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[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [libgo/] [go/] [encoding/] [binary/] [binary.go] - Blame information for rev 747

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1 747 jeremybenn 
// Copyright 2009 The Go Authors.  All rights reserved.
2 
// Use of this source code is governed by a BSD-style
3 
// license that can be found in the LICENSE file.
4 
 
5 
// Package binary implements translation between
6 
// unsigned integer values and byte sequences
7 
// and the reading and writing of fixed-size values.
8 
package binary
9 
 
10 
import (
11 
        "errors"
12 
        "io"
13 
        "math"
14 
        "reflect"
15 
)
16 
 
17 
// A ByteOrder specifies how to convert byte sequences into
18 
// 16-, 32-, or 64-bit unsigned integers.
19 
type ByteOrder interface {
20 
        Uint16([]byte) uint16
21 
        Uint32([]byte) uint32
22 
        Uint64([]byte) uint64
23 
        PutUint16([]byte, uint16)
24 
        PutUint32([]byte, uint32)
25 
        PutUint64([]byte, uint64)
26 
        String() string
27 
}
28 
 
29 
// This is byte instead of struct{} so that it can be compared,
30 
// allowing, e.g., order == binary.LittleEndian.
31 
type unused byte
32 
 
33 
// LittleEndian is the little-endian implementation of ByteOrder.
34 
var LittleEndian littleEndian
35 
 
36 
// BigEndian is the big-endian implementation of ByteOrder.
37 
var BigEndian bigEndian
38 
 
39 
type littleEndian unused
40 
 
41 
func (littleEndian) Uint16(b []byte) uint16 { return uint16(b[0]) | uint16(b[1])<<8 }
42 
 
43 
func (littleEndian) PutUint16(b []byte, v uint16) {
44 
        b[0] = byte(v)
45 
        b[1] = byte(v >> 8)
46 
}
47 
 
48 
func (littleEndian) Uint32(b []byte) uint32 {
49 
        return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
50 
}
51 
 
52 
func (littleEndian) PutUint32(b []byte, v uint32) {
53 
        b[0] = byte(v)
54 
        b[1] = byte(v >> 8)
55 
        b[2] = byte(v >> 16)
56 
        b[3] = byte(v >> 24)
57 
}
58 
 
59 
func (littleEndian) Uint64(b []byte) uint64 {
60 
        return uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 |
61 
                uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56
62 
}
63 
 
64 
func (littleEndian) PutUint64(b []byte, v uint64) {
65 
        b[0] = byte(v)
66 
        b[1] = byte(v >> 8)
67 
        b[2] = byte(v >> 16)
68 
        b[3] = byte(v >> 24)
69 
        b[4] = byte(v >> 32)
70 
        b[5] = byte(v >> 40)
71 
        b[6] = byte(v >> 48)
72 
        b[7] = byte(v >> 56)
73 
}
74 
 
75 
func (littleEndian) String() string { return "LittleEndian" }
76 
 
77 
func (littleEndian) GoString() string { return "binary.LittleEndian" }
78 
 
79 
type bigEndian unused
80 
 
81 
func (bigEndian) Uint16(b []byte) uint16 { return uint16(b[1]) | uint16(b[0])<<8 }
82 
 
83 
func (bigEndian) PutUint16(b []byte, v uint16) {
84 
        b[0] = byte(v >> 8)
85 
        b[1] = byte(v)
86 
}
87 
 
88 
func (bigEndian) Uint32(b []byte) uint32 {
89 
        return uint32(b[3]) | uint32(b[2])<<8 | uint32(b[1])<<16 | uint32(b[0])<<24
90 
}
91 
 
92 
func (bigEndian) PutUint32(b []byte, v uint32) {
93 
        b[0] = byte(v >> 24)
94 
        b[1] = byte(v >> 16)
95 
        b[2] = byte(v >> 8)
96 
        b[3] = byte(v)
97 
}
98 
 
99 
func (bigEndian) Uint64(b []byte) uint64 {
100 
        return uint64(b[7]) | uint64(b[6])<<8 | uint64(b[5])<<16 | uint64(b[4])<<24 |
101 
                uint64(b[3])<<32 | uint64(b[2])<<40 | uint64(b[1])<<48 | uint64(b[0])<<56
102 
}
103 
 
104 
func (bigEndian) PutUint64(b []byte, v uint64) {
105 
        b[0] = byte(v >> 56)
106 
        b[1] = byte(v >> 48)
107 
        b[2] = byte(v >> 40)
108 
        b[3] = byte(v >> 32)
109 
        b[4] = byte(v >> 24)
110 
        b[5] = byte(v >> 16)
111 
        b[6] = byte(v >> 8)
112 
        b[7] = byte(v)
113 
}
114 
 
115 
func (bigEndian) String() string { return "BigEndian" }
116 
 
117 
func (bigEndian) GoString() string { return "binary.BigEndian" }
118 
 
119 
// Read reads structured binary data from r into data.
120 
// Data must be a pointer to a fixed-size value or a slice
121 
// of fixed-size values.
122 
// A fixed-size value is either a fixed-size arithmetic
123 
// type (int8, uint8, int16, float32, complex64, ...)
124 
// or an array or struct containing only fixed-size values.
125 
// Bytes read from r are decoded using the specified byte order
126 
// and written to successive fields of the data.
127 
func Read(r io.Reader, order ByteOrder, data interface{}) error {
128 
        // Fast path for basic types.
129 
        if n := intDestSize(data); n != 0 {
130 
                var b [8]byte
131 
                bs := b[:n]
132 
                if _, err := io.ReadFull(r, bs); err != nil {
133 
                        return err
134 
                }
135 
                switch v := data.(type) {
136 
                case *int8:
137 
                        *v = int8(b[0])
138 
                case *uint8:
139 
                        *v = b[0]
140 
                case *int16:
141 
                        *v = int16(order.Uint16(bs))
142 
                case *uint16:
143 
                        *v = order.Uint16(bs)
144 
                case *int32:
145 
                        *v = int32(order.Uint32(bs))
146 
                case *uint32:
147 
                        *v = order.Uint32(bs)
148 
                case *int64:
149 
                        *v = int64(order.Uint64(bs))
150 
                case *uint64:
151 
                        *v = order.Uint64(bs)
152 
                }
153 
                return nil
154 
        }
155 
 
156 
        // Fallback to reflect-based.
157 
        var v reflect.Value
158 
        switch d := reflect.ValueOf(data); d.Kind() {
159 
        case reflect.Ptr:
160 
                v = d.Elem()
161 
        case reflect.Slice:
162 
                v = d
163 
        default:
164 
                return errors.New("binary.Read: invalid type " + d.Type().String())
165 
        }
166 
        size := dataSize(v)
167 
        if size < 0 {
168 
                return errors.New("binary.Read: invalid type " + v.Type().String())
169 
        }
170 
        d := &decoder{order: order, buf: make([]byte, size)}
171 
        if _, err := io.ReadFull(r, d.buf); err != nil {
172 
                return err
173 
        }
174 
        d.value(v)
175 
        return nil
176 
}
177 
 
178 
// Write writes the binary representation of data into w.
179 
// Data must be a fixed-size value or a pointer to
180 
// a fixed-size value.
181 
// A fixed-size value is either a fixed-size arithmetic
182 
// type (int8, uint8, int16, float32, complex64, ...)
183 
// or an array or struct containing only fixed-size values.
184 
// Bytes written to w are encoded using the specified byte order
185 
// and read from successive fields of the data.
186 
func Write(w io.Writer, order ByteOrder, data interface{}) error {
187 
        // Fast path for basic types.
188 
        var b [8]byte
189 
        var bs []byte
190 
        switch v := data.(type) {
191 
        case *int8:
192 
                bs = b[:1]
193 
                b[0] = byte(*v)
194 
        case int8:
195 
                bs = b[:1]
196 
                b[0] = byte(v)
197 
        case *uint8:
198 
                bs = b[:1]
199 
                b[0] = *v
200 
        case uint8:
201 
                bs = b[:1]
202 
                b[0] = byte(v)
203 
        case *int16:
204 
                bs = b[:2]
205 
                order.PutUint16(bs, uint16(*v))
206 
        case int16:
207 
                bs = b[:2]
208 
                order.PutUint16(bs, uint16(v))
209 
        case *uint16:
210 
                bs = b[:2]
211 
                order.PutUint16(bs, *v)
212 
        case uint16:
213 
                bs = b[:2]
214 
                order.PutUint16(bs, v)
215 
        case *int32:
216 
                bs = b[:4]
217 
                order.PutUint32(bs, uint32(*v))
218 
        case int32:
219 
                bs = b[:4]
220 
                order.PutUint32(bs, uint32(v))
221 
        case *uint32:
222 
                bs = b[:4]
223 
                order.PutUint32(bs, *v)
224 
        case uint32:
225 
                bs = b[:4]
226 
                order.PutUint32(bs, v)
227 
        case *int64:
228 
                bs = b[:8]
229 
                order.PutUint64(bs, uint64(*v))
230 
        case int64:
231 
                bs = b[:8]
232 
                order.PutUint64(bs, uint64(v))
233 
        case *uint64:
234 
                bs = b[:8]
235 
                order.PutUint64(bs, *v)
236 
        case uint64:
237 
                bs = b[:8]
238 
                order.PutUint64(bs, v)
239 
        }
240 
        if bs != nil {
241 
                _, err := w.Write(bs)
242 
                return err
243 
        }
244 
        v := reflect.Indirect(reflect.ValueOf(data))
245 
        size := dataSize(v)
246 
        if size < 0 {
247 
                return errors.New("binary.Write: invalid type " + v.Type().String())
248 
        }
249 
        buf := make([]byte, size)
250 
        e := &encoder{order: order, buf: buf}
251 
        e.value(v)
252 
        _, err := w.Write(buf)
253 
        return err
254 
}
255 
 
256 
// dataSize returns the number of bytes the actual data represented by v occupies in memory.
257 
// For compound structures, it sums the sizes of the elements. Thus, for instance, for a slice
258 
// it returns the length of the slice times the element size and does not count the memory
259 
// occupied by the header.
260 
func dataSize(v reflect.Value) int {
261 
        if v.Kind() == reflect.Slice {
262 
                elem := sizeof(v.Type().Elem())
263 
                if elem < 0 {
264 
                        return -1
265 
                }
266 
                return v.Len() * elem
267 
        }
268 
        return sizeof(v.Type())
269 
}
270 
 
271 
func sizeof(t reflect.Type) int {
272 
        switch t.Kind() {
273 
        case reflect.Array:
274 
                n := sizeof(t.Elem())
275 
                if n < 0 {
276 
                        return -1
277 
                }
278 
                return t.Len() * n
279 
 
280 
        case reflect.Struct:
281 
                sum := 0
282 
                for i, n := 0, t.NumField(); i < n; i++ {
283 
                        s := sizeof(t.Field(i).Type)
284 
                        if s < 0 {
285 
                                return -1
286 
                        }
287 
                        sum += s
288 
                }
289 
                return sum
290 
 
291 
        case reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64,
292 
                reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
293 
                reflect.Float32, reflect.Float64, reflect.Complex64, reflect.Complex128:
294 
                return int(t.Size())
295 
        }
296 
        return -1
297 
}
298 
 
299 
type decoder struct {
300 
        order ByteOrder
301 
        buf   []byte
302 
}
303 
 
304 
type encoder struct {
305 
        order ByteOrder
306 
        buf   []byte
307 
}
308 
 
309 
func (d *decoder) uint8() uint8 {
310 
        x := d.buf[0]
311 
        d.buf = d.buf[1:]
312 
        return x
313 
}
314 
 
315 
func (e *encoder) uint8(x uint8) {
316 
        e.buf[0] = x
317 
        e.buf = e.buf[1:]
318 
}
319 
 
320 
func (d *decoder) uint16() uint16 {
321 
        x := d.order.Uint16(d.buf[0:2])
322 
        d.buf = d.buf[2:]
323 
        return x
324 
}
325 
 
326 
func (e *encoder) uint16(x uint16) {
327 
        e.order.PutUint16(e.buf[0:2], x)
328 
        e.buf = e.buf[2:]
329 
}
330 
 
331 
func (d *decoder) uint32() uint32 {
332 
        x := d.order.Uint32(d.buf[0:4])
333 
        d.buf = d.buf[4:]
334 
        return x
335 
}
336 
 
337 
func (e *encoder) uint32(x uint32) {
338 
        e.order.PutUint32(e.buf[0:4], x)
339 
        e.buf = e.buf[4:]
340 
}
341 
 
342 
func (d *decoder) uint64() uint64 {
343 
        x := d.order.Uint64(d.buf[0:8])
344 
        d.buf = d.buf[8:]
345 
        return x
346 
}
347 
 
348 
func (e *encoder) uint64(x uint64) {
349 
        e.order.PutUint64(e.buf[0:8], x)
350 
        e.buf = e.buf[8:]
351 
}
352 
 
353 
func (d *decoder) int8() int8 { return int8(d.uint8()) }
354 
 
355 
func (e *encoder) int8(x int8) { e.uint8(uint8(x)) }
356 
 
357 
func (d *decoder) int16() int16 { return int16(d.uint16()) }
358 
 
359 
func (e *encoder) int16(x int16) { e.uint16(uint16(x)) }
360 
 
361 
func (d *decoder) int32() int32 { return int32(d.uint32()) }
362 
 
363 
func (e *encoder) int32(x int32) { e.uint32(uint32(x)) }
364 
 
365 
func (d *decoder) int64() int64 { return int64(d.uint64()) }
366 
 
367 
func (e *encoder) int64(x int64) { e.uint64(uint64(x)) }
368 
 
369 
func (d *decoder) value(v reflect.Value) {
370 
        switch v.Kind() {
371 
        case reflect.Array:
372 
                l := v.Len()
373 
                for i := 0; i < l; i++ {
374 
                        d.value(v.Index(i))
375 
                }
376 
        case reflect.Struct:
377 
                l := v.NumField()
378 
                for i := 0; i < l; i++ {
379 
                        d.value(v.Field(i))
380 
                }
381 
 
382 
        case reflect.Slice:
383 
                l := v.Len()
384 
                for i := 0; i < l; i++ {
385 
                        d.value(v.Index(i))
386 
                }
387 
 
388 
        case reflect.Int8:
389 
                v.SetInt(int64(d.int8()))
390 
        case reflect.Int16:
391 
                v.SetInt(int64(d.int16()))
392 
        case reflect.Int32:
393 
                v.SetInt(int64(d.int32()))
394 
        case reflect.Int64:
395 
                v.SetInt(d.int64())
396 
 
397 
        case reflect.Uint8:
398 
                v.SetUint(uint64(d.uint8()))
399 
        case reflect.Uint16:
400 
                v.SetUint(uint64(d.uint16()))
401 
        case reflect.Uint32:
402 
                v.SetUint(uint64(d.uint32()))
403 
        case reflect.Uint64:
404 
                v.SetUint(d.uint64())
405 
 
406 
        case reflect.Float32:
407 
                v.SetFloat(float64(math.Float32frombits(d.uint32())))
408 
        case reflect.Float64:
409 
                v.SetFloat(math.Float64frombits(d.uint64()))
410 
 
411 
        case reflect.Complex64:
412 
                v.SetComplex(complex(
413 
                        float64(math.Float32frombits(d.uint32())),
414 
                        float64(math.Float32frombits(d.uint32())),
415 
                ))
416 
        case reflect.Complex128:
417 
                v.SetComplex(complex(
418 
                        math.Float64frombits(d.uint64()),
419 
                        math.Float64frombits(d.uint64()),
420 
                ))
421 
        }
422 
}
423 
 
424 
func (e *encoder) value(v reflect.Value) {
425 
        switch v.Kind() {
426 
        case reflect.Array:
427 
                l := v.Len()
428 
                for i := 0; i < l; i++ {
429 
                        e.value(v.Index(i))
430 
                }
431 
        case reflect.Struct:
432 
                l := v.NumField()
433 
                for i := 0; i < l; i++ {
434 
                        e.value(v.Field(i))
435 
                }
436 
        case reflect.Slice:
437 
                l := v.Len()
438 
                for i := 0; i < l; i++ {
439 
                        e.value(v.Index(i))
440 
                }
441 
 
442 
        case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
443 
                switch v.Type().Kind() {
444 
                case reflect.Int8:
445 
                        e.int8(int8(v.Int()))
446 
                case reflect.Int16:
447 
                        e.int16(int16(v.Int()))
448 
                case reflect.Int32:
449 
                        e.int32(int32(v.Int()))
450 
                case reflect.Int64:
451 
                        e.int64(v.Int())
452 
                }
453 
 
454 
        case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
455 
                switch v.Type().Kind() {
456 
                case reflect.Uint8:
457 
                        e.uint8(uint8(v.Uint()))
458 
                case reflect.Uint16:
459 
                        e.uint16(uint16(v.Uint()))
460 
                case reflect.Uint32:
461 
                        e.uint32(uint32(v.Uint()))
462 
                case reflect.Uint64:
463 
                        e.uint64(v.Uint())
464 
                }
465 
 
466 
        case reflect.Float32, reflect.Float64:
467 
                switch v.Type().Kind() {
468 
                case reflect.Float32:
469 
                        e.uint32(math.Float32bits(float32(v.Float())))
470 
                case reflect.Float64:
471 
                        e.uint64(math.Float64bits(v.Float()))
472 
                }
473 
 
474 
        case reflect.Complex64, reflect.Complex128:
475 
                switch v.Type().Kind() {
476 
                case reflect.Complex64:
477 
                        x := v.Complex()
478 
                        e.uint32(math.Float32bits(float32(real(x))))
479 
                        e.uint32(math.Float32bits(float32(imag(x))))
480 
                case reflect.Complex128:
481 
                        x := v.Complex()
482 
                        e.uint64(math.Float64bits(real(x)))
483 
                        e.uint64(math.Float64bits(imag(x)))
484 
                }
485 
        }
486 
}
487 
 
488 
// intDestSize returns the size of the integer that ptrType points to,
489 
// or 0 if the type is not supported.
490 
func intDestSize(ptrType interface{}) int {
491 
        switch ptrType.(type) {
492 
        case *int8, *uint8:
493 
                return 1
494 
        case *int16, *uint16:
495 
                return 2
496 
        case *int32, *uint32:
497 
                return 4
498 
        case *int64, *uint64:
499 
                return 8
500 
        }
501 
        return 0
502 
}

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