Support for UUIDv7

docs/uuid.md

@@ -1,8 +1,9 @@
 # uuid: Universally Unique IDentifiers (UUIDs) in SQLite
 
-Limited support for [RFC 4122](https://www.ietf.org/rfc/rfc4122.txt) compliant UUIDs:
+Limited support for [RFC 4122](https://www.ietf.org/rfc/rfc4122.txt) and [RFC 9562](https://datatracker.ietf.org/doc/rfc9562/) compliant UUIDs:
 
 -   Generate a version 4 (random) UUID.
+-   Generate a version 7 (time-ordered, random) UUID.
 -   Convert a 16-byte blob into a well-formed UUID string and vice versa.
 
 Adapted from [uuid.c](https://sqlite.org/src/file/ext/misc/uuid.c) by D. Richard Hipp.
@@ -21,6 +22,18 @@ sqlite> select gen_random_uuid();
 8d144638-3baf-4901-a554-b541142c152b
 ```
 
+<h3 name="uuid7"><code>uuid7()</code></h3>
+
+Generate a version 7 (time-ordered, random) UUID.
+
+```
+sqlite> select uuid7();
+018ff383-3e37-7615-b764-c241f544e573
+
+sqlite> select uuid7();
+018ff383-94fd-70fa-8da6-339180b8e15d
+```
+
 <h3 name="uuid_str"><code>uuid_str(X)</code></h3>
 
 Converts a UUID `X` into a well-formed UUID string. `X` can be either a string or a blob.
@@ -39,13 +52,32 @@ sqlite> select hex(uuid_blob(uuid4()));
 7192B1B452964E809500CF0364476CD3
 ```
 
+<h3 name="uuid7_timestamp_ms"><code>uuid7_timestamp_ms(X)</code></h3>
+
+Extract unix timestamp in miliseconds from version 7 UUID `X`. Returns `NULL` if the detected UUID version is not 7.
+
+```
+sqlite> SELECT uuid7();
+018ff38a-a5c9-712d-bc80-0550b3ad41a2
+
+sqlite> SELECT uuid7_timestamp_ms('018ff38a-a5c9-712d-bc80-0550b3ad41a2');
+1717777901001
+
+sqlite> SELECT datetime(uuid7_timestamp_ms('018ff38a-a5c9-712d-bc80-0550b3ad41a2') / 1000, 'unixepoch');
+2024-06-07 16:31:41
+
+sqlite> SELECT uuid7_timestamp_ms(uuid4()) IS NULL;
+1
+```
+
 ## Installation and Usage
 
 SQLite command-line interface:
 
 ```
 sqlite> .load ./uuid
 sqlite> select uuid4();
+sqlite> select uuid7();
 ```
 
 See [How to Install an Extension](install.md) for usage with IDE, Python, etc.

src/uuid/extension.c

@@ -7,14 +7,19 @@
 // Universally Unique IDentifiers (UUIDs) in SQLite
 
 /*
- * This SQLite extension implements functions that handling RFC-4122 UUIDs
- * Three SQL functions are implemented:
+ * This SQLite extension implements functions that handling RFC-4122 for UUIDv4
+ * and RFC-9562 for UUIDv7
  *
- *     uuid4()       - generate a version 4 UUID as a string
- *     uuid_str(X)   - convert a UUID X into a well-formed UUID string
- *     uuid_blob(X)  - convert a UUID X into a 16-byte blob
+ * Five SQL functions are implemented:
  *
- * The output from uuid4() and uuid_str(X) are always well-formed RFC-4122
+ *     uuid4()                  - generate a version 4 UUID as a string
+ *     uuid7()                  - generate a version 7 UUID as a string
+ *     uuid_str(X)              - convert a UUID X into a well-formed UUID string
+ *     uuid_blob(X)             - convert a UUID X into a 16-byte blob
+ *     uuid7_timestamp_ms(X)    - extract unix timestamp in miliseconds
+ *                                from version 7 UUID X.
+ *
+ * The output from uuid4(), uuid7() and uuid_str(X) are always well-formed RFC-4122
  * UUID strings in this format:
  *
  *        xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx
@@ -58,6 +63,7 @@
 #include <assert.h>
 #include <ctype.h>
 #include <string.h>
+#include <time.h>
 
 #include "sqlite3ext.h"
 SQLITE_EXTENSION_INIT3
@@ -158,9 +164,9 @@ static const unsigned char* sqlite3_uuid_input_to_blob(sqlite3_value* pIn, /* In
 }
 
 /*
- * uuid_generate generates a version 4 UUID as a string
+ * uuid_v4_generate generates a version 4 UUID as a string
  */
-static void uuid_generate(sqlite3_context* context, int argc, sqlite3_value** argv) {
+static void uuid_v4_generate(sqlite3_context* context, int argc, sqlite3_value** argv) {
     unsigned char aBlob[16];
     unsigned char zStr[37];
     (void)argc;
@@ -172,6 +178,54 @@ static void uuid_generate(sqlite3_context* context, int argc, sqlite3_value** ar
     sqlite3_result_text(context, (char*)zStr, 36, SQLITE_TRANSIENT);
 }
 
+/*
+ * uuid_v7_generate generates a version 7 UUID as a string
+ */
+static void uuid_v7_generate(sqlite3_context* context, int argc, sqlite3_value** argv) {
+    unsigned char aBlob[16];
+    unsigned char zStr[37];
+    (void)argc;
+    (void)argv;
+
+    struct timespec ts;
+    timespec_get(&ts, TIME_UTC);
+    unsigned long long timestampMs = ts.tv_sec * 1000ULL + ts.tv_nsec / 1000000;
+
+    sqlite3_randomness(16, aBlob);
+    aBlob[0] = timestampMs >> 40;
+    aBlob[1] = timestampMs >> 32;
+    aBlob[2] = timestampMs >> 24;
+    aBlob[3] = timestampMs >> 16;
+    aBlob[4] = timestampMs >> 8;
+    aBlob[5] = timestampMs;
+    aBlob[6] = (aBlob[6] & 0x0f) + 0x70;
+    aBlob[8] = (aBlob[8] & 0x3f) + 0x80;
+    sqlite3_uuid_blob_to_str(aBlob, zStr);
+    sqlite3_result_text(context, (char*)zStr, 36, SQLITE_TRANSIENT);
+}
+
+/*
+ * uuid_v7_extract_timestamp_ms extract unix timestamp in miliseconds
+ * from a version 7 UUID.
+ * X can be either a string or a blob.
+ * If X is not a version 7 UUID, return NULL.
+ */
+static void uuid_v7_extract_timestamp_ms(sqlite3_context* context, int argc, sqlite3_value** argv) {
+    unsigned char aBlob[16];
+    const unsigned char* pBlob;
+    (void)argc;
+    pBlob = sqlite3_uuid_input_to_blob(argv[0], aBlob);
+    if (pBlob == 0 || (pBlob[6] >> 4) != 7)
+        return;
+
+    unsigned long long timestampMs = 0;
+    for (size_t i = 0; i < 6; ++i) {
+        timestampMs = (timestampMs << 8) + pBlob[i];
+    }
+
+    sqlite3_result_int64(context, timestampMs);
+}
+
 /*
  * uuid_str converts a UUID X into a well-formed UUID string.
  * X can be either a string or a blob.
@@ -205,9 +259,11 @@ static void uuid_blob(sqlite3_context* context, int argc, sqlite3_value** argv)
 int uuid_init(sqlite3* db) {
     static const int flags = SQLITE_UTF8 | SQLITE_INNOCUOUS;
     static const int det_flags = SQLITE_UTF8 | SQLITE_INNOCUOUS | SQLITE_DETERMINISTIC;
-    sqlite3_create_function(db, "uuid4", 0, flags, 0, uuid_generate, 0, 0);
+    sqlite3_create_function(db, "uuid4", 0, flags, 0, uuid_v4_generate, 0, 0);
+    sqlite3_create_function(db, "uuid7", 0, flags, 0, uuid_v7_generate, 0, 0);
+    sqlite3_create_function(db, "uuid7_timestamp_ms", 1, det_flags, 0, uuid_v7_extract_timestamp_ms, 0, 0);
     /* for postgresql compatibility */
-    sqlite3_create_function(db, "gen_random_uuid", 0, flags, 0, uuid_generate, 0, 0);
+    sqlite3_create_function(db, "gen_random_uuid", 0, flags, 0, uuid_v4_generate, 0, 0);
     sqlite3_create_function(db, "uuid_str", 1, det_flags, 0, uuid_str, 0, 0);
     sqlite3_create_function(db, "uuid_blob", 1, det_flags, 0, uuid_blob, 0, 0);
     return SQLITE_OK;

test/uuid.sql

@@ -23,4 +23,19 @@ select '12', typeof(uuid_blob('d5a80b20-0d8f-11e5-b8cb-080027b6ec40')) = 'blob';
 select '13', typeof(uuid_blob(uuid4())) = 'blob';
 select '14', uuid_blob('hello') is null;
 select '15', uuid_blob('') is null;
-select '16', uuid_blob(null) is null;
+select '16', uuid_blob(null) is null;
+
+-- uuid7
+select '17', uuid7() like '________-____-7___-____-____________';
+
+-- uuid7_timestamp_ms
+select '18', uuid7_timestamp_ms('018ff38a-a5c9-712d-bc80-0550b3ad41a2') = 1717777901001;
+select '19', uuid7_timestamp_ms('00000000-0000-7000-0000-000000000000') = 0;
+select '20', uuid7_timestamp_ms('ffffffff-ffff-7000-0000-000000000000') = 281474976710655;
+select '21', typeof(uuid7_timestamp_ms('018ff38a-a5c9-712d-bc80-0550b3ad41a2')) = 'integer';
+select '22', typeof(uuid7_timestamp_ms(uuid7())) = 'integer';
+select '23', uuid7_timestamp_ms('hello') is null;
+select '24', uuid7_timestamp_ms('') is null;
+select '25', uuid7_timestamp_ms(null) is null;
+select '26', uuid7_timestamp_ms('b2df66e7-bd9a-45f4-8c0d-b9fd73cc9f18') is null;
+select '27', uuid7_timestamp_ms(uuid4()) is null;