Line data Source code
1 : /*
2 : ** $Id: lutf8lib.c,v 1.16.1.1 2017/04/19 17:29:57 roberto Exp $
3 : ** Standard library for UTF-8 manipulation
4 : ** See Copyright Notice in lua.h
5 : */
6 :
7 : #define lutf8lib_c
8 : #define LUA_LIB
9 :
10 : #include "lprefix.h"
11 :
12 :
13 : #include <assert.h>
14 : #include <limits.h>
15 : #include <stdlib.h>
16 : #include <string.h>
17 :
18 : #include "lua.h"
19 :
20 : #include "lauxlib.h"
21 : #include "lualib.h"
22 :
23 : #define MAXUNICODE 0x10FFFF
24 :
25 : #define iscont(p) ((*(p) & 0xC0) == 0x80)
26 :
27 :
28 : /* from strlib */
29 : /* translate a relative string position: negative means back from end */
30 79 : static lua_Integer u_posrelat (lua_Integer pos, size_t len) {
31 79 : if (pos >= 0) return pos;
32 21 : else if (0u - (size_t)pos > len) return 0;
33 20 : else return (lua_Integer)len + pos + 1;
34 : }
35 :
36 :
37 : /*
38 : ** Decode one UTF-8 sequence, returning NULL if byte sequence is invalid.
39 : */
40 42 : static const char *utf8_decode (const char *o, int *val) {
41 : static const unsigned int limits[] = {0xFF, 0x7F, 0x7FF, 0xFFFF};
42 42 : const unsigned char *s = (const unsigned char *)o;
43 42 : unsigned int c = s[0];
44 42 : unsigned int res = 0; /* final result */
45 42 : if (c < 0x80) /* ascii? */
46 34 : res = c;
47 : else {
48 8 : int count = 0; /* to count number of continuation bytes */
49 18 : while (c & 0x40) { /* still have continuation bytes? */
50 13 : int cc = s[++count]; /* read next byte */
51 13 : if ((cc & 0xC0) != 0x80) /* not a continuation byte? */
52 3 : return NULL; /* invalid byte sequence */
53 10 : res = (res << 6) | (cc & 0x3F); /* add lower 6 bits from cont. byte */
54 10 : c <<= 1; /* to test next bit */
55 : }
56 5 : res |= ((c & 0x7F) << (count * 5)); /* add first byte */
57 5 : if (count > 3 || res > MAXUNICODE || res <= limits[count])
58 0 : return NULL; /* invalid byte sequence */
59 5 : s += count; /* skip continuation bytes read */
60 : }
61 39 : if (val) *val = res;
62 39 : return (const char *)s + 1; /* +1 to include first byte */
63 : }
64 :
65 :
66 : /*
67 : ** utf8len(s [, i [, j]]) --> number of characters that start in the
68 : ** range [i,j], or nil + current position if 's' is not well formed in
69 : ** that interval
70 : */
71 12 : static int utflen (lua_State *L) {
72 12 : int n = 0;
73 : size_t len;
74 12 : const char *s = luaL_checklstring(L, 1, &len);
75 12 : lua_Integer posi = u_posrelat(luaL_optinteger(L, 2, 1), len);
76 12 : lua_Integer posj = u_posrelat(luaL_optinteger(L, 3, -1), len);
77 12 : luaL_argcheck(L, 1 <= posi && --posi <= (lua_Integer)len, 2,
78 : "initial position out of string");
79 11 : luaL_argcheck(L, --posj < (lua_Integer)len, 3,
80 : "final position out of string");
81 31 : while (posi <= posj) {
82 21 : const char *s1 = utf8_decode(s + posi, NULL);
83 21 : if (s1 == NULL) { /* conversion error? */
84 1 : lua_pushnil(L); /* return nil ... */
85 1 : lua_pushinteger(L, posi + 1); /* ... and current position */
86 1 : return 2;
87 : }
88 20 : posi = s1 - s;
89 20 : n++;
90 : }
91 10 : lua_pushinteger(L, n);
92 10 : return 1;
93 : }
94 :
95 :
96 : /*
97 : ** codepoint(s, [i, [j]]) -> returns codepoints for all characters
98 : ** that start in the range [i,j]
99 : */
100 9 : static int codepoint (lua_State *L) {
101 : size_t len;
102 9 : const char *s = luaL_checklstring(L, 1, &len);
103 9 : lua_Integer posi = u_posrelat(luaL_optinteger(L, 2, 1), len);
104 9 : lua_Integer pose = u_posrelat(luaL_optinteger(L, 3, posi), len);
105 : int n;
106 : const char *se;
107 9 : luaL_argcheck(L, posi >= 1, 2, "out of range");
108 9 : luaL_argcheck(L, pose <= (lua_Integer)len, 3, "out of range");
109 7 : if (posi > pose) return 0; /* empty interval; return no values */
110 7 : if (pose - posi >= INT_MAX) /* (lua_Integer -> int) overflow? */
111 0 : return luaL_error(L, "string slice too long");
112 7 : n = (int)(pose - posi) + 1;
113 7 : luaL_checkstack(L, n, "string slice too long");
114 7 : n = 0;
115 7 : se = s + pose;
116 16 : for (s += posi - 1; s < se;) {
117 : int code;
118 10 : s = utf8_decode(s, &code);
119 10 : if (s == NULL)
120 1 : return luaL_error(L, "invalid UTF-8 code");
121 9 : lua_pushinteger(L, code);
122 9 : n++;
123 : }
124 6 : return n;
125 : }
126 :
127 :
128 17 : static void pushutfchar (lua_State *L, int arg) {
129 17 : lua_Integer code = luaL_checkinteger(L, arg);
130 16 : luaL_argcheck(L, 0 <= code && code <= MAXUNICODE, arg, "value out of range");
131 14 : lua_pushfstring(L, "%U", (long)code);
132 14 : }
133 :
134 :
135 : /*
136 : ** utfchar(n1, n2, ...) -> char(n1)..char(n2)...
137 : */
138 14 : static int utfchar (lua_State *L) {
139 14 : int n = lua_gettop(L); /* number of arguments */
140 14 : if (n == 1) /* optimize common case of single char */
141 10 : pushutfchar(L, 1);
142 : else {
143 : int i;
144 : luaL_Buffer b;
145 4 : luaL_buffinit(L, &b);
146 9 : for (i = 1; i <= n; i++) {
147 7 : pushutfchar(L, i);
148 5 : luaL_addvalue(&b);
149 : }
150 2 : luaL_pushresult(&b);
151 : }
152 11 : return 1;
153 : }
154 :
155 :
156 : /*
157 : ** offset(s, n, [i]) -> index where n-th character counting from
158 : ** position 'i' starts; 0 means character at 'i'.
159 : */
160 37 : static int byteoffset (lua_State *L) {
161 : size_t len;
162 37 : const char *s = luaL_checklstring(L, 1, &len);
163 37 : lua_Integer n = luaL_checkinteger(L, 2);
164 37 : lua_Integer posi = (n >= 0) ? 1 : len + 1;
165 37 : posi = u_posrelat(luaL_optinteger(L, 3, posi), len);
166 37 : luaL_argcheck(L, 1 <= posi && --posi <= (lua_Integer)len, 3,
167 : "position out of range");
168 36 : if (n == 0) {
169 : /* find beginning of current byte sequence */
170 9 : while (posi > 0 && iscont(s + posi)) posi--;
171 : }
172 : else {
173 30 : if (iscont(s + posi))
174 1 : return luaL_error(L, "initial position is a continuation byte");
175 29 : if (n < 0) {
176 26 : while (n < 0 && posi > 0) { /* move back */
177 : do { /* find beginning of previous character */
178 27 : posi--;
179 27 : } while (posi > 0 && iscont(s + posi));
180 15 : n++;
181 : }
182 : }
183 : else {
184 18 : n--; /* do not move for 1st character */
185 38 : while (n > 0 && posi < (lua_Integer)len) {
186 : do { /* find beginning of next character */
187 36 : posi++;
188 36 : } while (iscont(s + posi)); /* (cannot pass final '\0') */
189 20 : n--;
190 : }
191 : }
192 : }
193 35 : if (n == 0) /* did it find given character? */
194 26 : lua_pushinteger(L, posi + 1);
195 : else /* no such character */
196 9 : lua_pushnil(L);
197 35 : return 1;
198 : }
199 :
200 :
201 13 : static int iter_aux (lua_State *L) {
202 : size_t len;
203 13 : const char *s = luaL_checklstring(L, 1, &len);
204 13 : lua_Integer n = lua_tointeger(L, 2) - 1;
205 13 : if (n < 0) /* first iteration? */
206 3 : n = 0; /* start from here */
207 10 : else if (n < (lua_Integer)len) {
208 10 : n++; /* skip current byte */
209 12 : while (iscont(s + n)) n++; /* and its continuations */
210 : }
211 13 : if (n >= (lua_Integer)len)
212 2 : return 0; /* no more codepoints */
213 : else {
214 : int code;
215 11 : const char *next = utf8_decode(s + n, &code);
216 11 : if (next == NULL || iscont(next))
217 1 : return luaL_error(L, "invalid UTF-8 code");
218 10 : lua_pushinteger(L, n + 1);
219 10 : lua_pushinteger(L, code);
220 10 : return 2;
221 : }
222 : }
223 :
224 :
225 5 : static int iter_codes (lua_State *L) {
226 5 : luaL_checkstring(L, 1);
227 3 : lua_pushcfunction(L, iter_aux);
228 3 : lua_pushvalue(L, 1);
229 3 : lua_pushinteger(L, 0);
230 3 : return 3;
231 : }
232 :
233 :
234 : /* pattern to match a single UTF-8 character */
235 : #define UTF8PATT "[\0-\x7F\xC2-\xF4][\x80-\xBF]*"
236 :
237 :
238 : static const luaL_Reg funcs[] = {
239 : {"offset", byteoffset},
240 : {"codepoint", codepoint},
241 : {"char", utfchar},
242 : {"len", utflen},
243 : {"codes", iter_codes},
244 : /* placeholders */
245 : {"charpattern", NULL},
246 : {NULL, NULL}
247 : };
248 :
249 :
250 86 : LUAMOD_API int luaopen_utf8 (lua_State *L) {
251 86 : luaL_newlib(L, funcs);
252 86 : lua_pushlstring(L, UTF8PATT, sizeof(UTF8PATT)/sizeof(char) - 1);
253 86 : lua_setfield(L, -2, "charpattern");
254 86 : return 1;
255 : }
256 :
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