client/deps/liblua/lutf8lib.c

   1 /*
   2 ** $Id: lutf8lib.c $
   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
  24 #define MAXUNICODE      0x10FFFFu
  25
  26 #define MAXUTF          0x7FFFFFFFu
  27
  28
  29 #define MSGInvalid      "invalid UTF-8 code"
  30
  31 /*
  32 ** Integer type for decoded UTF-8 values; MAXUTF needs 31 bits.
  33 */
  34 #if (UINT_MAX >> 30) >= 1
  35 typedef unsigned int utfint;
  36 #else
  37 typedef unsigned long utfint;
  38 #endif
  39
  40
  41 #define iscont(c)       (((c) & 0xC0) == 0x80)
  42 #define iscontp(p)      iscont(*(p))
  43
  44
  45 /* from strlib */
  46 /* translate a relative string position: negative means back from end */
  47 static lua_Integer u_posrelat(lua_Integer pos, size_t len) {
  48     if (pos >= 0) return pos;
  49     else if (0u - (size_t)pos > len) return 0;
  50     else return (lua_Integer)len + pos + 1;
  51 }
  52
  53
  54 /*
  55 ** Decode one UTF-8 sequence, returning NULL if byte sequence is
  56 ** invalid.  The array 'limits' stores the minimum value for each
  57 ** sequence length, to check for overlong representations. Its first
  58 ** entry forces an error for non-ascii bytes with no continuation
  59 ** bytes (count == 0).
  60 */
  61 static const char *utf8_decode(const char *s, utfint *val, int strict) {
  62     static const utfint limits[] =
  63     {~(utfint)0, 0x80, 0x800, 0x10000u, 0x200000u, 0x4000000u};
  64     unsigned int c = (unsigned char)s[0];
  65     utfint res = 0;  /* final result */
  66     if (c < 0x80)  /* ascii? */
  67         res = c;
  68     else {
  69         int count = 0;  /* to count number of continuation bytes */
  70         for (; c & 0x40; c <<= 1) {  /* while it needs continuation bytes... */
  71             unsigned int cc = (unsigned char)s[++count];  /* read next byte */
  72             if (!iscont(cc))  /* not a continuation byte? */
  73                 return NULL;  /* invalid byte sequence */
  74             res = (res << 6) | (cc & 0x3F);  /* add lower 6 bits from cont. byte */
  75         }
  76         res |= ((utfint)(c & 0x7F) << (count * 5));  /* add first byte */
  77         if (count > 5 || res > MAXUTF || res < limits[count])
  78             return NULL;  /* invalid byte sequence */
  79         s += count;  /* skip continuation bytes read */
  80     }
  81     if (strict) {
  82         /* check for invalid code points; too large or surrogates */
  83         if (res > MAXUNICODE || (0xD800u <= res && res <= 0xDFFFu))
  84             return NULL;
  85     }
  86     if (val) *val = res;
  87     return s + 1;  /* +1 to include first byte */
  88 }
  89
  90
  91 /*
  92 ** utf8len(s [, i [, j [, lax]]]) --> number of characters that
  93 ** start in the range [i,j], or nil + current position if 's' is not
  94 ** well formed in that interval
  95 */
  96 static int utflen(lua_State *L) {
  97     lua_Integer n = 0;  /* counter for the number of characters */
  98     size_t len;  /* string length in bytes */
  99     const char *s = luaL_checklstring(L, 1, &len);
 100     lua_Integer posi = u_posrelat(luaL_optinteger(L, 2, 1), len);
 101     lua_Integer posj = u_posrelat(luaL_optinteger(L, 3, -1), len);
 102     int lax = lua_toboolean(L, 4);
 103     luaL_argcheck(L, 1 <= posi && --posi <= (lua_Integer)len, 2,
 104                   "initial position out of bounds");
 105     luaL_argcheck(L, --posj < (lua_Integer)len, 3,
 106                   "final position out of bounds");
 107     while (posi <= posj) {
 108         const char *s1 = utf8_decode(s + posi, NULL, !lax);
 109         if (s1 == NULL) {  /* conversion error? */
 110             luaL_pushfail(L);  /* return fail ... */
 111             lua_pushinteger(L, posi + 1);  /* ... and current position */
 112             return 2;
 113         }
 114         posi = s1 - s;
 115         n++;
 116     }
 117     lua_pushinteger(L, n);
 118     return 1;
 119 }
 120
 121
 122 /*
 123 ** codepoint(s, [i, [j [, lax]]]) -> returns codepoints for all
 124 ** characters that start in the range [i,j]
 125 */
 126 static int codepoint(lua_State *L) {
 127     size_t len;
 128     const char *s = luaL_checklstring(L, 1, &len);
 129     lua_Integer posi = u_posrelat(luaL_optinteger(L, 2, 1), len);
 130     lua_Integer pose = u_posrelat(luaL_optinteger(L, 3, posi), len);
 131     int lax = lua_toboolean(L, 4);
 132     int n;
 133     const char *se;
 134     luaL_argcheck(L, posi >= 1, 2, "out of bounds");
 135     luaL_argcheck(L, pose <= (lua_Integer)len, 3, "out of bounds");
 136     if (posi > pose) return 0;  /* empty interval; return no values */
 137     if (pose - posi >= INT_MAX)  /* (lua_Integer -> int) overflow? */
 138         return luaL_error(L, "string slice too long");
 139     n = (int)(pose -  posi) + 1;  /* upper bound for number of returns */
 140     luaL_checkstack(L, n, "string slice too long");
 141     n = 0;  /* count the number of returns */
 142     se = s + pose;  /* string end */
 143     for (s += posi - 1; s < se;) {
 144         utfint code;
 145         s = utf8_decode(s, &code, !lax);
 146         if (s == NULL)
 147             return luaL_error(L, MSGInvalid);
 148         lua_pushinteger(L, code);
 149         n++;
 150     }
 151     return n;
 152 }
 153
 154
 155 static void pushutfchar(lua_State *L, int arg) {
 156     lua_Unsigned code = (lua_Unsigned)luaL_checkinteger(L, arg);
 157     luaL_argcheck(L, code <= MAXUTF, arg, "value out of range");
 158     lua_pushfstring(L, "%U", (long)code);
 159 }
 160
 161
 162 /*
 163 ** utfchar(n1, n2, ...)  -> char(n1)..char(n2)...
 164 */
 165 static int utfchar(lua_State *L) {
 166     int n = lua_gettop(L);  /* number of arguments */
 167     if (n == 1)  /* optimize common case of single char */
 168         pushutfchar(L, 1);
 169     else {
 170         int i;
 171         luaL_Buffer b;
 172         luaL_buffinit(L, &b);
 173         for (i = 1; i <= n; i++) {
 174             pushutfchar(L, i);
 175             luaL_addvalue(&b);
 176         }
 177         luaL_pushresult(&b);
 178     }
 179     return 1;
 180 }
 181
 182
 183 /*
 184 ** offset(s, n, [i])  -> index where n-th character counting from
 185 **   position 'i' starts; 0 means character at 'i'.
 186 */
 187 static int byteoffset(lua_State *L) {
 188     size_t len;
 189     const char *s = luaL_checklstring(L, 1, &len);
 190     lua_Integer n  = luaL_checkinteger(L, 2);
 191     lua_Integer posi = (n >= 0) ? 1 : len + 1;
 192     posi = u_posrelat(luaL_optinteger(L, 3, posi), len);
 193     luaL_argcheck(L, 1 <= posi && --posi <= (lua_Integer)len, 3,
 194                   "position out of bounds");
 195     if (n == 0) {
 196         /* find beginning of current byte sequence */
 197         while (posi > 0 && iscontp(s + posi)) posi--;
 198     } else {
 199         if (iscontp(s + posi))
 200             return luaL_error(L, "initial position is a continuation byte");
 201         if (n < 0) {
 202             while (n < 0 && posi > 0) {  /* move back */
 203                 do {  /* find beginning of previous character */
 204                     posi--;
 205                 } while (posi > 0 && iscontp(s + posi));
 206                 n++;
 207             }
 208         } else {
 209             n--;  /* do not move for 1st character */
 210             while (n > 0 && posi < (lua_Integer)len) {
 211                 do {  /* find beginning of next character */
 212                     posi++;
 213                 } while (iscontp(s + posi));  /* (cannot pass final '\0') */
 214                 n--;
 215             }
 216         }
 217     }
 218     if (n == 0)  /* did it find given character? */
 219         lua_pushinteger(L, posi + 1);
 220     else  /* no such character */
 221         luaL_pushfail(L);
 222     return 1;
 223 }
 224
 225
 226 static int iter_aux(lua_State *L, int strict) {
 227     size_t len;
 228     const char *s = luaL_checklstring(L, 1, &len);
 229     lua_Unsigned n = (lua_Unsigned)lua_tointeger(L, 2);
 230     if (n < len) {
 231         while (iscontp(s + n)) n++;  /* go to next character */
 232     }
 233     if (n >= len)  /* (also handles original 'n' being negative) */
 234         return 0;  /* no more codepoints */
 235     else {
 236         utfint code;
 237         const char *next = utf8_decode(s + n, &code, strict);
 238         if (next == NULL || iscontp(next))
 239             return luaL_error(L, MSGInvalid);
 240         lua_pushinteger(L, n + 1);
 241         lua_pushinteger(L, code);
 242         return 2;
 243     }
 244 }
 245
 246
 247 static int iter_auxstrict(lua_State *L) {
 248     return iter_aux(L, 1);
 249 }
 250
 251 static int iter_auxlax(lua_State *L) {
 252     return iter_aux(L, 0);
 253 }
 254
 255
 256 static int iter_codes(lua_State *L) {
 257     int lax = lua_toboolean(L, 2);
 258     const char *s = luaL_checkstring(L, 1);
 259     luaL_argcheck(L, !iscontp(s), 1, MSGInvalid);
 260     lua_pushcfunction(L, lax ? iter_auxlax : iter_auxstrict);
 261     lua_pushvalue(L, 1);
 262     lua_pushinteger(L, 0);
 263     return 3;
 264 }
 265
 266
 267 /* pattern to match a single UTF-8 character */
 268 #define UTF8PATT        "[\0-\x7F\xC2-\xFD][\x80-\xBF]*"
 269
 270
 271 static const luaL_Reg funcs[] = {
 272     {"offset", byteoffset},
 273     {"codepoint", codepoint},
 274     {"char", utfchar},
 275     {"len", utflen},
 276     {"codes", iter_codes},
 277     /* placeholders */
 278     {"charpattern", NULL},
 279     {NULL, NULL}
 280 };
 281
 282
 283 LUAMOD_API int luaopen_utf8(lua_State *L) {
 284     luaL_newlib(L, funcs);
 285     lua_pushlstring(L, UTF8PATT, sizeof(UTF8PATT) / sizeof(char) - 1);
 286     lua_setfield(L, -2, "charpattern");
 287     return 1;
 288 }
 289