1 /**
2 * \file lengthcommon.cpp
3 * This file is part of LyX, the document processor.
4 * Licence details can be found in the file COPYING.
5 *
6 * \author Lars Gullik Bjønnes
7 * \author Matthias Ettrich
8 * \author John Levon
9 *
10 * Full author contact details are available in file CREDITS.
11 */
12
13 #include <config.h>
14
15 #include "Length.h"
16
17 #include "support/convert.h"
18 #include "support/gettext.h"
19 #include "support/lassert.h"
20 #include "support/lstrings.h"
21
22 using namespace std;
23 using namespace lyx::support;
24
25
26 namespace lyx {
27
28 // I am not sure if "mu" should be possible to select (Lgb)
29
30 // the latex units
31 char const * const unit_name[] = {
32 "bp", "cc", "cm", "dd", "em", "ex", "in", "mm", "mu",
33 "pc", "pt", "sp",
34 "text%", "col%", "page%", "line%",
35 "theight%", "pheight%", "baselineskip%", "" };
36
37 int const num_units = int(sizeof(unit_name) / sizeof(unit_name[0]) - 1);
38
39 // the LyX gui units
40 char const * const unit_name_gui[] = {
41 N_("bp"), N_("cc[[unit of measure]]"), N_("cm"), N_("dd"), N_("em"),
42 N_("ex"), N_("in[[unit of measure]]"), N_("mm"), N_("mu[[unit of measure]]"), N_("pc"),
43 N_("pt"), N_("sp"), N_("Text Width %"),
44 N_("Column Width %"), N_("Page Width %"), N_("Line Width %"),
45 N_("Text Height %"), N_("Page Height %"), N_("Line Distance %"), "" };
46
47
unitFromString(string const & data)48 Length::UNIT unitFromString(string const & data)
49 {
50 int i = 0;
51 while (i < num_units && data != unit_name[i])
52 ++i;
53 return static_cast<Length::UNIT>(i);
54 }
55
56
57 namespace {
58
59 /// skip n characters of input
lyx_advance(string & data,size_t n)60 inline void lyx_advance(string & data, size_t n)
61 {
62 data.erase(0, n);
63 }
64
65
66 /// return true when the input is at the end
isEndOfData(string const & data)67 inline bool isEndOfData(string const & data)
68 {
69 return ltrim(data).empty();
70 }
71
72
73 /**
74 * nextToken - return the next token in the input
75 * @param data input string
76 * @param number_index the current position in the number array
77 * @param unit_index the current position in the unit array
78 * @return a char representing the type of token returned
79 *
80 * The possible return values are :
81 * + stretch indicator for glue length
82 * - shrink indicator for glue length
83 * n a numeric value (stored in number array)
84 * u a unit type (stored in unit array)
85 * E parse error
86 */
nextToken(string & data,double * number,int & number_index,Length::UNIT * unit,int & unit_index)87 char nextToken(string & data, double * number, int & number_index,
88 Length::UNIT * unit, int & unit_index)
89 {
90 data = ltrim(data);
91
92 if (data.empty())
93 return '\0';
94
95 if (data[0] == '+') {
96 lyx_advance(data, 1);
97 return '+';
98 }
99
100 if (prefixIs(data, "plus")) {
101 lyx_advance(data, 4);
102 return '+';
103 }
104
105 if (data[0] == '-') {
106 lyx_advance(data, 1);
107 return '-';
108 }
109
110 if (prefixIs(data, "minus")) {
111 lyx_advance(data, 5);
112 return '-';
113 }
114
115 size_t i = data.find_first_not_of("0123456789.");
116
117 if (i != 0) {
118 if (number_index > 3)
119 return 'E';
120
121 string buffer;
122
123 // we have found some number
124 if (i == string::npos) {
125 buffer = data;
126 i = data.size() + 1;
127 } else {
128 buffer = data.substr(0, i);
129 }
130
131 lyx_advance(data, i);
132
133 if (isStrDbl(buffer)) {
134 number[number_index] = convert<double>(buffer);
135 ++number_index;
136 return 'n';
137 }
138 return 'E';
139 }
140
141 i = data.find_first_not_of("abcdefghijklmnopqrstuvwxyz%");
142 if (i != 0) {
143 if (unit_index > 3)
144 return 'E';
145
146 string buffer;
147
148 // we have found some alphabetical string
149 if (i == string::npos) {
150 buffer = data;
151 i = data.size() + 1;
152 } else {
153 buffer = data.substr(0, i);
154 }
155
156 // possibly we have "mmplus" string or similar
157 if (buffer.size() > 5 &&
158 (buffer.substr(2, 4) == string("plus") ||
159 buffer.substr(2, 5) == string("minus")))
160 {
161 lyx_advance(data, 2);
162 unit[unit_index] = unitFromString(buffer.substr(0, 2));
163 } else {
164 lyx_advance(data, i);
165 unit[unit_index] = unitFromString(buffer);
166 }
167
168 if (unit[unit_index] != Length::UNIT_NONE) {
169 ++unit_index;
170 return 'u';
171 }
172 return 'E'; // Error
173 }
174 return 'E'; // Error
175 }
176
177
178 /// latex representation of a vspace
179 struct LaTeXLength {
180 char const * pattern;
181 int plus_val_index;
182 int minus_val_index;
183 int plus_uni_index;
184 int minus_uni_index;
185 };
186
187
188 /// the possible formats for a vspace string
189 LaTeXLength table[] = {
190 { "nu", 0, 0, 0, 0 },
191 { "nu+nu", 2, 0, 2, 0 },
192 { "nu+nu-nu", 2, 3, 2, 3 },
193 { "nu+-nu", 2, 2, 2, 2 },
194 { "nu-nu", 0, 2, 0, 2 },
195 { "nu-nu+nu", 3, 2, 3, 2 },
196 { "nu-+nu", 2, 2, 2, 2 },
197 { "n+nu", 2, 0, 1, 0 },
198 { "n+n-nu", 2, 3, 1, 1 },
199 { "n+-nu", 2, 2, 1, 1 },
200 { "n-nu", 0, 2, 0, 1 },
201 { "n-n+nu", 3, 2, 1, 1 },
202 { "n-+nu", 2, 2, 1, 1 },
203 { "", 0, 0, 0, 0 } // sentinel, must be empty
204 };
205
206
207 } // namespace
208
209
stringFromUnit(int unit)210 const char * stringFromUnit(int unit)
211 {
212 if (unit < 0 || unit > num_units)
213 return 0;
214 return unit_name[unit];
215 }
216
217
isValidGlueLength(string const & data,GlueLength * result)218 bool isValidGlueLength(string const & data, GlueLength * result)
219 {
220 // This parser is table-driven. First, it constructs a "pattern"
221 // that describes the sequence of tokens in "data". For example,
222 // "n-nu" means: number, minus sign, number, unit. As we go along,
223 // numbers and units are stored into static arrays. Then, "pattern"
224 // is searched in the "table". If it is found, the associated
225 // table entries tell us which number and unit should go where
226 // in the Length structure. Example: if "data" has the "pattern"
227 // "nu+nu-nu", the associated table entries are "2, 3, 2, 3".
228 // That means, "plus_val" is the second number that was seen
229 // in the input, "minus_val" is the third number, and "plus_uni"
230 // and "minus_uni" are the second and third units, respectively.
231 // ("val" and "uni" are always the first items seen in "data".)
232 // This is the most elegant solution I could find -- a straight-
233 // forward approach leads to very long, tedious code that would be
234 // much harder to understand and maintain. (AS)
235
236 if (data.empty()) {
237 if (result)
238 *result = GlueLength();
239 return true;
240 }
241 string buffer = ltrim(data);
242
243 // To make isValidGlueLength recognize negative values as
244 // the first number this little hack is needed:
245 int val_sign = 1; // positive as default
246 switch (buffer[0]) {
247 case '-':
248 lyx_advance(buffer, 1);
249 val_sign = -1;
250 break;
251 case '+':
252 lyx_advance(buffer, 1);
253 break;
254 default:
255 break;
256 }
257 // end of hack
258
259 // used to return numeric values in parsing vspace
260 double number[4] = { 0, 0, 0, 0 };
261 // used to return unit types in parsing vspace
262 Length::UNIT unit[4] = {Length::UNIT_NONE, Length::UNIT_NONE,
263 Length::UNIT_NONE, Length::UNIT_NONE};
264 int number_index = 1; // entries at index 0 are sentinels
265 int unit_index = 1; // entries at index 0 are sentinels
266
267 // construct "pattern" from "data"
268 size_t const pattern_max_size = 20;
269 string pattern;
270 while (!isEndOfData(buffer)) {
271 if (pattern.size() > pattern_max_size)
272 return false;
273 char const c = nextToken(buffer, number, number_index, unit,
274 unit_index);
275 if (c == 'E')
276 return false;
277 pattern.push_back(c);
278 }
279
280 // search "pattern" in "table"
281 size_t table_index = 0;
282 while (pattern != table[table_index].pattern) {
283 ++table_index;
284 if (!*table[table_index].pattern)
285 return false;
286 }
287
288 // Get the values from the appropriate places. If an index
289 // is zero, the corresponding array value is zero or UNIT_NONE,
290 // so we needn't check this.
291 if (result) {
292 result->len_.value (number[1] * val_sign);
293 result->len_.unit (unit[1]);
294 result->plus_.value (number[table[table_index].plus_val_index]);
295 result->plus_.unit (unit [table[table_index].plus_uni_index]);
296 result->minus_.value(number[table[table_index].minus_val_index]);
297 result->minus_.unit (unit [table[table_index].minus_uni_index]);
298 }
299 return true;
300 }
301
302
isValidLength(string const & data,Length * result)303 bool isValidLength(string const & data, Length * result)
304 {
305 // This is a trimmed down version of isValidGlueLength.
306 // The parser may seem overkill for lengths without
307 // glue, but since we already have it, using it is
308 // easier than writing something from scratch.
309 if (data.empty()) {
310 if (result)
311 *result = Length();
312 return true;
313 }
314
315 string buffer = data;
316
317 // To make isValidLength recognize negative values
318 // this little hack is needed:
319 int val_sign = 1; // positive as default
320 switch (buffer[0]) {
321 case '-':
322 lyx_advance(buffer, 1);
323 val_sign = -1;
324 break;
325 case '+':
326 lyx_advance(buffer, 1);
327 // fall through
328 default:
329 // no action
330 break;
331 }
332 // end of hack
333
334 // used to return numeric values in parsing vspace
335 double number[4] = { 0, 0, 0, 0 };
336 // used to return unit types in parsing vspace
337 Length::UNIT unit[4] = {Length::UNIT_NONE, Length::UNIT_NONE,
338 Length::UNIT_NONE, Length::UNIT_NONE};
339 int number_index = 1; // entries at index 0 are sentinels
340 int unit_index = 1; // entries at index 0 are sentinels
341
342 // construct "pattern" from "data"
343 string pattern;
344 while (!isEndOfData(buffer)) {
345 if (pattern.size() > 2)
346 return false;
347 char const token = nextToken(buffer, number,
348 number_index, unit, unit_index);
349 if (token == 'E')
350 return false;
351 pattern += token;
352 }
353
354 // only the most basic pattern is accepted here
355 if (pattern != "nu")
356 return false;
357
358 // It _was_ a correct length string.
359 // Store away the values we found.
360 if (result) {
361 result->val_ = number[1] * val_sign;
362 result->unit_ = unit[1];
363 }
364 return true;
365 }
366
367 } // namespace lyx
368