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#ifndef PK_UUID_H
#define PK_UUID_H
#include "stddef.h"
#include <time.h>
struct pk_uuid {
alignas(max_align_t) unsigned char uuid[16];
};
const struct pk_uuid pk_uuid_zed = { .uuid = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } };
const struct pk_uuid pk_uuid_max = { .uuid = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF } };
#define pk_uuid_printf_format PK_Q(%.2x%.2x%.2x%.2x-%.2x%.2x-%.2x%.2x-%.2x%.2x-%.2x%.2x%.2x%.2x%.2x%.2x)
#define pk_uuid_printf_var(id) id.uuid[0], id.uuid[1], id.uuid[2], id.uuid[3], id.uuid[4], id.uuid[5], id.uuid[6], id.uuid[7], id.uuid[8], id.uuid[9], id.uuid[10], id.uuid[11], id.uuid[12], id.uuid[13], id.uuid[14], id.uuid[15]
void pk_uuid_init(time_t srand_seed);
void pk_uuid_teardown();
struct pk_uuid pk_uuid_new_v7();
bool pk_uuid_equals(struct pk_uuid lhs, struct pk_uuid rhs);
#if defined(__cplusplus)
#include <ostream>
#include <iomanip>
std::ostream& operator<<(std::ostream &o, const struct pk_uuid& uuid);
std::istream& operator>>(std::istream &i, struct pk_uuid& uuid);
bool operator==(const pk_uuid &lhs, const pk_uuid &rhs) { return pk_uuid_equals(lhs, rhs); }
bool operator!=(const pk_uuid &lhs, const pk_uuid &rhs) { return !pk_uuid_equals(lhs, rhs); }
#endif
#endif /* PK_UUID_H */
#ifdef PK_IMPL_UUID
#include <stdatomic.h>
#include <stdlib.h>
#include <stdint.h>
// TODO JCB - 2025-03-19
// This should have platform-specific defines
#ifndef PK_UUID_CLOCK
#ifdef CLOCK_TAI
#define PK_UUID_CLOCK CLOCK_TAI
#else
#define PK_UUID_CLOCK CLOCK_REALTIME
#endif
#endif
void
pk_uuid_init(time_t srand_seed)
{
// TODO 2025-03-19 - JCB
// pk.h should NOT be setting srand.
// Replace dependency on rand/srand with a sufficient rand() implementation.
// I would prefer if generating a UUID did not advance a global random.
// Consider creating a pkrand.h to resolve this.
srand(srand_seed);
}
void
pk_uuid_teardown()
{
}
struct pk_uuid
pk_uuid_new_v7()
{
const int n = 1;
uint32_t r;
// https://www.rfc-editor.org/rfc/rfc9562.html#name-uuid-version-7
struct pk_uuid ret;
struct timespec t;
clock_gettime(PK_UUID_CLOCK, &t);
uint32_t sec = (uint32_t)t.tv_sec;
uint32_t nsec = (uint32_t)t.tv_nsec;
// [000-047] (6 bytes) big-endian unix epoch
// TODO test this on a big-endian machine, I don't think this is correct.
// This `if` determines if we are big or little endian.
// A return value of 1 says we are little endian, so swap the bits.
if (*(char *)&n == 1) {
ret.uuid[0] = (uint8_t)((sec & 0xFF000000) >> 24);
ret.uuid[1] = (uint8_t)((sec & 0x00FF0000) >> 16);
ret.uuid[2] = (uint8_t)((sec & 0x0000FF00) >> 8);
ret.uuid[3] = (uint8_t)((sec & 0x000000FF) >> 0);
ret.uuid[4] = (uint8_t)((nsec & 0x0000FF00) >> 8);
ret.uuid[5] = (uint8_t)((nsec & 0x000000FF) >> 0);
} else {
ret.uuid[0] = (uint8_t)((sec & 0xFF000000) >> 0);
ret.uuid[1] = (uint8_t)((sec & 0x00FF0000) >> 8);
ret.uuid[2] = (uint8_t)((sec & 0x0000FF00) >> 16);
ret.uuid[3] = (uint8_t)((sec & 0x000000FF) >> 24);
ret.uuid[4] = (uint8_t)((nsec & 0xFF000000) >> 0);
ret.uuid[5] = (uint8_t)((nsec & 0x00FF0000) >> 8);
}
// [052-127] random
r = (uint32_t)rand();
if (*(char *)&n == 1) {
ret.uuid[8] = (uint8_t)((r & 0xFF000000) >> 24);
ret.uuid[9] = (uint8_t)((r & 0x00FF0000) >> 16);
ret.uuid[10] = (uint8_t)((r & 0x0000FF00) >> 8);
ret.uuid[11] = (uint8_t)((r & 0x000000FF) >> 0);
} else {
ret.uuid[8] = (uint8_t)((r & 0xFF000000) >> 0);
ret.uuid[9] = (uint8_t)((r & 0x00FF0000) >> 8);
ret.uuid[10] = (uint8_t)((r & 0x0000FF00) >> 16);
ret.uuid[11] = (uint8_t)((r & 0x000000FF) >> 24);
}
r = rand();
if (*(char *)&n == 1) {
ret.uuid[12] = (uint8_t)((r & 0xFF000000) >> 24);
ret.uuid[13] = (uint8_t)((r & 0x00FF0000) >> 16);
ret.uuid[14] = (uint8_t)((r & 0x0000FF00) >> 8);
ret.uuid[15] = (uint8_t)((r & 0x000000FF) >> 0);
} else {
ret.uuid[12] = (uint8_t)((r & 0xFF000000) >> 0);
ret.uuid[13] = (uint8_t)((r & 0x00FF0000) >> 8);
ret.uuid[14] = (uint8_t)((r & 0x0000FF00) >> 16);
ret.uuid[15] = (uint8_t)((r & 0x000000FF) >> 24);
}
ret.uuid[6] = ret.uuid[9] ^ ret.uuid[12];
ret.uuid[7] = ret.uuid[10] ^ ret.uuid[15];
// [048-051] v7 nibble
// version must be 0x7_
// 0x70 is 0b01110000
// 0x7F is 0b01111111
ret.uuid[6] |= 0x70;
ret.uuid[6] &= 0x7F;
// [064-065] 2-bit variant field
// variant must be 0b10
// 0x80 is 0b10000000
// 0xBF is 0b10111111
ret.uuid[8] |= 0x80;
ret.uuid[8] &= 0xBF;
return ret;
}
bool pk_uuid_equals(struct pk_uuid lhs, struct pk_uuid rhs)
{
int i;
for (i = 0; i < 16; ++i) {
if (lhs.uuid[i] != rhs.uuid[i]) return false;
}
return true;
}
#if defined(__cplusplus)
#include "./pkstn.h" /* deleteme */
std::ostream&
operator<<(std::ostream &o, const struct pk_uuid& uuid)
{
int i;
o << std::hex;
for (i = 0; i < 4; ++i) {
o << std::setw(2) << std::setfill('0');
o << (uint16_t)uuid.uuid[i];
}
o << "-";
for (i = 4; i < 6; ++i) {
o << std::setw(2) << std::setfill('0');
o << (uint16_t)uuid.uuid[i];
}
o << "-";
for (i = 6; i < 8; ++i) {
o << std::setw(2) << std::setfill('0');
o << (uint16_t)uuid.uuid[i];
}
o << "-";
for (i = 8; i < 10; ++i) {
o << std::setw(2) << std::setfill('0');
o << (uint16_t)uuid.uuid[i];
}
o << "-";
for (i = 10; i < 16; ++i) {
o << std::setw(2) << std::setfill('0');
o << (uint16_t)uuid.uuid[i];
}
return o;
}
std::istream&
operator>>(std::istream &i, struct pk_uuid& uuid)
{
char c[3];
char k = 0;
char offset = 0;
c[2] = '\0';
for (k = 0; k < 20; ++k) {
if (k == 4 || k == 7 || k == 10 || k == 13) {
offset += 1;
c[0] = i.peek();
if (c[0] != '-') {
goto err_out;
}
i.get(); // burn
continue;
}
i.get(c[0]);
i.get(c[1]);
if (pk_stn_uint8_t(&uuid.uuid[k - offset], c, 16) != PK_STN_RES_SUCCESS) {
goto err_out;
}
}
return i;
err_out:
i.seekg(-(((k + 1) * 2) + offset), std::ios_base::cur);
uuid = pk_uuid_zed;
return i;
}
#endif
#endif
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