1 /* Conversion loop frame work.
2 Copyright (C) 1998-2022 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19 /* This file provides a frame for the reader loop in all conversion modules.
20 The actual code must (of course) be provided in the actual module source
21 code but certain actions can be written down generically, with some
22 customization options which are these:
23
24 MIN_NEEDED_INPUT minimal number of input bytes needed for the next
25 conversion.
26 MIN_NEEDED_OUTPUT minimal number of bytes produced by the next round
27 of conversion.
28
29 MAX_NEEDED_INPUT you guess it, this is the maximal number of input
30 bytes needed. It defaults to MIN_NEEDED_INPUT
31 MAX_NEEDED_OUTPUT likewise for output bytes.
32
33 LOOPFCT name of the function created. If not specified
34 the name is `loop' but this prevents the use
35 of multiple functions in the same file.
36
37 BODY this is supposed to expand to the body of the loop.
38 The user must provide this.
39
40 EXTRA_LOOP_DECLS extra arguments passed from conversion loop call.
41
42 INIT_PARAMS code to define and initialize variables from params.
43 UPDATE_PARAMS code to store result in params.
44
45 ONEBYTE_BODY body of the specialized conversion function for a
46 single byte from the current character set to INTERNAL.
47 */
48
49 #include <assert.h>
50 #include <endian.h>
51 #include <iconv/gconv_int.h>
52 #include <stdint.h>
53 #include <string.h>
54 #include <wchar.h>
55 #include <sys/param.h> /* For MIN. */
56 #define __need_size_t
57 #include <stddef.h>
58 #include <libc-diag.h>
59
60 /* We have to provide support for machines which are not able to handled
61 unaligned memory accesses. Some of the character encodings have
62 representations with a fixed width of 2 or 4 bytes. But if we cannot
63 access unaligned memory we still have to read byte-wise. */
64 #undef FCTNAME2
65 #if _STRING_ARCH_unaligned || !defined DEFINE_UNALIGNED
66 /* We can handle unaligned memory access. */
67 # define get16(addr) *((const uint16_t *) (addr))
68 # define get32(addr) *((const uint32_t *) (addr))
69
70 /* We need no special support for writing values either. */
71 # define put16(addr, val) *((uint16_t *) (addr)) = (val)
72 # define put32(addr, val) *((uint32_t *) (addr)) = (val)
73
74 # define FCTNAME2(name) name
75 #else
76 /* Distinguish between big endian and little endian. */
77 # if __BYTE_ORDER == __LITTLE_ENDIAN
78 # define get16(addr) \
79 (((const unsigned char *) (addr))[1] << 8 \
80 | ((const unsigned char *) (addr))[0])
81 # define get32(addr) \
82 (((((const unsigned char *) (addr))[3] << 8 \
83 | ((const unsigned char *) (addr))[2]) << 8 \
84 | ((const unsigned char *) (addr))[1]) << 8 \
85 | ((const unsigned char *) (addr))[0])
86
87 # define put16(addr, val) \
88 ({ uint16_t __val = (val); \
89 ((unsigned char *) (addr))[0] = __val; \
90 ((unsigned char *) (addr))[1] = __val >> 8; \
91 (void) 0; })
92 # define put32(addr, val) \
93 ({ uint32_t __val = (val); \
94 ((unsigned char *) (addr))[0] = __val; \
95 __val >>= 8; \
96 ((unsigned char *) (addr))[1] = __val; \
97 __val >>= 8; \
98 ((unsigned char *) (addr))[2] = __val; \
99 __val >>= 8; \
100 ((unsigned char *) (addr))[3] = __val; \
101 (void) 0; })
102 # else
103 # define get16(addr) \
104 (((const unsigned char *) (addr))[0] << 8 \
105 | ((const unsigned char *) (addr))[1])
106 # define get32(addr) \
107 (((((const unsigned char *) (addr))[0] << 8 \
108 | ((const unsigned char *) (addr))[1]) << 8 \
109 | ((const unsigned char *) (addr))[2]) << 8 \
110 | ((const unsigned char *) (addr))[3])
111
112 # define put16(addr, val) \
113 ({ uint16_t __val = (val); \
114 ((unsigned char *) (addr))[1] = __val; \
115 ((unsigned char *) (addr))[0] = __val >> 8; \
116 (void) 0; })
117 # define put32(addr, val) \
118 ({ uint32_t __val = (val); \
119 ((unsigned char *) (addr))[3] = __val; \
120 __val >>= 8; \
121 ((unsigned char *) (addr))[2] = __val; \
122 __val >>= 8; \
123 ((unsigned char *) (addr))[1] = __val; \
124 __val >>= 8; \
125 ((unsigned char *) (addr))[0] = __val; \
126 (void) 0; })
127 # endif
128
129 # define FCTNAME2(name) name##_unaligned
130 #endif
131 #define FCTNAME(name) FCTNAME2(name)
132
133
134 /* We need at least one byte for the next round. */
135 #ifndef MIN_NEEDED_INPUT
136 # error "MIN_NEEDED_INPUT definition missing"
137 #elif MIN_NEEDED_INPUT < 1
138 # error "MIN_NEEDED_INPUT must be >= 1"
139 #endif
140
141 /* Let's see how many bytes we produce. */
142 #ifndef MAX_NEEDED_INPUT
143 # define MAX_NEEDED_INPUT MIN_NEEDED_INPUT
144 #endif
145
146 /* We produce at least one byte in the next round. */
147 #ifndef MIN_NEEDED_OUTPUT
148 # error "MIN_NEEDED_OUTPUT definition missing"
149 #elif MIN_NEEDED_OUTPUT < 1
150 # error "MIN_NEEDED_OUTPUT must be >= 1"
151 #endif
152
153 /* Let's see how many bytes we produce. */
154 #ifndef MAX_NEEDED_OUTPUT
155 # define MAX_NEEDED_OUTPUT MIN_NEEDED_OUTPUT
156 #endif
157
158 /* Default name for the function. */
159 #ifndef LOOPFCT
160 # define LOOPFCT loop
161 #endif
162
163 /* Make sure we have a loop body. */
164 #ifndef BODY
165 # error "Definition of BODY missing for function" LOOPFCT
166 #endif
167
168
169 /* If no arguments have to passed to the loop function define the macro
170 as empty. */
171 #ifndef EXTRA_LOOP_DECLS
172 # define EXTRA_LOOP_DECLS
173 #endif
174
175 /* Allow using UPDATE_PARAMS in macros where #ifdef UPDATE_PARAMS test
176 isn't possible. */
177 #ifndef UPDATE_PARAMS
178 # define UPDATE_PARAMS do { } while (0)
179 #endif
180 #ifndef REINIT_PARAMS
181 # define REINIT_PARAMS do { } while (0)
182 #endif
183
184
185 /* To make it easier for the writers of the modules, we define a macro
186 to test whether we have to ignore errors. */
187 #define ignore_errors_p() \
188 (irreversible != NULL && (flags & __GCONV_IGNORE_ERRORS))
189
190
191 /* Error handling for the FROM_LOOP direction, with ignoring of errors.
192 Note that we cannot use the do while (0) trick since `break' and
193 `continue' must reach certain points. */
194 #define STANDARD_FROM_LOOP_ERR_HANDLER(Incr) \
195 { \
196 result = __GCONV_ILLEGAL_INPUT; \
197 \
198 if (! ignore_errors_p ()) \
199 break; \
200 \
201 /* We ignore the invalid input byte sequence. */ \
202 inptr += (Incr); \
203 ++*irreversible; \
204 /* But we keep result == __GCONV_ILLEGAL_INPUT, because of the constraint \
205 that "iconv -c" must give the same exitcode as "iconv". */ \
206 continue; \
207 }
208
209 /* Error handling for the TO_LOOP direction, with use of transliteration/
210 transcription functions and ignoring of errors. Note that we cannot use
211 the do while (0) trick since `break' and `continue' must reach certain
212 points. */
213 #define STANDARD_TO_LOOP_ERR_HANDLER(Incr) \
214 { \
215 result = __GCONV_ILLEGAL_INPUT; \
216 \
217 if (irreversible == NULL) \
218 /* This means we are in call from __gconv_transliterate. In this \
219 case we are not doing any error recovery outself. */ \
220 break; \
221 \
222 /* If needed, flush any conversion state, so that __gconv_transliterate \
223 starts with current shift state. */ \
224 UPDATE_PARAMS; \
225 \
226 /* First try the transliteration methods. */ \
227 if ((step_data->__flags & __GCONV_TRANSLIT) != 0) \
228 result = __gconv_transliterate \
229 (step, step_data, *inptrp, \
230 &inptr, inend, &outptr, irreversible); \
231 \
232 REINIT_PARAMS; \
233 \
234 /* If any of them recognized the input continue with the loop. */ \
235 if (result != __GCONV_ILLEGAL_INPUT) \
236 { \
237 if (__glibc_unlikely (result == __GCONV_FULL_OUTPUT)) \
238 break; \
239 \
240 continue; \
241 } \
242 \
243 /* Next see whether we have to ignore the error. If not, stop. */ \
244 if (! ignore_errors_p ()) \
245 break; \
246 \
247 /* When we come here it means we ignore the character. */ \
248 ++*irreversible; \
249 inptr += Incr; \
250 /* But we keep result == __GCONV_ILLEGAL_INPUT, because of the constraint \
251 that "iconv -c" must give the same exitcode as "iconv". */ \
252 continue; \
253 }
254
255
256 /* With GCC 7 when compiling with -Os for 32-bit s390 the compiler
257 warns that the variable 'ch', in the definition of BODY in
258 sysdeps/s390/multiarch/8bit-generic.c, may be used uninitialized in
259 the call to UNICODE_TAG_HANDLER in that macro. This variable is
260 actually always initialized before use, in the prior loop if INDEX
261 is nonzero and in the following 'if' if INDEX is zero. That code
262 has a comment referencing this diagnostic disabling; updates in one
263 place may require updates in the other. */
264 DIAG_PUSH_NEEDS_COMMENT;
265 DIAG_IGNORE_Os_NEEDS_COMMENT (7, "-Wmaybe-uninitialized");
266 /* Handling of Unicode 3.1 TAG characters. Unicode recommends
267 "If language codes are not relevant to the particular processing
268 operation, then they should be ignored." This macro is usually
269 called right before STANDARD_TO_LOOP_ERR_HANDLER (Incr). */
270 #define UNICODE_TAG_HANDLER(Character, Incr) \
271 { \
272 /* TAG characters are those in the range U+E0000..U+E007F. */ \
273 if (((Character) >> 7) == (0xe0000 >> 7)) \
274 { \
275 inptr += Incr; \
276 continue; \
277 } \
278 }
279 DIAG_POP_NEEDS_COMMENT;
280
281
282 /* The function returns the status, as defined in gconv.h. */
283 static inline int
284 __attribute ((always_inline))
FCTNAME(LOOPFCT)285 FCTNAME (LOOPFCT) (struct __gconv_step *step,
286 struct __gconv_step_data *step_data,
287 const unsigned char **inptrp, const unsigned char *inend,
288 unsigned char **outptrp, const unsigned char *outend,
289 size_t *irreversible EXTRA_LOOP_DECLS)
290 {
291 #ifdef LOOP_NEED_STATE
292 mbstate_t *state = step_data->__statep;
293 #endif
294 #ifdef LOOP_NEED_FLAGS
295 int flags = step_data->__flags;
296 #endif
297 #ifdef LOOP_NEED_DATA
298 void *data = step->__data;
299 #endif
300 int result = __GCONV_EMPTY_INPUT;
301 const unsigned char *inptr = *inptrp;
302 unsigned char *outptr = *outptrp;
303
304 #ifdef INIT_PARAMS
305 INIT_PARAMS;
306 #endif
307
308 while (inptr != inend)
309 {
310 /* `if' cases for MIN_NEEDED_OUTPUT ==/!= 1 is made to help the
311 compiler generating better code. They will be optimized away
312 since MIN_NEEDED_OUTPUT is always a constant. */
313 if (MIN_NEEDED_INPUT > 1
314 && __builtin_expect (inptr + MIN_NEEDED_INPUT > inend, 0))
315 {
316 /* We don't have enough input for another complete input
317 character. */
318 result = __GCONV_INCOMPLETE_INPUT;
319 break;
320 }
321 if ((MIN_NEEDED_OUTPUT != 1
322 && __builtin_expect (outptr + MIN_NEEDED_OUTPUT > outend, 0))
323 || (MIN_NEEDED_OUTPUT == 1
324 && __builtin_expect (outptr >= outend, 0)))
325 {
326 /* Overflow in the output buffer. */
327 result = __GCONV_FULL_OUTPUT;
328 break;
329 }
330
331 /* Here comes the body the user provides. It can stop with
332 RESULT set to GCONV_INCOMPLETE_INPUT (if the size of the
333 input characters vary in size), GCONV_ILLEGAL_INPUT, or
334 GCONV_FULL_OUTPUT (if the output characters vary in size). */
335 BODY
336 }
337
338 /* Update the pointers pointed to by the parameters. */
339 *inptrp = inptr;
340 *outptrp = outptr;
341 UPDATE_PARAMS;
342
343 return result;
344 }
345
346
347 /* Include the file a second time to define the function to handle
348 unaligned access. */
349 #if !defined DEFINE_UNALIGNED && !_STRING_ARCH_unaligned \
350 && MIN_NEEDED_INPUT != 1 && MAX_NEEDED_INPUT % MIN_NEEDED_INPUT == 0 \
351 && MIN_NEEDED_OUTPUT != 1 && MAX_NEEDED_OUTPUT % MIN_NEEDED_OUTPUT == 0
352 # undef get16
353 # undef get32
354 # undef put16
355 # undef put32
356 # undef unaligned
357
358 # define DEFINE_UNALIGNED
359 # include "loop.c"
360 # undef DEFINE_UNALIGNED
361 #else
362 # if MAX_NEEDED_INPUT > 1
363 # define SINGLE(fct) SINGLE2 (fct)
364 # define SINGLE2(fct) fct##_single
365 static inline int
366 __attribute ((always_inline))
SINGLE(LOOPFCT)367 SINGLE(LOOPFCT) (struct __gconv_step *step,
368 struct __gconv_step_data *step_data,
369 const unsigned char **inptrp, const unsigned char *inend,
370 unsigned char **outptrp, unsigned char *outend,
371 size_t *irreversible EXTRA_LOOP_DECLS)
372 {
373 mbstate_t *state = step_data->__statep;
374 # ifdef LOOP_NEED_FLAGS
375 int flags = step_data->__flags;
376 # endif
377 # ifdef LOOP_NEED_DATA
378 void *data = step->__data;
379 # endif
380 int result = __GCONV_OK;
381 unsigned char bytebuf[MAX_NEEDED_INPUT];
382 const unsigned char *inptr = *inptrp;
383 unsigned char *outptr = *outptrp;
384 size_t inlen;
385
386 # ifdef INIT_PARAMS
387 INIT_PARAMS;
388 # endif
389
390 # ifdef UNPACK_BYTES
391 UNPACK_BYTES
392 # else
393 /* Add the bytes from the state to the input buffer. */
394 assert ((state->__count & 7) <= sizeof (state->__value));
395 for (inlen = 0; inlen < (size_t) (state->__count & 7); ++inlen)
396 bytebuf[inlen] = state->__value.__wchb[inlen];
397 # endif
398
399 /* Are there enough bytes in the input buffer? */
400 if (MIN_NEEDED_INPUT > 1
401 && __builtin_expect (inptr + (MIN_NEEDED_INPUT - inlen) > inend, 0))
402 {
403 *inptrp = inend;
404 # ifdef STORE_REST
405
406 /* Building with -O3 GCC emits a `array subscript is above array
407 bounds' warning. GCC BZ #64739 has been opened for this. */
408 DIAG_PUSH_NEEDS_COMMENT;
409 DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Warray-bounds");
410 while (inptr < inend)
411 bytebuf[inlen++] = *inptr++;
412 DIAG_POP_NEEDS_COMMENT;
413
414 inptr = bytebuf;
415 inptrp = &inptr;
416 inend = &bytebuf[inlen];
417
418 STORE_REST
419 # else
420 /* We don't have enough input for another complete input
421 character. */
422 size_t inlen_after = inlen + (inend - inptr);
423 assert (inlen_after <= sizeof (state->__value.__wchb));
424 for (; inlen < inlen_after; inlen++)
425 state->__value.__wchb[inlen] = *inptr++;
426 # endif
427
428 return __GCONV_INCOMPLETE_INPUT;
429 }
430
431 /* Enough space in output buffer. */
432 if ((MIN_NEEDED_OUTPUT != 1 && outptr + MIN_NEEDED_OUTPUT > outend)
433 || (MIN_NEEDED_OUTPUT == 1 && outptr >= outend))
434 /* Overflow in the output buffer. */
435 return __GCONV_FULL_OUTPUT;
436
437 /* Now add characters from the normal input buffer. */
438 if (inlen >= MAX_NEEDED_INPUT || inptr >= inend)
439 /* Avoid a -Wstringop-overflow= warning when this loop is
440 unrolled. The compiler cannot otherwise see that this is
441 unreachable because it depends on (state->__count & 7) not
442 being too large after a previous conversion step.
443 Starting with GCC 12, we also have mark the inptr >= inend
444 case as unreachable to omit the warning. Note that this SINGLE
445 function is only used to implement the mb*towc*() or wc*tomb*()
446 functions. Those functions use inptr and inend pointing to a
447 variable on stack, compute the inend pointer or explicitly check
448 the arguments which always leads to inptr < inend. */
449 __builtin_unreachable ();
450 do
451 bytebuf[inlen++] = *inptr++;
452 while (inlen < MAX_NEEDED_INPUT && inptr < inend);
453
454 inptr = bytebuf;
455 inend = &bytebuf[inlen];
456
457 do
458 {
459 BODY
460 }
461 while (0);
462
463 /* Now we either have produced an output character and consumed all the
464 bytes from the state and at least one more, or the character is still
465 incomplete, or we have some other error (like illegal input character,
466 no space in output buffer). */
467 if (__glibc_likely (inptr != bytebuf))
468 {
469 /* We found a new character. */
470 assert (inptr - bytebuf > (state->__count & 7));
471
472 *inptrp += inptr - bytebuf - (state->__count & 7);
473 *outptrp = outptr;
474
475 result = __GCONV_OK;
476
477 /* Clear the state buffer. */
478 # ifdef CLEAR_STATE
479 CLEAR_STATE;
480 # else
481 state->__count &= ~7;
482 # endif
483 }
484 else if (result == __GCONV_INCOMPLETE_INPUT)
485 {
486 /* This can only happen if we have less than MAX_NEEDED_INPUT bytes
487 available. */
488 assert (inend != &bytebuf[MAX_NEEDED_INPUT]);
489
490 *inptrp += inend - bytebuf - (state->__count & 7);
491 # ifdef STORE_REST
492 inptrp = &inptr;
493
494 STORE_REST
495 # else
496 /* We don't have enough input for another complete input
497 character. */
498 assert (inend - inptr > (state->__count & ~7));
499 assert (inend - inptr <= sizeof (state->__value.__wchb));
500 state->__count = (state->__count & ~7) | (inend - inptr);
501 for (inlen = 0; inlen < inend - inptr; inlen++)
502 state->__value.__wchb[inlen] = inptr[inlen];
503 inptr = inend;
504 # endif
505 }
506
507 return result;
508 }
509 # undef SINGLE
510 # undef SINGLE2
511 # endif
512
513
514 # ifdef ONEBYTE_BODY
515 /* Define the shortcut function for btowc. */
516 static wint_t
517 gconv_btowc (struct __gconv_step *step, unsigned char c)
518 ONEBYTE_BODY
519 # define FROM_ONEBYTE gconv_btowc
520 # endif
521
522 #endif
523
524 /* We remove the macro definitions so that we can include this file again
525 for the definition of another function. */
526 #undef MIN_NEEDED_INPUT
527 #undef MAX_NEEDED_INPUT
528 #undef MIN_NEEDED_OUTPUT
529 #undef MAX_NEEDED_OUTPUT
530 #undef LOOPFCT
531 #undef BODY
532 #undef LOOPFCT
533 #undef EXTRA_LOOP_DECLS
534 #undef INIT_PARAMS
535 #undef UPDATE_PARAMS
536 #undef REINIT_PARAMS
537 #undef ONEBYTE_BODY
538 #undef UNPACK_BYTES
539 #undef CLEAR_STATE
540 #undef LOOP_NEED_STATE
541 #undef LOOP_NEED_FLAGS
542 #undef LOOP_NEED_DATA
543 #undef get16
544 #undef get32
545 #undef put16
546 #undef put32
547 #undef unaligned
548