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Commit | Line | Data |
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107c1cdb ND |
1 | package msgpack |
2 | ||
3 | import ( | |
4 | "fmt" | |
5 | "reflect" | |
6 | ||
7 | "github.com/vmihailenco/msgpack/codes" | |
8 | ) | |
9 | ||
10 | const sliceElemsAllocLimit = 1e4 | |
11 | ||
12 | var sliceStringPtrType = reflect.TypeOf((*[]string)(nil)) | |
13 | ||
14 | // DecodeArrayLen decodes array length. Length is -1 when array is nil. | |
15 | func (d *Decoder) DecodeArrayLen() (int, error) { | |
16 | c, err := d.readCode() | |
17 | if err != nil { | |
18 | return 0, err | |
19 | } | |
20 | return d.arrayLen(c) | |
21 | } | |
22 | ||
23 | func (d *Decoder) arrayLen(c codes.Code) (int, error) { | |
24 | if c == codes.Nil { | |
25 | return -1, nil | |
26 | } else if c >= codes.FixedArrayLow && c <= codes.FixedArrayHigh { | |
27 | return int(c & codes.FixedArrayMask), nil | |
28 | } | |
29 | switch c { | |
30 | case codes.Array16: | |
31 | n, err := d.uint16() | |
32 | return int(n), err | |
33 | case codes.Array32: | |
34 | n, err := d.uint32() | |
35 | return int(n), err | |
36 | } | |
37 | return 0, fmt.Errorf("msgpack: invalid code=%x decoding array length", c) | |
38 | } | |
39 | ||
40 | func decodeStringSliceValue(d *Decoder, v reflect.Value) error { | |
41 | ptr := v.Addr().Convert(sliceStringPtrType).Interface().(*[]string) | |
42 | return d.decodeStringSlicePtr(ptr) | |
43 | } | |
44 | ||
45 | func (d *Decoder) decodeStringSlicePtr(ptr *[]string) error { | |
46 | n, err := d.DecodeArrayLen() | |
47 | if err != nil { | |
48 | return err | |
49 | } | |
50 | if n == -1 { | |
51 | return nil | |
52 | } | |
53 | ||
54 | ss := setStringsCap(*ptr, n) | |
55 | for i := 0; i < n; i++ { | |
56 | s, err := d.DecodeString() | |
57 | if err != nil { | |
58 | return err | |
59 | } | |
60 | ss = append(ss, s) | |
61 | } | |
62 | *ptr = ss | |
63 | ||
64 | return nil | |
65 | } | |
66 | ||
67 | func setStringsCap(s []string, n int) []string { | |
68 | if n > sliceElemsAllocLimit { | |
69 | n = sliceElemsAllocLimit | |
70 | } | |
71 | ||
72 | if s == nil { | |
73 | return make([]string, 0, n) | |
74 | } | |
75 | ||
76 | if cap(s) >= n { | |
77 | return s[:0] | |
78 | } | |
79 | ||
80 | s = s[:cap(s)] | |
81 | s = append(s, make([]string, n-len(s))...) | |
82 | return s[:0] | |
83 | } | |
84 | ||
85 | func decodeSliceValue(d *Decoder, v reflect.Value) error { | |
86 | n, err := d.DecodeArrayLen() | |
87 | if err != nil { | |
88 | return err | |
89 | } | |
90 | ||
91 | if n == -1 { | |
92 | v.Set(reflect.Zero(v.Type())) | |
93 | return nil | |
94 | } | |
95 | if n == 0 && v.IsNil() { | |
96 | v.Set(reflect.MakeSlice(v.Type(), 0, 0)) | |
97 | return nil | |
98 | } | |
99 | ||
100 | if v.Cap() >= n { | |
101 | v.Set(v.Slice(0, n)) | |
102 | } else if v.Len() < v.Cap() { | |
103 | v.Set(v.Slice(0, v.Cap())) | |
104 | } | |
105 | ||
106 | for i := 0; i < n; i++ { | |
107 | if i >= v.Len() { | |
108 | v.Set(growSliceValue(v, n)) | |
109 | } | |
110 | sv := v.Index(i) | |
111 | if err := d.DecodeValue(sv); err != nil { | |
112 | return err | |
113 | } | |
114 | } | |
115 | ||
116 | return nil | |
117 | } | |
118 | ||
119 | func growSliceValue(v reflect.Value, n int) reflect.Value { | |
120 | diff := n - v.Len() | |
121 | if diff > sliceElemsAllocLimit { | |
122 | diff = sliceElemsAllocLimit | |
123 | } | |
124 | v = reflect.AppendSlice(v, reflect.MakeSlice(v.Type(), diff, diff)) | |
125 | return v | |
126 | } | |
127 | ||
128 | func decodeArrayValue(d *Decoder, v reflect.Value) error { | |
129 | n, err := d.DecodeArrayLen() | |
130 | if err != nil { | |
131 | return err | |
132 | } | |
133 | ||
134 | if n == -1 { | |
135 | return nil | |
136 | } | |
137 | ||
138 | if n > v.Len() { | |
139 | return fmt.Errorf("%s len is %d, but msgpack has %d elements", v.Type(), v.Len(), n) | |
140 | } | |
141 | for i := 0; i < n; i++ { | |
142 | sv := v.Index(i) | |
143 | if err := d.DecodeValue(sv); err != nil { | |
144 | return err | |
145 | } | |
146 | } | |
147 | ||
148 | return nil | |
149 | } | |
150 | ||
151 | func (d *Decoder) DecodeSlice() ([]interface{}, error) { | |
152 | c, err := d.readCode() | |
153 | if err != nil { | |
154 | return nil, err | |
155 | } | |
156 | return d.decodeSlice(c) | |
157 | } | |
158 | ||
159 | func (d *Decoder) decodeSlice(c codes.Code) ([]interface{}, error) { | |
160 | n, err := d.arrayLen(c) | |
161 | if err != nil { | |
162 | return nil, err | |
163 | } | |
164 | if n == -1 { | |
165 | return nil, nil | |
166 | } | |
167 | ||
168 | s := make([]interface{}, 0, min(n, sliceElemsAllocLimit)) | |
169 | for i := 0; i < n; i++ { | |
170 | v, err := d.decodeInterfaceCond() | |
171 | if err != nil { | |
172 | return nil, err | |
173 | } | |
174 | s = append(s, v) | |
175 | } | |
176 | ||
177 | return s, nil | |
178 | } | |
179 | ||
180 | func (d *Decoder) skipSlice(c codes.Code) error { | |
181 | n, err := d.arrayLen(c) | |
182 | if err != nil { | |
183 | return err | |
184 | } | |
185 | ||
186 | for i := 0; i < n; i++ { | |
187 | if err := d.Skip(); err != nil { | |
188 | return err | |
189 | } | |
190 | } | |
191 | ||
192 | return nil | |
193 | } |