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 <freetype/internal/ftdebug.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; /* for FT_QNEW */
58 CF2_Stack stack = NULL;
59
60
61 if ( FT_QNEW( stack ) )
62 return NULL;
63
64 stack->memory = memory;
65 stack->error = e;
66
67 /* allocate the stack buffer */
68 if ( FT_QNEW_ARRAY( stack->buffer, stackSize ) )
69 {
70 FT_FREE( stack );
71 return NULL;
72 }
73
74 stack->stackSize = stackSize;
75 stack->top = stack->buffer; /* empty stack */
76
77 return stack;
78 }
79
80
81 FT_LOCAL_DEF( void )
82 cf2_stack_free( CF2_Stack stack )
83 {
84 if ( stack )
85 {
86 FT_Memory memory = stack->memory;
87
88 /* free the buffer */
89 FT_FREE( stack->buffer );
90
91 /* free the main structure */
92 FT_FREE( stack );
93 }
94 }
95
96
97 FT_LOCAL_DEF( CF2_UInt )
98 cf2_stack_count( CF2_Stack stack )
99 {
100 return (CF2_UInt)( stack->top - stack->buffer );
101 }
102
103
104 FT_LOCAL_DEF( void )
105 cf2_stack_pushInt( CF2_Stack stack,
106 CF2_Int val )
107 {
108 if ( stack->top == stack->buffer + stack->stackSize )
109 {
110 CF2_SET_ERROR( stack->error, Stack_Overflow );
111 return; /* stack overflow */
112 }
113
114 stack->top->u.i = val;
115 stack->top->type = CF2_NumberInt;
116 stack->top++;
117 }
118
119
120 FT_LOCAL_DEF( void )
121 cf2_stack_pushFixed( CF2_Stack stack,
122 CF2_Fixed val )
123 {
124 if ( stack->top == stack->buffer + stack->stackSize )
125 {
126 CF2_SET_ERROR( stack->error, Stack_Overflow );
127 return; /* stack overflow */
128 }
129
130 stack->top->u.r = val;
131 stack->top->type = CF2_NumberFixed;
132 stack->top++;
133 }
134
135
136 /* this function is only allowed to pop an integer type */
137 FT_LOCAL_DEF( CF2_Int )
138 cf2_stack_popInt( CF2_Stack stack )
139 {
140 if ( stack->top == stack->buffer )
141 {
142 CF2_SET_ERROR( stack->error, Stack_Underflow );
143 return 0; /* underflow */
144 }
145 if ( stack->top[-1].type != CF2_NumberInt )
146 {
147 CF2_SET_ERROR( stack->error, Syntax_Error );
148 return 0; /* type mismatch */
149 }
150
151 stack->top--;
152
153 return stack->top->u.i;
154 }
155
156
157 /* Note: type mismatch is silently cast */
158 /* TODO: check this */
159 FT_LOCAL_DEF( CF2_Fixed )
160 cf2_stack_popFixed( CF2_Stack stack )
161 {
162 if ( stack->top == stack->buffer )
163 {
164 CF2_SET_ERROR( stack->error, Stack_Underflow );
165 return cf2_intToFixed( 0 ); /* underflow */
166 }
167
168 stack->top--;
169
170 switch ( stack->top->type )
171 {
172 case CF2_NumberInt:
173 return cf2_intToFixed( stack->top->u.i );
174 case CF2_NumberFrac:
175 return cf2_fracToFixed( stack->top->u.f );
176 default:
177 return stack->top->u.r;
178 }
179 }
180
181
182 /* Note: type mismatch is silently cast */
183 /* TODO: check this */
184 FT_LOCAL_DEF( CF2_Fixed )
185 cf2_stack_getReal( CF2_Stack stack,
186 CF2_UInt idx )
187 {
188 FT_ASSERT( cf2_stack_count( stack ) <= stack->stackSize );
189
190 if ( idx >= cf2_stack_count( stack ) )
191 {
192 CF2_SET_ERROR( stack->error, Stack_Overflow );
193 return cf2_intToFixed( 0 ); /* bounds error */
194 }
195
196 switch ( stack->buffer[idx].type )
197 {
198 case CF2_NumberInt:
199 return cf2_intToFixed( stack->buffer[idx].u.i );
200 case CF2_NumberFrac:
201 return cf2_fracToFixed( stack->buffer[idx].u.f );
202 default:
203 return stack->buffer[idx].u.r;
204 }
205 }
206
207
208 /* provide random access to stack */
209 FT_LOCAL_DEF( void )
210 cf2_stack_setReal( CF2_Stack stack,
211 CF2_UInt idx,
212 CF2_Fixed val )
213 {
214 if ( idx > cf2_stack_count( stack ) )
215 {
216 CF2_SET_ERROR( stack->error, Stack_Overflow );
217 return;
218 }
219
220 stack->buffer[idx].u.r = val;
221 stack->buffer[idx].type = CF2_NumberFixed;
222 }
223
224
225 /* discard (pop) num values from stack */
226 FT_LOCAL_DEF( void )
227 cf2_stack_pop( CF2_Stack stack,
228 CF2_UInt num )
229 {
230 if ( num > cf2_stack_count( stack ) )
231 {
232 CF2_SET_ERROR( stack->error, Stack_Underflow );
233 return;
234 }
235 stack->top -= num;
236 }
237
238
239 FT_LOCAL_DEF( void )
240 cf2_stack_roll( CF2_Stack stack,
241 CF2_Int count,
242 CF2_Int shift )
243 {
244 /* we initialize this variable to avoid compiler warnings */
245 CF2_StackNumber last = { { 0 }, CF2_NumberInt };
246
247 CF2_Int start_idx, idx, i;
248
249
250 if ( count < 2 )
251 return; /* nothing to do (values 0 and 1), or undefined value */
252
253 if ( (CF2_UInt)count > cf2_stack_count( stack ) )
254 {
255 CF2_SET_ERROR( stack->error, Stack_Overflow );
256 return;
257 }
258
259 /* before C99 it is implementation-defined whether */
260 /* the result of `%' is negative if the first operand */
261 /* is negative */
262 if ( shift < 0 )
263 shift = -( ( -shift ) % count );
264 else
265 shift %= count;
266
267 if ( shift == 0 )
268 return; /* nothing to do */
269
270 /* We use the following algorithm to do the rolling, */
271 /* which needs two temporary variables only. */
272 /* */
273 /* Example: */
274 /* */
275 /* count = 8 */
276 /* shift = 2 */
277 /* */
278 /* stack indices before roll: 7 6 5 4 3 2 1 0 */
279 /* stack indices after roll: 1 0 7 6 5 4 3 2 */
280 /* */
281 /* The value of index 0 gets moved to index 2, while */
282 /* the old value of index 2 gets moved to index 4, */
283 /* and so on. We thus have the following copying */
284 /* chains for shift value 2. */
285 /* */
286 /* 0 -> 2 -> 4 -> 6 -> 0 */
287 /* 1 -> 3 -> 5 -> 7 -> 1 */
288 /* */
289 /* If `count' and `shift' are incommensurable, we */
290 /* have a single chain only. Otherwise, increase */
291 /* the start index by 1 after the first chain, then */
292 /* do the next chain until all elements in all */
293 /* chains are handled. */
294
295 start_idx = -1;
296 idx = -1;
297 for ( i = 0; i < count; i++ )
298 {
299 CF2_StackNumber tmp;
300
301
302 if ( start_idx == idx )
303 {
304 start_idx++;
305 idx = start_idx;
306 last = stack->buffer[idx];
307 }
308
309 idx += shift;
310 if ( idx >= count )
311 idx -= count;
312 else if ( idx < 0 )
313 idx += count;
314
315 tmp = stack->buffer[idx];
316 stack->buffer[idx] = last;
317 last = tmp;
318 }
319 }
320
321
322 FT_LOCAL_DEF( void )
323 cf2_stack_clear( CF2_Stack stack )
324 {
325 stack->top = stack->buffer;
326 }
327
328
329 /* END */