1 /*

     2 ** $Id: lstrlib.c,v 1.132.1.4 2008/07/11 17:27:21 roberto Exp $

     3 ** Standard library for string operations and pattern-matching

     4 ** See Copyright Notice in lua.h

     5 */

     6 

     7 

     8 #include <ctype.h>

     9 #include <stddef.h>

    10 #include <stdio.h>

    11 #include <stdlib.h>

    12 #include <string.h>

    13 

    14 #define lstrlib_c

    15 #define LUA_LIB

    16 

    17 #include "lua.h"

    18 

    19 #include "lauxlib.h"

    20 #include "lualib.h"

    21 

    22 

    23 /* macro to `unsign' a character */

    24 #define uchar(c)        ((unsigned char)(c))

    25 

    26 

    27 

    28 static int str_len (lua_State *L) {

    29   size_t l;

    30   luaL_checklstring(L, 1, &l);

    31   lua_pushinteger(L, l);

    32   return 1;

    33 }

    34 

    35 

    36 static ptrdiff_t posrelat (ptrdiff_t pos, size_t len) {

    37   /* relative string position: negative means back from end */

    38   if (pos < 0) pos += (ptrdiff_t)len + 1;

    39   return (pos >= 0) ? pos : 0;

    40 }

    41 

    42 

    43 static int str_sub (lua_State *L) {

    44   size_t l;

    45   const char *s = luaL_checklstring(L, 1, &l);

    46   ptrdiff_t start = posrelat(luaL_checkinteger(L, 2), l);

    47   ptrdiff_t end = posrelat(luaL_optinteger(L, 3, -1), l);

    48   if (start < 1) start = 1;

    49   if (end > (ptrdiff_t)l) end = (ptrdiff_t)l;

    50   if (start <= end)

    51     lua_pushlstring(L, s+start-1, end-start+1);

    52   else lua_pushliteral(L, "");

    53   return 1;

    54 }

    55 

    56 

    57 static int str_reverse (lua_State *L) {

    58   size_t l;

    59   luaL_Buffer b;

    60   const char *s = luaL_checklstring(L, 1, &l);

    61   luaL_buffinit(L, &b);

    62   while (l--) luaL_addchar(&b, s[l]);

    63   luaL_pushresult(&b);

    64   return 1;

    65 }

    66 

    67 

    68 static int str_lower (lua_State *L) {

    69   size_t l;

    70   size_t i;

    71   luaL_Buffer b;

    72   const char *s = luaL_checklstring(L, 1, &l);

    73   luaL_buffinit(L, &b);

    74   for (i=0; i<l; i++)

    75     luaL_addchar(&b, tolower(uchar(s[i])));

    76   luaL_pushresult(&b);

    77   return 1;

    78 }

    79 

    80 

    81 static int str_upper (lua_State *L) {

    82   size_t l;

    83   size_t i;

    84   luaL_Buffer b;

    85   const char *s = luaL_checklstring(L, 1, &l);

    86   luaL_buffinit(L, &b);

    87   for (i=0; i<l; i++)

    88     luaL_addchar(&b, toupper(uchar(s[i])));

    89   luaL_pushresult(&b);

    90   return 1;

    91 }

    92 

    93 static int str_rep (lua_State *L) {

    94   size_t l;

    95   luaL_Buffer b;

    96   const char *s = luaL_checklstring(L, 1, &l);

    97   int n = luaL_checkint(L, 2);

    98   luaL_buffinit(L, &b);

    99   while (n-- > 0)

   100     luaL_addlstring(&b, s, l);

   101   luaL_pushresult(&b);

   102   return 1;

   103 }

   104 

   105 

   106 static int str_byte (lua_State *L) {

   107   size_t l;

   108   const char *s = luaL_checklstring(L, 1, &l);

   109   ptrdiff_t posi = posrelat(luaL_optinteger(L, 2, 1), l);

   110   ptrdiff_t pose = posrelat(luaL_optinteger(L, 3, posi), l);

   111   int n, i;

   112   if (posi <= 0) posi = 1;

   113   if ((size_t)pose > l) pose = l;

   114   if (posi > pose) return 0;  /* empty interval; return no values */

   115   n = (int)(pose -  posi + 1);

   116   if (posi + n <= pose)  /* overflow? */

   117     luaL_error(L, "string slice too long");

   118   luaL_checkstack(L, n, "string slice too long");

   119   for (i=0; i<n; i++)

   120     lua_pushinteger(L, uchar(s[posi+i-1]));

   121   return n;

   122 }

   123 

   124 

   125 static int str_char (lua_State *L) {

   126   int n = lua_gettop(L);  /* number of arguments */

   127   int i;

   128   luaL_Buffer b;

   129   luaL_buffinit(L, &b);

   130   for (i=1; i<=n; i++) {

   131     int c = luaL_checkint(L, i);

   132     luaL_argcheck(L, uchar(c) == c, i, "invalid value");

   133     luaL_addchar(&b, uchar(c));

   134   }

   135   luaL_pushresult(&b);

   136   return 1;

   137 }

   138 

   139 

   140 static int writer (lua_State *L, const void* b, size_t size, void* B) {

   141   (void)L;

   142   luaL_addlstring((luaL_Buffer*) B, (const char *)b, size);

   143   return 0;

   144 }

   145 

   146 

   147 static int str_dump (lua_State *L) {

   148   luaL_Buffer b;

   149   luaL_checktype(L, 1, LUA_TFUNCTION);

   150   lua_settop(L, 1);

   151   luaL_buffinit(L,&b);

   152   if (lua_dump(L, writer, &b) != 0)

   153     luaL_error(L, "unable to dump given function");

   154   luaL_pushresult(&b);

   155   return 1;

   156 }

   157 

   158 

   159 

   160 /*

   161 ** {======================================================

   162 ** PATTERN MATCHING

   163 ** =======================================================

   164 */

   165 

   166 

   167 #define CAP_UNFINISHED	(-1)

   168 #define CAP_POSITION	(-2)

   169 

   170 typedef struct MatchState {

   171   const char *src_init;  /* init of source string */

   172   const char *src_end;  /* end (`\0') of source string */

   173   lua_State *L;

   174   int level;  /* total number of captures (finished or unfinished) */

   175   struct {

   176     const char *init;

   177     ptrdiff_t len;

   178   } capture[LUA_MAXCAPTURES];

   179 } MatchState;

   180 

   181 

   182 #define L_ESC		'%'

   183 #define SPECIALS	"^$*+?.([%-"

   184 

   185 

   186 static int check_capture (MatchState *ms, int l) {

   187   l -= '1';

   188   if (l < 0 || l >= ms->level || ms->capture[l].len == CAP_UNFINISHED)

   189     return luaL_error(ms->L, "invalid capture index");

   190   return l;

   191 }

   192 

   193 

   194 static int capture_to_close (MatchState *ms) {

   195   int level = ms->level;

   196   for (level--; level>=0; level--)

   197     if (ms->capture[level].len == CAP_UNFINISHED) return level;

   198   return luaL_error(ms->L, "invalid pattern capture");

   199 }

   200 

   201 

   202 static const char *classend (MatchState *ms, const char *p) {

   203   switch (*p++) {

   204     case L_ESC: {

   205       if (*p == '\0')

   206         luaL_error(ms->L, "malformed pattern (ends with " LUA_QL("%%") ")");

   207       return p+1;

   208     }

   209     case '[': {

   210       if (*p == '^') p++;

   211       do {  /* look for a `]' */

   212         if (*p == '\0')

   213           luaL_error(ms->L, "malformed pattern (missing " LUA_QL("]") ")");

   214         if (*(p++) == L_ESC && *p != '\0')

   215           p++;  /* skip escapes (e.g. `%]') */

   216       } while (*p != ']');

   217       return p+1;

   218     }

   219     default: {

   220       return p;

   221     }

   222   }

   223 }

   224 

   225 

   226 static int match_class (int c, int cl) {

   227   int res;

   228   switch (tolower(cl)) {

   229     case 'a' : res = isalpha(c); break;

   230     case 'c' : res = iscntrl(c); break;

   231     case 'd' : res = isdigit(c); break;

   232     case 'l' : res = islower(c); break;

   233     case 'p' : res = ispunct(c); break;

   234     case 's' : res = isspace(c); break;

   235     case 'u' : res = isupper(c); break;

   236     case 'w' : res = isalnum(c); break;

   237     case 'x' : res = isxdigit(c); break;

   238     case 'z' : res = (c == 0); break;

   239     default: return (cl == c);

   240   }

   241   return (islower(cl) ? res : !res);

   242 }

   243 

   244 

   245 static int matchbracketclass (int c, const char *p, const char *ec) {

   246   int sig = 1;

   247   if (*(p+1) == '^') {

   248     sig = 0;

   249     p++;  /* skip the `^' */

   250   }

   251   while (++p < ec) {

   252     if (*p == L_ESC) {

   253       p++;

   254       if (match_class(c, uchar(*p)))

   255         return sig;

   256     }

   257     else if ((*(p+1) == '-') && (p+2 < ec)) {

   258       p+=2;

   259       if (uchar(*(p-2)) <= c && c <= uchar(*p))

   260         return sig;

   261     }

   262     else if (uchar(*p) == c) return sig;

   263   }

   264   return !sig;

   265 }

   266 

   267 

   268 static int singlematch (int c, const char *p, const char *ep) {

   269   switch (*p) {

   270     case '.': return 1;  /* matches any char */

   271     case L_ESC: return match_class(c, uchar(*(p+1)));

   272     case '[': return matchbracketclass(c, p, ep-1);

   273     default:  return (uchar(*p) == c);

   274   }

   275 }

   276 

   277 

   278 static const char *match (MatchState *ms, const char *s, const char *p);

   279 

   280 

   281 static const char *matchbalance (MatchState *ms, const char *s,

   282                                    const char *p) {

   283   if (*p == 0 || *(p+1) == 0)

   284     luaL_error(ms->L, "unbalanced pattern");

   285   if (*s != *p) return NULL;

   286   else {

   287     int b = *p;

   288     int e = *(p+1);

   289     int cont = 1;

   290     while (++s < ms->src_end) {

   291       if (*s == e) {

   292         if (--cont == 0) return s+1;

   293       }

   294       else if (*s == b) cont++;

   295     }

   296   }

   297   return NULL;  /* string ends out of balance */

   298 }

   299 

   300 

   301 static const char *max_expand (MatchState *ms, const char *s,

   302                                  const char *p, const char *ep) {

   303   ptrdiff_t i = 0;  /* counts maximum expand for item */

   304   while ((s+i)<ms->src_end && singlematch(uchar(*(s+i)), p, ep))

   305     i++;

   306   /* keeps trying to match with the maximum repetitions */

   307   while (i>=0) {

   308     const char *res = match(ms, (s+i), ep+1);

   309     if (res) return res;

   310     i--;  /* else didn't match; reduce 1 repetition to try again */

   311   }

   312   return NULL;

   313 }

   314 

   315 

   316 static const char *min_expand (MatchState *ms, const char *s,

   317                                  const char *p, const char *ep) {

   318   for (;;) {

   319     const char *res = match(ms, s, ep+1);

   320     if (res != NULL)

   321       return res;

   322     else if (s<ms->src_end && singlematch(uchar(*s), p, ep))

   323       s++;  /* try with one more repetition */

   324     else return NULL;

   325   }

   326 }

   327 

   328 

   329 static const char *start_capture (MatchState *ms, const char *s,

   330                                     const char *p, int what) {

   331   const char *res;

   332   int level = ms->level;

   333   if (level >= LUA_MAXCAPTURES) luaL_error(ms->L, "too many captures");

   334   ms->capture[level].init = s;

   335   ms->capture[level].len = what;

   336   ms->level = level+1;

   337   if ((res=match(ms, s, p)) == NULL)  /* match failed? */

   338     ms->level--;  /* undo capture */

   339   return res;

   340 }

   341 

   342 

   343 static const char *end_capture (MatchState *ms, const char *s,

   344                                   const char *p) {

   345   int l = capture_to_close(ms);

   346   const char *res;

   347   ms->capture[l].len = s - ms->capture[l].init;  /* close capture */

   348   if ((res = match(ms, s, p)) == NULL)  /* match failed? */

   349     ms->capture[l].len = CAP_UNFINISHED;  /* undo capture */

   350   return res;

   351 }

   352 

   353 

   354 static const char *match_capture (MatchState *ms, const char *s, int l) {

   355   size_t len;

   356   l = check_capture(ms, l);

   357   len = ms->capture[l].len;

   358   if ((size_t)(ms->src_end-s) >= len &&

   359       memcmp(ms->capture[l].init, s, len) == 0)

   360     return s+len;

   361   else return NULL;

   362 }

   363 

   364 

   365 static const char *match (MatchState *ms, const char *s, const char *p) {

   366   init: /* using goto's to optimize tail recursion */

   367   switch (*p) {

   368     case '(': {  /* start capture */

   369       if (*(p+1) == ')')  /* position capture? */

   370         return start_capture(ms, s, p+2, CAP_POSITION);

   371       else

   372         return start_capture(ms, s, p+1, CAP_UNFINISHED);

   373     }

   374     case ')': {  /* end capture */

   375       return end_capture(ms, s, p+1);

   376     }

   377     case L_ESC: {

   378       switch (*(p+1)) {

   379         case 'b': {  /* balanced string? */

   380           s = matchbalance(ms, s, p+2);

   381           if (s == NULL) return NULL;

   382           p+=4; goto init;  /* else return match(ms, s, p+4); */

   383         }

   384         case 'f': {  /* frontier? */

   385           const char *ep; char previous;

   386           p += 2;

   387           if (*p != '[')

   388             luaL_error(ms->L, "missing " LUA_QL("[") " after "

   389                                LUA_QL("%%f") " in pattern");

   390           ep = classend(ms, p);  /* points to what is next */

   391           previous = (s == ms->src_init) ? '\0' : *(s-1);

   392           if (matchbracketclass(uchar(previous), p, ep-1) ||

   393              !matchbracketclass(uchar(*s), p, ep-1)) return NULL;

   394           p=ep; goto init;  /* else return match(ms, s, ep); */

   395         }

   396         default: {

   397           if (isdigit(uchar(*(p+1)))) {  /* capture results (%0-%9)? */

   398             s = match_capture(ms, s, uchar(*(p+1)));

   399             if (s == NULL) return NULL;

   400             p+=2; goto init;  /* else return match(ms, s, p+2) */

   401           }

   402           goto dflt;  /* case default */

   403         }

   404       }

   405     }

   406     case '\0': {  /* end of pattern */

   407       return s;  /* match succeeded */

   408     }

   409     case '$': {

   410       if (*(p+1) == '\0')  /* is the `$' the last char in pattern? */

   411         return (s == ms->src_end) ? s : NULL;  /* check end of string */

   412       else goto dflt;

   413     }

   414     default: dflt: {  /* it is a pattern item */

   415       const char *ep = classend(ms, p);  /* points to what is next */

   416       int m = s<ms->src_end && singlematch(uchar(*s), p, ep);

   417       switch (*ep) {

   418         case '?': {  /* optional */

   419           const char *res;

   420           if (m && ((res=match(ms, s+1, ep+1)) != NULL))

   421             return res;

   422           p=ep+1; goto init;  /* else return match(ms, s, ep+1); */

   423         }

   424         case '*': {  /* 0 or more repetitions */

   425           return max_expand(ms, s, p, ep);

   426         }

   427         case '+': {  /* 1 or more repetitions */

   428           return (m ? max_expand(ms, s+1, p, ep) : NULL);

   429         }

   430         case '-': {  /* 0 or more repetitions (minimum) */

   431           return min_expand(ms, s, p, ep);

   432         }

   433         default: {

   434           if (!m) return NULL;

   435           s++; p=ep; goto init;  /* else return match(ms, s+1, ep); */

   436         }

   437       }

   438     }

   439   }

   440 }

   441 

   442 

   443 

   444 static const char *lmemfind (const char *s1, size_t l1,

   445                                const char *s2, size_t l2) {

   446   if (l2 == 0) return s1;  /* empty strings are everywhere */

   447   else if (l2 > l1) return NULL;  /* avoids a negative `l1' */

   448   else {

   449     const char *init;  /* to search for a `*s2' inside `s1' */

   450     l2--;  /* 1st char will be checked by `memchr' */

   451     l1 = l1-l2;  /* `s2' cannot be found after that */

   452     while (l1 > 0 && (init = (const char *)memchr(s1, *s2, l1)) != NULL) {

   453       init++;   /* 1st char is already checked */

   454       if (memcmp(init, s2+1, l2) == 0)

   455         return init-1;

   456       else {  /* correct `l1' and `s1' to try again */

   457         l1 -= init-s1;

   458         s1 = init;

   459       }

   460     }

   461     return NULL;  /* not found */

   462   }

   463 }

   464 

   465 

   466 static void push_onecapture (MatchState *ms, int i, const char *s,

   467                                                     const char *e) {

   468   if (i >= ms->level) {

   469     if (i == 0)  /* ms->level == 0, too */

   470       lua_pushlstring(ms->L, s, e - s);  /* add whole match */

   471     else

   472       luaL_error(ms->L, "invalid capture index");

   473   }

   474   else {

   475     ptrdiff_t l = ms->capture[i].len;

   476     if (l == CAP_UNFINISHED) luaL_error(ms->L, "unfinished capture");

   477     if (l == CAP_POSITION)

   478       lua_pushinteger(ms->L, ms->capture[i].init - ms->src_init + 1);

   479     else

   480       lua_pushlstring(ms->L, ms->capture[i].init, l);

   481   }

   482 }

   483 

   484 

   485 static int push_captures (MatchState *ms, const char *s, const char *e) {

   486   int i;

   487   int nlevels = (ms->level == 0 && s) ? 1 : ms->level;

   488   luaL_checkstack(ms->L, nlevels, "too many captures");

   489   for (i = 0; i < nlevels; i++)

   490     push_onecapture(ms, i, s, e);

   491   return nlevels;  /* number of strings pushed */

   492 }

   493 

   494 

   495 static int str_find_aux (lua_State *L, int find) {

   496   size_t l1, l2;

   497   const char *s = luaL_checklstring(L, 1, &l1);

   498   const char *p = luaL_checklstring(L, 2, &l2);

   499   ptrdiff_t init = posrelat(luaL_optinteger(L, 3, 1), l1) - 1;

   500   if (init < 0) init = 0;

   501   else if ((size_t)(init) > l1) init = (ptrdiff_t)l1;

   502   if (find && (lua_toboolean(L, 4) ||  /* explicit request? */

   503       strpbrk(p, SPECIALS) == NULL)) {  /* or no special characters? */

   504     /* do a plain search */

   505     const char *s2 = lmemfind(s+init, l1-init, p, l2);

   506     if (s2) {

   507       lua_pushinteger(L, s2-s+1);

   508       lua_pushinteger(L, s2-s+l2);

   509       return 2;

   510     }

   511   }

   512   else {

   513     MatchState ms;

   514     int anchor = (*p == '^') ? (p++, 1) : 0;

   515     const char *s1=s+init;

   516     ms.L = L;

   517     ms.src_init = s;

   518     ms.src_end = s+l1;

   519     do {

   520       const char *res;

   521       ms.level = 0;

   522       if ((res=match(&ms, s1, p)) != NULL) {

   523         if (find) {

   524           lua_pushinteger(L, s1-s+1);  /* start */

   525           lua_pushinteger(L, res-s);   /* end */

   526           return push_captures(&ms, NULL, 0) + 2;

   527         }

   528         else

   529           return push_captures(&ms, s1, res);

   530       }

   531     } while (s1++ < ms.src_end && !anchor);

   532   }

   533   lua_pushnil(L);  /* not found */

   534   return 1;

   535 }

   536 

   537 

   538 static int str_find (lua_State *L) {

   539   return str_find_aux(L, 1);

   540 }

   541 

   542 

   543 static int str_match (lua_State *L) {

   544   return str_find_aux(L, 0);

   545 }

   546 

   547 

   548 static int gmatch_aux (lua_State *L) {

   549   MatchState ms;

   550   size_t ls;

   551   const char *s = lua_tolstring(L, lua_upvalueindex(1), &ls);

   552   const char *p = lua_tostring(L, lua_upvalueindex(2));

   553   const char *src;

   554   ms.L = L;

   555   ms.src_init = s;

   556   ms.src_end = s+ls;

   557   for (src = s + (size_t)lua_tointeger(L, lua_upvalueindex(3));

   558        src <= ms.src_end;

   559        src++) {

   560     const char *e;

   561     ms.level = 0;

   562     if ((e = match(&ms, src, p)) != NULL) {

   563       lua_Integer newstart = e-s;

   564       if (e == src) newstart++;  /* empty match? go at least one position */

   565       lua_pushinteger(L, newstart);

   566       lua_replace(L, lua_upvalueindex(3));

   567       return push_captures(&ms, src, e);

   568     }

   569   }

   570   return 0;  /* not found */

   571 }

   572 

   573 

   574 static int gmatch (lua_State *L) {

   575   luaL_checkstring(L, 1);

   576   luaL_checkstring(L, 2);

   577   lua_settop(L, 2);

   578   lua_pushinteger(L, 0);

   579   lua_pushcclosure(L, gmatch_aux, 3);

   580   return 1;

   581 }

   582 

   583 

   584 static int gfind_nodef (lua_State *L) {

   585   return luaL_error(L, LUA_QL("string.gfind") " was renamed to "

   586                        LUA_QL("string.gmatch"));

   587 }

   588 

   589 

   590 static void add_s (MatchState *ms, luaL_Buffer *b, const char *s,

   591                                                    const char *e) {

   592   size_t l, i;

   593   const char *news = lua_tolstring(ms->L, 3, &l);

   594   for (i = 0; i < l; i++) {

   595     if (news[i] != L_ESC)

   596       luaL_addchar(b, news[i]);

   597     else {

   598       i++;  /* skip ESC */

   599       if (!isdigit(uchar(news[i])))

   600         luaL_addchar(b, news[i]);

   601       else if (news[i] == '0')

   602           luaL_addlstring(b, s, e - s);

   603       else {

   604         push_onecapture(ms, news[i] - '1', s, e);

   605         luaL_addvalue(b);  /* add capture to accumulated result */

   606       }

   607     }

   608   }

   609 }

   610 

   611 

   612 static void add_value (MatchState *ms, luaL_Buffer *b, const char *s,

   613                                                        const char *e) {

   614   lua_State *L = ms->L;

   615   switch (lua_type(L, 3)) {

   616     case LUA_TNUMBER:

   617     case LUA_TSTRING: {

   618       add_s(ms, b, s, e);

   619       return;

   620     }

   621     case LUA_TFUNCTION: {

   622       int n;

   623       lua_pushvalue(L, 3);

   624       n = push_captures(ms, s, e);

   625       lua_call(L, n, 1);

   626       break;

   627     }

   628     case LUA_TTABLE: {

   629       push_onecapture(ms, 0, s, e);

   630       lua_gettable(L, 3);

   631       break;

   632     }

   633   }

   634   if (!lua_toboolean(L, -1)) {  /* nil or false? */

   635     lua_pop(L, 1);

   636     lua_pushlstring(L, s, e - s);  /* keep original text */

   637   }

   638   else if (!lua_isstring(L, -1))

   639     luaL_error(L, "invalid replacement value (a %s)", luaL_typename(L, -1)); 

   640   luaL_addvalue(b);  /* add result to accumulator */

   641 }

   642 

   643 

   644 static int str_gsub (lua_State *L) {

   645   size_t srcl;

   646   const char *src = luaL_checklstring(L, 1, &srcl);

   647   const char *p = luaL_checkstring(L, 2);

   648   int  tr = lua_type(L, 3);

   649   int max_s = luaL_optint(L, 4, srcl+1);

   650   int anchor = (*p == '^') ? (p++, 1) : 0;

   651   int n = 0;

   652   MatchState ms;

   653   luaL_Buffer b;

   654   luaL_argcheck(L, tr == LUA_TNUMBER || tr == LUA_TSTRING ||

   655                    tr == LUA_TFUNCTION || tr == LUA_TTABLE, 3,

   656                       "string/function/table expected");

   657   luaL_buffinit(L, &b);

   658   ms.L = L;

   659   ms.src_init = src;

   660   ms.src_end = src+srcl;

   661   while (n < max_s) {

   662     const char *e;

   663     ms.level = 0;

   664     e = match(&ms, src, p);

   665     if (e) {

   666       n++;

   667       add_value(&ms, &b, src, e);

   668     }

   669     if (e && e>src) /* non empty match? */

   670       src = e;  /* skip it */

   671     else if (src < ms.src_end)

   672       luaL_addchar(&b, *src++);

   673     else break;

   674     if (anchor) break;

   675   }

   676   luaL_addlstring(&b, src, ms.src_end-src);

   677   luaL_pushresult(&b);

   678   lua_pushinteger(L, n);  /* number of substitutions */

   679   return 2;

   680 }

   681 

   682 /* }====================================================== */

   683 

   684 

   685 /* maximum size of each formatted item (> len(format('%99.99f', -1e308))) */

   686 #define MAX_ITEM	512

   687 /* valid flags in a format specification */

   688 #define FLAGS	"-+ #0"

   689 /*

   690 ** maximum size of each format specification (such as '%-099.99d')

   691 ** (+10 accounts for %99.99x plus margin of error)

   692 */

   693 #define MAX_FORMAT	(sizeof(FLAGS) + sizeof(LUA_INTFRMLEN) + 10)

   694 

   695 

   696 static void addquoted (lua_State *L, luaL_Buffer *b, int arg) {

   697   size_t l;

   698   const char *s = luaL_checklstring(L, arg, &l);

   699   luaL_addchar(b, '"');

   700   while (l--) {

   701     switch (*s) {

   702       case '"': case '\\': case '\n': {

   703         luaL_addchar(b, '\\');

   704         luaL_addchar(b, *s);

   705         break;

   706       }

   707       case '\r': {

   708         luaL_addlstring(b, "\\r", 2);

   709         break;

   710       }

   711       case '\0': {

   712         luaL_addlstring(b, "\\000", 4);

   713         break;

   714       }

   715       default: {

   716         luaL_addchar(b, *s);

   717         break;

   718       }

   719     }

   720     s++;

   721   }

   722   luaL_addchar(b, '"');

   723 }

   724 

   725 static const char *scanformat (lua_State *L, const char *strfrmt, char *form) {

   726   const char *p = strfrmt;

   727   while (*p != '\0' && strchr(FLAGS, *p) != NULL) p++;  /* skip flags */

   728   if ((size_t)(p - strfrmt) >= sizeof(FLAGS))

   729     luaL_error(L, "invalid format (repeated flags)");

   730   if (isdigit(uchar(*p))) p++;  /* skip width */

   731   if (isdigit(uchar(*p))) p++;  /* (2 digits at most) */

   732   if (*p == '.') {

   733     p++;

   734     if (isdigit(uchar(*p))) p++;  /* skip precision */

   735     if (isdigit(uchar(*p))) p++;  /* (2 digits at most) */

   736   }

   737   if (isdigit(uchar(*p)))

   738     luaL_error(L, "invalid format (width or precision too long)");

   739   *(form++) = '%';

   740   strncpy(form, strfrmt, p - strfrmt + 1);

   741   form += p - strfrmt + 1;

   742   *form = '\0';

   743   return p;

   744 }

   745 

   746 

   747 static void addintlen (char *form) {

   748   size_t l = strlen(form);

   749   char spec = form[l - 1];

   750   strcpy(form + l - 1, LUA_INTFRMLEN);

   751   form[l + sizeof(LUA_INTFRMLEN) - 2] = spec;

   752   form[l + sizeof(LUA_INTFRMLEN) - 1] = '\0';

   753 }

   754 

   755 

   756 static int str_format (lua_State *L) {

   757   int arg = 1;

   758   size_t sfl;

   759   const char *strfrmt = luaL_checklstring(L, arg, &sfl);

   760   const char *strfrmt_end = strfrmt+sfl;

   761   luaL_Buffer b;

   762   luaL_buffinit(L, &b);

   763   while (strfrmt < strfrmt_end) {

   764     if (*strfrmt != L_ESC)

   765       luaL_addchar(&b, *strfrmt++);

   766     else if (*++strfrmt == L_ESC)

   767       luaL_addchar(&b, *strfrmt++);  /* %% */

   768     else { /* format item */

   769       char form[MAX_FORMAT];  /* to store the format (`%...') */

   770       char buff[MAX_ITEM];  /* to store the formatted item */

   771       arg++;

   772       strfrmt = scanformat(L, strfrmt, form);

   773       switch (*strfrmt++) {

   774         case 'c': {

   775           sprintf(buff, form, (int)luaL_checknumber(L, arg));

   776           break;

   777         }

   778         case 'd':  case 'i': {

   779           addintlen(form);

   780           sprintf(buff, form, (LUA_INTFRM_T)luaL_checknumber(L, arg));

   781           break;

   782         }

   783         case 'o':  case 'u':  case 'x':  case 'X': {

   784           addintlen(form);

   785           sprintf(buff, form, (unsigned LUA_INTFRM_T)luaL_checknumber(L, arg));

   786           break;

   787         }

   788         case 'e':  case 'E': case 'f':

   789         case 'g': case 'G': {

   790           sprintf(buff, form, (double)luaL_checknumber(L, arg));

   791           break;

   792         }

   793         case 'q': {

   794           addquoted(L, &b, arg);

   795           continue;  /* skip the 'addsize' at the end */

   796         }

   797         case 's': {

   798           size_t l;

   799           const char *s = luaL_checklstring(L, arg, &l);

   800           if (!strchr(form, '.') && l >= 100) {

   801             /* no precision and string is too long to be formatted;

   802                keep original string */

   803             lua_pushvalue(L, arg);

   804             luaL_addvalue(&b);

   805             continue;  /* skip the `addsize' at the end */

   806           }

   807           else {

   808             sprintf(buff, form, s);

   809             break;

   810           }

   811         }

   812         default: {  /* also treat cases `pnLlh' */

   813           return luaL_error(L, "invalid option " LUA_QL("%%%c") " to "

   814                                LUA_QL("format"), *(strfrmt - 1));

   815         }

   816       }

   817       luaL_addlstring(&b, buff, strlen(buff));

   818     }

   819   }

   820   luaL_pushresult(&b);

   821   return 1;

   822 }

   823 

   824 

   825 static const luaL_Reg strlib[] = {

   826   {"byte", str_byte},

   827   {"char", str_char},

   828   {"dump", str_dump},

   829   {"find", str_find},

   830   {"format", str_format},

   831   {"gfind", gfind_nodef},

   832   {"gmatch", gmatch},

   833   {"gsub", str_gsub},

   834   {"len", str_len},

   835   {"lower", str_lower},

   836   {"match", str_match},

   837   {"rep", str_rep},

   838   {"reverse", str_reverse},

   839   {"sub", str_sub},

   840   {"upper", str_upper},

   841   {NULL, NULL}

   842 };

   843 

   844 

   845 static void createmetatable (lua_State *L) {

   846   lua_createtable(L, 0, 1);  /* create metatable for strings */

   847   lua_pushliteral(L, "");  /* dummy string */

   848   lua_pushvalue(L, -2);

   849   lua_setmetatable(L, -2);  /* set string metatable */

   850   lua_pop(L, 1);  /* pop dummy string */

   851   lua_pushvalue(L, -2);  /* string library... */

   852   lua_setfield(L, -2, "__index");  /* ...is the __index metamethod */

   853   lua_pop(L, 1);  /* pop metatable */

   854 }

   855 

   856 

   857 /*

   858 ** Open string library

   859 */

   860 LUALIB_API int luaopen_string (lua_State *L) {

   861   luaL_register(L, LUA_STRLIBNAME, strlib);

   862 #if defined(LUA_COMPAT_GFIND)

   863   lua_getfield(L, -1, "gmatch");

   864   lua_setfield(L, -2, "gfind");

   865 #endif

   866   createmetatable(L);

   867   return 1;

   868 }

   869