forked from patrickxb/mpack
/
pack_reader.go
247 lines (209 loc) · 5.53 KB
/
pack_reader.go
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package mpack
import (
"encoding/binary"
"errors"
"fmt"
"github.com/okcupid/jsonw"
"io"
"log"
)
type PackReader struct {
reader io.Reader
framed bool
offset int
first bool
}
func (pr *PackReader) expectFraming() bool {
return pr.framed && pr.first
}
func NewPackReader(r io.Reader, f bool) *PackReader {
result := new(PackReader)
result.reader = r
result.framed = f
result.offset = 0
result.first = true
return result
}
func (pr *PackReader) incOffset(i int) {
pr.offset += i
}
func (pr *PackReader) ReadBinary(result interface{}) error {
e := binary.Read(pr.reader, binary.BigEndian, result)
if e == nil {
pr.incOffset(binary.Size(result))
}
return e
}
func (pr *PackReader) ReadUint8() (tmp uint8, e error) { e = pr.ReadBinary(&tmp); return }
func (pr *PackReader) ReadUint32() (tmp uint32, e error) { e = pr.ReadBinary(&tmp); return }
func (pr *PackReader) ReadUint16() (tmp uint16, e error) { e = pr.ReadBinary(&tmp); return }
func (pr *PackReader) ReadUint64() (tmp uint64, e error) { e = pr.ReadBinary(&tmp); return }
func (pr *PackReader) ReadInt16() (tmp int16, e error) { e = pr.ReadBinary(&tmp); return }
func (pr *PackReader) ReadInt32() (tmp int32, e error) { e = pr.ReadBinary(&tmp); return }
func (pr *PackReader) ReadInt64() (tmp uint64, e error) { e = pr.ReadBinary(&tmp); return }
func (pr *PackReader) ReadFloat32() (tmp float32, e error) { e = pr.ReadBinary(&tmp); return }
func (pr *PackReader) ReadFloat64() (tmp float64, e error) { e = pr.ReadBinary(&tmp); return }
func (pr *PackReader) unpackRaw(length uint32) (res string, e error) {
e = nil
var n int
if length > 0 {
bytes := make([]byte, length)
// NB: We need to be worried about a short read here,
// so we keep reading until we've filled the expected
// number of bytes!
n, e = io.ReadFull(pr.reader, bytes)
if e == nil {
pr.incOffset(n)
res = string(bytes)
} else {
log.Printf("error in unpack raw (len=%d): %s\n", length, e)
}
}
return
}
func (pr *PackReader) unpackArray(length uint32) (res []interface{}, e error) {
res = nil
e = nil
res = make([]interface{}, length)
for i := uint32(0); e == nil && i < length; i++ {
var elt interface{}
elt, _, e = pr.unpack()
if e == nil {
res[i] = elt
}
}
return
}
func (pr *PackReader) unpackMap(length uint32) (res map[string]interface{}, err error) {
res = make(map[string]interface{})
err = nil
for i := uint32(0); err == nil && i < length; i++ {
var key, val interface{}
key, _, err = pr.unpack()
if err == nil {
val, _, err = pr.unpack()
}
if err != nil {
/* noop */
} else if s, ok := key.(string); ok {
res[s] = val
} else {
msg := fmt.Sprintf("non-string keys for maps not allowed (%s)", key)
err = errors.New(msg)
}
}
return res, err
}
func (pr *PackReader) unpack() (interface{}, int, error) {
frame := 0
frame_len := 0
var b uint8
var err error = nil
var iRes interface{} = nil
var framed bool = pr.expectFraming()
// Threaded implementation won't need to worry, so we can
// just throw the framing away....
if framed {
pr.first = false
var tmp interface{}
tmp, frame_len, err = pr.unpack()
if err == nil {
w := jsonw.NewWrapper(tmp)
frame, err = w.GetInt()
if err == nil {
// Reset the offset so that we start counting from the
// inside of the frame
pr.offset = 0
}
}
}
if err == nil {
b, err = pr.ReadUint8()
}
doswitch := false
if err == nil {
if b <= positive_fix_max {
iRes = b
} else if b >= negative_fix_min && b <= negative_fix_max {
iRes = int8(b)
} else if b >= type_fix_raw && b <= type_fix_raw_max {
iRes, err = pr.unpackRaw(uint32(b & fix_raw_count_mask))
} else if b >= type_fix_array_min && b <= type_fix_array_max {
iRes, err = pr.unpackArray(uint32(b & fix_array_count_mask))
} else if b >= type_fix_map_min && b <= type_fix_map_max {
iRes, err = pr.unpackMap(uint32(b & fix_map_count_mask))
} else {
doswitch = true
}
}
if doswitch && err == nil {
switch b {
case type_nil:
case type_false:
iRes = false
case type_true:
iRes = true
case type_uint8:
iRes, err = pr.ReadUint8()
case type_uint16:
iRes, err = pr.ReadUint16()
case type_uint32:
iRes, err = pr.ReadUint32()
case type_uint64:
iRes, err = pr.ReadUint64()
case type_int16:
iRes, err = pr.ReadInt16()
case type_int32:
iRes, err = pr.ReadInt32()
case type_int64:
iRes, err = pr.ReadInt64()
case type_float:
iRes, err = pr.ReadFloat32()
case type_double:
iRes, err = pr.ReadFloat64()
case type_raw16:
var length uint16
length, err = pr.ReadUint16()
if err == nil {
iRes, err = pr.unpackRaw(uint32(length))
}
case type_raw32:
var length uint32
length, err = pr.ReadUint32()
if err == nil {
iRes, err = pr.unpackRaw(length)
}
case type_array16:
var length uint16
length, err := pr.ReadUint16()
if err == nil {
iRes, err = pr.unpackArray(uint32(length))
}
case type_array32:
var length uint32
length, err = pr.ReadUint32()
if err == nil {
iRes, err = pr.unpackArray(length)
}
case type_map16:
var length uint16
length, err = pr.ReadUint16()
if err == nil {
iRes, err = pr.unpackMap(uint32(length))
}
case type_map32:
var length uint32
length, err = pr.ReadUint32()
if err == nil {
iRes, err = pr.unpackMap(length)
}
default:
log.Printf("unhandled type prefix: %x\n", b)
}
}
numRead := pr.offset
if framed && err == nil && numRead != frame {
log.Printf("bad frame value: %d v %d\n", numRead, frame)
}
return iRes, numRead + frame_len, err
}