mirror of
https://github.com/systemd/systemd
synced 2024-07-20 17:56:25 +00:00
sd-id128: add compound literal love to sd_id128_to_string() + id128_to_uuid_string()
This commit is contained in:
Lennart Poettering
parent
f3ce631bbc
commit
c970388b22
|
|
@ -633,7 +633,10 @@ manpages = [
|
|||
'sd_id128_get_machine_app_specific'],
|
||||
''],
|
||||
['sd_id128_randomize', '3', [], ''],
|
||||
['sd_id128_to_string', '3', ['sd_id128_from_string'], ''],
|
||||
['sd_id128_to_string',
|
||||
'3',
|
||||
['SD_ID128_STRING_MAX', 'SD_ID128_TO_STRING', 'sd_id128_from_string'],
|
||||
''],
|
||||
['sd_is_fifo',
|
||||
'3',
|
||||
['sd_is_mq',
|
||||
|
|
|
|||
|
|
@ -17,7 +17,9 @@
|
|||
|
||||
<refnamediv>
|
||||
<refname>sd_id128_to_string</refname>
|
||||
<refname>SD_ID128_TO_STRING</refname>
|
||||
<refname>sd_id128_from_string</refname>
|
||||
<refname>SD_ID128_STRING_MAX</refname>
|
||||
<refpurpose>Format or parse 128-bit IDs as strings</refpurpose>
|
||||
</refnamediv>
|
||||
|
||||
|
|
@ -25,9 +27,13 @@
|
|||
<funcsynopsis>
|
||||
<funcsynopsisinfo>#include <systemd/sd-id128.h></funcsynopsisinfo>
|
||||
|
||||
<funcsynopsisinfo>#define SD_ID128_STRING_MAX 33U</funcsynopsisinfo>
|
||||
|
||||
<funcsynopsisinfo>#define SD_ID128_TO_STRING(id) …</funcsynopsisinfo>
|
||||
|
||||
<funcprototype>
|
||||
<funcdef>char *<function>sd_id128_to_string</function></funcdef>
|
||||
<paramdef>sd_id128_t <parameter>id</parameter>, char <parameter>s</parameter>[33]</paramdef>
|
||||
<paramdef>sd_id128_t <parameter>id</parameter>, char <parameter>s</parameter>[static SD_ID128_STRING_MAX]</paramdef>
|
||||
</funcprototype>
|
||||
|
||||
<funcprototype>
|
||||
|
|
@ -41,47 +47,48 @@
|
|||
<refsect1>
|
||||
<title>Description</title>
|
||||
|
||||
<para><function>sd_id128_to_string()</function> formats a 128-bit
|
||||
ID as a character string. It expects the ID and a string array
|
||||
capable of storing 33 characters. The ID will be formatted as 32
|
||||
lowercase hexadecimal digits and be terminated by a
|
||||
<constant>NUL</constant> byte.</para>
|
||||
<para><function>sd_id128_to_string()</function> formats a 128-bit ID as a character string. It expects
|
||||
the ID and a string array capable of storing 33 characters
|
||||
(<constant>SD_ID128_STRING_MAX</constant>). The ID will be formatted as 32 lowercase hexadecimal digits
|
||||
and be terminated by a <constant>NUL</constant> byte.</para>
|
||||
|
||||
<para><function>sd_id128_from_string()</function> implements the reverse operation: it takes a 33 character string
|
||||
with 32 hexadecimal digits (either lowercase or uppercase, terminated by <constant>NUL</constant>) and parses them
|
||||
back into a 128-bit ID returned in <parameter>ret</parameter>. Alternatively, this call can also parse a
|
||||
37-character string with a 128-bit ID formatted as RFC UUID. If <parameter>ret</parameter> is passed as
|
||||
<constant>NULL</constant> the function will validate the passed ID string, but not actually return it in parsed
|
||||
form.</para>
|
||||
<para><function>SD_ID128_TO_STRING()</function> is a macro that wraps
|
||||
<function>sd_id128_to_string()</function> and passes an appropriately sized buffer as second argument,
|
||||
allocated as C99 compound literal. Each use will thus implicitly acquire a suitable buffer on the stack
|
||||
which remains valid until the end of the current code block. This is usually the simplest way to acquire
|
||||
a string representation of a 128-bit ID in a buffer that is valid in the current code block.</para>
|
||||
|
||||
<para><function>sd_id128_from_string()</function> implements the reverse operation: it takes a 33
|
||||
character string with 32 hexadecimal digits (either lowercase or uppercase, terminated by
|
||||
<constant>NUL</constant>) and parses them back into a 128-bit ID returned in
|
||||
<parameter>ret</parameter>. Alternatively, this call can also parse a 37-character string with a 128-bit
|
||||
ID formatted as RFC UUID. If <parameter>ret</parameter> is passed as <constant>NULL</constant> the
|
||||
function will validate the passed ID string, but not actually return it in parsed form.</para>
|
||||
|
||||
<para>Note that when parsing 37 character UUIDs this is done strictly in Big Endian byte order,
|
||||
i.e. according to <ulink url="https://tools.ietf.org/html/rfc4122">RFC4122</ulink> Variant 1
|
||||
rules, even if the UUID encodes a different variant. This matches behaviour in various other Linux
|
||||
userspace tools. It's probably wise to avoid UUIDs of other variant types.</para>
|
||||
i.e. according to <ulink url="https://tools.ietf.org/html/rfc4122">RFC4122</ulink> Variant 1 rules, even
|
||||
if the UUID encodes a different variant. This matches behaviour in various other Linux userspace
|
||||
tools. It's probably wise to avoid UUIDs of other variant types.</para>
|
||||
|
||||
<para>For more information about the <literal>sd_id128_t</literal>
|
||||
type see
|
||||
<citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
|
||||
Note that these calls operate the same way on all architectures,
|
||||
i.e. the results do not depend on endianness.</para>
|
||||
<para>For more information about the <literal>sd_id128_t</literal> type see
|
||||
<citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>3</manvolnum></citerefentry>. Note that
|
||||
these calls operate the same way on all architectures, i.e. the results do not depend on
|
||||
endianness.</para>
|
||||
|
||||
<para>When formatting a 128-bit ID into a string, it is often
|
||||
easier to use a format string for
|
||||
<citerefentry project='man-pages'><refentrytitle>printf</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
|
||||
This is easily done using the
|
||||
<constant>SD_ID128_FORMAT_STR</constant> and <function>SD_ID128_FORMAT_VAL()</function> macros. For
|
||||
more information see
|
||||
<para>When formatting a 128-bit ID into a string, it is often easier to use a format string for
|
||||
<citerefentry
|
||||
project='man-pages'><refentrytitle>printf</refentrytitle><manvolnum>3</manvolnum></citerefentry>. This
|
||||
is easily done using the <constant>SD_ID128_FORMAT_STR</constant> and
|
||||
<function>SD_ID128_FORMAT_VAL()</function> macros. For more information see
|
||||
<citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
|
||||
</refsect1>
|
||||
|
||||
<refsect1>
|
||||
<title>Return Value</title>
|
||||
|
||||
<para><function>sd_id128_to_string()</function> always succeeds
|
||||
and returns a pointer to the string array passed in.
|
||||
<function>sd_id128_from_string()</function> returns 0 on success, in
|
||||
which case <parameter>ret</parameter> is filled in, or a negative
|
||||
errno-style error code.</para>
|
||||
<para><function>sd_id128_to_string()</function> always succeeds and returns a pointer to the string array
|
||||
passed in. <function>sd_id128_from_string()</function> returns 0 on success, in which case
|
||||
<parameter>ret</parameter> is filled in, or a negative errno-style error code.</para>
|
||||
</refsect1>
|
||||
|
||||
<xi:include href="libsystemd-pkgconfig.xml" />
|
||||
|
|
|
|||
|
|
@ -12,6 +12,8 @@
|
|||
|
||||
char *id128_to_uuid_string(sd_id128_t id, char s[static ID128_UUID_STRING_MAX]);
|
||||
|
||||
#define ID128_TO_UUID_STRING(id) id128_to_uuid_string((id), (char[ID128_UUID_STRING_MAX]) {})
|
||||
|
||||
bool id128_is_valid(const char *s) _pure_;
|
||||
|
||||
typedef enum Id128Format {
|
||||
|
|
|
|||
|
|
@ -34,11 +34,13 @@ union sd_id128 {
|
|||
uint64_t qwords[2];
|
||||
};
|
||||
|
||||
#define SD_ID128_STRING_MAX 33
|
||||
#define SD_ID128_STRING_MAX 33U
|
||||
|
||||
char *sd_id128_to_string(sd_id128_t id, char s[_SD_ARRAY_STATIC SD_ID128_STRING_MAX]);
|
||||
int sd_id128_from_string(const char *s, sd_id128_t *ret);
|
||||
|
||||
#define SD_ID128_TO_STRING(id) sd_id128_to_string((id), (char[SD_ID128_STRING_MAX]) {})
|
||||
|
||||
int sd_id128_randomize(sd_id128_t *ret);
|
||||
|
||||
int sd_id128_get_machine(sd_id128_t *ret);
|
||||
|
|
|
|||
Loading…
Reference in a new issue