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1 // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file | |
2 // for details. All rights reserved. Use of this source code is governed by a | |
3 // BSD-style license that can be found in the LICENSE file. | |
4 | |
5 #include "vm/json.h" | |
6 | |
7 #include "platform/assert.h" | |
8 #include "platform/utils.h" | |
9 #include "vm/os.h" | |
10 | |
11 namespace dart { | |
12 | |
13 | |
14 JSONScanner::JSONScanner(const char* json_text) { | |
15 SetText(json_text); | |
16 } | |
17 | |
18 | |
19 void JSONScanner::SetText(const char* json_text) { | |
20 current_pos_ = json_text; | |
21 token_start_ = json_text; | |
22 token_length_ = 0; | |
23 token_ = TokenIllegal; | |
24 } | |
25 | |
26 | |
27 void JSONScanner::Recognize(Token t) { | |
28 ++current_pos_; | |
29 token_ = t; | |
30 } | |
31 | |
32 | |
33 bool JSONScanner::IsLetter(char ch) const { | |
34 return (('A' <= ch) && (ch <= 'Z')) || (('a' <= ch) && (ch <= 'z')); | |
35 } | |
36 | |
37 | |
38 bool JSONScanner::IsDigit(char ch) const { | |
39 return ('0' <= ch) && (ch <= '9'); | |
40 } | |
41 | |
42 | |
43 bool JSONScanner::IsLiteral(const char* literal) { | |
44 int i = 0; | |
45 while ((literal[i] != '\0') && (current_pos_[i] == literal[i])) { | |
46 i++; | |
47 } | |
48 if ((literal[i] == '\0') && !IsLetter(current_pos_[i])) { | |
49 current_pos_ += i; | |
50 return true; | |
51 } | |
52 return false; | |
53 } | |
54 | |
55 | |
56 bool JSONScanner::IsStringLiteral(const char* literal) const { | |
57 if (token_ != TokenString) { | |
58 return false; | |
59 } | |
60 int i = 0; | |
61 while ((i < token_length_) && (token_start_[i] == literal[i])) { | |
62 i++; | |
63 } | |
64 return (i == token_length_) && (literal[i] == '\0'); | |
65 } | |
66 | |
67 | |
68 void JSONScanner::Skip(Token matching_token) { | |
69 while (!EOM() && (token_ != TokenIllegal)) { | |
70 Scan(); | |
71 if (token_ == TokenLBrace) { | |
72 Skip(TokenRBrace); | |
73 } else if (token_ == TokenLBrack) { | |
74 Skip(TokenRBrack); | |
75 } else if (token_ == matching_token) { | |
76 return; | |
77 } else if ((token_ == TokenRBrace) || (token_ == TokenRBrack)) { | |
78 // Mismatched brace or bracket. | |
79 token_ = TokenIllegal; | |
80 } | |
81 } | |
82 } | |
83 | |
84 | |
85 void JSONScanner::ScanString() { | |
86 ASSERT(*current_pos_ == '"'); | |
87 ++current_pos_; | |
88 token_start_ = current_pos_; | |
89 while (*current_pos_ != '"') { | |
90 if (*current_pos_ == '\0') { | |
91 token_length_ = 0; | |
92 token_ = TokenIllegal; | |
93 return; | |
94 } else if (*current_pos_ == '\\') { | |
95 // TODO(hausner): Implement escape sequence. | |
96 UNIMPLEMENTED(); | |
97 } else if (*current_pos_ < 0) { | |
98 // UTF-8 not supported. | |
99 token_length_ = 0; | |
100 token_ = TokenIllegal; | |
101 return; | |
102 } else { | |
103 ++current_pos_; | |
104 } | |
105 } | |
106 token_ = TokenString; | |
107 token_length_ = current_pos_ - token_start_; | |
108 ++current_pos_; | |
109 } | |
110 | |
111 | |
112 void JSONScanner::ScanNumber() { | |
113 if (*current_pos_ == '-') { | |
114 ++current_pos_; | |
115 } | |
116 if (!IsDigit(*current_pos_)) { | |
117 token_ = TokenIllegal; | |
118 token_length_ = 0; | |
119 return; | |
120 } | |
121 while (IsDigit(*current_pos_)) { | |
122 ++current_pos_; | |
123 } | |
124 if ((*current_pos_ == '.') || | |
125 (*current_pos_ == 'e') || | |
126 (*current_pos_ == 'E')) { | |
127 // Floating point numbers not supported. | |
128 token_ = TokenIllegal; | |
129 token_length_ = 0; | |
130 return; | |
131 } | |
132 token_ = TokenInteger; | |
133 token_length_ = current_pos_ - token_start_; | |
134 } | |
135 | |
136 | |
137 void JSONScanner::Scan() { | |
138 while ((*current_pos_ == ' ') || | |
139 (*current_pos_ == '\t') || | |
140 (*current_pos_ == '\n')) { | |
141 ++current_pos_; | |
142 } | |
143 token_start_ = current_pos_; | |
144 if (*current_pos_ == '\0') { | |
145 token_length_ = 0; | |
146 token_ = TokenEOM; | |
147 return; | |
148 } | |
149 switch (*current_pos_) { | |
150 case '{': | |
151 Recognize(TokenLBrace); | |
152 break; | |
153 case '}': | |
154 Recognize(TokenRBrace); | |
155 break; | |
156 case '[': | |
157 Recognize(TokenLBrack); | |
158 break; | |
159 case ']': | |
160 Recognize(TokenRBrack); | |
161 break; | |
162 case ':': | |
163 Recognize(TokenColon); | |
164 break; | |
165 case ',': | |
166 Recognize(TokenComma); | |
167 break; | |
168 case '"': | |
169 ScanString(); | |
170 break; | |
171 case '0': | |
172 case '1': | |
173 case '2': | |
174 case '3': | |
175 case '4': | |
176 case '5': | |
177 case '6': | |
178 case '7': | |
179 case '8': | |
180 case '9': | |
181 case '-': | |
182 ScanNumber(); | |
183 break; | |
184 default: | |
185 if (IsLiteral("true")) { | |
186 token_ = TokenTrue; | |
187 token_length_ = 4; | |
188 } else if (IsLiteral("false")) { | |
189 token_ = TokenFalse; | |
190 token_length_ = 5; | |
191 } else if (IsLiteral("null")) { | |
192 token_ = TokenNull; | |
193 token_length_ = 4; | |
194 } else { | |
195 token_length_ = 0; | |
196 token_ = TokenIllegal; | |
197 } | |
198 } | |
199 } | |
200 | |
201 | |
202 JSONReader::JSONReader(const char* json_object) | |
203 : scanner_(json_object) { | |
204 Set(json_object); | |
205 } | |
206 | |
207 void JSONReader::Set(const char* json_object) { | |
208 scanner_.SetText(json_object); | |
209 json_object_ = json_object; | |
210 error_ = false; | |
211 } | |
212 | |
213 | |
214 bool JSONReader::Seek(const char* name) { | |
215 scanner_.SetText(json_object_); | |
216 scanner_.Scan(); | |
217 if (scanner_.CurrentToken() != JSONScanner::TokenLBrace) { | |
218 error_ = true; | |
219 return false; | |
220 } | |
221 scanner_.Scan(); | |
222 while (scanner_.CurrentToken() == JSONScanner::TokenString) { | |
223 bool found = scanner_.IsStringLiteral(name); | |
224 scanner_.Scan(); | |
225 if (scanner_.CurrentToken() != JSONScanner::TokenColon) { | |
226 error_ = true; | |
227 return false; | |
228 } | |
229 scanner_.Scan(); | |
230 switch (scanner_.CurrentToken()) { | |
231 case JSONScanner::TokenString: | |
232 case JSONScanner::TokenInteger: | |
233 case JSONScanner::TokenLBrace: | |
234 case JSONScanner::TokenLBrack: | |
235 case JSONScanner::TokenTrue: | |
236 case JSONScanner::TokenFalse: | |
237 case JSONScanner::TokenNull: | |
238 // Found a legal value. | |
239 if (found) { | |
240 return true; | |
241 } | |
242 break; | |
243 default: | |
244 error_ = true; | |
245 return false; | |
246 } | |
247 // Skip the value. | |
248 if (scanner_.CurrentToken() == JSONScanner::TokenLBrace) { | |
249 scanner_.Skip(JSONScanner::TokenRBrace); | |
250 if (scanner_.CurrentToken() != JSONScanner::TokenRBrace) { | |
251 error_ = true; | |
252 return false; | |
253 } | |
254 } else if (scanner_.CurrentToken() == JSONScanner::TokenLBrack) { | |
255 scanner_.Skip(JSONScanner::TokenRBrack); | |
256 if (scanner_.CurrentToken() != JSONScanner::TokenRBrack) { | |
257 error_ = true; | |
258 return false; | |
259 } | |
260 } | |
261 scanner_.Scan(); // Value or closing brace or bracket. | |
262 if (scanner_.CurrentToken() == JSONScanner::TokenComma) { | |
263 scanner_.Scan(); | |
264 } else { | |
265 // End of json object or malformed object. Value not found. | |
266 error_ = true; | |
267 break; | |
268 } | |
269 } | |
270 return false; | |
271 } | |
272 | |
273 | |
274 JSONReader::JSONType JSONReader::Type() const { | |
275 if (error_) { | |
276 return kNone; | |
277 } | |
278 switch (scanner_.CurrentToken()) { | |
279 case JSONScanner::TokenString: | |
280 return kString; | |
281 case JSONScanner::TokenInteger: | |
282 return kInteger; | |
283 case JSONScanner::TokenLBrace: | |
284 return kObject; | |
285 case JSONScanner::TokenLBrack: | |
286 return kArray; | |
287 case JSONScanner::TokenTrue: | |
288 case JSONScanner::TokenFalse: | |
289 case JSONScanner::TokenNull: | |
290 return kLiteral; | |
291 default: | |
292 return kNone; | |
293 } | |
294 } | |
295 | |
296 | |
297 TextBuffer::TextBuffer(intptr_t buf_size) { | |
298 ASSERT(buf_size > 0); | |
299 buf_ = reinterpret_cast<char*>(malloc(buf_size)); | |
300 buf_size_ = buf_size; | |
301 Clear(); | |
302 } | |
303 | |
304 | |
305 TextBuffer::~TextBuffer() { | |
306 free(buf_); | |
307 buf_ = NULL; | |
308 } | |
309 | |
310 | |
311 void TextBuffer::Clear() { | |
312 msg_len_ = 0; | |
313 buf_[0] = '\0'; | |
314 } | |
315 | |
316 | |
317 intptr_t TextBuffer::Printf(const char* format, ...) { | |
318 va_list args; | |
319 va_start(args, format); | |
320 intptr_t remaining = buf_size_ - msg_len_; | |
321 ASSERT(remaining >= 0); | |
322 intptr_t len = OS::VSNPrint(buf_ + msg_len_, remaining, format, args); | |
323 va_end(args); | |
324 if (len >= remaining) { | |
325 const int kBufferSpareCapacity = 64; // Somewhat arbitrary. | |
326 GrowBuffer(len + kBufferSpareCapacity); | |
327 remaining = buf_size_ - msg_len_; | |
328 ASSERT(remaining > len); | |
329 va_list args2; | |
330 va_start(args2, format); | |
331 intptr_t len2 = OS::VSNPrint(buf_ + msg_len_, remaining, format, args2); | |
332 va_end(args2); | |
333 ASSERT(len == len2); | |
334 } | |
335 msg_len_ += len; | |
336 buf_[msg_len_] = '\0'; | |
337 return len; | |
338 } | |
339 | |
340 | |
341 void TextBuffer::GrowBuffer(intptr_t len) { | |
342 intptr_t new_size = buf_size_ + len; | |
343 char* new_buf = reinterpret_cast<char*>(realloc(buf_, new_size)); | |
344 ASSERT(new_buf != NULL); | |
345 buf_ = new_buf; | |
346 buf_size_ = new_size; | |
347 } | |
348 | |
349 } // namespace dart | |
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