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1 //
2 // Copyright (C) 2002-2005  3Dlabs Inc. Ltd.
3 // Copyright (C) 2013 LunarG, Inc.
4 //
5 // All rights reserved.
6 //
7 // Redistribution and use in source and binary forms, with or without
8 // modification, are permitted provided that the following conditions
9 // are met:
10 //
11 //    Redistributions of source code must retain the above copyright
12 //    notice, this list of conditions and the following disclaimer.
13 //
14 //    Redistributions in binary form must reproduce the above
15 //    copyright notice, this list of conditions and the following
16 //    disclaimer in the documentation and/or other materials provided
17 //    with the distribution.
18 //
19 //    Neither the name of 3Dlabs Inc. Ltd. nor the names of its
20 //    contributors may be used to endorse or promote products derived
21 //    from this software without specific prior written permission.
22 //
23 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
24 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
25 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
26 // FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
27 // COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
28 // INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
29 // BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
30 // LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
31 // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 // LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
33 // ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
34 // POSSIBILITY OF SUCH DAMAGE.
35 //
36 #ifndef _GLSLANG_SCAN_INCLUDED_
37 #define _GLSLANG_SCAN_INCLUDED_
38 
39 #include "Versions.h"
40 
41 namespace glslang {
42 
43 // Use a global end-of-input character, so no translation is needed across
44 // layers of encapsulation.  Characters are all 8 bit, and positive, so there is
45 // no aliasing of character 255 onto -1, for example.
46 const int EndOfInput = -1;
47 
48 //
49 // A character scanner that seamlessly, on read-only strings, reads across an
50 // array of strings without assuming null termination.
51 //
52 class TInputScanner {
53 public:
54     TInputScanner(int n, const char* const s[], size_t L[], const char* const* names = nullptr,
55                   int b = 0, int f = 0, bool single = false) :
numSources(n)56         numSources(n),
57          // up to this point, common usage is "char*", but now we need positive 8-bit characters
58         sources(reinterpret_cast<const unsigned char* const *>(s)),
59         lengths(L), currentSource(0), currentChar(0), stringBias(b), finale(f), singleLogical(single),
60         endOfFileReached(false)
61     {
62         loc = new TSourceLoc[numSources];
63         for (int i = 0; i < numSources; ++i) {
64             loc[i].init(i - stringBias);
65         }
66         if (names != nullptr) {
67             for (int i = 0; i < numSources; ++i)
68                 loc[i].name = names[i] != nullptr ? NewPoolTString(names[i]) : nullptr;
69         }
70         loc[currentSource].line = 1;
71         logicalSourceLoc.init(1);
72         logicalSourceLoc.name = loc[0].name;
73     }
74 
~TInputScanner()75     virtual ~TInputScanner()
76     {
77         delete [] loc;
78     }
79 
80     // retrieve the next character and advance one character
get()81     int get()
82     {
83         int ret = peek();
84         if (ret == EndOfInput)
85             return ret;
86         ++loc[currentSource].column;
87         ++logicalSourceLoc.column;
88         if (ret == '\n') {
89             ++loc[currentSource].line;
90             ++logicalSourceLoc.line;
91             logicalSourceLoc.column = 0;
92             loc[currentSource].column = 0;
93         }
94         advance();
95 
96         return ret;
97     }
98 
99     // retrieve the next character, no advance
peek()100     int peek()
101     {
102         if (currentSource >= numSources) {
103             endOfFileReached = true;
104             return EndOfInput;
105         }
106         // Make sure we do not read off the end of a string.
107         // N.B. Sources can have a length of 0.
108         int sourceToRead = currentSource;
109         size_t charToRead = currentChar;
110         while(charToRead >= lengths[sourceToRead]) {
111             charToRead = 0;
112             sourceToRead += 1;
113             if (sourceToRead >= numSources) {
114                 return EndOfInput;
115             }
116         }
117 
118         // Here, we care about making negative valued characters positive
119         return sources[sourceToRead][charToRead];
120     }
121 
122     // go back one character
unget()123     void unget()
124     {
125         // Do not roll back once we've reached the end of the file.
126         if (endOfFileReached)
127             return;
128 
129         if (currentChar > 0) {
130             --currentChar;
131             --loc[currentSource].column;
132             --logicalSourceLoc.column;
133             if (loc[currentSource].column < 0) {
134                 // We've moved back past a new line. Find the
135                 // previous newline (or start of the file) to compute
136                 // the column count on the now current line.
137                 size_t chIndex = currentChar;
138                 while (chIndex > 0) {
139                     if (sources[currentSource][chIndex] == '\n') {
140                         break;
141                     }
142                     --chIndex;
143                 }
144                 logicalSourceLoc.column = (int)(currentChar - chIndex);
145                 loc[currentSource].column = (int)(currentChar - chIndex);
146             }
147         } else {
148             do {
149                 --currentSource;
150             } while (currentSource > 0 && lengths[currentSource] == 0);
151             if (lengths[currentSource] == 0) {
152                 // set to 0 if we've backed up to the start of an empty string
153                 currentChar = 0;
154             } else
155                 currentChar = lengths[currentSource] - 1;
156         }
157         if (peek() == '\n') {
158             --loc[currentSource].line;
159             --logicalSourceLoc.line;
160         }
161     }
162 
163     // for #line override
setLine(int newLine)164     void setLine(int newLine)
165     {
166         logicalSourceLoc.line = newLine;
167         loc[getLastValidSourceIndex()].line = newLine;
168     }
169 
170     // for #line override in filename based parsing
setFile(const char * filename)171     void setFile(const char* filename)
172     {
173         TString* fn_tstr = NewPoolTString(filename);
174         logicalSourceLoc.name = fn_tstr;
175         loc[getLastValidSourceIndex()].name = fn_tstr;
176     }
177 
setFile(const char * filename,int i)178     void setFile(const char* filename, int i)
179     {
180         TString* fn_tstr = NewPoolTString(filename);
181         if (i == getLastValidSourceIndex()) {
182             logicalSourceLoc.name = fn_tstr;
183         }
184         loc[i].name = fn_tstr;
185     }
186 
setString(int newString)187     void setString(int newString)
188     {
189         logicalSourceLoc.string = newString;
190         loc[getLastValidSourceIndex()].string = newString;
191         logicalSourceLoc.name = nullptr;
192         loc[getLastValidSourceIndex()].name = nullptr;
193     }
194 
195     // for #include content indentation
setColumn(int col)196     void setColumn(int col)
197     {
198         logicalSourceLoc.column = col;
199         loc[getLastValidSourceIndex()].column = col;
200     }
201 
setEndOfInput()202     void setEndOfInput()
203     {
204         endOfFileReached = true;
205         currentSource = numSources;
206     }
207 
atEndOfInput()208     bool atEndOfInput() const { return endOfFileReached; }
209 
getSourceLoc()210     const TSourceLoc& getSourceLoc() const
211     {
212         if (singleLogical) {
213             return logicalSourceLoc;
214         } else {
215             return loc[std::max(0, std::min(currentSource, numSources - finale - 1))];
216         }
217     }
218     // Returns the index (starting from 0) of the most recent valid source string we are reading from.
getLastValidSourceIndex()219     int getLastValidSourceIndex() const { return std::min(currentSource, numSources - 1); }
220 
221     void consumeWhiteSpace(bool& foundNonSpaceTab);
222     bool consumeComment();
223     void consumeWhitespaceComment(bool& foundNonSpaceTab);
224     bool scanVersion(int& version, EProfile& profile, bool& notFirstToken);
225 
226 protected:
227 
228     // advance one character
advance()229     void advance()
230     {
231         ++currentChar;
232         if (currentChar >= lengths[currentSource]) {
233             ++currentSource;
234             if (currentSource < numSources) {
235                 loc[currentSource].string = loc[currentSource - 1].string + 1;
236                 loc[currentSource].line = 1;
237                 loc[currentSource].column = 0;
238             }
239             while (currentSource < numSources && lengths[currentSource] == 0) {
240                 ++currentSource;
241                 if (currentSource < numSources) {
242                     loc[currentSource].string = loc[currentSource - 1].string + 1;
243                     loc[currentSource].line = 1;
244                     loc[currentSource].column = 0;
245                 }
246             }
247             currentChar = 0;
248         }
249     }
250 
251     int numSources;                      // number of strings in source
252     const unsigned char* const *sources; // array of strings; must be converted to positive values on use, to avoid aliasing with -1 as EndOfInput
253     const size_t *lengths;               // length of each string
254     int currentSource;
255     size_t currentChar;
256 
257     // This is for reporting what string/line an error occurred on, and can be overridden by #line.
258     // It remembers the last state of each source string as it is left for the next one, so unget()
259     // can restore that state.
260     TSourceLoc* loc;  // an array
261 
262     int stringBias;   // the first string that is the user's string number 0
263     int finale;       // number of internal strings after user's last string
264 
265     TSourceLoc logicalSourceLoc;
266     bool singleLogical; // treats the strings as a single logical string.
267                         // locations will be reported from the first string.
268 
269     // Set to true once peek() returns EndOfFile, so that we won't roll back
270     // once we've reached EndOfFile.
271     bool endOfFileReached;
272 };
273 
274 } // end namespace glslang
275 
276 #endif // _GLSLANG_SCAN_INCLUDED_
277