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/* SPDX-License-Identifier: GPL-2.0-or-later */
/** \file
* \ingroup bli
*/
#include "BLI_assert.h"
#include "BLI_string.h"
#include "BLI_uuid.h"
#include <cstdio>
#include <cstring>
#include <ctime>
#include <random>
#include <sstream>
#include <string>
#include <tuple>
/* Ensure the UUID struct doesn't have any padding, to be compatible with memcmp(). */
static_assert(sizeof(bUUID) == 16, "expect UUIDs to be 128 bit exactly");
bUUID BLI_uuid_generate_random()
{
static std::mt19937_64 rng = []() {
std::mt19937_64 rng;
/* Ensure the RNG really can output 64-bit values. */
static_assert(std::mt19937_64::min() == 0LL);
static_assert(std::mt19937_64::max() == 0xffffffffffffffffLL);
struct timespec ts;
#ifdef __APPLE__
/* `timespec_get()` is only available on macOS 10.15+, so until that's the minimum version
* supported by Blender, use another function to get the timespec.
*
* `clock_gettime()` is only available on POSIX, so not on Windows; Linux uses the newer C++11
* function `timespec_get()` as well. */
clock_gettime(CLOCK_REALTIME, &ts);
#else
timespec_get(&ts, TIME_UTC);
#endif
/* XOR the nanosecond and second fields, just in case the clock only has seconds resolution. */
uint64_t seed = ts.tv_nsec;
seed ^= ts.tv_sec;
rng.seed(seed);
return rng;
}();
bUUID uuid;
/* RFC4122 suggests setting certain bits to a fixed value, and then randomizing the remaining
* bits. The opposite is easier to implement, though, so that's what's done here. */
/* Read two 64-bit numbers to randomize all 128 bits of the UUID. */
uint64_t *uuid_as_int64 = reinterpret_cast<uint64_t *>(&uuid);
uuid_as_int64[0] = rng();
uuid_as_int64[1] = rng();
/* Set the most significant four bits to 0b0100 to indicate version 4 (random UUID). */
uuid.time_hi_and_version &= ~0xF000;
uuid.time_hi_and_version |= 0x4000;
/* Set the most significant two bits to 0b10 to indicate compatibility with RFC4122. */
uuid.clock_seq_hi_and_reserved &= ~0x40;
uuid.clock_seq_hi_and_reserved |= 0x80;
return uuid;
}
bUUID BLI_uuid_nil()
{
const bUUID nil = {0, 0, 0, 0, 0, {0}};
return nil;
}
bool BLI_uuid_is_nil(bUUID uuid)
{
return BLI_uuid_equal(BLI_uuid_nil(), uuid);
}
bool BLI_uuid_equal(const bUUID uuid1, const bUUID uuid2)
{
return std::memcmp(&uuid1, &uuid2, sizeof(uuid1)) == 0;
}
void BLI_uuid_format(char *buffer, const bUUID uuid)
{
BLI_sprintf(buffer,
"%08x-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x",
uuid.time_low,
uuid.time_mid,
uuid.time_hi_and_version,
uuid.clock_seq_hi_and_reserved,
uuid.clock_seq_low,
uuid.node[0],
uuid.node[1],
uuid.node[2],
uuid.node[3],
uuid.node[4],
uuid.node[5]);
}
bool BLI_uuid_parse_string(bUUID *uuid, const char *buffer)
{
const int fields_parsed_num = std::sscanf(
buffer,
"%8x-%4hx-%4hx-%2hhx%2hhx-%2hhx%2hhx%2hhx%2hhx%2hhx%2hhx",
&uuid->time_low,
&uuid->time_mid,
&uuid->time_hi_and_version,
&uuid->clock_seq_hi_and_reserved,
&uuid->clock_seq_low,
&uuid->node[0],
&uuid->node[1],
&uuid->node[2],
&uuid->node[3],
&uuid->node[4],
&uuid->node[5]);
return fields_parsed_num == 11;
}
std::ostream &operator<<(std::ostream &stream, bUUID uuid)
{
std::string buffer(36, '\0');
BLI_uuid_format(buffer.data(), uuid);
stream << buffer;
return stream;
}
namespace blender {
bUUID::bUUID(const std::initializer_list<uint32_t> field_values)
{
BLI_assert_msg(field_values.size() == 11, "bUUID requires 5 regular fields + 6 `node` values");
const auto *field_iter = field_values.begin();
this->time_low = *field_iter++;
this->time_mid = uint16_t(*field_iter++);
this->time_hi_and_version = uint16_t(*field_iter++);
this->clock_seq_hi_and_reserved = uint8_t(*field_iter++);
this->clock_seq_low = uint8_t(*field_iter++);
std::copy(field_iter, field_values.end(), this->node);
}
bUUID::bUUID(const std::string &string_formatted_uuid)
{
const bool parsed_ok = BLI_uuid_parse_string(this, string_formatted_uuid.c_str());
if (!parsed_ok) {
std::stringstream ss;
ss << "invalid UUID string " << string_formatted_uuid;
throw std::runtime_error(ss.str());
}
}
bUUID::bUUID(const ::bUUID &struct_uuid)
{
*(static_cast<::bUUID *>(this)) = struct_uuid;
}
uint64_t bUUID::hash() const
{
/* Convert the struct into two 64-bit numbers, and XOR them to get the hash. */
const uint64_t *uuid_as_int64 = reinterpret_cast<const uint64_t *>(this);
return uuid_as_int64[0] ^ uuid_as_int64[1];
}
bool operator==(const bUUID uuid1, const bUUID uuid2)
{
return BLI_uuid_equal(uuid1, uuid2);
}
bool operator!=(const bUUID uuid1, const bUUID uuid2)
{
return !(uuid1 == uuid2);
}
bool operator<(const bUUID uuid1, const bUUID uuid2)
{
auto simple_fields1 = std::tie(uuid1.time_low,
uuid1.time_mid,
uuid1.time_hi_and_version,
uuid1.clock_seq_hi_and_reserved,
uuid1.clock_seq_low);
auto simple_fields2 = std::tie(uuid2.time_low,
uuid2.time_mid,
uuid2.time_hi_and_version,
uuid2.clock_seq_hi_and_reserved,
uuid2.clock_seq_low);
if (simple_fields1 == simple_fields2) {
return std::memcmp(uuid1.node, uuid2.node, sizeof(uuid1.node)) < 0;
}
return simple_fields1 < simple_fields2;
}
} // namespace blender
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