Initial commit

util/litconv.go

@@ -0,0 +1,121 @@
+
+//Copyright 2013 Vastech SA (PTY) LTD
+//
+//   Licensed under the Apache License, Version 2.0 (the "License");
+//   you may not use this file except in compliance with the License.
+//   You may obtain a copy of the License at
+//
+//       http://www.apache.org/licenses/LICENSE-2.0
+//
+//   Unless required by applicable law or agreed to in writing, software
+//   distributed under the License is distributed on an "AS IS" BASIS,
+//   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//   See the License for the specific language governing permissions and
+//   limitations under the License.
+
+package util
+
+import (
+	"fmt"
+	"strconv"
+	"unicode"
+	"unicode/utf8"
+)
+
+/* Interface */
+
+/*
+Convert the literal value of a scanned token to rune
+*/
+func RuneValue(lit []byte) rune {
+	if lit[1] == '\\' {
+		return escapeCharVal(lit)
+	}
+	r, size := utf8.DecodeRune(lit[1:])
+	if size != len(lit)-2 {
+		panic(fmt.Sprintf("Error decoding rune. Lit: %s, rune: %d, size%d\n", lit, r, size))
+	}
+	return r
+}
+
+/*
+Convert the literal value of a scanned token to int64
+*/
+func IntValue(lit []byte) (int64, error) {
+	return strconv.ParseInt(string(lit), 10, 64)
+}
+
+/*
+Convert the literal value of a scanned token to uint64
+*/
+func UintValue(lit []byte) (uint64, error) {
+	return strconv.ParseUint(string(lit), 10, 64)
+}
+
+/* Util */
+
+func escapeCharVal(lit []byte) rune {
+	var i, base, max uint32
+	offset := 2
+	switch lit[offset] {
+	case 'a':
+		return '\a'
+	case 'b':
+		return '\b'
+	case 'f':
+		return '\f'
+	case 'n':
+		return '\n'
+	case 'r':
+		return '\r'
+	case 't':
+		return '\t'
+	case 'v':
+		return '\v'
+	case '\\':
+		return '\\'
+	case '\'':
+		return '\''
+	case '0', '1', '2', '3', '4', '5', '6', '7':
+		i, base, max = 3, 8, 255
+	case 'x':
+		i, base, max = 2, 16, 255
+		offset++
+	case 'u':
+		i, base, max = 4, 16, unicode.MaxRune
+		offset++
+	case 'U':
+		i, base, max = 8, 16, unicode.MaxRune
+		offset++
+	default:
+		panic(fmt.Sprintf("Error decoding character literal: %s\n", lit))
+	}
+
+	var x uint32
+	for ; i > 0 && offset < len(lit)-1; i-- {
+		ch, size := utf8.DecodeRune(lit[offset:])
+		offset += size
+		d := uint32(digitVal(ch))
+		if d >= base {
+			panic(fmt.Sprintf("charVal(%s): illegal character (%c) in escape sequence. size=%d, offset=%d", lit, ch, size, offset))
+		}
+		x = x*base + d
+	}
+	if x > max || 0xD800 <= x && x < 0xE000 {
+		panic(fmt.Sprintf("Error decoding escape char value. Lit:%s, offset:%d, escape sequence is invalid Unicode code point\n", lit, offset))
+	}
+
+	return rune(x)
+}
+
+func digitVal(ch rune) int {
+	switch {
+	case '0' <= ch && ch <= '9':
+		return int(ch) - '0'
+	case 'a' <= ch && ch <= 'f':
+		return int(ch) - 'a' + 10
+	case 'A' <= ch && ch <= 'F':
+		return int(ch) - 'A' + 10
+	}
+	return 16 // larger than any legal digit val
+}

util/rune.go

@@ -0,0 +1,52 @@
+
+//Copyright 2013 Vastech SA (PTY) LTD
+//
+//   Licensed under the Apache License, Version 2.0 (the "License");
+//   you may not use this file except in compliance with the License.
+//   You may obtain a copy of the License at
+//
+//       http://www.apache.org/licenses/LICENSE-2.0
+//
+//   Unless required by applicable law or agreed to in writing, software
+//   distributed under the License is distributed on an "AS IS" BASIS,
+//   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//   See the License for the specific language governing permissions and
+//   limitations under the License.
+
+package util
+
+import (
+	"fmt"
+)
+
+func RuneToString(r rune) string {
+	if r >= 0x20 && r < 0x7f {
+		return fmt.Sprintf("'%c'", r)
+	}
+	switch r {
+	case 0x07:
+		return "'\\a'"
+	case 0x08:
+		return "'\\b'"
+	case 0x0C:
+		return "'\\f'"
+	case 0x0A:
+		return "'\\n'"
+	case 0x0D:
+		return "'\\r'"
+	case 0x09:
+		return "'\\t'"
+	case 0x0b:
+		return "'\\v'"
+	case 0x5c:
+		return "'\\\\\\'"
+	case 0x27:
+		return "'\\''"
+	case 0x22:
+		return "'\\\"'"
+	}
+	if r < 0x10000 {
+		return fmt.Sprintf("\\u%04x", r)
+	}
+	return fmt.Sprintf("\\U%08x", r)
+}