Lua TeamLua 5.3.0-rc017ba73111 years agoHistory
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/*** $Id: lutf8lib.c,v 1.13 2014/11/02 19:19:04 roberto Exp $** Standard library for UTF-8 manipulation** See Copyright Notice in lua.h*/ #define lutf8lib_c#define LUA_LIB #include "lprefix.h"  #include <assert.h>#include <stdlib.h>#include <string.h> #include "lua.h" #include "lauxlib.h"#include "lualib.h" #define MAXUNICODE	0x10FFFF #define iscont(p)	((*(p) & 0xC0) == 0x80)  /* from strlib *//* translate a relative string position: negative means back from end */static lua_Integer u_posrelat (lua_Integer pos, size_t len) {  if (pos >= 0) return pos;  else if (0u - (size_t)pos > len) return 0;  else return (lua_Integer)len + pos + 1;}  /*** Decode one UTF-8 sequence, returning NULL if byte sequence is invalid.*/static const char *utf8_decode (const char *o, int *val) {  static unsigned int limits[] = {0xFF, 0x7F, 0x7FF, 0xFFFF};  const unsigned char *s = (const unsigned char *)o;  unsigned int c = s[0];  unsigned int res = 0;  /* final result */  if (c < 0x80)  /* ascii? */    res = c;  else {    int count = 0;  /* to count number of continuation bytes */    while (c & 0x40) {  /* still have continuation bytes? */      int cc = s[++count];  /* read next byte */      if ((cc & 0xC0) != 0x80)  /* not a continuation byte? */        return NULL;  /* invalid byte sequence */      res = (res << 6) | (cc & 0x3F);  /* add lower 6 bits from cont. byte */      c <<= 1;  /* to test next bit */    }    res |= ((c & 0x7F) << (count * 5));  /* add first byte */    if (count > 3 || res > MAXUNICODE || res <= limits[count])      return NULL;  /* invalid byte sequence */    s += count;  /* skip continuation bytes read */  }  if (val) *val = res;  return (const char *)s + 1;  /* +1 to include first byte */}  /*** utf8len(s [, i [, j]]) --> number of characters that start in the** range [i,j], or nil + current position if 's' is not well formed in** that interval*/static int utflen (lua_State *L) {  int n = 0;  size_t len;  const char *s = luaL_checklstring(L, 1, &len);  lua_Integer posi = u_posrelat(luaL_optinteger(L, 2, 1), len);  lua_Integer posj = u_posrelat(luaL_optinteger(L, 3, -1), len);  luaL_argcheck(L, 1 <= posi && --posi <= (lua_Integer)len, 2,                   "initial position out of string");  luaL_argcheck(L, --posj < (lua_Integer)len, 3,                   "final position out of string");  while (posi <= posj) {    const char *s1 = utf8_decode(s + posi, NULL);    if (s1 == NULL) {  /* conversion error? */      lua_pushnil(L);  /* return nil ... */      lua_pushinteger(L, posi + 1);  /* ... and current position */      return 2;    }    posi = s1 - s;    n++;  }  lua_pushinteger(L, n);  return 1;}  /*** codepoint(s, [i, [j]])  -> returns codepoints for all characters** that start in the range [i,j]*/static int codepoint (lua_State *L) {  size_t len;  const char *s = luaL_checklstring(L, 1, &len);  lua_Integer posi = u_posrelat(luaL_optinteger(L, 2, 1), len);  lua_Integer pose = u_posrelat(luaL_optinteger(L, 3, posi), len);  int n;  const char *se;  luaL_argcheck(L, posi >= 1, 2, "out of range");  luaL_argcheck(L, pose <= (lua_Integer)len, 3, "out of range");  if (posi > pose) return 0;  /* empty interval; return no values */  n = (int)(pose -  posi + 1);  if (posi + n <= pose)  /* (lua_Integer -> int) overflow? */    return luaL_error(L, "string slice too long");  luaL_checkstack(L, n, "string slice too long");  n = 0;  se = s + pose;  for (s += posi - 1; s < se;) {    int code;    s = utf8_decode(s, &code);    if (s == NULL)      return luaL_error(L, "invalid UTF-8 code");    lua_pushinteger(L, code);    n++;  }  return n;}  static void pushutfchar (lua_State *L, int arg) {  lua_Integer code = luaL_checkinteger(L, arg);  luaL_argcheck(L, 0 <= code && code <= MAXUNICODE, arg, "value out of range");  lua_pushfstring(L, "%U", (long)code);}  /*** utfchar(n1, n2, ...)  -> char(n1)..char(n2)...*/static int utfchar (lua_State *L) {  int n = lua_gettop(L);  /* number of arguments */  if (n == 1)  /* optimize common case of single char */    pushutfchar(L, 1);  else {    int i;    luaL_Buffer b;    luaL_buffinit(L, &b);    for (i = 1; i <= n; i++) {      pushutfchar(L, i);      luaL_addvalue(&b);    }    luaL_pushresult(&b);  }  return 1;}  /*** offset(s, n, [i])  -> index where n-th character counting from**   position 'i' starts; 0 means character at 'i'.*/static int byteoffset (lua_State *L) {  size_t len;  const char *s = luaL_checklstring(L, 1, &len);  lua_Integer n  = luaL_checkinteger(L, 2);  lua_Integer posi = (n >= 0) ? 1 : len + 1;  posi = u_posrelat(luaL_optinteger(L, 3, posi), len);  luaL_argcheck(L, 1 <= posi && --posi <= (lua_Integer)len, 3,                   "position out of range");  if (n == 0) {    /* find beginning of current byte sequence */    while (posi > 0 && iscont(s + posi)) posi--;  }  else {    if (iscont(s + posi))      luaL_error(L, "initial position is a continuation byte");    if (n < 0) {       while (n < 0 && posi > 0) {  /* move back */         do {  /* find beginning of previous character */           posi--;         } while (posi > 0 && iscont(s + posi));         n++;       }     }     else {       n--;  /* do not move for 1st character */       while (n > 0 && posi < (lua_Integer)len) {         do {  /* find beginning of next character */           posi++;         } while (iscont(s + posi));  /* (cannot pass final '\0') */         n--;       }     }  }  if (n == 0)  /* did it find given character? */    lua_pushinteger(L, posi + 1);  else  /* no such character */    lua_pushnil(L);  return 1;  }  static int iter_aux (lua_State *L) {  size_t len;  const char *s = luaL_checklstring(L, 1, &len);  lua_Integer n = lua_tointeger(L, 2) - 1;  if (n < 0)  /* first iteration? */    n = 0;  /* start from here */  else if (n < (lua_Integer)len) {    n++;  /* skip current byte */    while (iscont(s + n)) n++;  /* and its continuations */  }  if (n >= (lua_Integer)len)    return 0;  /* no more codepoints */  else {    int code;    const char *next = utf8_decode(s + n, &code);    if (next == NULL || iscont(next))      return luaL_error(L, "invalid UTF-8 code");    lua_pushinteger(L, n + 1);    lua_pushinteger(L, code);    return 2;  }}  static int iter_codes (lua_State *L) {  luaL_checkstring(L, 1);  lua_pushcfunction(L, iter_aux);  lua_pushvalue(L, 1);  lua_pushinteger(L, 0);  return 3;}  /* pattern to match a single UTF-8 character */#define UTF8PATT	"[\0-\x7F\xC2-\xF4][\x80-\xBF]*"  static struct luaL_Reg funcs[] = {  {"offset", byteoffset},  {"codepoint", codepoint},  {"char", utfchar},  {"len", utflen},  {"codes", iter_codes},  /* placeholders */  {"charpattern", NULL},  {NULL, NULL}};  LUAMOD_API int luaopen_utf8 (lua_State *L) {  luaL_newlib(L, funcs);  lua_pushliteral(L, UTF8PATT);  lua_setfield(L, -2, "charpattern");  return 1;}