gen_const.go

package generator

import (
	"bytes"
	"fmt"
	"io"
	"path/filepath"

	tl "github.com/astro-cn/c-for-go/translator"
)

func (gen *Generator) writeDefinesGroup(wr io.Writer, defines []*tl.CDecl) (n int) {
	writeStartConst(wr)
	for _, decl := range defines {
		if !decl.IsDefine {
			continue
		}
		name := gen.tr.TransformName(tl.TargetConst, decl.Name)
		if decl.Value == nil && string(name) == decl.Expression {
			continue
		}
		fmt.Fprintf(wr, "// %s as defined in %s\n", name,
			filepath.ToSlash(gen.tr.SrcLocation(tl.TargetConst, decl.Name, decl.Position)))

		if decl.Value != nil {
			fmt.Fprintf(wr, "%s = %v", name, decl.Value)
		} else if len(decl.Expression) > 0 {
			fmt.Fprintf(wr, "%s = %s", name, decl.Expression)
		} else {
			// In this case, it's nil or the expression is zero length.
			// fmt.Fprint(wr, name)
		}
		writeSpace(wr, 1)
		n++
	}
	writeEndConst(wr)
	return
}

func (gen *Generator) writeConstDeclaration(wr io.Writer, decl *tl.CDecl) {
	declName := gen.tr.TransformName(tl.TargetConst, decl.Name)
	if decl.Value == nil && string(declName) == decl.Expression {
		return
	}
	fmt.Fprintf(wr, "// %s as declared in %s\n", declName,
		filepath.ToSlash(gen.tr.SrcLocation(tl.TargetConst, decl.Name, decl.Position)))
	goSpec := gen.tr.TranslateSpec(decl.Spec)

	if decl.Value != nil {
		fmt.Fprintf(wr, "const %s %s = %v", declName, goSpec, decl.Value)
		return
	} else if len(decl.Expression) > 0 {
		fmt.Fprintf(wr, "const %s %s = %s", declName, goSpec, decl.Expression)
		return
	}
	// const must have values, otherwise variable
	fmt.Fprintf(wr, "var %s %s", declName, goSpec)
}

func (gen *Generator) expandEnumAnonymous(wr io.Writer, decl *tl.CDecl, namesSeen map[string]bool) {
	var typeName []byte
	var hasType bool
	if decl.IsTypedef {
		if typeName = gen.tr.TransformName(tl.TargetType, decl.Name); len(typeName) > 0 {
			hasType = true
		}
	}

	spec := decl.Spec.(*tl.CEnumSpec)
	if hasType {
		enumType := gen.tr.TranslateSpec(&spec.Type)
		fmt.Fprintf(wr, "// %s as declared in %s\n", typeName,
			filepath.ToSlash(gen.tr.SrcLocation(tl.TargetConst, decl.Name, decl.Position)))
		fmt.Fprintf(wr, "type %s %s\n", typeName, enumType)
		writeSpace(wr, 1)
		fmt.Fprintf(wr, "// %s enumeration from %s\n", typeName,
			filepath.ToSlash(gen.tr.SrcLocation(tl.TargetConst, decl.Name, decl.Position)))
	}
	writeStartConst(wr)
	for i, m := range spec.Members {
		if !gen.tr.IsAcceptableName(tl.TargetConst, m.Name) {
			continue
		}
		mName := gen.tr.TransformName(tl.TargetConst, m.Name)
		if len(mName) == 0 {
			continue
		} else if namesSeen[string(mName)] {
			continue
		} else {
			namesSeen[string(mName)] = true
		}
		if !hasType {
			fmt.Fprintf(wr, "// %s as declared in %s\n", mName,
				filepath.ToSlash(gen.tr.SrcLocation(tl.TargetConst, m.Name, m.Position)))
		}
		switch {
		case m.Value != nil:
			if hasType {
				fmt.Fprintf(wr, "%s %s = %s\n", mName, typeName, iotaOnZero(i, m.Value))
				continue
			}
			fmt.Fprintf(wr, "%s = %s\n", mName, iotaOnZero(i, m.Value))
		case len(m.Expression) > 0:
			if hasType {
				fmt.Fprintf(wr, "%s %s = %s\n", mName, typeName, iotaOnZero(i, m.Expression))
				continue
			}
			fmt.Fprintf(wr, "%s = %s\n", mName, iotaOnZero(i, m.Expression))
		default:
			if i == 0 && hasType {
				fmt.Fprintf(wr, "%s %s = iota\n", mName, typeName)
				continue
			} else if i == 0 {
				fmt.Fprintf(wr, "%s = iota\n", mName)
			}
			fmt.Fprintf(wr, "%s\n", mName)
		}
	}
	writeEndConst(wr)
	writeSpace(wr, 1)
}

func (gen *Generator) expandEnum(wr io.Writer, decl *tl.CDecl, namesSeen map[string]bool) {
	var declName []byte
	var isTypedef bool
	if decl.IsTypedef {
		if declName = gen.tr.TransformName(tl.TargetType, decl.Name); len(declName) > 0 {
			isTypedef = true
		}
	}

	spec := decl.Spec.(*tl.CEnumSpec)
	tagName := gen.tr.TransformName(tl.TargetType, decl.Spec.GetBase())
	enumType := gen.tr.TranslateSpec(&spec.Type)
	fmt.Fprintf(wr, "// %s as declared in %s\n", tagName,
		filepath.ToSlash(gen.tr.SrcLocation(tl.TargetConst, decl.Name, decl.Position)))
	fmt.Fprintf(wr, "type %s %s\n", tagName, enumType)
	writeSpace(wr, 1)
	if isTypedef {
		if !bytes.Equal(tagName, declName) && len(declName) > 0 {
			// alias type decl name to the tag
			fmt.Fprintf(wr, "// %s as declared in %s\n", declName,
				filepath.ToSlash(gen.tr.SrcLocation(tl.TargetConst, decl.Name, decl.Position)))
			fmt.Fprintf(wr, "type %s %s", declName, tagName)
			writeSpace(wr, 1)
		}
	}

	fmt.Fprintf(wr, "// %s enumeration from %s\n", tagName,
		filepath.ToSlash(gen.tr.SrcLocation(tl.TargetConst, decl.Name, decl.Position)))
	writeStartConst(wr)
	for i, m := range spec.Members {
		if !gen.tr.IsAcceptableName(tl.TargetConst, m.Name) {
			continue
		}
		mName := gen.tr.TransformName(tl.TargetConst, m.Name)
		if len(mName) == 0 {
			continue
		} else if namesSeen[string(mName)] {
			continue
		} else {
			namesSeen[string(mName)] = true
		}
		switch {
		case m.Value != nil:
			fmt.Fprintf(wr, "%s %s = %v\n", mName, declName, iotaOnZero(i, m.Value))
		case len(m.Expression) > 0:
			fmt.Fprintf(wr, "%s %s = %v\n", mName, declName, iotaOnZero(i, m.Expression))
		default:
			if i == 0 {
				fmt.Fprintf(wr, "%s %s = iota\n", mName, declName)
				continue
			}
			fmt.Fprintf(wr, "%s\n", mName)
		}
	}
	writeEndConst(wr)
	writeSpace(wr, 1)
}

func iotaOnZero(i int, v interface{}) string {
	result := fmt.Sprintf("%v", v)
	if i == 0 {
		if result == "0" {
			return "iota"
		}
	}
	return result
}

func writeStartConst(wr io.Writer) {
	fmt.Fprintln(wr, "const (")
}

func writeEndConst(wr io.Writer) {
	fmt.Fprintln(wr, ")")
}