feat: Add timezone location support

gnovm/stdlibs/generated.go

@@ -1017,6 +1017,40 @@ var nativeFuncs = [...]NativeFunc{
 			))
 		},
 	},
+	{
+		"time",
+		"loadFromEmbeddedTZData",
+		[]gno.FieldTypeExpr{
+			{Name: gno.N("p0"), Type: gno.X("string")},
+		},
+		[]gno.FieldTypeExpr{
+			{Name: gno.N("r0"), Type: gno.X("[]byte")},
+			{Name: gno.N("r1"), Type: gno.X("bool")},
+		},
+		false,
+		func(m *gno.Machine) {
+			b := m.LastBlock()
+			var (
+				p0  string
+				rp0 = reflect.ValueOf(&p0).Elem()
+			)
+
+			gno.Gno2GoValue(b.GetPointerTo(nil, gno.NewValuePathBlock(1, 0, "")).TV, rp0)
+
+			r0, r1 := libs_time.X_loadFromEmbeddedTZData(p0)
+
+			m.PushValue(gno.Go2GnoValue(
+				m.Alloc,
+				m.Store,
+				reflect.ValueOf(&r0).Elem(),
+			))
+			m.PushValue(gno.Go2GnoValue(
+				m.Alloc,
+				m.Store,
+				reflect.ValueOf(&r1).Elem(),
+			))
+		},
+	},
 }
 
 var initOrder = [...]string{

gnovm/stdlibs/time/timezoneinfo.gno

@@ -622,6 +622,8 @@ var errLocation = errors.New("time: invalid location name")
 
 var zoneinfo *string
 
+func loadFromEmbeddedTZData(name string) ([]byte, bool) // injected
+
 // XXX var zoneinfoOnce sync.Once
 
 // LoadLocation returns the Location with the given name.
@@ -640,41 +642,19 @@ var zoneinfo *string
 // - $GOROOT/lib/time/zoneinfo.zip
 // - the time/tzdata package, if it was imported
 func LoadLocation(name string) (*Location, error) {
-	panic("XXX LoadLocation not yet implemented")
-	/*
-		if name == "" || name == "UTC" {
-			return UTC, nil
-		}
-		if name == "Local" {
-			return Local, nil
-		}
-		if containsDotDot(name) || name[0] == '/' || name[0] == '\\' {
-			// No valid IANA Time Zone name contains a single dot,
-			// much less dot dot. Likewise, none begin with a slash.
-			return nil, errLocation
-		}
-		zoneinfoOnce.Do(func() {
-			env, _ := syscall.Getenv("ZONEINFO")
-			zoneinfo = &env
-		})
-		var firstErr error
-		if *zoneinfo != "" {
-			if zoneData, err := loadTzinfoFromDirOrZip(*zoneinfo, name); err == nil {
-				if z, err := LoadLocationFromTZData(name, zoneData); err == nil {
-					return z, nil
-				}
-				firstErr = err
-			} else if err != syscall.ENOENT {
-				firstErr = err
-			}
-		}
-		if z, err := loadLocation(name, platformZoneSources); err == nil {
-			return z, nil
-		} else if firstErr == nil {
-			firstErr = err
-		}
-		return nil, firstErr
-	*/
+	if name == "" || name == "UTC" {
+		return UTC, nil
+	}
+	if name == "Local" {
+		return Local, nil
+	}
+	if containsDotDot(name) || name[0] == '/' || name[0] == '\\' {
+		// No valid IANA Time Zone name contains a single dot,
+		// much less dot dot. Likewise, none begin with a slash.
+		return nil, errLocation
+	}
+
+	return loadLocation(name)
 }
 
 // containsDotDot reports whether s contains "..".

gnovm/stdlibs/time/tzdata.go

@@ -0,0 +1,74 @@
+package time
+
+// locationDefinitions are loaded during initialization using modified code from:
+// https://cs.opensource.google/go/go/+/refs/tags/go1.23.0:src/time/tzdata/tzdata.go
+var locationDefinitions = make(map[string][]byte)
+
+func init() {
+	const (
+		zecheader = 0x06054b50
+		zcheader  = 0x02014b50
+		ztailsize = 22
+
+		zheadersize = 30
+		zheader     = 0x04034b50
+	)
+
+	z := zipdata
+
+	idx := len(z) - ztailsize
+	n := get2s(z[idx+10:])
+	idx = get4s(z[idx+16:])
+
+	for i := 0; i < n; i++ {
+		// See time.loadTzinfoFromZip for zip entry layout.
+		if get4s(z[idx:]) != zcheader {
+			break
+		}
+		meth := get2s(z[idx+10:])
+		size := get4s(z[idx+24:])
+		namelen := get2s(z[idx+28:])
+		xlen := get2s(z[idx+30:])
+		fclen := get2s(z[idx+32:])
+		off := get4s(z[idx+42:])
+		zname := z[idx+46 : idx+46+namelen]
+		idx += 46 + namelen + xlen + fclen
+
+		if meth != 0 {
+			panic("unsupported compression for " + zname + " in embedded tzdata")
+		}
+
+		// See time.loadTzinfoFromZip for zip per-file header layout.
+		nidx := off
+		if get4s(z[nidx:]) != zheader ||
+			get2s(z[nidx+8:]) != meth ||
+			get2s(z[nidx+26:]) != namelen {
+			panic("corrupt embedded tzdata")
+		}
+
+		nxlen := get2s(z[nidx+28:])
+		nidx += 30 + namelen + nxlen
+		locationDefinitions[zname] = []byte(z[nidx : nidx+size])
+	}
+}
+
+// get4s returns the little-endian 32-bit value at the start of s.
+func get4s(s string) int {
+	if len(s) < 4 {
+		return 0
+	}
+	return int(s[0]) | int(s[1])<<8 | int(s[2])<<16 | int(s[3])<<24
+}
+
+// get2s returns the little-endian 16-bit value at the start of s.
+func get2s(s string) int {
+	if len(s) < 2 {
+		return 0
+	}
+	return int(s[0]) | int(s[1])<<8
+}
+
+func X_loadFromEmbeddedTZData(name string) ([]byte, bool) {
+	definition, ok := locationDefinitions[name]
+	return definition, ok
+}