1// Copyright (c) 2012, 2013 Ugorji Nwoke. All rights reserved.
2// Use of this source code is governed by a BSD-style license found in the LICENSE file.
3
4package codec
5
6import "math"
7
8const (
9	_               uint8 = iota
10	simpleVdNil           = 1
11	simpleVdFalse         = 2
12	simpleVdTrue          = 3
13	simpleVdFloat32       = 4
14	simpleVdFloat64       = 5
15
16	// each lasts for 4 (ie n, n+1, n+2, n+3)
17	simpleVdPosInt = 8
18	simpleVdNegInt = 12
19
20	// containers: each lasts for 4 (ie n, n+1, n+2, ... n+7)
21	simpleVdString    = 216
22	simpleVdByteArray = 224
23	simpleVdArray     = 232
24	simpleVdMap       = 240
25	simpleVdExt       = 248
26)
27
28type simpleEncDriver struct {
29	h *SimpleHandle
30	w encWriter
31	//b [8]byte
32}
33
34func (e *simpleEncDriver) isBuiltinType(rt uintptr) bool {
35	return false
36}
37
38func (e *simpleEncDriver) encodeBuiltin(rt uintptr, v interface{}) {
39}
40
41func (e *simpleEncDriver) encodeNil() {
42	e.w.writen1(simpleVdNil)
43}
44
45func (e *simpleEncDriver) encodeBool(b bool) {
46	if b {
47		e.w.writen1(simpleVdTrue)
48	} else {
49		e.w.writen1(simpleVdFalse)
50	}
51}
52
53func (e *simpleEncDriver) encodeFloat32(f float32) {
54	e.w.writen1(simpleVdFloat32)
55	e.w.writeUint32(math.Float32bits(f))
56}
57
58func (e *simpleEncDriver) encodeFloat64(f float64) {
59	e.w.writen1(simpleVdFloat64)
60	e.w.writeUint64(math.Float64bits(f))
61}
62
63func (e *simpleEncDriver) encodeInt(v int64) {
64	if v < 0 {
65		e.encUint(uint64(-v), simpleVdNegInt)
66	} else {
67		e.encUint(uint64(v), simpleVdPosInt)
68	}
69}
70
71func (e *simpleEncDriver) encodeUint(v uint64) {
72	e.encUint(v, simpleVdPosInt)
73}
74
75func (e *simpleEncDriver) encUint(v uint64, bd uint8) {
76	switch {
77	case v <= math.MaxUint8:
78		e.w.writen2(bd, uint8(v))
79	case v <= math.MaxUint16:
80		e.w.writen1(bd + 1)
81		e.w.writeUint16(uint16(v))
82	case v <= math.MaxUint32:
83		e.w.writen1(bd + 2)
84		e.w.writeUint32(uint32(v))
85	case v <= math.MaxUint64:
86		e.w.writen1(bd + 3)
87		e.w.writeUint64(v)
88	}
89}
90
91func (e *simpleEncDriver) encLen(bd byte, length int) {
92	switch {
93	case length == 0:
94		e.w.writen1(bd)
95	case length <= math.MaxUint8:
96		e.w.writen1(bd + 1)
97		e.w.writen1(uint8(length))
98	case length <= math.MaxUint16:
99		e.w.writen1(bd + 2)
100		e.w.writeUint16(uint16(length))
101	case int64(length) <= math.MaxUint32:
102		e.w.writen1(bd + 3)
103		e.w.writeUint32(uint32(length))
104	default:
105		e.w.writen1(bd + 4)
106		e.w.writeUint64(uint64(length))
107	}
108}
109
110func (e *simpleEncDriver) encodeExtPreamble(xtag byte, length int) {
111	e.encLen(simpleVdExt, length)
112	e.w.writen1(xtag)
113}
114
115func (e *simpleEncDriver) encodeArrayPreamble(length int) {
116	e.encLen(simpleVdArray, length)
117}
118
119func (e *simpleEncDriver) encodeMapPreamble(length int) {
120	e.encLen(simpleVdMap, length)
121}
122
123func (e *simpleEncDriver) encodeString(c charEncoding, v string) {
124	e.encLen(simpleVdString, len(v))
125	e.w.writestr(v)
126}
127
128func (e *simpleEncDriver) encodeSymbol(v string) {
129	e.encodeString(c_UTF8, v)
130}
131
132func (e *simpleEncDriver) encodeStringBytes(c charEncoding, v []byte) {
133	e.encLen(simpleVdByteArray, len(v))
134	e.w.writeb(v)
135}
136
137//------------------------------------
138
139type simpleDecDriver struct {
140	h      *SimpleHandle
141	r      decReader
142	bdRead bool
143	bdType valueType
144	bd     byte
145	//b      [8]byte
146}
147
148func (d *simpleDecDriver) initReadNext() {
149	if d.bdRead {
150		return
151	}
152	d.bd = d.r.readn1()
153	d.bdRead = true
154	d.bdType = valueTypeUnset
155}
156
157func (d *simpleDecDriver) currentEncodedType() valueType {
158	if d.bdType == valueTypeUnset {
159		switch d.bd {
160		case simpleVdNil:
161			d.bdType = valueTypeNil
162		case simpleVdTrue, simpleVdFalse:
163			d.bdType = valueTypeBool
164		case simpleVdPosInt, simpleVdPosInt + 1, simpleVdPosInt + 2, simpleVdPosInt + 3:
165			d.bdType = valueTypeUint
166		case simpleVdNegInt, simpleVdNegInt + 1, simpleVdNegInt + 2, simpleVdNegInt + 3:
167			d.bdType = valueTypeInt
168		case simpleVdFloat32, simpleVdFloat64:
169			d.bdType = valueTypeFloat
170		case simpleVdString, simpleVdString + 1, simpleVdString + 2, simpleVdString + 3, simpleVdString + 4:
171			d.bdType = valueTypeString
172		case simpleVdByteArray, simpleVdByteArray + 1, simpleVdByteArray + 2, simpleVdByteArray + 3, simpleVdByteArray + 4:
173			d.bdType = valueTypeBytes
174		case simpleVdExt, simpleVdExt + 1, simpleVdExt + 2, simpleVdExt + 3, simpleVdExt + 4:
175			d.bdType = valueTypeExt
176		case simpleVdArray, simpleVdArray + 1, simpleVdArray + 2, simpleVdArray + 3, simpleVdArray + 4:
177			d.bdType = valueTypeArray
178		case simpleVdMap, simpleVdMap + 1, simpleVdMap + 2, simpleVdMap + 3, simpleVdMap + 4:
179			d.bdType = valueTypeMap
180		default:
181			decErr("currentEncodedType: Unrecognized d.vd: 0x%x", d.bd)
182		}
183	}
184	return d.bdType
185}
186
187func (d *simpleDecDriver) tryDecodeAsNil() bool {
188	if d.bd == simpleVdNil {
189		d.bdRead = false
190		return true
191	}
192	return false
193}
194
195func (d *simpleDecDriver) isBuiltinType(rt uintptr) bool {
196	return false
197}
198
199func (d *simpleDecDriver) decodeBuiltin(rt uintptr, v interface{}) {
200}
201
202func (d *simpleDecDriver) decIntAny() (ui uint64, i int64, neg bool) {
203	switch d.bd {
204	case simpleVdPosInt:
205		ui = uint64(d.r.readn1())
206		i = int64(ui)
207	case simpleVdPosInt + 1:
208		ui = uint64(d.r.readUint16())
209		i = int64(ui)
210	case simpleVdPosInt + 2:
211		ui = uint64(d.r.readUint32())
212		i = int64(ui)
213	case simpleVdPosInt + 3:
214		ui = uint64(d.r.readUint64())
215		i = int64(ui)
216	case simpleVdNegInt:
217		ui = uint64(d.r.readn1())
218		i = -(int64(ui))
219		neg = true
220	case simpleVdNegInt + 1:
221		ui = uint64(d.r.readUint16())
222		i = -(int64(ui))
223		neg = true
224	case simpleVdNegInt + 2:
225		ui = uint64(d.r.readUint32())
226		i = -(int64(ui))
227		neg = true
228	case simpleVdNegInt + 3:
229		ui = uint64(d.r.readUint64())
230		i = -(int64(ui))
231		neg = true
232	default:
233		decErr("decIntAny: Integer only valid from pos/neg integer1..8. Invalid descriptor: %v", d.bd)
234	}
235	// don't do this check, because callers may only want the unsigned value.
236	// if ui > math.MaxInt64 {
237	// 	decErr("decIntAny: Integer out of range for signed int64: %v", ui)
238	// }
239	return
240}
241
242func (d *simpleDecDriver) decodeInt(bitsize uint8) (i int64) {
243	_, i, _ = d.decIntAny()
244	checkOverflow(0, i, bitsize)
245	d.bdRead = false
246	return
247}
248
249func (d *simpleDecDriver) decodeUint(bitsize uint8) (ui uint64) {
250	ui, i, neg := d.decIntAny()
251	if neg {
252		decErr("Assigning negative signed value: %v, to unsigned type", i)
253	}
254	checkOverflow(ui, 0, bitsize)
255	d.bdRead = false
256	return
257}
258
259func (d *simpleDecDriver) decodeFloat(chkOverflow32 bool) (f float64) {
260	switch d.bd {
261	case simpleVdFloat32:
262		f = float64(math.Float32frombits(d.r.readUint32()))
263	case simpleVdFloat64:
264		f = math.Float64frombits(d.r.readUint64())
265	default:
266		if d.bd >= simpleVdPosInt && d.bd <= simpleVdNegInt+3 {
267			_, i, _ := d.decIntAny()
268			f = float64(i)
269		} else {
270			decErr("Float only valid from float32/64: Invalid descriptor: %v", d.bd)
271		}
272	}
273	checkOverflowFloat32(f, chkOverflow32)
274	d.bdRead = false
275	return
276}
277
278// bool can be decoded from bool only (single byte).
279func (d *simpleDecDriver) decodeBool() (b bool) {
280	switch d.bd {
281	case simpleVdTrue:
282		b = true
283	case simpleVdFalse:
284	default:
285		decErr("Invalid single-byte value for bool: %s: %x", msgBadDesc, d.bd)
286	}
287	d.bdRead = false
288	return
289}
290
291func (d *simpleDecDriver) readMapLen() (length int) {
292	d.bdRead = false
293	return d.decLen()
294}
295
296func (d *simpleDecDriver) readArrayLen() (length int) {
297	d.bdRead = false
298	return d.decLen()
299}
300
301func (d *simpleDecDriver) decLen() int {
302	switch d.bd % 8 {
303	case 0:
304		return 0
305	case 1:
306		return int(d.r.readn1())
307	case 2:
308		return int(d.r.readUint16())
309	case 3:
310		ui := uint64(d.r.readUint32())
311		checkOverflow(ui, 0, intBitsize)
312		return int(ui)
313	case 4:
314		ui := d.r.readUint64()
315		checkOverflow(ui, 0, intBitsize)
316		return int(ui)
317	}
318	decErr("decLen: Cannot read length: bd%8 must be in range 0..4. Got: %d", d.bd%8)
319	return -1
320}
321
322func (d *simpleDecDriver) decodeString() (s string) {
323	s = string(d.r.readn(d.decLen()))
324	d.bdRead = false
325	return
326}
327
328func (d *simpleDecDriver) decodeBytes(bs []byte) (bsOut []byte, changed bool) {
329	if clen := d.decLen(); clen > 0 {
330		// if no contents in stream, don't update the passed byteslice
331		if len(bs) != clen {
332			if len(bs) > clen {
333				bs = bs[:clen]
334			} else {
335				bs = make([]byte, clen)
336			}
337			bsOut = bs
338			changed = true
339		}
340		d.r.readb(bs)
341	}
342	d.bdRead = false
343	return
344}
345
346func (d *simpleDecDriver) decodeExt(verifyTag bool, tag byte) (xtag byte, xbs []byte) {
347	switch d.bd {
348	case simpleVdExt, simpleVdExt + 1, simpleVdExt + 2, simpleVdExt + 3, simpleVdExt + 4:
349		l := d.decLen()
350		xtag = d.r.readn1()
351		if verifyTag && xtag != tag {
352			decErr("Wrong extension tag. Got %b. Expecting: %v", xtag, tag)
353		}
354		xbs = d.r.readn(l)
355	case simpleVdByteArray, simpleVdByteArray + 1, simpleVdByteArray + 2, simpleVdByteArray + 3, simpleVdByteArray + 4:
356		xbs, _ = d.decodeBytes(nil)
357	default:
358		decErr("Invalid d.vd for extensions (Expecting extensions or byte array). Got: 0x%x", d.bd)
359	}
360	d.bdRead = false
361	return
362}
363
364func (d *simpleDecDriver) decodeNaked() (v interface{}, vt valueType, decodeFurther bool) {
365	d.initReadNext()
366
367	switch d.bd {
368	case simpleVdNil:
369		vt = valueTypeNil
370	case simpleVdFalse:
371		vt = valueTypeBool
372		v = false
373	case simpleVdTrue:
374		vt = valueTypeBool
375		v = true
376	case simpleVdPosInt, simpleVdPosInt + 1, simpleVdPosInt + 2, simpleVdPosInt + 3:
377		vt = valueTypeUint
378		ui, _, _ := d.decIntAny()
379		v = ui
380	case simpleVdNegInt, simpleVdNegInt + 1, simpleVdNegInt + 2, simpleVdNegInt + 3:
381		vt = valueTypeInt
382		_, i, _ := d.decIntAny()
383		v = i
384	case simpleVdFloat32:
385		vt = valueTypeFloat
386		v = d.decodeFloat(true)
387	case simpleVdFloat64:
388		vt = valueTypeFloat
389		v = d.decodeFloat(false)
390	case simpleVdString, simpleVdString + 1, simpleVdString + 2, simpleVdString + 3, simpleVdString + 4:
391		vt = valueTypeString
392		v = d.decodeString()
393	case simpleVdByteArray, simpleVdByteArray + 1, simpleVdByteArray + 2, simpleVdByteArray + 3, simpleVdByteArray + 4:
394		vt = valueTypeBytes
395		v, _ = d.decodeBytes(nil)
396	case simpleVdExt, simpleVdExt + 1, simpleVdExt + 2, simpleVdExt + 3, simpleVdExt + 4:
397		vt = valueTypeExt
398		l := d.decLen()
399		var re RawExt
400		re.Tag = d.r.readn1()
401		re.Data = d.r.readn(l)
402		v = &re
403		vt = valueTypeExt
404	case simpleVdArray, simpleVdArray + 1, simpleVdArray + 2, simpleVdArray + 3, simpleVdArray + 4:
405		vt = valueTypeArray
406		decodeFurther = true
407	case simpleVdMap, simpleVdMap + 1, simpleVdMap + 2, simpleVdMap + 3, simpleVdMap + 4:
408		vt = valueTypeMap
409		decodeFurther = true
410	default:
411		decErr("decodeNaked: Unrecognized d.vd: 0x%x", d.bd)
412	}
413
414	if !decodeFurther {
415		d.bdRead = false
416	}
417	return
418}
419
420//------------------------------------
421
422// SimpleHandle is a Handle for a very simple encoding format.
423//
424// simple is a simplistic codec similar to binc, but not as compact.
425//   - Encoding of a value is always preceeded by the descriptor byte (bd)
426//   - True, false, nil are encoded fully in 1 byte (the descriptor)
427//   - Integers (intXXX, uintXXX) are encoded in 1, 2, 4 or 8 bytes (plus a descriptor byte).
428//     There are positive (uintXXX and intXXX >= 0) and negative (intXXX < 0) integers.
429//   - Floats are encoded in 4 or 8 bytes (plus a descriptor byte)
430//   - Lenght of containers (strings, bytes, array, map, extensions)
431//     are encoded in 0, 1, 2, 4 or 8 bytes.
432//     Zero-length containers have no length encoded.
433//     For others, the number of bytes is given by pow(2, bd%3)
434//   - maps are encoded as [bd] [length] [[key][value]]...
435//   - arrays are encoded as [bd] [length] [value]...
436//   - extensions are encoded as [bd] [length] [tag] [byte]...
437//   - strings/bytearrays are encoded as [bd] [length] [byte]...
438//
439// The full spec will be published soon.
440type SimpleHandle struct {
441	BasicHandle
442}
443
444func (h *SimpleHandle) newEncDriver(w encWriter) encDriver {
445	return &simpleEncDriver{w: w, h: h}
446}
447
448func (h *SimpleHandle) newDecDriver(r decReader) decDriver {
449	return &simpleDecDriver{r: r, h: h}
450}
451
452func (_ *SimpleHandle) writeExt() bool {
453	return true
454}
455
456func (h *SimpleHandle) getBasicHandle() *BasicHandle {
457	return &h.BasicHandle
458}
459
460var _ decDriver = (*simpleDecDriver)(nil)
461var _ encDriver = (*simpleEncDriver)(nil)
462