mirror of
https://github.com/golang/go
synced 2024-10-03 09:21:21 -06:00
fmt.Scan: refactor the implementation so format-driven and normal scanning use the same function.
simplifies the code significantly. Still TODO: - proper format handling - strings R=rsc CC=golang-dev https://golang.org/cl/1432041
This commit is contained in:
Rob Pike
parent
e6600ea17d
commit
8af4acf59d
@ -251,9 +251,23 @@ var intBits = uint(reflect.Typeof(int(0)).Size() * 8)
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var uintptrBits = uint(reflect.Typeof(int(0)).Size() * 8)
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var complexError = os.ErrorString("syntax error scanning complex number")
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// okVerb verifies that the verb is present in the list, setting s.err appropriately if not.
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func (s *ss) okVerb(verb int, okVerbs, typ string) bool {
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if s.err != nil { // don't overwrite error
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return false
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}
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for _, v := range okVerbs {
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if v == verb {
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return true
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}
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}
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s.err = os.ErrorString("bad verb %" + string(verb) + " for " + typ)
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return false
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}
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// scanBool converts the token to a boolean value.
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func (s *ss) scanBool(tok string) bool {
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if s.err != nil {
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func (s *ss) scanBool(verb int, tok string) bool {
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if !s.okVerb(verb, "tv", "boolean") {
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return false
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}
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var b bool
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@ -261,9 +275,27 @@ func (s *ss) scanBool(tok string) bool {
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return b
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}
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func (s *ss) getBase(verb int) int {
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s.okVerb(verb, "bdoxXv", "integer") // sets s.err
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base := 10
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switch verb {
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case 'b':
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base = 2
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case 'o':
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base = 8
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case 'x', 'X':
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base = 16
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}
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return base
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}
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// convertInt returns the value of the integer
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// stored in the token, checking for overflow. Any error is stored in s.err.
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func (s *ss) convertInt(tok string, bitSize uint, base int) (i int64) {
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func (s *ss) convertInt(verb int, tok string, bitSize uint) (i int64) {
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base := s.getBase(verb)
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if s.err != nil {
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return 0
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}
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i, s.err = strconv.Btoi64(tok, base)
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x := (i << (64 - bitSize)) >> (64 - bitSize)
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if x != i {
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@ -274,7 +306,11 @@ func (s *ss) convertInt(tok string, bitSize uint, base int) (i int64) {
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// convertUint returns the value of the unsigned integer
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// stored in the token, checking for overflow. Any error is stored in s.err.
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func (s *ss) convertUint(tok string, bitSize uint, base int) (i uint64) {
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func (s *ss) convertUint(verb int, tok string, bitSize uint) (i uint64) {
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base := s.getBase(verb)
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if s.err != nil {
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return 0
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}
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i, s.err = strconv.Btoui64(tok, base)
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x := (i << (64 - bitSize)) >> (64 - bitSize)
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if x != i {
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@ -283,79 +319,6 @@ func (s *ss) convertUint(tok string, bitSize uint, base int) (i uint64) {
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return i
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}
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// scanInteger converts the token to an integer in the appropriate base
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// and stores the result according to the type of the field.
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func (s *ss) scanInteger(tok string, field interface{}, base int) {
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switch v := field.(type) {
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case *int:
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*v = int(s.convertInt(tok, intBits, base))
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return
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case *int8:
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*v = int8(s.convertInt(tok, 8, base))
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return
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case *int16:
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*v = int16(s.convertInt(tok, 16, base))
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return
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case *int32:
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*v = int32(s.convertInt(tok, 32, base))
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return
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case *int64:
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*v = s.convertInt(tok, 64, base)
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return
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case *uint:
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*v = uint(s.convertUint(tok, intBits, base))
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return
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case *uint8:
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*v = uint8(s.convertUint(tok, 8, base))
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return
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case *uint16:
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*v = uint16(s.convertUint(tok, 16, base))
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return
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case *uint32:
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*v = uint32(s.convertUint(tok, 32, base))
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return
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case *uint64:
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*v = uint64(s.convertUint(tok, 64, base))
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return
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case *uintptr:
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*v = uintptr(s.convertUint(tok, uintptrBits, base))
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return
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}
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// Not a basic type; probably a renamed type. We need to use reflection.
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v := reflect.NewValue(field)
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ptr, ok := v.(*reflect.PtrValue)
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if !ok {
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s.typeError(field, "integer")
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return
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}
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switch v := ptr.Elem().(type) {
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case *reflect.IntValue:
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v.Set(int(s.convertInt(tok, intBits, base)))
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case *reflect.Int8Value:
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v.Set(int8(s.convertInt(tok, 8, base)))
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case *reflect.Int16Value:
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v.Set(int16(s.convertInt(tok, 16, base)))
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case *reflect.Int32Value:
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v.Set(int32(s.convertInt(tok, 32, base)))
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case *reflect.Int64Value:
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v.Set(s.convertInt(tok, 64, base))
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case *reflect.UintValue:
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v.Set(uint(s.convertUint(tok, intBits, base)))
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case *reflect.Uint8Value:
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v.Set(uint8(s.convertUint(tok, 8, base)))
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case *reflect.Uint16Value:
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v.Set(uint16(s.convertUint(tok, 16, base)))
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case *reflect.Uint32Value:
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v.Set(uint32(s.convertUint(tok, 32, base)))
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case *reflect.Uint64Value:
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v.Set(s.convertUint(tok, 64, base))
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case *reflect.UintptrValue:
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v.Set(uintptr(s.convertUint(tok, uintptrBits, base)))
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default:
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s.err = os.ErrorString("internal error: unknown int type")
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}
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}
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// complexParts returns the strings representing the real and imaginary parts of the string.
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func (s *ss) complexParts(str string) (real, imag string) {
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if len(str) > 2 && str[0] == '(' && str[len(str)-1] == ')' {
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@ -436,9 +399,6 @@ func (s *ss) scanFloat64(str string) float64 {
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// If we're reading complex64, atof will parse float32s and convert them
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// to float64's to avoid reproducing this code for each complex type.
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func (s *ss) scanComplex(tok string, atof func(*ss, string) float64) complex128 {
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if s.err != nil {
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return 0
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}
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sreal, simag := s.complexParts(tok)
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if s.err != nil {
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return 0
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@ -455,15 +415,22 @@ func (s *ss) scanComplex(tok string, atof func(*ss, string) float64) complex128
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return cmplx(real, imag)
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}
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const floatVerbs = "eEfFgGv"
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// scanOne scans a single value, deriving the scanner from the type of the argument.
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func (s *ss) scanOne(field interface{}) {
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func (s *ss) scanOne(verb int, field interface{}) {
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// If the parameter has its own Scan method, use that.
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if v, ok := field.(Scanner); ok {
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s.err = v.Scan(s)
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return
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}
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tok := s.token()
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if s.err != nil {
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return
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}
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switch v := field.(type) {
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case *bool:
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*v = s.scanBool(tok)
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*v = s.scanBool(verb, tok)
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case *complex:
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*v = complex(s.scanComplex(tok, (*ss).scanFloat))
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case *complex64:
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@ -471,62 +438,73 @@ func (s *ss) scanOne(field interface{}) {
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case *complex128:
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*v = s.scanComplex(tok, (*ss).scanFloat64)
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case *int:
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*v = int(s.convertInt(tok, intBits, 10))
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*v = int(s.convertInt(verb, tok, intBits))
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case *int8:
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*v = int8(s.convertInt(tok, 8, 10))
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*v = int8(s.convertInt(verb, tok, 8))
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case *int16:
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*v = int16(s.convertInt(tok, 16, 10))
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*v = int16(s.convertInt(verb, tok, 16))
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case *int32:
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*v = int32(s.convertInt(tok, 32, 10))
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*v = int32(s.convertInt(verb, tok, 32))
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case *int64:
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*v = s.convertInt(tok, intBits, 10)
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*v = s.convertInt(verb, tok, intBits)
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case *uint:
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*v = uint(s.convertUint(tok, intBits, 10))
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*v = uint(s.convertUint(verb, tok, intBits))
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case *uint8:
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*v = uint8(s.convertUint(tok, 8, 10))
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*v = uint8(s.convertUint(verb, tok, 8))
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case *uint16:
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*v = uint16(s.convertUint(tok, 16, 10))
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*v = uint16(s.convertUint(verb, tok, 16))
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case *uint32:
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*v = uint32(s.convertUint(tok, 32, 10))
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*v = uint32(s.convertUint(verb, tok, 32))
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case *uint64:
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*v = s.convertUint(tok, 64, 10)
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*v = s.convertUint(verb, tok, 64)
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case *uintptr:
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*v = uintptr(s.convertUint(tok, uintptrBits, 10))
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*v = uintptr(s.convertUint(verb, tok, uintptrBits))
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case *float:
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if s.err == nil {
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if s.okVerb(verb, floatVerbs, "float") {
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*v, s.err = strconv.Atof(tok)
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} else {
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*v = 0
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}
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case *float32:
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if s.err == nil {
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if s.okVerb(verb, floatVerbs, "float32") {
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*v, s.err = strconv.Atof32(tok)
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} else {
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*v = 0
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}
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case *float64:
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if s.err == nil {
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if s.okVerb(verb, floatVerbs, "float64") {
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*v, s.err = strconv.Atof64(tok)
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} else {
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*v = 0
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}
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case *string:
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*v = tok
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default:
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t := reflect.Typeof(v)
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str := t.String()
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ptr, ok := t.(*reflect.PtrType)
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val := reflect.NewValue(v)
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ptr, ok := val.(*reflect.PtrValue)
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if !ok {
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s.err = os.ErrorString("Scan: type not a pointer: " + str)
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s.err = os.ErrorString("Scan: type not a pointer: " + val.Type().String())
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return
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}
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switch ptr.Elem().(type) {
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case *reflect.IntType, *reflect.Int8Type, *reflect.Int16Type, *reflect.Int32Type, *reflect.Int64Type:
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s.scanInteger(tok, v, 10)
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case *reflect.UintType, *reflect.Uint8Type, *reflect.Uint16Type, *reflect.Uint32Type, *reflect.Uint64Type, *reflect.UintptrType:
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s.scanInteger(tok, v, 10)
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switch v := ptr.Elem().(type) {
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case *reflect.IntValue:
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v.Set(int(s.convertInt(verb, tok, intBits)))
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case *reflect.Int8Value:
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v.Set(int8(s.convertInt(verb, tok, 8)))
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case *reflect.Int16Value:
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v.Set(int16(s.convertInt(verb, tok, 16)))
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case *reflect.Int32Value:
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v.Set(int32(s.convertInt(verb, tok, 32)))
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case *reflect.Int64Value:
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v.Set(s.convertInt(verb, tok, 64))
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case *reflect.UintValue:
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v.Set(uint(s.convertUint(verb, tok, intBits)))
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case *reflect.Uint8Value:
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v.Set(uint8(s.convertUint(verb, tok, 8)))
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case *reflect.Uint16Value:
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v.Set(uint16(s.convertUint(verb, tok, 16)))
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case *reflect.Uint32Value:
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v.Set(uint32(s.convertUint(verb, tok, 32)))
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case *reflect.Uint64Value:
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v.Set(s.convertUint(verb, tok, 64))
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case *reflect.UintptrValue:
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v.Set(uintptr(s.convertUint(verb, tok, uintptrBits)))
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default:
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s.err = os.ErrorString("Scan: can't handle type: " + t.String())
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s.err = os.ErrorString("Scan: can't handle type: " + val.Type().String())
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}
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}
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}
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@ -535,15 +513,7 @@ func (s *ss) scanOne(field interface{}) {
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// At the moment, it handles only pointers to basic types.
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func (s *ss) doScan(a []interface{}) int {
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for fieldnum, field := range a {
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// If the parameter has its own Scan method, use that.
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if v, ok := field.(Scanner); ok {
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s.err = v.Scan(s)
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if s.err != nil {
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return fieldnum
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}
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continue
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}
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s.scanOne(field)
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s.scanOne('v', field)
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if s.err != nil {
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return fieldnum
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}
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@ -592,48 +562,18 @@ func (s *ss) doScanf(format string, a []interface{}) int {
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// TODO: WHAT NOW?
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continue
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}
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if fieldnum >= len(a) { // out of operands
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s.err = os.ErrorString("too few operands for format %" + format[i-w:])
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return fieldnum
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break
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}
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field := a[fieldnum]
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fieldnum++
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// If the parameter has its own Scan method, use that.
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if v, ok := field.(Scanner); ok {
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s.err = v.Scan(s)
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if s.err != nil {
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return fieldnum - 1
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}
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continue
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}
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if c == 'v' {
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// Default format works; just call doScan, but note that it will scan for the token
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s.scanOne(field)
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} else {
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tok := s.token()
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switch c {
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case 't':
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if v, ok := field.(*bool); ok {
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*v = s.scanBool(tok)
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} else {
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s.typeError(field, "boolean")
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}
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case 'b':
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s.scanInteger(tok, field, 2)
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case 'o':
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s.scanInteger(tok, field, 8)
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case 'd':
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s.scanInteger(tok, field, 10)
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case 'x', 'X':
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s.scanInteger(tok, field, 16)
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default:
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s.err = os.ErrorString("unknown scanning verb %" + format[i-w:])
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}
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if s.err != nil {
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return fieldnum - 1
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}
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s.scanOne(c, field)
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if s.err != nil {
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break
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}
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fieldnum++
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}
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return fieldnum
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}
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@ -170,15 +170,15 @@ var scanfTests = []ScanfTest{
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// Renamed types
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ScanfTest{"%v", "101\n", &renamedIntVal, renamedInt(101)},
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ScanfTest{"%d", "102\n", &renamedIntVal, renamedInt(102)},
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ScanfTest{"%o", "0146\n", &renamedIntVal, renamedInt(102)},
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ScanfTest{"%v", "103\n", &renamedUintVal, renamedUint(103)},
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ScanfTest{"%d", "104\n", &renamedUintVal, renamedUint(104)},
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ScanfTest{"%d", "105\n", &renamedInt8Val, renamedInt8(105)},
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ScanfTest{"%d", "106\n", &renamedInt16Val, renamedInt16(106)},
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ScanfTest{"%d", "107\n", &renamedInt32Val, renamedInt32(107)},
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ScanfTest{"%d", "108\n", &renamedInt64Val, renamedInt64(108)},
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ScanfTest{"%d", "109\n", &renamedUint8Val, renamedUint8(109)},
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ScanfTest{"%d", "110\n", &renamedUint16Val, renamedUint16(110)},
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ScanfTest{"%x", "6D\n", &renamedUint8Val, renamedUint8(109)},
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ScanfTest{"%o", "0156\n", &renamedUint16Val, renamedUint16(110)},
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ScanfTest{"%d", "111\n", &renamedUint32Val, renamedUint32(111)},
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ScanfTest{"%d", "112\n", &renamedUint64Val, renamedUint64(112)},
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ScanfTest{"%d", "113\n", &renamedUintptrVal, renamedUintptr(113)},
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