vendor tsgo

tools/tsgo/internal/api/encoder/stringtable.go

@@ -0,0 +1,68 @@
+package encoder
+
+import (
+	"strings"
+
+	"github.com/microsoft/typescript-go/internal/ast"
+)
+
+type stringTable struct {
+	fileText     string
+	otherStrings *strings.Builder
+	// offsets are pos/end pairs
+	offsets []uint32
+}
+
+func newStringTable(fileText string, stringCount int) *stringTable {
+	builder := &strings.Builder{}
+	return &stringTable{
+		fileText:     fileText,
+		otherStrings: builder,
+		offsets:      make([]uint32, 0, stringCount*2),
+	}
+}
+
+func (t *stringTable) add(text string, kind ast.Kind, pos int, end int) uint32 {
+	index := uint32(len(t.offsets))
+	if kind == ast.KindSourceFile {
+		t.offsets = append(t.offsets, uint32(pos), uint32(end))
+		return index
+	}
+	length := len(text)
+	if end-pos > 0 && end <= len(t.fileText) {
+		// pos includes leading trivia, but we can usually infer the actual start of the
+		// string from the kind and end
+		endOffset := 0
+		if kind == ast.KindStringLiteral || kind == ast.KindTemplateTail || kind == ast.KindNoSubstitutionTemplateLiteral {
+			endOffset = 1
+		}
+		end = end - endOffset
+		start := end - length
+		fileSlice := t.fileText[start:end]
+		if fileSlice == text {
+			t.offsets = append(t.offsets, uint32(start), uint32(end))
+			return index
+		}
+	}
+	// no exact match, so we need to add it to the string table
+	offset := len(t.fileText) + t.otherStrings.Len()
+	t.otherStrings.WriteString(text)
+	t.offsets = append(t.offsets, uint32(offset), uint32(offset+length))
+	return index
+}
+
+func (t *stringTable) encode() []byte {
+	result := make([]byte, 0, t.encodedLength())
+	result = appendUint32s(result, t.offsets...)
+	result = append(result, t.fileText...)
+	result = append(result, t.otherStrings.String()...)
+	return result
+}
+
+func (t *stringTable) stringLength() int {
+	return len(t.fileText) + t.otherStrings.Len()
+}
+
+func (t *stringTable) encodedLength() int {
+	return len(t.offsets)*4 + len(t.fileText) + t.otherStrings.Len()
+}