % 10000);
- q = d2 / 10000;
-
- d3 = q + 281 * d3;
- if (!d3)
- goto done;
- buf = put_dec_full4(buf, d3 % 10000);
- q = d3 / 10000;
- if (!q)
- goto done;
- buf = put_dec_full4(buf, q);
- done:
- while (buf[-1] == '0')
+ q += 281 * d3;
+ buf += 12;
+ if (q)
+ buf = put_dec_trunc8(buf, q);
+ else while (buf[-1] == '0')
--buf;
return buf;
@@ -990,7 +987,7 @@ int kptr_restrict __read_mostly;
* - 'm' For a 6-byte MAC address, it prints the hex address without colons
* - 'MF' For a 6-byte MAC FDDI address, it prints the address
* with a dash-separated hex notation
- * - '[mM]R For a 6-byte MAC address, Reverse order (Bluetooth)
+ * - '[mM]R' For a 6-byte MAC address, Reverse order (Bluetooth)
* - 'I' [46] for IPv4/IPv6 addresses printed in the usual way
* IPv4 uses dot-separated decimal without leading 0's (1.2.3.4)
* IPv6 uses colon separated network-order 16 bit hex with leading 0's
@@ -1341,7 +1338,10 @@ qualifier:
* %pR output the address range in a struct resource with decoded flags
* %pr output the address range in a struct resource with raw flags
* %pM output a 6-byte MAC address with colons
+ * %pMR output a 6-byte MAC address with colons in reversed order
+ * %pMF output a 6-byte MAC address with dashes
* %pm output a 6-byte MAC address without colons
+ * %pmR output a 6-byte MAC address without colons in reversed order
* %pI4 print an IPv4 address without leading zeros
* %pi4 print an IPv4 address with leading zeros
* %pI6 print an IPv6 address with colons
@@ -2017,7 +2017,7 @@ int vsscanf(const char *buf, const char *fmt, va_list args)
s16 field_width;
bool is_sign;
- while (*fmt && *str) {
+ while (*fmt) {
/* skip any white space in format */
/* white space in format matchs any amount of
* white space, including none, in the input.
@@ -2042,6 +2042,8 @@ int vsscanf(const char *buf, const char *fmt, va_list args)
* advance both strings to next white space
*/
if (*fmt == '*') {
+ if (!*str)
+ break;
while (!isspace(*fmt) && *fmt != '%' && *fmt)
fmt++;
while (!isspace(*str) && *str)
@@ -2070,7 +2072,17 @@ int vsscanf(const char *buf, const char *fmt, va_list args)
}
}
- if (!*fmt || !*str)
+ if (!*fmt)
+ break;
+
+ if (*fmt == 'n') {
+ /* return number of characters read so far */
+ *va_arg(args, int *) = str - buf;
+ ++fmt;
+ continue;
+ }
+
+ if (!*str)
break;
base = 10;
@@ -2103,13 +2115,6 @@ int vsscanf(const char *buf, const char *fmt, va_list args)
num++;
}
continue;
- case 'n':
- /* return number of characters read so far */
- {
- int *i = (int *)va_arg(args, int*);
- *i = str - buf;
- }
- continue;
case 'o':
base = 8;
break;
@@ -2210,16 +2215,6 @@ int vsscanf(const char *buf, const char *fmt, va_list args)
str = next;
}
- /*
- * Now we've come all the way through so either the input string or the
- * format ended. In the former case, there can be a %n at the current
- * position in the format that needs to be filled.
- */
- if (*fmt == '%' && *(fmt + 1) == 'n') {
- int *p = (int *)va_arg(args, int *);
- *p = str - buf;
- }
-
return num;
}
EXPORT_SYMBOL(vsscanf);
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-10-31 21:06:11 +0000