/[pcre]/code/trunk/pcre_valid_utf8.c
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revision 236 by ph10, Tue Sep 11 12:57:06 2007 UTC revision 1261 by ph10, Wed Feb 27 16:27:01 2013 UTC
# Line 6  Line 6 
6  and semantics are as close as possible to those of the Perl 5 language.  and semantics are as close as possible to those of the Perl 5 language.
7    
8                         Written by Philip Hazel                         Written by Philip Hazel
9             Copyright (c) 1997-2007 University of Cambridge             Copyright (c) 1997-2013 University of Cambridge
10    
11  -----------------------------------------------------------------------------  -----------------------------------------------------------------------------
12  Redistribution and use in source and binary forms, with or without  Redistribution and use in source and binary forms, with or without
# Line 54  strings. */ Line 54  strings. */
54  *************************************************/  *************************************************/
55    
56  /* This function is called (optionally) at the start of compile or match, to  /* This function is called (optionally) at the start of compile or match, to
57  validate that a supposed UTF-8 string is actually valid. The early check means  check that a supposed UTF-8 string is actually valid. The early check means
58  that subsequent code can assume it is dealing with a valid string. The check  that subsequent code can assume it is dealing with a valid string. The check
59  can be turned off for maximum performance, but the consequences of supplying  can be turned off for maximum performance, but the consequences of supplying an
60  an invalid string are then undefined.  invalid string are then undefined.
61    
62  Originally, this function checked according to RFC 2279, allowing for values in  Originally, this function checked according to RFC 2279, allowing for values in
63  the range 0 to 0x7fffffff, up to 6 bytes long, but ensuring that they were in  the range 0 to 0x7fffffff, up to 6 bytes long, but ensuring that they were in
64  the canonical format. Once somebody had pointed out RFC 3629 to me (it  the canonical format. Once somebody had pointed out RFC 3629 to me (it
65  obsoletes 2279), additional restrictions were applies. The values are now  obsoletes 2279), additional restrictions were applied. The values are now
66  limited to be between 0 and 0x0010ffff, no more than 4 bytes long, and the  limited to be between 0 and 0x0010ffff, no more than 4 bytes long, and the
67  subrange 0xd000 to 0xdfff is excluded.  subrange 0xd000 to 0xdfff is excluded. However, the format of 5-byte and 6-byte
68    characters is still checked.
69    
70    From release 8.13 more information about the details of the error are passed
71    back in the returned value:
72    
73    PCRE_UTF8_ERR0   No error
74    PCRE_UTF8_ERR1   Missing 1 byte at the end of the string
75    PCRE_UTF8_ERR2   Missing 2 bytes at the end of the string
76    PCRE_UTF8_ERR3   Missing 3 bytes at the end of the string
77    PCRE_UTF8_ERR4   Missing 4 bytes at the end of the string
78    PCRE_UTF8_ERR5   Missing 5 bytes at the end of the string
79    PCRE_UTF8_ERR6   2nd-byte's two top bits are not 0x80
80    PCRE_UTF8_ERR7   3rd-byte's two top bits are not 0x80
81    PCRE_UTF8_ERR8   4th-byte's two top bits are not 0x80
82    PCRE_UTF8_ERR9   5th-byte's two top bits are not 0x80
83    PCRE_UTF8_ERR10  6th-byte's two top bits are not 0x80
84    PCRE_UTF8_ERR11  5-byte character is not permitted by RFC 3629
85    PCRE_UTF8_ERR12  6-byte character is not permitted by RFC 3629
86    PCRE_UTF8_ERR13  4-byte character with value > 0x10ffff is not permitted
87    PCRE_UTF8_ERR14  3-byte character with value 0xd000-0xdfff is not permitted
88    PCRE_UTF8_ERR15  Overlong 2-byte sequence
89    PCRE_UTF8_ERR16  Overlong 3-byte sequence
90    PCRE_UTF8_ERR17  Overlong 4-byte sequence
91    PCRE_UTF8_ERR18  Overlong 5-byte sequence (won't ever occur)
92    PCRE_UTF8_ERR19  Overlong 6-byte sequence (won't ever occur)
93    PCRE_UTF8_ERR20  Isolated 0x80 byte (not within UTF-8 character)
94    PCRE_UTF8_ERR21  Byte with the illegal value 0xfe or 0xff
95    PCRE_UTF8_ERR22  Unused (was non-character)
96    
97  Arguments:  Arguments:
98    string       points to the string    string       points to the string
99    length       length of string, or -1 if the string is zero-terminated    length       length of string, or -1 if the string is zero-terminated
100      errp         pointer to an error position offset variable
101    
102  Returns:       < 0    if the string is a valid UTF-8 string  Returns:       = 0    if the string is a valid UTF-8 string
103                 >= 0   otherwise; the value is the offset of the bad byte                 > 0    otherwise, setting the offset of the bad character
104  */  */
105    
106  int  int
107  _pcre_valid_utf8(const uschar *string, int length)  PRIV(valid_utf)(PCRE_PUCHAR string, int length, int *erroroffset)
108  {  {
109  #ifdef SUPPORT_UTF8  #ifdef SUPPORT_UTF
110  register const uschar *p;  register PCRE_PUCHAR p;
111    
112  if (length < 0)  if (length < 0)
113    {    {
114    for (p = string; *p != 0; p++);    for (p = string; *p != 0; p++);
115    length = p - string;    length = (int)(p - string);
116    }    }
117    
118  for (p = string; length-- > 0; p++)  for (p = string; length-- > 0; p++)
119    {    {
120    register int ab;    register pcre_uchar ab, c, d;
121    register int c = *p;  
122    if (c < 128) continue;    c = *p;
123    if (c < 0xc0) return p - string;    if (c < 128) continue;                /* ASCII character */
124    ab = _pcre_utf8_table4[c & 0x3f];     /* Number of additional bytes */  
125    if (length < ab || ab > 3) return p - string;    if (c < 0xc0)                         /* Isolated 10xx xxxx byte */
126    length -= ab;      {
127        *erroroffset = (int)(p - string);
128        return PCRE_UTF8_ERR20;
129        }
130    
131      if (c >= 0xfe)                        /* Invalid 0xfe or 0xff bytes */
132        {
133        *erroroffset = (int)(p - string);
134        return PCRE_UTF8_ERR21;
135        }
136    
137      ab = PRIV(utf8_table4)[c & 0x3f];     /* Number of additional bytes */
138      if (length < ab)
139        {
140        *erroroffset = (int)(p - string);          /* Missing bytes */
141        return ab - length;                 /* Codes ERR1 to ERR5 */
142        }
143      length -= ab;                         /* Length remaining */
144    
145    /* Check top bits in the second byte */    /* Check top bits in the second byte */
   if ((*(++p) & 0xc0) != 0x80) return p - string;  
146    
147    /* Check for overlong sequences for each different length, and for the    if (((d = *(++p)) & 0xc0) != 0x80)
148    excluded range 0xd000 to 0xdfff.  */      {
149        *erroroffset = (int)(p - string) - 1;
150        return PCRE_UTF8_ERR6;
151        }
152    
153      /* For each length, check that the remaining bytes start with the 0x80 bit
154      set and not the 0x40 bit. Then check for an overlong sequence, and for the
155      excluded range 0xd800 to 0xdfff. */
156    
157    switch (ab)    switch (ab)
158      {      {
159      /* Check for xx00 000x (overlong sequence) */      /* 2-byte character. No further bytes to check for 0x80. Check first byte
160        for for xx00 000x (overlong sequence). */
161    
162      case 1:      case 1: if ((c & 0x3e) == 0)
163      if ((c & 0x3e) == 0) return p - string;        {
164      continue;   /* We know there aren't any more bytes to check */        *erroroffset = (int)(p - string) - 1;
165          return PCRE_UTF8_ERR15;
166          }
167        break;
168    
169      /* Check for 1110 0000, xx0x xxxx (overlong sequence) or      /* 3-byte character. Check third byte for 0x80. Then check first 2 bytes
170                   1110 1101, 1010 xxxx (0xd000 - 0xdfff) */        for 1110 0000, xx0x xxxx (overlong sequence) or
171              1110 1101, 1010 xxxx (0xd800 - 0xdfff) */
172    
173      case 2:      case 2:
174      if ((c == 0xe0 && (*p & 0x20) == 0) ||      if ((*(++p) & 0xc0) != 0x80)     /* Third byte */
175          (c == 0xed && *p >= 0xa0))        {
176        return p - string;        *erroroffset = (int)(p - string) - 2;
177          return PCRE_UTF8_ERR7;
178          }
179        if (c == 0xe0 && (d & 0x20) == 0)
180          {
181          *erroroffset = (int)(p - string) - 2;
182          return PCRE_UTF8_ERR16;
183          }
184        if (c == 0xed && d >= 0xa0)
185          {
186          *erroroffset = (int)(p - string) - 2;
187          return PCRE_UTF8_ERR14;
188          }
189      break;      break;
190    
191      /* Check for 1111 0000, xx00 xxxx (overlong sequence) or      /* 4-byte character. Check 3rd and 4th bytes for 0x80. Then check first 2
192         greater than 0x0010ffff (f4 8f bf bf) */         bytes for for 1111 0000, xx00 xxxx (overlong sequence), then check for a
193           character greater than 0x0010ffff (f4 8f bf bf) */
194    
195      case 3:      case 3:
196      if ((c == 0xf0 && (*p & 0x30) == 0) ||      if ((*(++p) & 0xc0) != 0x80)     /* Third byte */
197          (c > 0xf4 ) ||        {
198          (c == 0xf4 && *p > 0x8f))        *erroroffset = (int)(p - string) - 2;
199        return p - string;        return PCRE_UTF8_ERR7;
200          }
201        if ((*(++p) & 0xc0) != 0x80)     /* Fourth byte */
202          {
203          *erroroffset = (int)(p - string) - 3;
204          return PCRE_UTF8_ERR8;
205          }
206        if (c == 0xf0 && (d & 0x30) == 0)
207          {
208          *erroroffset = (int)(p - string) - 3;
209          return PCRE_UTF8_ERR17;
210          }
211        if (c > 0xf4 || (c == 0xf4 && d > 0x8f))
212          {
213          *erroroffset = (int)(p - string) - 3;
214          return PCRE_UTF8_ERR13;
215          }
216      break;      break;
217    
218  #if 0      /* 5-byte and 6-byte characters are not allowed by RFC 3629, and will be
219      /* These cases can no longer occur, as we restrict to a maximum of four      rejected by the length test below. However, we do the appropriate tests
220      bytes nowadays. Leave the code here in case we ever want to add an option      here so that overlong sequences get diagnosed, and also in case there is
221      for longer sequences. */      ever an option for handling these larger code points. */
222    
223        /* 5-byte character. Check 3rd, 4th, and 5th bytes for 0x80. Then check for
224        1111 1000, xx00 0xxx */
225    
     /* Check for 1111 1000, xx00 0xxx */  
226      case 4:      case 4:
227      if (c == 0xf8 && (*p & 0x38) == 0) return p - string;      if ((*(++p) & 0xc0) != 0x80)     /* Third byte */
228          {
229          *erroroffset = (int)(p - string) - 2;
230          return PCRE_UTF8_ERR7;
231          }
232        if ((*(++p) & 0xc0) != 0x80)     /* Fourth byte */
233          {
234          *erroroffset = (int)(p - string) - 3;
235          return PCRE_UTF8_ERR8;
236          }
237        if ((*(++p) & 0xc0) != 0x80)     /* Fifth byte */
238          {
239          *erroroffset = (int)(p - string) - 4;
240          return PCRE_UTF8_ERR9;
241          }
242        if (c == 0xf8 && (d & 0x38) == 0)
243          {
244          *erroroffset = (int)(p - string) - 4;
245          return PCRE_UTF8_ERR18;
246          }
247      break;      break;
248    
249      /* Check for leading 0xfe or 0xff, and then for 1111 1100, xx00 00xx */      /* 6-byte character. Check 3rd-6th bytes for 0x80. Then check for
250        1111 1100, xx00 00xx. */
251    
252      case 5:      case 5:
253      if (c == 0xfe || c == 0xff ||      if ((*(++p) & 0xc0) != 0x80)     /* Third byte */
254         (c == 0xfc && (*p & 0x3c) == 0)) return p - string;        {
255          *erroroffset = (int)(p - string) - 2;
256          return PCRE_UTF8_ERR7;
257          }
258        if ((*(++p) & 0xc0) != 0x80)     /* Fourth byte */
259          {
260          *erroroffset = (int)(p - string) - 3;
261          return PCRE_UTF8_ERR8;
262          }
263        if ((*(++p) & 0xc0) != 0x80)     /* Fifth byte */
264          {
265          *erroroffset = (int)(p - string) - 4;
266          return PCRE_UTF8_ERR9;
267          }
268        if ((*(++p) & 0xc0) != 0x80)     /* Sixth byte */
269          {
270          *erroroffset = (int)(p - string) - 5;
271          return PCRE_UTF8_ERR10;
272          }
273        if (c == 0xfc && (d & 0x3c) == 0)
274          {
275          *erroroffset = (int)(p - string) - 5;
276          return PCRE_UTF8_ERR19;
277          }
278      break;      break;
 #endif  
   
279      }      }
280    
281    /* Check for valid bytes after the 2nd, if any; all must start 10 */    /* Character is valid under RFC 2279, but 4-byte and 5-byte characters are
282    while (--ab > 0)    excluded by RFC 3629. The pointer p is currently at the last byte of the
283      character. */
284    
285      if (ab > 3)
286      {      {
287      if ((*(++p) & 0xc0) != 0x80) return p - string;      *erroroffset = (int)(p - string) - ab;
288        return (ab == 4)? PCRE_UTF8_ERR11 : PCRE_UTF8_ERR12;
289      }      }
290    }    }
291    
292    #else  /* Not SUPPORT_UTF */
293    (void)(string);  /* Keep picky compilers happy */
294    (void)(length);
295    (void)(erroroffset);
296  #endif  #endif
297    
298  return -1;  return PCRE_UTF8_ERR0;   /* This indicates success */
299  }  }
300    
301  /* End of pcre_valid_utf8.c */  /* End of pcre_valid_utf8.c */

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