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tools/nolibc/stdlib: add utoh() and u64toh()

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This adds a pair of functions to emit hex values.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Willy Tarreau 2022-02-07 17:23:29 +01:00 committed by Paul E. McKenney
parent b1c21e7d99
commit 5f493178ef
1 changed files with 80 additions and 0 deletions
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80
tools/include/nolibc/stdlib.h
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@ -52,6 +52,46 @@ int atoi(const char *s)
return atol(s);
}
/* Converts the unsigned long integer <in> to its hex representation into
* buffer <buffer>, which must be long enough to store the number and the
* trailing zero (17 bytes for "ffffffffffffffff" or 9 for "ffffffff"). The
* buffer is filled from the first byte, and the number of characters emitted
* (not counting the trailing zero) is returned. The function is constructed
* in a way to optimize the code size and avoid any divide that could add a
* dependency on large external functions.
*/
static __attribute__((unused))
int utoh_r(unsigned long in, char *buffer)
{
signed char pos = (~0UL > 0xfffffffful) ? 60 : 28;
int digits = 0;
int dig;
do {
dig = in >> pos;
in -= (uint64_t)dig << pos;
pos -= 4;
if (dig || digits || pos < 0) {
if (dig > 9)
dig += 'a' - '0' - 10;
buffer[digits++] = '0' + dig;
}
} while (pos >= 0);
buffer[digits] = 0;
return digits;
}
/* converts unsigned long <in> to an hex string using the static itoa_buffer
* and returns the pointer to that string.
*/
static inline __attribute__((unused))
char *utoh(unsigned long in)
{
utoh_r(in, itoa_buffer);
return itoa_buffer;
}
/* Converts the unsigned long integer <in> to its string representation into
* buffer <buffer>, which must be long enough to store the number and the
* trailing zero (21 bytes for 18446744073709551615 in 64-bit, 11 for
@ -144,6 +184,46 @@ char *utoa(unsigned long in)
return itoa_buffer;
}
/* Converts the unsigned 64-bit integer <in> to its hex representation into
* buffer <buffer>, which must be long enough to store the number and the
* trailing zero (17 bytes for "ffffffffffffffff"). The buffer is filled from
* the first byte, and the number of characters emitted (not counting the
* trailing zero) is returned. The function is constructed in a way to optimize
* the code size and avoid any divide that could add a dependency on large
* external functions.
*/
static __attribute__((unused))
int u64toh_r(uint64_t in, char *buffer)
{
signed char pos = 60;
int digits = 0;
int dig;
do {
dig = in >> pos;
in -= (uint64_t)dig << pos;
pos -= 4;
if (dig || digits || pos < 0) {
if (dig > 9)
dig += 'a' - '0' - 10;
buffer[digits++] = '0' + dig;
}
} while (pos >= 0);
buffer[digits] = 0;
return digits;
}
/* converts uint64_t <in> to an hex string using the static itoa_buffer and
* returns the pointer to that string.
*/
static inline __attribute__((unused))
char *u64toh(uint64_t in)
{
u64toh_r(in, itoa_buffer);
return itoa_buffer;
}
/* Converts the unsigned 64-bit integer <in> to its string representation into
* buffer <buffer>, which must be long enough to store the number and the
* trailing zero (21 bytes for 18446744073709551615). The buffer is filled from