v1.16.7

ADDED:
* uuidx
FIXED:
* sprigx docs consistency

.githooks/pre-commit/01-docgen

@@ -19,6 +19,12 @@ for f in $(find . -type f -iname "README.adoc"); do
         asciidoctor -a ROOTDIR="${orig}/" -o "${newf}" "${f}"
 	echo "Generated ${newf} from ${f}"
         git add "${newf}"
+        if command -v asciidoctor-pdf &> /dev/null;
+	then
+		newf="${pfx}.pdf"
+
+        	asciidoctor-pdf -a ROOTDIR="${orig}/" -o "${newf}" "${f}"
+	fi
         if command -v pandoc &> /dev/null;
         then
 		newf="${pfx}.md"

.gitignore

@@ -19,12 +19,13 @@
 .idea/
 
 # https://github.com/github/gitignore/blob/master/Go.gitignore
-# Binaries for programs and plugins
+# Binaries for programs and plugins and other data
 *.exe
 *.exe~
 *.dll
 *.so
 *.dylib
+*.pdf
 
 # Test binary, built with `go test -c`
 *.test

TODO

@@ -0,0 +1 @@
+- validx: validator functions for https://pkg.go.dev/github.com/go-playground/validator/v10

go.sum

@@ -69,3 +69,4 @@ golang.org/x/sys v0.40.0 h1:DBZZqJ2Rkml6QMQsZywtnjnnGvHza6BTfYFWY9kjEWQ=
 golang.org/x/sys v0.40.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+r00t2.io/sysutils v1.16.2/go.mod h1:iXK+ALOwIdRKjAJIE5USlkZ669SVDHBNNuYhunsznH8=

tplx/sprigx/TODO

@@ -0,0 +1,14 @@
+- osReadFileBytes
+- osReadFileStr
+- osReadDir
+
+- `dns*` funcs (net)
+- `url*` funcs (net/url)
+- `uuid*` funcs (github.com/google/uuid and r00t2.io/goutils/uuidx)
+
+- `http*` funcs:
+-- `httpReq`: returns a net/http.Request
+-- `http<Method>`: performs <Method> (? seems redundant if exposing httpReq)
+-- also have `resty*` funcs?
+
+- i should probably explicitly provide a "safe" set vs. "full" set. can just mod the map func getters to accept a "safeOnly" bool param.

tplx/sprigx/consts.go

@@ -1,6 +1,8 @@
 package sprigx
 
 import (
+	`net`
+	`net/netip`
 	`os`
 	`os/user`
 	`path`
@@ -17,6 +19,7 @@ import (
 	psnet `github.com/shirou/gopsutil/v4/net`
 	`github.com/shirou/gopsutil/v4/process`
 	`github.com/shirou/gopsutil/v4/sensors`
+	`go4.org/netipx`
 	`r00t2.io/goutils/timex`
 	`r00t2.io/sysutils`
 )
@@ -30,6 +33,40 @@ var (
 			"Meta"/Template-Helpers
 		*/
 		"metaIsNil": metaIsNil,
+		/*
+			Networking (net)
+		*/
+		"netCidrMask":     net.CIDRMask,
+		"netExtractAddr":  netExtractAddr,
+		"netExtractHost":  netExtractHost,
+		"netExtractIpnet": netExtractIpnet,
+		"netExtractPort":  netExtractPort,
+		"netIfaces":       net.Interfaces,
+		"netIp4Mask":      netIp4Mask,
+		"netJoinHostPort": net.JoinHostPort,
+		"netParseIP":      net.ParseIP,
+		/*
+			Networking (net/netip)
+		*/
+		"netipAddrPort":      netip.AddrPortFrom,
+		"netipParseAddr":     netip.ParseAddr,
+		"netipParseAddrPort": netip.ParseAddrPort,
+		"netipParsePrefix":   netip.ParsePrefix,
+		"netipPrefix":        netip.PrefixFrom,
+		/*
+			Networking (go4.org/netipx)
+		*/
+		"netipxAddrIpNet":   netipx.AddrIPNet,
+		"netipxCmpPfx":      netipx.ComparePrefix,
+		"netipxFromStdAddr": netipxFromStdAddr,
+		"netipxFromIp":      netipxFromIp,
+		"netipxFromIpNet":   netipxFromIpNet,
+		"netipxParseRange":  netipx.ParseIPRange,
+		"netipxPfxAddr":     netipx.ParsePrefixOrAddr,
+		"netipxPfxIpNet":    netipx.PrefixIPNet,
+		"netipxPfxLast":     netipx.PrefixLastIP,
+		"netipxPfxRange":    netipx.RangeOfPrefix,
+		"netipxRange":       netipx.IPRangeFrom,
 		/*
 			Numbers/Math
 		*/

tplx/sprigx/docinfo.html

@@ -0,0 +1,77 @@
+<!-- https://stackoverflow.com/a/34481639 -->
+<!-- Generate a nice TOC -->
+<script src="https://code.jquery.com/jquery-1.11.3.min.js"></script>
+<script src="https://code.jquery.com/ui/1.11.4/jquery-ui.min.js"></script>
+<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery.tocify/1.9.0/javascripts/jquery.tocify.min.js"></script>
+<!-- We do not need the tocify CSS because the asciidoc CSS already provides most of what we neeed -->
+
+<style>
+.tocify-header {
+    font-style: italic;
+}
+
+.tocify-subheader {
+    font-style: normal;
+    font-size: 90%;
+}
+
+.tocify ul {
+    margin: 0;
+ }
+
+.tocify-focus {
+    color: #7a2518; 
+    background-color: rgba(0, 0, 0, 0.1);
+}
+
+.tocify-focus > a {
+    color: #7a2518; 
+}
+</style>
+
+<script type="text/javascript">
+    $(function () {
+        // Add a new container for the tocify toc into the existing toc so we can re-use its
+        // styling
+        $("#toc").append("<div id='generated-toc'></div>");
+        $("#generated-toc").tocify({
+            extendPage: true,
+            context: "#content",
+            highlightOnScroll: true,
+            hideEffect: "slideUp",
+            // Use the IDs that asciidoc already provides so that TOC links and intra-document
+            // links are the same. Anything else might confuse users when they create bookmarks.
+            hashGenerator: function(text, element) {
+                return $(element).attr("id");
+            },
+            // Smooth scrolling doesn't work properly if we use the asciidoc IDs
+            smoothScroll: false,
+            // Set to 'none' to use the tocify classes
+            theme: "none",
+            // Handle book (may contain h1) and article (only h2 deeper)
+            selectors: $( "#content" ).has( "h1" ).size() > 0 ? "h1,h2,h3,h4,h5" : "h2,h3,h4,h5",
+            ignoreSelector: ".discrete"
+        });
+
+        // Switch between static asciidoc toc and dynamic tocify toc based on browser size
+        // This is set to match the media selectors in the asciidoc CSS
+        // Without this, we keep the dynamic toc even if it is moved from the side to preamble
+        // position which will cause odd scrolling behavior
+        var handleTocOnResize = function() {
+            if ($(document).width() < 768) {
+                $("#generated-toc").hide();
+                $(".sectlevel0").show();
+                $(".sectlevel1").show();
+            }
+            else {
+                $("#generated-toc").show();
+                $(".sectlevel0").hide();
+                $(".sectlevel1").hide();
+            }
+        }
+
+        $(window).resize(handleTocOnResize);
+        handleTocOnResize();
+    });
+</script>
+

tplx/sprigx/errs.go

@@ -5,7 +5,12 @@ import (
 )
 
 var (
+	ErrBadAddr     error = errors.New("invalid/bad address")
+	ErrBadAddrPort error = errors.New("invalid/bad address/port")
 	ErrBadMonth    error = errors.New("could not determine/parse month")
+	ErrBadNet      error = errors.New("invalid/bad network")
+	ErrOverflow    error = errors.New("integer/buffer overflow")
 	ErrBadType     error = errors.New("an invalid/unknown type was passed")
 	ErrNilVal      error = errors.New("a nil value was passed")
+	ErrUnderflow   error = errors.New("integer/buffer underflow")
 )

tplx/sprigx/funcs_tpl_net.go

@@ -0,0 +1,82 @@
+package sprigx
+
+import (
+	`math`
+	`net`
+	`strconv`
+)
+
+// netExtractAddr calls net.ParseCIDR and returns the net.IP from it.
+func netExtractAddr(s string) (addr net.IP, err error) {
+
+	if addr, _, err = net.ParseCIDR(s); err != nil {
+		return
+	}
+
+	return
+}
+
+// netExtractHost extracts the host component from hostPort.
+func netExtractHost(hostPort string) (host string, err error) {
+
+	if host, _, err = net.SplitHostPort(hostPort); err != nil {
+		return
+	}
+
+	return
+}
+
+// netExtractIpnet calls net.ParseCIDR and returns the net.IPNet from it.
+func netExtractIpnet(s string) (ipnet *net.IPNet, err error) {
+
+	if _, ipnet, err = net.ParseCIDR(s); err != nil {
+		return
+	}
+
+	return
+}
+
+// netExtractPort extracts the port component from hostPort.
+func netExtractPort(hostPort string) (port uint16, err error) {
+
+	var portStr string
+	var u64 uint64
+
+	if _, portStr, err = net.SplitHostPort(hostPort); err != nil {
+		return
+	}
+
+	if u64, err = strconv.ParseUint(portStr, 10, 16); err != nil {
+		return
+	}
+	port = uint16(u64)
+
+	return
+}
+
+// netIp4Mask is a more flexible wrapper around net.IPv4Mask.
+func netIp4Mask(a, b, c, d any) (mask net.IPMask, err error) {
+
+	var idx int
+	var elem any
+	var elemInt int
+	var mBytes [4]byte
+	var orig [4]any = [4]any{a, b, c, d}
+
+	for idx, elem = range orig {
+		if elemInt, _, err = toPosInt(elem); err != nil {
+			return
+		}
+		if elemInt > math.MaxUint8 {
+			err = ErrOverflow
+			return
+		}
+		mBytes[idx] = byte(uint8(elemInt))
+	}
+
+	mask = net.IPv4Mask(
+		mBytes[0], mBytes[1], mBytes[2], mBytes[3],
+	)
+
+	return
+}

tplx/sprigx/funcs_tpl_netipx.go

@@ -0,0 +1,47 @@
+package sprigx
+
+import (
+	`net`
+	`net/netip`
+
+	`go4.org/netipx`
+)
+
+// netipxFromStdAddr wraps go4.org/netipx.FromStdAddr to comply with Go template requirements.
+func netipxFromStdAddr(ip net.IP, port int, zone string) (addrPort netip.AddrPort, err error) {
+
+	var ok bool
+
+	if addrPort, ok = netipx.FromStdAddr(ip, port, zone); !ok {
+		err = ErrBadAddrPort
+		return
+	}
+
+	return
+}
+
+// netipxFromIp wraps go4.org/netipx.FromStdIP to comply with Go template requirements.
+func netipxFromIp(ip net.IP) (addr netip.Addr, err error) {
+
+	var ok bool
+
+	if addr, ok = netipx.FromStdIP(ip); !ok {
+		err = ErrBadAddr
+		return
+	}
+
+	return
+}
+
+// netipxFromIpNet wraps go4.org/netipx.FromStdIPNet to comply with Go template requirements.
+func netipxFromIpNet(ipnet *net.IPNet) (pfx netip.Prefix, err error) {
+
+	var ok bool
+
+	if pfx, ok = netipx.FromStdIPNet(ipnet); !ok {
+		err = ErrBadNet
+		return
+	}
+
+	return
+}

uuidx/consts.go

@@ -0,0 +1,11 @@
+package uuidx
+
+const (
+	RfcNone RfcGen = iota
+	Rfc4122
+	Rfc9562
+)
+
+const (
+	MsGuidThreshold int = 4
+)

uuidx/doc.go

@@ -0,0 +1,73 @@
+/*
+Package uuidx intends to supplement [github.com/google/uuid].
+
+# Microsoft GUID Shenanigans
+
+The following functions are provided to deal with [Microsoft's incompetence]:
+
+	* [DetectMsGuid] (a confidence'd determination if a UUID is a Microsoft GUID or not)
+	* [IsFlippedEndian] for flipped-endian [uuid.UUID] comparison (e.g. a is the Microsoft-flipped-endian version of b)
+	* [IsMsGuid] (wraps [DetectMsGuid] and returns true if confidence is reasonably strong that it's a Microsoft GUID)
+	* [IsRfc] (the inverse of IsMsGuid, but also checks for strict RFC compliance and returns which RFC)
+	* [MsGuidToUuid] (explicitly convert/ensure a GUID/UUID is likely a UUID)
+	* [ToggleUuidMsGuid] (blindly flip the endianness of selected byte ranges for MS GUID <-> UUID conversion)
+	* [UuidToMsGuid] (explicitly convert/ensure a GUID/UUID is likely an MS GUID)
+
+Microsoft, in their typical insanity, uses a proprietary UUID format (usually referred to as the "Microsoft GUID Format"
+or "Mixed-Endian Format").
+
+Normally for, for example a UUIDv4, it's structured as thus per RFC 9562 [§ 5.4] (which obsoletes RFC 4122 [§ 4.4]):
+
+	       A               B               C               D                E
+	HEX(BE(uint32))-HEX(BE(uint16))-HEX(BE(uint16))-HEX(BE(<uint16>), BE(<6 bytes>))
+
+(where <BE> is big-endian packing).
+
+However, thanks to Microsoft we can't have nice things. They decided to completely ignore the standard, and
+instead keep D/E as big-endian *but use little-endian* for A through C inclusive:
+
+	       A               B               C               D                E
+	HEX(LE(uint32))-HEX(LE(uint16))-HEX(LE(uint16))-HEX(BE(<uint16>), BE(<6 bytes>))
+
+"Surely that had SOME reason to do that," you may say to yourself, "they wouldn't make some arbitrary formatting
+change from a standard just because."
+
+You would be wrong. To my knowledge, they have never provided any technological justfification to this insanity,
+and now it's infected its way into a slew of other technologies they've had their grubby little hands involved in
+(e.g. UEFI). And it's of course too late to change.
+
+So anyways here's a library to make dealing with Microsoft's hubris a little easier.
+
+# Validation/Verification
+
+Aside from trying to address Microsoft silliness, there are some additional functions:
+
+	* [Equal] for [uuid.UUID] comparison
+	* [IsMaxUUID] (if a given [uuid.UUID] is an RFC 9562 [§ 5.10] UUID)
+	* [IsNilUUID] (if a given [uuid.UUID] is an RFC 9562 [§ 5.9] UUID)
+	* [IsValid] (If an RFC can be considered safely conformant to RFC spec)
+
+# Future Incorporation/Deprecation/Obsolescence
+
+Worth keeping an eye on are:
+
+	* https://github.com/google/uuid/pull/192
+	* https://github.com/golang/go/issues/62026
+	* https://github.com/golang/go/issues/76319
+		(generally it's a bad idea for an API addition overall, but some good ideas were raised)
+
+Some of these additions may deprecate/obsolete components of this package.
+I'll try to keep them around but mark as deprecated as they are (if they are),
+but I make no concrete promises - I hate making new major releases in Go's
+[silly module architecture] even more than I do keeping old deprecated code around.
+So caveat emptor.
+
+[Microsoft's incompetence]: https://learn.microsoft.com/en-us/windows/win32/api/guiddef/ns-guiddef-guid
+[§ 5.4]: https://datatracker.ietf.org/doc/html/rfc9562#section-5.4
+[§ 4.4]: https://datatracker.ietf.org/doc/html/rfc4122#section-4.4
+[§ 5.9]: https://datatracker.ietf.org/doc/html/rfc9562#section-5.9
+[§ 5.10]: https://datatracker.ietf.org/doc/html/rfc9562#section-5.10
+[github:google/uuid#192]: https://github.com/google/uuid/pull/192
+[silly module architecture]: https://go.dev/doc/modules/major-version
+*/
+package uuidx

uuidx/funcs.go

@@ -0,0 +1,461 @@
+package uuidx
+
+import (
+	"github.com/google/uuid"
+)
+
+/*
+DetectMsGuid tries to guess if a given [uuid.UUID] is actually a Microsoft GUID or not.
+
+Note that there are technically *two* types of Microsoft GUIDs:
+
+	* One is predictable, and defined in RFC 9562 [§ 4.2] as a known variant.
+		Detecting this is very easy and (assuming an RFC-compliant UUID is originally passed) is detectable with 100% confidence.
+		It's also legacy, and Microsoft no longer uses this format. Because they are insane and enjoy the suffering of others.
+	* The other, MODERN Microsoft GUID currently in use is the endianness-flipped version (see [ToggleUuidMsGuid]).
+		This is impossible to 100% determine, but analysis can get *pretty* close.
+
+cs is a confidence scoring. As more logic is added, it *is* mathematically possible
+(though unlikely) that cs == 0, so the caller is then responsible for making further
+guesswork based on contextual analysis ("Did I get this UUID/GUID from an Active Directory attribute?"
+"Is it a SID constant?" etc.).
+
+A score > 0 indicates a confidence leaning towards the provided UUID/GUID being a Microsoft GUID.
+A score < 0 indicates a confidence leaning towards the provided UUID/GUID *not* being a Microsoft GUID.
+Note that a score of < 0 does not necessarily indicate it is a *proper, standard RFC-compliant UUID*,
+simply that it is likely NOT a Microsoft GUID. [IsRfc] will be of further help in these cases.
+
+csFlip indicates a score for the [ToggleUuidMsGuid]-flipped version of u.
+It follows the same rules for thresholds and such as cs, but may be awarded different confidence levels
+internally due to different chances of false positives.
+If both cs and csFlip are > 0 but csFlip > cs, it is better to assume that u is *not* in the flipped-endian format
+but *is* a Microsoft GUID (in other words, it is likely that u has *already been flipped* to proper/consistent endianness
+instead of being a mixed-endian GUID).
+
+In some cases where flipped-endianness does not matter (e.g. [IsNilUUID], [IsMaxUUID]),
+cs and csFlip will be equal.
+
+*Randomly-generated* GUIDs on Windows Server 2000-family and up are almost always UUIDv4.
+Pre-Windows Server 2000 family *OR* any *statically-defined* GUIDs (schemaIDGUID, rightsGUID, CLSID constants, etc.)
+are all over the place - TYPICALLY UUIDv1, but it's nothing predictable enough to be useful in definitive classification.
+COM interfaces are all OVER the place in UUID version, but usually *not* UUIDv4.
+
+A target/expected UUID version can be provided via tgtVer. To disable version analysis, use 0 (or 0x00, etc.).
+It is *highly* recommended to provide a tgtVer if it is known; it can significantly boost confidence in the correct direction.
+A warning, though - if a *wrong* tgtVer IS specified, it can negatively affect confidence accuracy.
+Thus if you aren't ABSOLUTELY certain of the target UUID version, it's better to use 0/0x00 to disable the check.
+Providing a target version is key to breaking some ties (e.g. both cs and csFlip are equal).
+For example, the given RFC-compliant UUIDv4:
+
+	8d8e35ae-58d2-4d28-b09d-ffffffffffff
+
+when flipped evaluates to an RFC-compliant UUIDv2:
+
+	ae358e8d-d258-284d-b09d-ffffffffffff
+
+and in this case, cs and csFlip will both end up as 0.
+Providing a tgtVer of 4 shifts this to a proper "tie-breaker" of cs == -3 and csFlip == 0.
+Similarly, the endian-flipped UUIDv4 evaluates as a UUIDv2:
+
+	9856ea36-c2ca-2347-af0c-3b42f76c9eca
+
+from the original unflipped UUIDv4:
+
+	36ea5698-cac2-4723-af0c-3b42f76c9eca
+
+which results in a cs == 1 and csFlip == 0 - not very high confidence (but at least a correct and non-zero lean).
+Providing a tgtVer == 4 changes this to cs == 7 and csFlip == 0, which is *much* more decisive.
+
+UUIDs/GUIDs found to be strictly RFC-conforming (via [IsRfc], which returns false for Microsoft GUIDs)
+are *heavily* weighted negatively.
+
+Confidence levels can be generally considered as the following:
+
+	cs >= 7: Likely Microsoft GUID (mixed-endian)
+	cs >= 4: Likely Microsoft GUID
+	0 < cs < 4: Leans Microsoft GUID, but untrusted
+	cs == 0: Entirely ambiguous/indeterminate
+	-4 < cs < 0: Leans UUID/non-Microsoft GUID but untrusted
+	cs <= -5: Likely UUID/not Microsoft GUID
+	csFlip >=cs && csFlip >= 4: Likely a pre-flipped (ToggleUuidMsGuid'd) Microsoft GUID
+
+[§ 4.2]: https://datatracker.ietf.org/doc/html/rfc9562#section-4.2
+*/
+
+func DetectMsGuid(u uuid.UUID, tgtVer uuid.Version) (cs, csFlip int) {
+
+	var isRfc bool
+	var flippedRfc bool
+	var flipped uuid.UUID = ToggleUuidMsGuid(u)
+
+	// These are the exact same when flipped, and are statically defined.
+	if IsNilUUID(u) || IsMaxUUID(u) {
+		cs = -12
+		csFlip = -12
+		return
+	}
+
+	// Most/all(?) Microsoft GUIDs are not NCS.
+	if IsNcs(u) {
+		cs -= 2
+	}
+	if IsNcs(flipped) {
+		// The flipped has a higher likelihood of false-pos, so we don't score it as confidently.
+		csFlip -= 1
+	}
+
+	if u.Version() == 0 {
+		if u.Variant() == uuid.Microsoft {
+			cs += 10
+		} else {
+			cs -= 2
+		}
+	}
+	if flipped.Version() == 0 {
+		if flipped.Variant() == uuid.Microsoft {
+			csFlip += 4
+		} else {
+			csFlip -= 1
+		}
+	}
+
+	// Valid RFC version and variant. IsRfc returns false for the Microsoft Variant and version == 0.
+	// Modern MS uses an RFC 4122 variant indicator but flips the endianness.
+	isRfc, _ = IsRfc(u)
+	flippedRfc, _ = IsRfc(flipped)
+	if u.Variant() == uuid.RFC4122 { // This might be the strongest indicator.
+		if isRfc && !flippedRfc {
+			// This is *very* strong of being an MS GUID.
+			cs -= 8
+			csFlip += 4
+		} else if !isRfc && flippedRfc {
+			// It probably is an MS GUID but was already flipped.
+			csFlip += 6
+		} else if isRfc && flippedRfc {
+			/*
+				If both are RFC-compat, it's a weird case where
+				it actually IS RFC compliant and by chance the flipped is *also* RFC compat.
+				An example of this is:
+					8d8e35ae-58d2-4d28-b09d-ffffffffffff
+				Which has the flipped version of:
+					ae358e8d-d258-284d-b09d-ffffffffffff
+				The original is a v4, the flipped evaluates as a v2!
+
+				Providing a target version breaks this away to a definitive score.
+			*/
+		}
+	}
+
+	// *HEAVILY* weigh a provided version.
+	if tgtVer != 0 {
+		// NCS does some weird things to the versioning field. We return early on it though.
+		// MS GUIDs have a pretty small chance of matching,
+		// but their flipped counterpart SHOULD match versions.
+		if flipped.Version() == tgtVer {
+			cs += 7
+		} else {
+			cs -= 3
+		}
+	} else {
+		// Give a *very small* boost to flippedRfc and flipped.Version() == 4, since it's so common.
+		// Don't make this too high though since the version is explicitly specified as unknown.
+		if flippedRfc && flipped.Version() == 4 {
+			cs += 1
+		}
+	}
+
+	return
+}
+
+/*
+Equal returns `true` if [uuid.UUID] the two provided [uuid.UUID] are the same.
+
+Currently it just wraps:
+
+	eq = a == b
+
+but is provided as a safety guarantee if the underlying structures/types should change.
+*/
+func Equal(a, b uuid.UUID) (eq bool) {
+
+	eq = a == b
+
+	return
+}
+
+/*
+IsFlippedEndian can be used to check if [uuid.UUID] is a direct endian-flipped ([ToggleUuidMsGuid])
+of b (or vice versa, obviously).
+
+It simply wraps:
+
+		isFlipped = Equal(a, ToggleUuidMsGuid(b))
+
+but can be useful for shorthand/readability.
+*/
+func IsFlippedEndian(a, b uuid.UUID) (isFlipped bool) {
+
+	isFlipped = Equal(a, ToggleUuidMsGuid(b))
+
+	return
+}
+
+/*
+IsMaxUUID returns `true` if the specified UUID is explicitly an RFC-defined
+"Max UUID". (You may also see it specified in some places as the "Omni UUID".)
+
+For details, see RFC 9562 [§ 5.10].
+
+[§ 5.10]: https://datatracker.ietf.org/doc/html/rfc9562#section-5.10
+*/
+func IsMaxUUID(u uuid.UUID) (isMax bool) {
+
+	isMax = u == uuid.Max
+
+	return
+}
+
+/*
+IsMsGuid wraps
+
+	if cmp, _ = DetectMsGuid(msGUID, tgtVer); cmp < -3 {
+		isMs = true
+	}
+
+Note that [uuid.Microsoft] is an actual RFC-defined variant, but *Microsoft no longer uses it*
+and in MODERN implementations do the endianness flip [ToggleUuidMsGuid] of (USUALLY) a UUIDv4.
+
+See [DetectMsGuid] for a more in-depth result that will let you use the confidence level directly,
+and for details on the weird things that can go wrong with this guesswork.
+
+Note that this won't be 100% reliable due to math things, but it should be reliable enough most of the time.
+
+See also [MsGuidToUuid] and [UuidToMsGuid].
+*/
+func IsMsGuid(msGUID uuid.UUID, tgtVer uuid.Version) (isMs bool) {
+
+	var cmp int
+
+	if cmp, _ = DetectMsGuid(msGUID, tgtVer); cmp < -3 {
+		isMs = true
+	}
+
+	return
+}
+
+/*
+IsNcs is shorthand for:
+
+	isNcs = u.Variant() == uuid.Reserved
+
+See also the notes in [IsRfc].
+*/
+func IsNcs(u uuid.UUID) (isNcs bool) {
+
+	// https://archive.org/details/networkcomputing0000zahn/page/10/mode/1up
+
+	isNcs = u.Variant() == uuid.Reserved
+
+	return
+}
+
+/*
+IsNilUUID returns `true` if the specified UUID is explicitly an RFC-defined
+"Nil UUID".
+
+For details, see RFC 9562 [§ 5.9].
+
+[§ 5.9]: https://datatracker.ietf.org/doc/html/rfc9562#section-5.9
+*/
+func IsNilUUID(u uuid.UUID) (isNil bool) {
+
+	isNil = u == uuid.Nil
+
+	return
+}
+
+/*
+IsRfc returns `true` if the specified UUID is a proper standard RFC UUID.
+
+Because Microsoft is insane, rfc will be false even if it's a (legacy) Microsoft form
+of an RFC UUID. Use [IsMsGuid] for that.
+
+In the special case of u being a valid NCS UUID, rfc will be false but gen will be [Rfc4122].
+This is because RFC 9652 deprecates the NCS UUID. See [IsNcs].
+(You are highly unlikely to encounter an NCS UUID "in the wild" unless you are receiving
+a UUID from someone who severely misunderstands that UUIDs are structured/versioned/typed
+and thinks they're just random byes in hex with hyphens in certain places.)
+(They aren't that, if you're one of those someones.)
+
+Nil UUID ([IsNilUUID]) and Max UUID ([IsMaxUUID]) return true with RFCs 4122 and RFC 9562 respectively.
+*/
+func IsRfc(u uuid.UUID) (rfc bool, gen RfcGen) {
+
+	if IsNilUUID(u) {
+		rfc = true
+		gen = Rfc4122
+		return
+	}
+	if IsMaxUUID(u) {
+		rfc = true
+		gen = Rfc9562
+		return
+	}
+	if IsNcs(u) {
+		gen = Rfc4122
+		return
+	}
+
+	// TODO: Are there any sub-version checks that can be applied?
+	switch u.Variant() {
+	case uuid.Invalid, uuid.Microsoft, uuid.Future:
+		return
+	case uuid.RFC4122:
+		if !(0x01 <= u.Version() && u.Version() <= 0x08) {
+			return
+		}
+		rfc = true
+		gen = Rfc4122
+		// 4122 only covers UUIDv1 through UUIDv5.
+		if 0x06 <= u.Version() && u.Version() <= 0x08 {
+			gen = Rfc9562
+		}
+	default: // Safety net in case upstream adds a uuid.RFC9562 variant or something.
+		if !(0x01 <= u.Version() && u.Version() <= 0x08) {
+			return
+		}
+		if u.Variant() < uuid.Future {
+			return
+		}
+		rfc = true
+		gen = RfcNone
+		// 4122 only covers UUIDv1 through UUIDv5.
+		if 0x06 <= u.Version() && u.Version() <= 0x08 {
+			gen = Rfc9562
+		}
+	}
+
+	return
+}
+
+/*
+IsValid indicates if the given [uuid.UUID] strictly conforms to RFC.
+
+A Nil UUID (as in RFC 9562 [§ 5.9], not a `nil` *uuid.UUID) will return `true`
+as it IS technically defined per RFC despite not conforming to a version.
+Use [IsNilUUID] to further determine that.
+
+Likewise, a Max UUID (RFC 9562 [§ 5.10]) will return `true` as it is also
+defined per RFC despite not conforming to a version.
+Use [IsMaxUUID] to further determine that.
+
+Microsoft GUIDs will always return false since they defy RFC.
+Use [IsMsGuid] to check for that condition.
+
+[§ 5.9]: https://datatracker.ietf.org/doc/html/rfc9562#section-5.9
+[§ 5.10]: https://datatracker.ietf.org/doc/html/rfc9562#section-5.10
+*/
+func IsValid(u uuid.UUID) (valid bool) {
+
+	if IsNilUUID(u) {
+		valid = true
+		return
+	}
+	if IsMaxUUID(u) {
+		valid = true
+		return
+	}
+
+	switch u.Variant() {
+	case uuid.Invalid, uuid.Reserved, uuid.Microsoft, uuid.Future:
+		return
+	case uuid.RFC4122:
+		valid = true
+	// TODO: If they add an RFC9562 or something, need a case here.
+	default:
+		return
+	}
+
+	// If we got here, it *should* be RFC.
+	if valid, _ = IsRfc(u); !valid {
+		return
+	}
+
+	return
+}
+
+/*
+MsGuidToUuid converts a Microsoft GUID to a UUID.
+
+If [IsMsGuid] is false for msGUID, u will be equal to msGUID.
+
+See [UuidToMsGuid] for the inverse, and [IsRfc] to check
+if the result is a strictly conforming UUID.
+*/
+func MsGuidToUuid(msGUID uuid.UUID) (u uuid.UUID) {
+
+	if !IsMsGuid(msGUID, 0x00) {
+		u = msGUID
+		return
+	}
+	u = ToggleUuidMsGuid(msGUID)
+
+	return
+}
+
+/*
+ToggleUuidMsGuid switches the src to it's "other" format:
+
+	* if it's a Microsoft GUID, it will be converted to a UUID
+	* if it's a UUID, it will be converted to a Microsoft GUID
+
+No detection ([IsRfc], [IsMsGuid], etc.) nor validation/verification ([IsValid]) is performed,
+which is why this is a "toggle" - it just flips some endianness for certain byte ranges.
+
+If you prefer something a little more explicit, see [MsGuidToUuid] and/or [UuidToMsGuid].
+Alternatively call [IsMsGuid] or [IsRfc] directly.
+*/
+func ToggleUuidMsGuid(orig uuid.UUID) (converted uuid.UUID) {
+
+	var cb [16]byte
+	var ob [16]byte = orig
+
+	// Can just directly map the allocations;
+	// the operation is the exact same regardless of whether the original is RFC and target is MS or vice versa.
+	cb = [16]byte{
+		// THESE GET ENDIAN-SWAPPED
+		ob[3], ob[2], ob[1], ob[0], // "A"
+		ob[5], ob[4], // "B"
+		ob[7], ob[6], // "C"
+		// THESE STAY THE SAME (should be BE for both)
+		ob[8], ob[9], ob[10], ob[11], // "D"
+		ob[12], ob[13], ob[14], ob[15], // "E"
+	}
+
+	converted = uuid.UUID(cb)
+
+	return
+}
+
+/*
+UuidToMsGuid converts a UUID to a Microsoft GUID.
+
+If [DetectMsGuid] indicates a good likelihood for u already being a Microsoft GUID
+(greater than or equal) to [MsGuidThreshold], msGUID will be equal to u.
+(If it detects it as unflipped endianness, it will automatically be flipped by this function.)
+
+See [MsGuidToUuid] for the inverse.
+*/
+func UuidToMsGuid(u uuid.UUID) (msGUID uuid.UUID) {
+
+	var msCmp int
+	var flipped int
+
+	if msCmp, flipped = DetectMsGuid(u, 0x00); msCmp >= MsGuidThreshold && msCmp > flipped {
+		msGUID = u
+		return
+	}
+	msGUID = ToggleUuidMsGuid(u)
+
+	return
+}

uuidx/funcs_rfcgen.go

@@ -0,0 +1,22 @@
+package uuidx
+
+// String conforms an [RfcGen] to a [fmt.Stringer] interface.
+func (g *RfcGen) String() (s string) {
+
+	if g == nil {
+		s = "UNSPECIFIED_NIL"
+	}
+
+	switch *g {
+	case RfcNone:
+		s = "INVALID"
+	case Rfc4122:
+		s = "RFC 4122"
+	case Rfc9562:
+		s = "RFC 9562"
+	default:
+		s = "UNKNOWN"
+	}
+
+	return
+}

uuidx/types.go

@@ -0,0 +1,5 @@
+package uuidx
+
+type (
+	RfcGen uint8
+)