1 /***************************************************************************/
2 /* */
3 /* psstack.c */
4 /* */
5 /* Adobe's code for emulating a CFF stack (body). */
6 /* */
7 /* Copyright 2007-2013 Adobe Systems Incorporated. */
8 /* */
9 /* This software, and all works of authorship, whether in source or */
10 /* object code form as indicated by the copyright notice(s) included */
11 /* herein (collectively, the "Work") is made available, and may only be */
12 /* used, modified, and distributed under the FreeType Project License, */
13 /* LICENSE.TXT. Additionally, subject to the terms and conditions of the */
14 /* FreeType Project License, each contributor to the Work hereby grants */
15 /* to any individual or legal entity exercising permissions granted by */
16 /* the FreeType Project License and this section (hereafter, "You" or */
17 /* "Your") a perpetual, worldwide, non-exclusive, no-charge, */
18 /* royalty-free, irrevocable (except as stated in this section) patent */
19 /* license to make, have made, use, offer to sell, sell, import, and */
20 /* otherwise transfer the Work, where such license applies only to those */
21 /* patent claims licensable by such contributor that are necessarily */
22 /* infringed by their contribution(s) alone or by combination of their */
23 /* contribution(s) with the Work to which such contribution(s) was */
24 /* submitted. If You institute patent litigation against any entity */
25 /* (including a cross-claim or counterclaim in a lawsuit) alleging that */
26 /* the Work or a contribution incorporated within the Work constitutes */
27 /* direct or contributory patent infringement, then any patent licenses */
28 /* granted to You under this License for that Work shall terminate as of */
29 /* the date such litigation is filed. */
30 /* */
31 /* By using, modifying, or distributing the Work you indicate that you */
32 /* have read and understood the terms and conditions of the */
33 /* FreeType Project License as well as those provided in this section, */
34 /* and you accept them fully. */
35 /* */
36 /***************************************************************************/
37
38
39 #include "psft.h"
40 #include FT_INTERNAL_DEBUG_H
41
42 #include "psglue.h"
43 #include "psfont.h"
44 #include "psstack.h"
45
46 #include "pserror.h"
47
48
49 /* Allocate and initialize an instance of CF2_Stack. */
50 /* Note: This function returns NULL on error (does not set */
51 /* `error'). */
52 FT_LOCAL_DEF( CF2_Stack )
53 cf2_stack_init( FT_Memory memory,
54 FT_Error* e,
55 FT_UInt stackSize )
56 {
57 FT_Error error = FT_Err_Ok; /* for FT_NEW */
58
59 CF2_Stack stack = NULL;
60
61
62 if ( !FT_NEW( stack ) )
63 {
64 /* initialize the structure; FT_NEW zeroes it */
65 stack->memory = memory;
66 stack->error = e;
67 }
68
69 /* allocate the stack buffer */
70 if ( FT_NEW_ARRAY( stack->buffer, stackSize ) )
71 {
72 FT_FREE( stack );
73 return NULL;
74 }
75
76 stack->stackSize = stackSize;
77 stack->top = stack->buffer; /* empty stack */
78
79 return stack;
80 }
81
82
83 FT_LOCAL_DEF( void )
84 cf2_stack_free( CF2_Stack stack )
85 {
86 if ( stack )
87 {
88 FT_Memory memory = stack->memory;
89
90 /* free the buffer */
91 FT_FREE( stack->buffer );
92
93 /* free the main structure */
94 FT_FREE( stack );
95 }
96 }
97
98
99 FT_LOCAL_DEF( CF2_UInt )
100 cf2_stack_count( CF2_Stack stack )
101 {
102 return (CF2_UInt)( stack->top - stack->buffer );
103 }
104
105
106 FT_LOCAL_DEF( void )
107 cf2_stack_pushInt( CF2_Stack stack,
108 CF2_Int val )
109 {
110 if ( stack->top == stack->buffer + stack->stackSize )
111 {
112 CF2_SET_ERROR( stack->error, Stack_Overflow );
113 return; /* stack overflow */
114 }
115
116 stack->top->u.i = val;
117 stack->top->type = CF2_NumberInt;
118 stack->top++;
119 }
120
121
122 FT_LOCAL_DEF( void )
123 cf2_stack_pushFixed( CF2_Stack stack,
124 CF2_Fixed val )
125 {
126 if ( stack->top == stack->buffer + stack->stackSize )
127 {
128 CF2_SET_ERROR( stack->error, Stack_Overflow );
129 return; /* stack overflow */
130 }
131
132 stack->top->u.r = val;
133 stack->top->type = CF2_NumberFixed;
134 stack->top++;
135 }
136
137
138 /* this function is only allowed to pop an integer type */
139 FT_LOCAL_DEF( CF2_Int )
140 cf2_stack_popInt( CF2_Stack stack )
141 {
142 if ( stack->top == stack->buffer )
143 {
144 CF2_SET_ERROR( stack->error, Stack_Underflow );
145 return 0; /* underflow */
146 }
147 if ( stack->top[-1].type != CF2_NumberInt )
148 {
149 CF2_SET_ERROR( stack->error, Syntax_Error );
150 return 0; /* type mismatch */
151 }
152
153 stack->top--;
154
155 return stack->top->u.i;
156 }
157
158
159 /* Note: type mismatch is silently cast */
160 /* TODO: check this */
161 FT_LOCAL_DEF( CF2_Fixed )
162 cf2_stack_popFixed( CF2_Stack stack )
163 {
164 if ( stack->top == stack->buffer )
165 {
166 CF2_SET_ERROR( stack->error, Stack_Underflow );
167 return cf2_intToFixed( 0 ); /* underflow */
168 }
169
170 stack->top--;
171
172 switch ( stack->top->type )
173 {
174 case CF2_NumberInt:
175 return cf2_intToFixed( stack->top->u.i );
176 case CF2_NumberFrac:
177 return cf2_fracToFixed( stack->top->u.f );
178 default:
179 return stack->top->u.r;
180 }
181 }
182
183
184 /* Note: type mismatch is silently cast */
185 /* TODO: check this */
186 FT_LOCAL_DEF( CF2_Fixed )
187 cf2_stack_getReal( CF2_Stack stack,
188 CF2_UInt idx )
189 {
190 FT_ASSERT( cf2_stack_count( stack ) <= stack->stackSize );
191
192 if ( idx >= cf2_stack_count( stack ) )
193 {
194 CF2_SET_ERROR( stack->error, Stack_Overflow );
195 return cf2_intToFixed( 0 ); /* bounds error */
196 }
197
198 switch ( stack->buffer[idx].type )
199 {
200 case CF2_NumberInt:
201 return cf2_intToFixed( stack->buffer[idx].u.i );
202 case CF2_NumberFrac:
203 return cf2_fracToFixed( stack->buffer[idx].u.f );
204 default:
205 return stack->buffer[idx].u.r;
206 }
207 }
208
209
210 /* provide random access to stack */
211 FT_LOCAL_DEF( void )
212 cf2_stack_setReal( CF2_Stack stack,
213 CF2_UInt idx,
214 CF2_Fixed val )
215 {
216 if ( idx > cf2_stack_count( stack ) )
217 {
218 CF2_SET_ERROR( stack->error, Stack_Overflow );
219 return;
220 }
221
222 stack->buffer[idx].u.r = val;
223 stack->buffer[idx].type = CF2_NumberFixed;
224 }
225
226
227 /* discard (pop) num values from stack */
228 FT_LOCAL_DEF( void )
229 cf2_stack_pop( CF2_Stack stack,
230 CF2_UInt num )
231 {
232 if ( num > cf2_stack_count( stack ) )
233 {
234 CF2_SET_ERROR( stack->error, Stack_Underflow );
235 return;
236 }
237 stack->top -= num;
238 }
239
240
241 FT_LOCAL_DEF( void )
242 cf2_stack_roll( CF2_Stack stack,
243 CF2_Int count,
244 CF2_Int shift )
245 {
246 /* we initialize this variable to avoid compiler warnings */
247 CF2_StackNumber last = { { 0 }, CF2_NumberInt };
248
249 CF2_Int start_idx, idx, i;
250
251
252 if ( count < 2 )
253 return; /* nothing to do (values 0 and 1), or undefined value */
254
255 if ( (CF2_UInt)count > cf2_stack_count( stack ) )
256 {
257 CF2_SET_ERROR( stack->error, Stack_Overflow );
258 return;
259 }
260
261 if ( shift < 0 )
262 shift = -( ( -shift ) % count );
263 else
264 shift %= count;
265
266 if ( shift == 0 )
267 return; /* nothing to do */
268
269 /* We use the following algorithm to do the rolling, */
270 /* which needs two temporary variables only. */
271 /* */
272 /* Example: */
273 /* */
274 /* count = 8 */
275 /* shift = 2 */
276 /* */
277 /* stack indices before roll: 7 6 5 4 3 2 1 0 */
278 /* stack indices after roll: 1 0 7 6 5 4 3 2 */
279 /* */
280 /* The value of index 0 gets moved to index 2, while */
281 /* the old value of index 2 gets moved to index 4, */
282 /* and so on. We thus have the following copying */
283 /* chains for shift value 2. */
284 /* */
285 /* 0 -> 2 -> 4 -> 6 -> 0 */
286 /* 1 -> 3 -> 5 -> 7 -> 1 */
287 /* */
288 /* If `count' and `shift' are incommensurable, we */
289 /* have a single chain only. Otherwise, increase */
290 /* the start index by 1 after the first chain, then */
291 /* do the next chain until all elements in all */
292 /* chains are handled. */
293
294 start_idx = -1;
295 idx = -1;
296 for ( i = 0; i < count; i++ )
297 {
298 CF2_StackNumber tmp;
299
300
301 if ( start_idx == idx )
302 {
303 start_idx++;
304 idx = start_idx;
305 last = stack->buffer[idx];
306 }
307
308 idx += shift;
309 if ( idx >= count )
310 idx -= count;
311 else if ( idx < 0 )
312 idx += count;
313
314 tmp = stack->buffer[idx];
315 stack->buffer[idx] = last;
316 last = tmp;
317 }
318 }
319
320
321 FT_LOCAL_DEF( void )
322 cf2_stack_clear( CF2_Stack stack )
323 {
324 stack->top = stack->buffer;
325 }
326
327
328 /* END */