utf8

.github/workflows/ci.yml

@@ -0,0 +1,15 @@
+name: go test
+
+on: [push]
+
+jobs:
+  build:
+    runs-on: ubicloud-standard-2-ubuntu-2204-arm
+    steps:
+      - uses: actions/checkout@v4
+      - name: Setup Go
+        uses: actions/setup-go@v5
+        with:
+          go-version: "1.22"
+      - run: go get .
+      - run: go test

LICENSE

@@ -0,0 +1,14 @@
+BSD Zero Clause License
+
+Copyright (c) 2024 PeerDB
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+PERFORMANCE OF THIS SOFTWARE.

go.mod

@@ -0,0 +1,7 @@
+module github.com/PeerDB-io/gluautf8
+
+go 1.20
+
+require (
+	github.com/yuin/gopher-lua v1.1.1
+)

go.sum

@@ -0,0 +1,2 @@
+github.com/yuin/gopher-lua v1.1.1 h1:kYKnWBjvbNP4XLT3+bPEwAXJx262OhaHDWDVOPjL46M=
+github.com/yuin/gopher-lua v1.1.1/go.mod h1:GBR0iDaNXjAgGg9zfCvksxSRnQx76gclCIb7kdAd1Pw=

readme.md

@@ -0,0 +1,17 @@
+# utf8 for gopher-lua
+
+Implements Lua 5.3 [utf8](https://www.lua.org/manual/5.3/manual.html#6.5) for [gopher-lua](https://github.com/yuin/gopher-lua). To use, call
+```go
+import (
+	"github.com/PeerDB-io/gluautf8"
+)
+
+// add so that `local utf8 = require("utf8")` works
+L.PreloadModule("utf8", gluautf8.Loader)
+
+// or add to global env
+L.Push(ls.NewFunction(gluautf8.Loader))
+L.Call(0, 1)
+L.Env.RawSetString("utf8", L.Get(-1))
+L.Pop(1)
+```

utf8.go

@@ -0,0 +1,210 @@
+package gluautf8
+
+import (
+	"unicode/utf8"
+	"unsafe"
+
+	"github.com/yuin/gopher-lua"
+)
+
+var Utf8charpattern = lua.LString([]byte{
+	'[', 0, '-', 0x7f, 0xc2, '-', 0xf4, ']',
+	'[', 0x80, '-', 0xbf, ']', '*',
+})
+
+func Loader(ls *lua.LState) int {
+	m := ls.SetFuncs(ls.CreateTable(0, 6), map[string]lua.LGFunction{
+		"char":      Utf8char,
+		"codes":     Utf8codes,
+		"codepoint": Utf8codepoint,
+		"len":       Utf8len,
+		"offset":    Utf8offset,
+	})
+	m.RawSetString("charpattern", Utf8charpattern)
+	ls.Push(m)
+	return 1
+}
+
+func Utf8char(ls *lua.LState) int {
+	args := ls.GetTop()
+	b := make([]byte, 0, args)
+	for i := 1; i <= args; i += 1 {
+		r := rune(ls.CheckInt(i))
+		if r > '\U0010FFFF' {
+			ls.RaiseError("value out of range")
+		}
+		b = utf8.AppendRune(b, r)
+	}
+	ls.Push(lua.LString(unsafe.String(unsafe.SliceData(b), len(b))))
+	return 1
+}
+
+func utf8iter(ls *lua.LState) int {
+	s := ls.CheckString(1)
+	n := ls.CheckInt(2) - 1
+	if n < 0 {
+		n = 0
+	} else if n < len(s) {
+		for {
+			n += 1
+			if n == len(s) || utf8.RuneStart(s[n]) {
+				break
+			}
+		}
+	}
+	if n >= len(s) {
+		return 0
+	}
+	r, _ := utf8.DecodeRuneInString(s[n:])
+	if r == utf8.RuneError {
+		ls.RaiseError("invalid UTF-8 code")
+	}
+	ls.Push(lua.LNumber(n + 1))
+	ls.Push(lua.LNumber(r))
+	return 2
+}
+
+func Utf8codes(ls *lua.LState) int {
+	s := ls.CheckString(1)
+	ls.Push(ls.NewFunction(utf8iter))
+	ls.Push(lua.LString(s))
+	ls.Push(lua.LNumber(0))
+	return 3
+}
+
+func Utf8codepoint(ls *lua.LState) int {
+	s := ls.CheckString(1)
+	i := ls.OptInt(2, 1)
+	j := ls.OptInt(3, i)
+	i -= 1
+	if i < 0 {
+		i += len(s) + 1
+	}
+	if j < 0 {
+		j += len(s) + 1
+	}
+	if j <= i || i == len(s)+1 {
+		return 0
+	}
+	if i < 0 || i > len(s) || j < 1 || j > len(s) {
+		ls.RaiseError("position out of range")
+	}
+
+	n := 0
+	for {
+		if i >= j {
+			return n
+		}
+		n += 1
+		r, size := utf8.DecodeRuneInString(s[i:])
+		ls.Push(lua.LNumber(r))
+		i += size
+		if r == utf8.RuneError {
+			ls.RaiseError("invalid UTF-8 code")
+		}
+	}
+}
+
+func Utf8len(ls *lua.LState) int {
+	s := ls.CheckString(1)
+	i := int(ls.OptNumber(2, 1))
+	j := int(ls.OptNumber(3, -1))
+	if i < 0 {
+		i += len(s)
+	} else {
+		i -= 1
+	}
+	if j < 0 {
+		j += len(s) + 1
+	}
+	l := 0
+	for {
+		if i >= j {
+			ls.Push(lua.LNumber(l))
+			return 1
+		}
+		l += 1
+		r, size := utf8.DecodeRuneInString(s[i:])
+		if r == utf8.RuneError {
+			ls.Push(lua.LFalse)
+			ls.Push(lua.LNumber(i + 1))
+			return 2
+		}
+		i += size
+	}
+}
+
+func Utf8offset(ls *lua.LState) int {
+	s := ls.CheckString(1)
+	n := ls.CheckInt(2)
+	var i int
+	if n < 0 {
+		i = ls.OptInt(3, len(s)+1)
+	} else {
+		i = ls.OptInt(3, 1)
+	}
+	if i < 0 {
+		i += len(s)
+	} else {
+		i -= 1
+	}
+	if i < 0 || i > len(s) {
+		ls.RaiseError("position out of range")
+	}
+
+	if n == 0 {
+		if i < len(s) {
+			for i > 0 {
+				if utf8.RuneStart(s[i]) {
+					break
+				}
+				i -= 1
+			}
+		}
+		ls.Push(lua.LNumber(i + 1))
+		return 1
+	} else if i < len(s) && !utf8.RuneStart(s[i]) {
+		ls.RaiseError("initial position is a continuation byte")
+	}
+
+	if n > 0 {
+		n -= 1
+		for {
+			if n == 0 {
+				ls.Push(lua.LNumber(i + 1))
+				return 1
+			}
+			if i >= len(s) {
+				break
+			}
+			n -= 1
+			r, size := utf8.DecodeRuneInString(s[i:])
+			if r == utf8.RuneError {
+				ls.Push(lua.LFalse)
+				ls.Push(lua.LNumber(i + 1))
+				return 2
+			}
+			i += size
+		}
+	} else {
+		for {
+			if i <= 0 {
+				break
+			}
+			n += 1
+			r, size := utf8.DecodeLastRuneInString(s[:i])
+			if r == utf8.RuneError {
+				ls.Push(lua.LFalse)
+				ls.Push(lua.LNumber(i + 1))
+				return 2
+			}
+			i -= size
+			if n == 0 {
+				ls.Push(lua.LNumber(i + 1))
+				return 1
+			}
+		}
+	}
+	ls.Push(lua.LNil)
+	return 1
+}