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3// Copyright (C) 2013 LunarG, Inc.
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36#ifndef _GLSLANG_SCAN_INCLUDED_
37#define _GLSLANG_SCAN_INCLUDED_
38
39#include "Versions.h"
40
41namespace 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.
46const 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//
52class TInputScanner {
53public:
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) :
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
75 virtual ~TInputScanner()
76 {
77 delete [] loc;
78 }
79
80 // retrieve the next character and advance one character
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
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
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
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
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
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
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
196 void setColumn(int col)
197 {
198 logicalSourceLoc.column = col;
199 loc[getLastValidSourceIndex()].column = col;
200 }
201
202 void setEndOfInput()
203 {
204 endOfFileReached = true;
205 currentSource = numSources;
206 }
207
208 bool atEndOfInput() const { return endOfFileReached; }
209
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.
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
226protected:
227
228 // advance one character
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