1 /* Conversion module for ISO-2022-KR.
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 #include <dlfcn.h>
20 #include <gconv.h>
21 #include <stdint.h>
22 #include <string.h>
23 #include "ksc5601.h"
24 
25 #include <assert.h>
26 
27 /* This makes obvious what everybody knows: 0x1b is the Esc character.  */
28 #define ESC	0x1b
29 
30 /* The shift sequences for this charset (it does not use ESC).  */
31 #define SI	0x0f
32 #define SO	0x0e
33 
34 /* Definitions used in the body of the `gconv' function.  */
35 #define CHARSET_NAME		"ISO-2022-KR//"
36 #define DEFINE_INIT		1
37 #define DEFINE_FINI		1
38 #define FROM_LOOP		from_iso2022kr_loop
39 #define TO_LOOP			to_iso2022kr_loop
40 #define MIN_NEEDED_FROM		1
41 #define MAX_NEEDED_FROM		4
42 #define MIN_NEEDED_TO		4
43 #define MAX_NEEDED_TO		4
44 #define ONE_DIRECTION		0
45 #define PREPARE_LOOP \
46   int save_set;								      \
47   int *setp = &data->__statep->__count;					      \
48   if (!FROM_DIRECTION && !data->__internal_use				      \
49       && data->__invocation_counter == 0)				      \
50     {									      \
51       /* Emit the designator sequence.  */				      \
52       if (outbuf + 4 > outend)						      \
53 	return __GCONV_FULL_OUTPUT;					      \
54 									      \
55       *outbuf++ = ESC;							      \
56       *outbuf++ = '$';							      \
57       *outbuf++ = ')';							      \
58       *outbuf++ = 'C';							      \
59     }
60 #define EXTRA_LOOP_ARGS		, setp
61 
62 
63 /* The COUNT element of the state keeps track of the currently selected
64    character set.  The possible values are:  */
65 enum
66 {
67   ASCII_set = 0,
68   KSC5601_set = 8
69 };
70 
71 
72 /* Since this is a stateful encoding we have to provide code which resets
73    the output state to the initial state.  This has to be done during the
74    flushing.  */
75 #define EMIT_SHIFT_TO_INIT \
76   if (data->__statep->__count != ASCII_set)				      \
77     {									      \
78       if (FROM_DIRECTION)						      \
79 	{								      \
80 	  /* It's easy, we don't have to emit anything, we just reset the     \
81 	     state for the input.  */					      \
82 	  data->__statep->__count &= 7;					      \
83 	  data->__statep->__count |= ASCII_set;				      \
84 	}								      \
85       else								      \
86 	{								      \
87 	  /* We are not in the initial state.  To switch back we have	      \
88 	     to emit `SI'.  */						      \
89 	  if (__glibc_unlikely (outbuf == outend))			      \
90 	    /* We don't have enough room in the output buffer.  */	      \
91 	    status = __GCONV_FULL_OUTPUT;				      \
92 	  else								      \
93 	    {								      \
94 	      /* Write out the shift sequence.  */			      \
95 	      *outbuf++ = SI;						      \
96 	      data->__statep->__count = ASCII_set;			      \
97 	    }								      \
98 	}								      \
99     }
100 
101 
102 /* Since we might have to reset input pointer we must be able to save
103    and retore the state.  */
104 #define SAVE_RESET_STATE(Save) \
105   if (Save)								      \
106     save_set = *setp;							      \
107   else									      \
108     *setp = save_set
109 
110 
111 /* First define the conversion function from ISO-2022-KR to UCS4.  */
112 #define MIN_NEEDED_INPUT	MIN_NEEDED_FROM
113 #define MAX_NEEDED_INPUT	MAX_NEEDED_FROM
114 #define MIN_NEEDED_OUTPUT	MIN_NEEDED_TO
115 #define LOOPFCT			FROM_LOOP
116 #define BODY \
117   {									      \
118     uint32_t ch = *inptr;						      \
119 									      \
120     /* This is a 7bit character set, disallow all 8bit characters.  */	      \
121     if (__glibc_unlikely (ch > 0x7f))					      \
122       STANDARD_FROM_LOOP_ERR_HANDLER (1);				      \
123 									      \
124     /* Recognize escape sequences.  */					      \
125     if (__builtin_expect (ch, 0) == ESC)				      \
126       {									      \
127 	/* We don't really have to handle escape sequences since all the      \
128 	   switching is done using the SI and SO bytes.  But we have to	      \
129 	   recognize `Esc $ ) C' since this is a kind of flag for this	      \
130 	   encoding.  We simply ignore it.  */				      \
131 	if (__builtin_expect (inptr + 2 > inend, 0)			      \
132 	    || (inptr[1] == '$'						      \
133 		&& (__builtin_expect (inptr + 3 > inend, 0)		      \
134 		    || (inptr[2] == ')'					      \
135 			&& __builtin_expect (inptr + 4 > inend, 0)))))	      \
136 	  {								      \
137 	    result = __GCONV_INCOMPLETE_INPUT;				      \
138 	    break;							      \
139 	  }								      \
140 	if (inptr[1] == '$' && inptr[2] == ')' && inptr[3] == 'C')	      \
141 	  {								      \
142 	    /* Yeah, yeah, we know this is ISO 2022-KR.  */		      \
143 	    inptr += 4;							      \
144 	    continue;							      \
145 	  }								      \
146       }									      \
147     else if (__builtin_expect (ch, 0) == SO)				      \
148       {									      \
149 	/* Switch to use KSC.  */					      \
150 	++inptr;							      \
151 	set = KSC5601_set;						      \
152 	continue;							      \
153       }									      \
154     else if (__builtin_expect (ch, 0) == SI)				      \
155       {									      \
156 	/* Switch to use ASCII.  */					      \
157 	++inptr;							      \
158 	set = ASCII_set;						      \
159 	continue;							      \
160       }									      \
161 									      \
162     if (set == ASCII_set)						      \
163       {									      \
164 	/* Almost done, just advance the input pointer.  */		      \
165 	++inptr;							      \
166       }									      \
167     else								      \
168       {									      \
169 	assert (set == KSC5601_set);					      \
170 									      \
171 	/* Use the KSC 5601 table.  */					      \
172 	ch = ksc5601_to_ucs4 (&inptr, inend - inptr, 0);		      \
173 									      \
174 	if (__glibc_unlikely (ch == 0))					      \
175 	  {								      \
176 	    result = __GCONV_INCOMPLETE_INPUT;				      \
177 	    break;							      \
178 	  }								      \
179 	else if (__glibc_unlikely (ch == __UNKNOWN_10646_CHAR))		      \
180 	  {								      \
181 	    STANDARD_FROM_LOOP_ERR_HANDLER (1);				      \
182 	  }								      \
183       }									      \
184 									      \
185     put32 (outptr, ch);							      \
186     outptr += 4;							      \
187   }
188 #define LOOP_NEED_FLAGS
189 #define EXTRA_LOOP_DECLS	, int *setp
190 #define INIT_PARAMS		int set = *setp
191 #define UPDATE_PARAMS		*setp = set
192 #include <iconv/loop.c>
193 
194 
195 /* Next, define the other direction.  */
196 #define MIN_NEEDED_INPUT	MIN_NEEDED_TO
197 #define MIN_NEEDED_OUTPUT	MIN_NEEDED_FROM
198 #define MAX_NEEDED_OUTPUT	MAX_NEEDED_FROM
199 #define LOOPFCT			TO_LOOP
200 #define BODY \
201   {									      \
202     uint32_t ch = get32 (inptr);					      \
203 									      \
204     /* First see whether we can write the character using the currently	      \
205        selected character set.  */					      \
206     if (ch < 0x80)							      \
207       {									      \
208 	if (set != ASCII_set)						      \
209 	  {								      \
210 	    *outptr++ = SI;						      \
211 	    set = ASCII_set;						      \
212 	    if (__glibc_unlikely (outptr == outend))			      \
213 	      {								      \
214 		result = __GCONV_FULL_OUTPUT;				      \
215 		break;							      \
216 	      }								      \
217 	  }								      \
218  									      \
219 	*outptr++ = ch;							      \
220       }									      \
221     else								      \
222       {									      \
223 	unsigned char buf[2];						      \
224 	/* Fake initialization to keep gcc quiet.  */			      \
225 	asm ("" : "=m" (buf));						      \
226 									      \
227 	size_t written = ucs4_to_ksc5601 (ch, buf, 2);			      \
228 	if (__builtin_expect (written, 0) == __UNKNOWN_10646_CHAR)	      \
229 	  {								      \
230 	    UNICODE_TAG_HANDLER (ch, 4);				      \
231 									      \
232 	    /* Illegal character.  */					      \
233 	    STANDARD_TO_LOOP_ERR_HANDLER (4);				      \
234 	  }								      \
235 	else								      \
236 	  {								      \
237 	    assert (written == 2);					      \
238 									      \
239 	    /* We use KSC 5601.  */					      \
240 	    if (set != KSC5601_set)					      \
241 	      {								      \
242 		*outptr++ = SO;						      \
243 		set = KSC5601_set;					      \
244 	      }								      \
245 									      \
246 	    if (__glibc_unlikely (outptr + 2 > outend))			      \
247 	      {								      \
248 		result = __GCONV_FULL_OUTPUT;				      \
249 		break;							      \
250 	      }								      \
251 									      \
252 	    *outptr++ = buf[0];						      \
253 	    *outptr++ = buf[1];						      \
254 	  }								      \
255       }									      \
256 									      \
257     /* Now that we wrote the output increment the input pointer.  */	      \
258     inptr += 4;								      \
259   }
260 #define LOOP_NEED_FLAGS
261 #define EXTRA_LOOP_DECLS	, int *setp
262 #define INIT_PARAMS		int set = *setp
263 #define REINIT_PARAMS		set = *setp
264 #define UPDATE_PARAMS		*setp = set
265 #include <iconv/loop.c>
266 
267 
268 /* Now define the toplevel functions.  */
269 #include <iconv/skeleton.c>
270