From a047b135ca416584178a6adde64cc156ab637431 Mon Sep 17 00:00:00 2001 From: Luke Shumaker Date: Mon, 27 Jan 2020 19:35:32 -0500 Subject: Have RRD.UnmarshalBinary() avoid parsing things repeatedly --- rrdformat/rrdbinary/decode.go | 319 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 319 insertions(+) create mode 100644 rrdformat/rrdbinary/decode.go (limited to 'rrdformat/rrdbinary/decode.go') diff --git a/rrdformat/rrdbinary/decode.go b/rrdformat/rrdbinary/decode.go new file mode 100644 index 0000000..f3ae80e --- /dev/null +++ b/rrdformat/rrdbinary/decode.go @@ -0,0 +1,319 @@ +package rrdbinary + +import ( + "bytes" + "fmt" + "math" + "reflect" + "strconv" + "strings" +) + +type Decoder struct { + arch Architecture + pos int + data []byte +} + +func NewDecoder(arch Architecture, data []byte) *Decoder { + return &Decoder{ + arch: arch, + pos: 0, + data: data, + } +} + +type unmarshaler interface { + unmarshalRRD(d *Decoder, tag string) error +} + +func Unmarshal(arch Architecture, data []byte, ptr interface{}) error { + decoder := NewDecoder(arch, data) + if err := decoder.Decode(ptr, ""); err != nil { + return err + } + if err := decoder.Decode(&EOF{}, ""); err != nil { + return err + } + return nil +} + +func (d *Decoder) binError(ctxLen int, msg string) error { + return NewBinError(msg, d.data, d.pos, ctxLen) +} + +func (d *Decoder) binErrorf(ctxLen int, format string, a ...interface{}) error { + return d.binError(ctxLen, fmt.Sprintf(format, a...)) +} + +func (d *Decoder) Decode(ptr interface{}, tag string) error { + ptrValue := reflect.ValueOf(ptr) + if ptrValue.Kind() != reflect.Ptr { + return typeErrorf("ptr is a %v, not a pointer", ptrValue.Kind()) + } + return d.decode(ptrValue, tag) +} + +func (d *Decoder) decode(v reflect.Value, tag string) error { + if v.CanInterface() { + if u, ok := v.Interface().(unmarshaler); ok { + return u.unmarshalRRD(d, tag) + } + } + switch v.Type().Kind() { + case reflect.Struct: + return d.decodeStruct(v, tag) + case reflect.Array, reflect.Slice: + return d.decodeList(v, tag) + default: + return typeErrorf("invalid type for rrdbinary.Decoder: %v", v.Type()) + } +} + +func (d *Decoder) decodeStruct(v reflect.Value, tag string) error { + panicUnless(v.Kind() == reflect.Struct) + panicUnless(v.CanSet()) + + if tag != "" { + return typeErrorf("invalid rrdbinary struct tag for struct: %q", tag) + } + + for i := 0; i < v.NumField(); i++ { + fieldInfo := v.Type().Field(i) + tag := fieldInfo.Tag.Get("rrdbinary") + if tag == "-" { + continue + } + if err := d.decode(v.Field(i), tag); err != nil { + return fmt.Errorf("field %s: %w", fieldInfo.Name, err) + } + } + return nil +} + +func (d *Decoder) decodeList(v reflect.Value, tag string) error { + panicUnless(v.Kind() == reflect.Array || v.Kind() == reflect.Slice) + panicUnless(v.CanSet()) + + for i := 0; i < v.Len(); i++ { + if err := d.decode(v.Index(i), tag); err != nil { + return fmt.Errorf("index %d: %w", i, err) + } + } + return nil +} + +func (obj *String) unmarshalRRD(d *Decoder, tag string) error { + size := 0 + switch { + case tag == "": + // do nothing + case strings.HasPrefix(tag, "size="): + var err error + size, err = strconv.Atoi(strings.TrimPrefix(tag, "size=")) + if err != nil { + return typeErrorf("invalid rrdbinary struct tag for string: %q", tag) + } + default: + return typeErrorf("invalid rrdbinary struct tag for string: %q", tag) + } + + data := d.data[d.pos:] + if size > 0 { + if len(data) < size { + return d.binErrorf(size, "unexpected end-of-file in %d-byte string", size) + } + data = data[:size] + } + + nul := bytes.IndexByte(data, 0) + if nul < 0 { + if size > 0 { + return d.binErrorf(size, "missing null-terminator on %d-byte string", size) + } else { + return d.binErrorf(16, "unexpected end-of-file looking for null-terminator on string") + } + } + + if size > 0 { + for _, byte := range data[nul:] { + if byte != 0 { + return d.binErrorf(size, "garbage data after null-terminator on fixed %d-byte string", size) + } + } + } else { + size = nul + 1 + } + + *obj = String(data[:nul]) + d.pos += size + return nil +} + +func (obj *Float) unmarshalRRD(d *Decoder, tag string) error { + if d.arch.FloatWidth != 8 { + return archErrorf("rrdbinary does not support FloatWidth=%d; only supports 8", d.arch.FloatWidth) + } + if tag != "" { + return typeErrorf("invalid rrdbinary struct tag for float: %q", tag) + } + + data := d.data[d.pos:] + + padding := 0 + if d.pos%d.arch.FloatAlign != 0 { + padding = d.arch.FloatAlign - (d.pos % d.arch.FloatAlign) + } + if len(data) < padding { + return d.binErrorf(padding+d.arch.FloatWidth, "unexpected end-of-file in %d-byte padding-before-float", padding) + } + data = data[padding:] + + if len(data) < d.arch.FloatWidth { + return d.binErrorf(d.arch.FloatWidth, "unexpected end-of-file in %d-byte float", d.arch.FloatWidth) + } + + *obj = Float(math.Float64frombits(d.arch.ByteOrder.Uint64(data))) + d.pos += padding + d.arch.FloatWidth + return nil +} + +func (obj *Uint) unmarshalRRD(d *Decoder, tag string) error { + if d.arch.IntWidth != 4 && d.arch.IntWidth != 8 { + return archErrorf("rrdbinary does not support IntWidth=%d; only supports 4 or 8", d.arch.IntWidth) + } + if tag != "" { + return typeErrorf("invalid rrdbinary struct tag for uint: %q", tag) + } + + data := d.data[d.pos:] + + padding := 0 + if d.pos%d.arch.IntAlign != 0 { + padding = d.arch.IntAlign - (d.pos % d.arch.IntAlign) + } + if len(data) < padding { + return d.binErrorf(padding+d.arch.IntWidth, "unexpected end-of-file in %d-byte padding-before-uint", padding) + } + data = data[padding:] + + if len(data) < d.arch.IntWidth { + return d.binErrorf(d.arch.IntWidth, "unexpected end-of-file in %d-byte uint", d.arch.IntWidth) + } + + switch d.arch.IntWidth { + case 4: + *obj = Uint(d.arch.ByteOrder.Uint32(data)) + case 8: + *obj = Uint(d.arch.ByteOrder.Uint64(data)) + } + d.pos += padding + d.arch.IntWidth + return nil +} + +func (obj *Int) unmarshalRRD(d *Decoder, tag string) error { + if d.arch.IntWidth != 4 && d.arch.IntWidth != 8 { + return archErrorf("rrdbinary does not support IntWidth=%d; only supports 4 or 8", d.arch.IntWidth) + } + if tag != "" { + return typeErrorf("invalid rrdbinary struct tag for int: %q", tag) + } + + data := d.data[d.pos:] + + padding := 0 + if d.pos%d.arch.IntAlign != 0 { + padding = d.arch.IntAlign - (d.pos % d.arch.IntAlign) + } + if len(data) < padding { + return d.binErrorf(padding+d.arch.IntWidth, "unexpected end-of-file in %d-byte padding-before-int", padding) + } + data = data[padding:] + + if len(data) < d.arch.IntWidth { + return d.binErrorf(d.arch.IntWidth, "unexpected end-of-file in %d-byte int", d.arch.IntWidth) + } + + switch d.arch.IntWidth { + case 4: + *obj = Int(int32(d.arch.ByteOrder.Uint32(data))) + case 8: + *obj = Int(d.arch.ByteOrder.Uint64(data)) + } + d.pos += padding + d.arch.IntWidth + return nil +} + +func (obj *Unival) unmarshalRRD(d *Decoder, tag string) error { + if d.arch.UnivalWidth != 8 { + return archErrorf("rrdbinary does not support UnivalWidth=%d; only supports 8", d.arch.UnivalWidth) + } + if tag != "" { + return typeErrorf("invalid rrdbinary struct tag for unival: %q", tag) + } + + data := d.data[d.pos:] + + padding := 0 + if d.pos%d.arch.UnivalAlign != 0 { + padding = d.arch.UnivalAlign - (d.pos % d.arch.UnivalAlign) + } + if len(data) < padding { + return d.binErrorf(padding+d.arch.UnivalWidth, "unexpected end-of-file in %d-byte padding-before-unival", padding) + } + data = data[padding:] + + if len(data) < d.arch.UnivalWidth { + return d.binErrorf(d.arch.UnivalWidth, "unexpected end-of-file in %d-byte unival", d.arch.UnivalWidth) + } + + *obj = Unival(d.arch.ByteOrder.Uint64(data)) + d.pos += padding + d.arch.UnivalWidth + return nil +} + +func (obj *Time) unmarshalRRD(d *Decoder, tag string) error { + if d.arch.TimeWidth != 4 && d.arch.TimeWidth != 8 { + return archErrorf("rrdbinary does not support TimeWidth=%d; only supports 4 or 8", d.arch.TimeWidth) + } + if tag != "" { + return typeErrorf("invalid rrdbinary struct tag for time: %q", tag) + } + + data := d.data[d.pos:] + + padding := 0 + if d.pos%d.arch.TimeAlign != 0 { + padding = d.arch.TimeAlign - (d.pos % d.arch.TimeAlign) + } + if len(data) < padding { + return d.binErrorf(padding+d.arch.TimeWidth, "unexpected end-of-file in %d-byte padding-before-time", padding) + } + data = data[padding:] + + if len(data) < d.arch.TimeWidth { + return d.binErrorf(d.arch.TimeWidth, "unexpected end-of-file in %d-byte time", d.arch.TimeWidth) + } + + switch d.arch.TimeWidth { + case 4: + *obj = Time(int32(d.arch.ByteOrder.Uint32(data))) + case 8: + *obj = Time(d.arch.ByteOrder.Uint64(data)) + } + d.pos += padding + d.arch.TimeWidth + return nil +} + +func (_ *EOF) unmarshalRRD(d *Decoder, tag string) error { + if tag != "" { + return typeErrorf("invalid rrdbinary struct tag for eof: %q", tag) + } + + data := d.data[d.pos:] + if len(data) > 0 { + return d.binErrorf(16, "extra %d bytes of data after expected end-of-file", len(data)) + } + + return nil +} -- cgit v1.2.3