Add `core:encoding/uuid`

1 files changed, 159 insertions, 0 deletions

diff --git a/core/encoding/uuid/generation.odin b/core/encoding/uuid/generation.odin
new file mode 100644
index 000000000..fe05d3ebd
--- /dev/null
+++ b/core/encoding/uuid/generation.odin
@@ -0,0 +1,159 @@
+package uuid
+
+import "core:crypto/legacy/md5"
+import "core:crypto/legacy/sha1"
+import "core:math/rand"
+import "core:mem"
+
+/*
+Generate a version 3 UUID.
+
+This UUID is generated from a name within a namespace.
+MD5 is used to hash the name with the namespace to produce the UUID.
+
+Inputs:
+- namespace: Another `Identifier` that is used to represent the underlying namespace.
+  This can be any one of the `Namespace_*` values provided in this package.
+- name: The byte slice used to generate the name on top of the namespace.
+
+Returns:
+- result: The generated UUID.
+*/
+generate_v3_bytes :: proc(
+	namespace: Identifier,
+	name: []byte,
+) -> (
+	result: Identifier,
+) {
+	namespace := namespace
+
+	ctx: md5.Context
+	md5.init(&ctx)
+	md5.update(&ctx, namespace.bytes[:])
+	md5.update(&ctx, name)
+	md5.final(&ctx, result.bytes[:])
+
+	result.bytes[VERSION_BYTE_INDEX] &= 0x0F
+	result.bytes[VERSION_BYTE_INDEX] |= 0x30
+
+	result.bytes[VARIANT_BYTE_INDEX] &= 0x3F
+	result.bytes[VARIANT_BYTE_INDEX] |= 0x80
+
+	return
+}
+
+/*
+Generate a version 3 UUID.
+
+This UUID is generated from a name within a namespace.
+MD5 is used to hash the name with the namespace to produce the UUID.
+
+Inputs:
+- namespace: Another `Identifier` that is used to represent the underlying namespace.
+  This can be any one of the `Namespace_*` values provided in this package.
+- name: The string used to generate the name on top of the namespace.
+
+Returns:
+- result: The generated UUID.
+*/
+generate_v3_string :: proc(
+	namespace: Identifier,
+	name: string,
+) -> (
+	result: Identifier,
+) {
+	return generate_v3_bytes(namespace, transmute([]byte)name)
+}
+
+generate_v3 :: proc {
+	generate_v3_bytes,
+	generate_v3_string,
+}
+
+/*
+Generate a version 4 UUID.
+
+This UUID will be pseudorandom, save for 6 pre-determined version and variant bits.
+
+Returns:
+- result: The generated UUID.
+*/
+generate_v4 :: proc() -> (result: Identifier) {
+	result.integer = transmute(u128be)rand.uint128()
+
+	result.bytes[VERSION_BYTE_INDEX] &= 0x0F
+	result.bytes[VERSION_BYTE_INDEX] |= 0x40
+
+	result.bytes[VARIANT_BYTE_INDEX] &= 0x3F
+	result.bytes[VARIANT_BYTE_INDEX] |= 0x80
+
+	return
+}
+
+/*
+Generate a version 5 UUID.
+
+This UUID is generated from a name within a namespace.
+SHA1 is used to hash the name with the namespace to produce the UUID.
+
+Inputs:
+- namespace: Another `Identifier` that is used to represent the underlying namespace.
+  This can be any one of the `Namespace_*` values provided in this package.
+- name: The byte slice used to generate the name on top of the namespace.
+
+Returns:
+- result: The generated UUID.
+*/
+generate_v5_bytes :: proc(
+	namespace: Identifier,
+	name: []byte,
+) -> (
+	result: Identifier,
+) {
+	namespace := namespace
+	digest: [sha1.DIGEST_SIZE]byte
+
+	ctx: sha1.Context
+	sha1.init(&ctx)
+	sha1.update(&ctx, namespace.bytes[:])
+	sha1.update(&ctx, name)
+	sha1.final(&ctx, digest[:])
+
+	mem.copy_non_overlapping(&result.bytes, &digest, 16)
+
+	result.bytes[VERSION_BYTE_INDEX] &= 0x0F
+	result.bytes[VERSION_BYTE_INDEX] |= 0x50
+
+	result.bytes[VARIANT_BYTE_INDEX] &= 0x3F
+	result.bytes[VARIANT_BYTE_INDEX] |= 0x80
+
+	return
+}
+
+/*
+Generate a version 5 UUID.
+
+This UUID is generated from a name within a namespace.
+SHA1 is used to hash the name with the namespace to produce the UUID.
+
+Inputs:
+- namespace: Another `Identifier` that is used to represent the underlying namespace.
+  This can be any one of the `Namespace_*` values provided in this package.
+- name: The string used to generate the name on top of the namespace.
+
+Returns:
+- result: The generated UUID.
+*/
+generate_v5_string :: proc(
+	namespace: Identifier,
+	name: string,
+) -> (
+	result: Identifier,
+) {
+	return generate_v5_bytes(namespace, transmute([]byte)name)
+}
+
+generate_v5 :: proc {
+	generate_v5_bytes,
+	generate_v5_string,
+}