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  1. /*
  2. ** $Id: lstrlib.c,v 1.178.1.1 2013/04/12 18:48:47 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. /*
  24. ** maximum number of captures that a pattern can do during
  25. ** pattern-matching. This limit is arbitrary.
  26. */
  27. #if !defined(LUA_MAXCAPTURES)
  28. #define LUA_MAXCAPTURES         32
  29. #endif
  30.  
  31.  
  32. /* macro to `unsign' a character */
  33. #define uchar(c)        ((unsigned char)(c))
  34.  
  35.  
  36.  
  37. static int str_len (lua_State *L) {
  38.   size_t l;
  39.   luaL_checklstring(L, 1, &l);
  40.   lua_pushinteger(L, (lua_Integer)l);
  41.   return 1;
  42. }
  43.  
  44.  
  45. /* translate a relative string position: negative means back from end */
  46. static size_t posrelat (ptrdiff_t pos, size_t len) {
  47.   if (pos >= 0) return (size_t)pos;
  48.   else if (0u - (size_t)pos > len) return 0;
  49.   else return len - ((size_t)-pos) + 1;
  50. }
  51.  
  52.  
  53. static int str_sub (lua_State *L) {
  54.   size_t l;
  55.   const char *s = luaL_checklstring(L, 1, &l);
  56.   size_t start = posrelat(luaL_checkinteger(L, 2), l);
  57.   size_t end = posrelat(luaL_optinteger(L, 3, -1), l);
  58.   if (start < 1) start = 1;
  59.   if (end > l) end = l;
  60.   if (start <= end)
  61.     lua_pushlstring(L, s + start - 1, end - start + 1);
  62.   else lua_pushliteral(L, "");
  63.   return 1;
  64. }
  65.  
  66.  
  67. static int str_reverse (lua_State *L) {
  68.   size_t l, i;
  69.   luaL_Buffer b;
  70.   const char *s = luaL_checklstring(L, 1, &l);
  71.   char *p = luaL_buffinitsize(L, &b, l);
  72.   for (i = 0; i < l; i++)
  73.     p[i] = s[l - i - 1];
  74.   luaL_pushresultsize(&b, l);
  75.   return 1;
  76. }
  77.  
  78.  
  79. static int str_lower (lua_State *L) {
  80.   size_t l;
  81.   size_t i;
  82.   luaL_Buffer b;
  83.   const char *s = luaL_checklstring(L, 1, &l);
  84.   char *p = luaL_buffinitsize(L, &b, l);
  85.   for (i=0; i<l; i++)
  86.     p[i] = tolower(uchar(s[i]));
  87.   luaL_pushresultsize(&b, l);
  88.   return 1;
  89. }
  90.  
  91.  
  92. static int str_upper (lua_State *L) {
  93.   size_t l;
  94.   size_t i;
  95.   luaL_Buffer b;
  96.   const char *s = luaL_checklstring(L, 1, &l);
  97.   char *p = luaL_buffinitsize(L, &b, l);
  98.   for (i=0; i<l; i++)
  99.     p[i] = toupper(uchar(s[i]));
  100.   luaL_pushresultsize(&b, l);
  101.   return 1;
  102. }
  103.  
  104.  
  105. /* reasonable limit to avoid arithmetic overflow */
  106. #define MAXSIZE         ((~(size_t)0) >> 1)
  107.  
  108. static int str_rep (lua_State *L) {
  109.   size_t l, lsep;
  110.   const char *s = luaL_checklstring(L, 1, &l);
  111.   int n = luaL_checkint(L, 2);
  112.   const char *sep = luaL_optlstring(L, 3, "", &lsep);
  113.   if (n <= 0) lua_pushliteral(L, "");
  114.   else if (l + lsep < l || l + lsep >= MAXSIZE / n)  /* may overflow? */
  115.     return luaL_error(L, "resulting string too large");
  116.   else {
  117.     size_t totallen = n * l + (n - 1) * lsep;
  118.     luaL_Buffer b;
  119.     char *p = luaL_buffinitsize(L, &b, totallen);
  120.     while (n-- > 1) {  /* first n-1 copies (followed by separator) */
  121.       memcpy(p, s, l * sizeof(char)); p += l;
  122.       if (lsep > 0) {  /* avoid empty 'memcpy' (may be expensive) */
  123.         memcpy(p, sep, lsep * sizeof(char)); p += lsep;
  124.       }
  125.     }
  126.     memcpy(p, s, l * sizeof(char));  /* last copy (not followed by separator) */
  127.     luaL_pushresultsize(&b, totallen);
  128.   }
  129.   return 1;
  130. }
  131.  
  132.  
  133. static int str_byte (lua_State *L) {
  134.   size_t l;
  135.   const char *s = luaL_checklstring(L, 1, &l);
  136.   size_t posi = posrelat(luaL_optinteger(L, 2, 1), l);
  137.   size_t pose = posrelat(luaL_optinteger(L, 3, posi), l);
  138.   int n, i;
  139.   if (posi < 1) posi = 1;
  140.   if (pose > l) pose = l;
  141.   if (posi > pose) return 0;  /* empty interval; return no values */
  142.   n = (int)(pose -  posi + 1);
  143.   if (posi + n <= pose)  /* (size_t -> int) overflow? */
  144.     return luaL_error(L, "string slice too long");
  145.   luaL_checkstack(L, n, "string slice too long");
  146.   for (i=0; i<n; i++)
  147.     lua_pushinteger(L, uchar(s[posi+i-1]));
  148.   return n;
  149. }
  150.  
  151.  
  152. static int str_char (lua_State *L) {
  153.   int n = lua_gettop(L);  /* number of arguments */
  154.   int i;
  155.   luaL_Buffer b;
  156.   char *p = luaL_buffinitsize(L, &b, n);
  157.   for (i=1; i<=n; i++) {
  158.     int c = luaL_checkint(L, i);
  159.     luaL_argcheck(L, uchar(c) == c, i, "value out of range");
  160.     p[i - 1] = uchar(c);
  161.   }
  162.   luaL_pushresultsize(&b, n);
  163.   return 1;
  164. }
  165.  
  166.  
  167. static int writer (lua_State *L, const void* b, size_t size, void* B) {
  168.   (void)L;
  169.   luaL_addlstring((luaL_Buffer*) B, (const char *)b, size);
  170.   return 0;
  171. }
  172.  
  173.  
  174. static int str_dump (lua_State *L) {
  175.   luaL_Buffer b;
  176.   luaL_checktype(L, 1, LUA_TFUNCTION);
  177.   lua_settop(L, 1);
  178.   luaL_buffinit(L,&b);
  179.   if (lua_dump(L, writer, &b) != 0)
  180.     return luaL_error(L, "unable to dump given function");
  181.   luaL_pushresult(&b);
  182.   return 1;
  183. }
  184.  
  185.  
  186.  
  187. /*
  188. ** {======================================================
  189. ** PATTERN MATCHING
  190. ** =======================================================
  191. */
  192.  
  193.  
  194. #define CAP_UNFINISHED  (-1)
  195. #define CAP_POSITION    (-2)
  196.  
  197.  
  198. typedef struct MatchState {
  199.   int matchdepth;  /* control for recursive depth (to avoid C stack overflow) */
  200.   const char *src_init;  /* init of source string */
  201.   const char *src_end;  /* end ('\0') of source string */
  202.   const char *p_end;  /* end ('\0') of pattern */
  203.   lua_State *L;
  204.   int level;  /* total number of captures (finished or unfinished) */
  205.   struct {
  206.     const char *init;
  207.     ptrdiff_t len;
  208.   } capture[LUA_MAXCAPTURES];
  209. } MatchState;
  210.  
  211.  
  212. /* recursive function */
  213. static const char *match (MatchState *ms, const char *s, const char *p);
  214.  
  215.  
  216. /* maximum recursion depth for 'match' */
  217. #if !defined(MAXCCALLS)
  218. #define MAXCCALLS       200
  219. #endif
  220.  
  221.  
  222. #define L_ESC           '%'
  223. #define SPECIALS        "^$*+?.([%-"
  224.  
  225.  
  226. static int check_capture (MatchState *ms, int l) {
  227.   l -= '1';
  228.   if (l < 0 || l >= ms->level || ms->capture[l].len == CAP_UNFINISHED)
  229.     return luaL_error(ms->L, "invalid capture index %%%d", l + 1);
  230.   return l;
  231. }
  232.  
  233.  
  234. static int capture_to_close (MatchState *ms) {
  235.   int level = ms->level;
  236.   for (level--; level>=0; level--)
  237.     if (ms->capture[level].len == CAP_UNFINISHED) return level;
  238.   return luaL_error(ms->L, "invalid pattern capture");
  239. }
  240.  
  241.  
  242. static const char *classend (MatchState *ms, const char *p) {
  243.   switch (*p++) {
  244.     case L_ESC: {
  245.       if (p == ms->p_end)
  246.         luaL_error(ms->L, "malformed pattern (ends with " LUA_QL("%%") ")");
  247.       return p+1;
  248.     }
  249.     case '[': {
  250.       if (*p == '^') p++;
  251.       do {  /* look for a `]' */
  252.         if (p == ms->p_end)
  253.           luaL_error(ms->L, "malformed pattern (missing " LUA_QL("]") ")");
  254.         if (*(p++) == L_ESC && p < ms->p_end)
  255.           p++;  /* skip escapes (e.g. `%]') */
  256.       } while (*p != ']');
  257.       return p+1;
  258.     }
  259.     default: {
  260.       return p;
  261.     }
  262.   }
  263. }
  264.  
  265.  
  266. static int match_class (int c, int cl) {
  267.   int res;
  268.   switch (tolower(cl)) {
  269.     case 'a' : res = isalpha(c); break;
  270.     case 'c' : res = iscntrl(c); break;
  271.     case 'd' : res = isdigit(c); break;
  272.     case 'g' : res = isgraph(c); break;
  273.     case 'l' : res = islower(c); break;
  274.     case 'p' : res = ispunct(c); break;
  275.     case 's' : res = isspace(c); break;
  276.     case 'u' : res = isupper(c); break;
  277.     case 'w' : res = isalnum(c); break;
  278.     case 'x' : res = isxdigit(c); break;
  279.     case 'z' : res = (c == 0); break;  /* deprecated option */
  280.     default: return (cl == c);
  281.   }
  282.   return (islower(cl) ? res : !res);
  283. }
  284.  
  285.  
  286. static int matchbracketclass (int c, const char *p, const char *ec) {
  287.   int sig = 1;
  288.   if (*(p+1) == '^') {
  289.     sig = 0;
  290.     p++;  /* skip the `^' */
  291.   }
  292.   while (++p < ec) {
  293.     if (*p == L_ESC) {
  294.       p++;
  295.       if (match_class(c, uchar(*p)))
  296.         return sig;
  297.     }
  298.     else if ((*(p+1) == '-') && (p+2 < ec)) {
  299.       p+=2;
  300.       if (uchar(*(p-2)) <= c && c <= uchar(*p))
  301.         return sig;
  302.     }
  303.     else if (uchar(*p) == c) return sig;
  304.   }
  305.   return !sig;
  306. }
  307.  
  308.  
  309. static int singlematch (MatchState *ms, const char *s, const char *p,
  310.                         const char *ep) {
  311.   if (s >= ms->src_end)
  312.     return 0;
  313.   else {
  314.     int c = uchar(*s);
  315.     switch (*p) {
  316.       case '.': return 1;  /* matches any char */
  317.       case L_ESC: return match_class(c, uchar(*(p+1)));
  318.       case '[': return matchbracketclass(c, p, ep-1);
  319.       default:  return (uchar(*p) == c);
  320.     }
  321.   }
  322. }
  323.  
  324.  
  325. static const char *matchbalance (MatchState *ms, const char *s,
  326.                                    const char *p) {
  327.   if (p >= ms->p_end - 1)
  328.     luaL_error(ms->L, "malformed pattern "
  329.                       "(missing arguments to " LUA_QL("%%b") ")");
  330.   if (*s != *p) return NULL;
  331.   else {
  332.     int b = *p;
  333.     int e = *(p+1);
  334.     int cont = 1;
  335.     while (++s < ms->src_end) {
  336.       if (*s == e) {
  337.         if (--cont == 0) return s+1;
  338.       }
  339.       else if (*s == b) cont++;
  340.     }
  341.   }
  342.   return NULL;  /* string ends out of balance */
  343. }
  344.  
  345.  
  346. static const char *max_expand (MatchState *ms, const char *s,
  347.                                  const char *p, const char *ep) {
  348.   ptrdiff_t i = 0;  /* counts maximum expand for item */
  349.   while (singlematch(ms, s + i, p, ep))
  350.     i++;
  351.   /* keeps trying to match with the maximum repetitions */
  352.   while (i>=0) {
  353.     const char *res = match(ms, (s+i), ep+1);
  354.     if (res) return res;
  355.     i--;  /* else didn't match; reduce 1 repetition to try again */
  356.   }
  357.   return NULL;
  358. }
  359.  
  360.  
  361. static const char *min_expand (MatchState *ms, const char *s,
  362.                                  const char *p, const char *ep) {
  363.   for (;;) {
  364.     const char *res = match(ms, s, ep+1);
  365.     if (res != NULL)
  366.       return res;
  367.     else if (singlematch(ms, s, p, ep))
  368.       s++;  /* try with one more repetition */
  369.     else return NULL;
  370.   }
  371. }
  372.  
  373.  
  374. static const char *start_capture (MatchState *ms, const char *s,
  375.                                     const char *p, int what) {
  376.   const char *res;
  377.   int level = ms->level;
  378.   if (level >= LUA_MAXCAPTURES) luaL_error(ms->L, "too many captures");
  379.   ms->capture[level].init = s;
  380.   ms->capture[level].len = what;
  381.   ms->level = level+1;
  382.   if ((res=match(ms, s, p)) == NULL)  /* match failed? */
  383.     ms->level--;  /* undo capture */
  384.   return res;
  385. }
  386.  
  387.  
  388. static const char *end_capture (MatchState *ms, const char *s,
  389.                                   const char *p) {
  390.   int l = capture_to_close(ms);
  391.   const char *res;
  392.   ms->capture[l].len = s - ms->capture[l].init;  /* close capture */
  393.   if ((res = match(ms, s, p)) == NULL)  /* match failed? */
  394.     ms->capture[l].len = CAP_UNFINISHED;  /* undo capture */
  395.   return res;
  396. }
  397.  
  398.  
  399. static const char *match_capture (MatchState *ms, const char *s, int l) {
  400.   size_t len;
  401.   l = check_capture(ms, l);
  402.   len = ms->capture[l].len;
  403.   if ((size_t)(ms->src_end-s) >= len &&
  404.       memcmp(ms->capture[l].init, s, len) == 0)
  405.     return s+len;
  406.   else return NULL;
  407. }
  408.  
  409.  
  410. static const char *match (MatchState *ms, const char *s, const char *p) {
  411.   if (ms->matchdepth-- == 0)
  412.     luaL_error(ms->L, "pattern too complex");
  413.   init: /* using goto's to optimize tail recursion */
  414.   if (p != ms->p_end) {  /* end of pattern? */
  415.     switch (*p) {
  416.       case '(': {  /* start capture */
  417.         if (*(p + 1) == ')')  /* position capture? */
  418.           s = start_capture(ms, s, p + 2, CAP_POSITION);
  419.         else
  420.           s = start_capture(ms, s, p + 1, CAP_UNFINISHED);
  421.         break;
  422.       }
  423.       case ')': {  /* end capture */
  424.         s = end_capture(ms, s, p + 1);
  425.         break;
  426.       }
  427.       case '$': {
  428.         if ((p + 1) != ms->p_end)  /* is the `$' the last char in pattern? */
  429.           goto dflt;  /* no; go to default */
  430.         s = (s == ms->src_end) ? s : NULL;  /* check end of string */
  431.         break;
  432.       }
  433.       case L_ESC: {  /* escaped sequences not in the format class[*+?-]? */
  434.         switch (*(p + 1)) {
  435.           case 'b': {  /* balanced string? */
  436.             s = matchbalance(ms, s, p + 2);
  437.             if (s != NULL) {
  438.               p += 4; goto init;  /* return match(ms, s, p + 4); */
  439.             }  /* else fail (s == NULL) */
  440.             break;
  441.           }
  442.           case 'f': {  /* frontier? */
  443.             const char *ep; char previous;
  444.             p += 2;
  445.             if (*p != '[')
  446.               luaL_error(ms->L, "missing " LUA_QL("[") " after "
  447.                                  LUA_QL("%%f") " in pattern");
  448.             ep = classend(ms, p);  /* points to what is next */
  449.             previous = (s == ms->src_init) ? '\0' : *(s - 1);
  450.             if (!matchbracketclass(uchar(previous), p, ep - 1) &&
  451.                matchbracketclass(uchar(*s), p, ep - 1)) {
  452.               p = ep; goto init;  /* return match(ms, s, ep); */
  453.             }
  454.             s = NULL;  /* match failed */
  455.             break;
  456.           }
  457.           case '0': case '1': case '2': case '3':
  458.           case '4': case '5': case '6': case '7':
  459.           case '8': case '9': {  /* capture results (%0-%9)? */
  460.             s = match_capture(ms, s, uchar(*(p + 1)));
  461.             if (s != NULL) {
  462.               p += 2; goto init;  /* return match(ms, s, p + 2) */
  463.             }
  464.             break;
  465.           }
  466.           default: goto dflt;
  467.         }
  468.         break;
  469.       }
  470.       default: dflt: {  /* pattern class plus optional suffix */
  471.         const char *ep = classend(ms, p);  /* points to optional suffix */
  472.         /* does not match at least once? */
  473.         if (!singlematch(ms, s, p, ep)) {
  474.           if (*ep == '*' || *ep == '?' || *ep == '-') {  /* accept empty? */
  475.             p = ep + 1; goto init;  /* return match(ms, s, ep + 1); */
  476.           }
  477.           else  /* '+' or no suffix */
  478.             s = NULL;  /* fail */
  479.         }
  480.         else {  /* matched once */
  481.           switch (*ep) {  /* handle optional suffix */
  482.             case '?': {  /* optional */
  483.               const char *res;
  484.               if ((res = match(ms, s + 1, ep + 1)) != NULL)
  485.                 s = res;
  486.               else {
  487.                 p = ep + 1; goto init;  /* else return match(ms, s, ep + 1); */
  488.               }
  489.               break;
  490.             }
  491.             case '+':  /* 1 or more repetitions */
  492.               s++;  /* 1 match already done */
  493.               /* go through */
  494.             case '*':  /* 0 or more repetitions */
  495.               s = max_expand(ms, s, p, ep);
  496.               break;
  497.             case '-':  /* 0 or more repetitions (minimum) */
  498.               s = min_expand(ms, s, p, ep);
  499.               break;
  500.             default:  /* no suffix */
  501.               s++; p = ep; goto init;  /* return match(ms, s + 1, ep); */
  502.           }
  503.         }
  504.         break;
  505.       }
  506.     }
  507.   }
  508.   ms->matchdepth++;
  509.   return s;
  510. }
  511.  
  512.  
  513.  
  514. static const char *lmemfind (const char *s1, size_t l1,
  515.                                const char *s2, size_t l2) {
  516.   if (l2 == 0) return s1;  /* empty strings are everywhere */
  517.   else if (l2 > l1) return NULL;  /* avoids a negative `l1' */
  518.   else {
  519.     const char *init;  /* to search for a `*s2' inside `s1' */
  520.     l2--;  /* 1st char will be checked by `memchr' */
  521.     l1 = l1-l2;  /* `s2' cannot be found after that */
  522.     while (l1 > 0 && (init = (const char *)memchr(s1, *s2, l1)) != NULL) {
  523.       init++;   /* 1st char is already checked */
  524.       if (memcmp(init, s2+1, l2) == 0)
  525.         return init-1;
  526.       else {  /* correct `l1' and `s1' to try again */
  527.         l1 -= init-s1;
  528.         s1 = init;
  529.       }
  530.     }
  531.     return NULL;  /* not found */
  532.   }
  533. }
  534.  
  535.  
  536. static void push_onecapture (MatchState *ms, int i, const char *s,
  537.                                                     const char *e) {
  538.   if (i >= ms->level) {
  539.     if (i == 0)  /* ms->level == 0, too */
  540.       lua_pushlstring(ms->L, s, e - s);  /* add whole match */
  541.     else
  542.       luaL_error(ms->L, "invalid capture index");
  543.   }
  544.   else {
  545.     ptrdiff_t l = ms->capture[i].len;
  546.     if (l == CAP_UNFINISHED) luaL_error(ms->L, "unfinished capture");
  547.     if (l == CAP_POSITION)
  548.       lua_pushinteger(ms->L, ms->capture[i].init - ms->src_init + 1);
  549.     else
  550.       lua_pushlstring(ms->L, ms->capture[i].init, l);
  551.   }
  552. }
  553.  
  554.  
  555. static int push_captures (MatchState *ms, const char *s, const char *e) {
  556.   int i;
  557.   int nlevels = (ms->level == 0 && s) ? 1 : ms->level;
  558.   luaL_checkstack(ms->L, nlevels, "too many captures");
  559.   for (i = 0; i < nlevels; i++)
  560.     push_onecapture(ms, i, s, e);
  561.   return nlevels;  /* number of strings pushed */
  562. }
  563.  
  564.  
  565. /* check whether pattern has no special characters */
  566. static int nospecials (const char *p, size_t l) {
  567.   size_t upto = 0;
  568.   do {
  569.     if (strpbrk(p + upto, SPECIALS))
  570.       return 0;  /* pattern has a special character */
  571.     upto += strlen(p + upto) + 1;  /* may have more after \0 */
  572.   } while (upto <= l);
  573.   return 1;  /* no special chars found */
  574. }
  575.  
  576.  
  577. static int str_find_aux (lua_State *L, int find) {
  578.   size_t ls, lp;
  579.   const char *s = luaL_checklstring(L, 1, &ls);
  580.   const char *p = luaL_checklstring(L, 2, &lp);
  581.   size_t init = posrelat(luaL_optinteger(L, 3, 1), ls);
  582.   if (init < 1) init = 1;
  583.   else if (init > ls + 1) {  /* start after string's end? */
  584.     lua_pushnil(L);  /* cannot find anything */
  585.     return 1;
  586.   }
  587.   /* explicit request or no special characters? */
  588.   if (find && (lua_toboolean(L, 4) || nospecials(p, lp))) {
  589.     /* do a plain search */
  590.     const char *s2 = lmemfind(s + init - 1, ls - init + 1, p, lp);
  591.     if (s2) {
  592.       lua_pushinteger(L, s2 - s + 1);
  593.       lua_pushinteger(L, s2 - s + lp);
  594.       return 2;
  595.     }
  596.   }
  597.   else {
  598.     MatchState ms;
  599.     const char *s1 = s + init - 1;
  600.     int anchor = (*p == '^');
  601.     if (anchor) {
  602.       p++; lp--;  /* skip anchor character */
  603.     }
  604.     ms.L = L;
  605.     ms.matchdepth = MAXCCALLS;
  606.     ms.src_init = s;
  607.     ms.src_end = s + ls;
  608.     ms.p_end = p + lp;
  609.     do {
  610.       const char *res;
  611.       ms.level = 0;
  612.       lua_assert(ms.matchdepth == MAXCCALLS);
  613.       if ((res=match(&ms, s1, p)) != NULL) {
  614.         if (find) {
  615.           lua_pushinteger(L, s1 - s + 1);  /* start */
  616.           lua_pushinteger(L, res - s);   /* end */
  617.           return push_captures(&ms, NULL, 0) + 2;
  618.         }
  619.         else
  620.           return push_captures(&ms, s1, res);
  621.       }
  622.     } while (s1++ < ms.src_end && !anchor);
  623.   }
  624.   lua_pushnil(L);  /* not found */
  625.   return 1;
  626. }
  627.  
  628.  
  629. static int str_find (lua_State *L) {
  630.   return str_find_aux(L, 1);
  631. }
  632.  
  633.  
  634. static int str_match (lua_State *L) {
  635.   return str_find_aux(L, 0);
  636. }
  637.  
  638.  
  639. static int gmatch_aux (lua_State *L) {
  640.   MatchState ms;
  641.   size_t ls, lp;
  642.   const char *s = lua_tolstring(L, lua_upvalueindex(1), &ls);
  643.   const char *p = lua_tolstring(L, lua_upvalueindex(2), &lp);
  644.   const char *src;
  645.   ms.L = L;
  646.   ms.matchdepth = MAXCCALLS;
  647.   ms.src_init = s;
  648.   ms.src_end = s+ls;
  649.   ms.p_end = p + lp;
  650.   for (src = s + (size_t)lua_tointeger(L, lua_upvalueindex(3));
  651.        src <= ms.src_end;
  652.        src++) {
  653.     const char *e;
  654.     ms.level = 0;
  655.     lua_assert(ms.matchdepth == MAXCCALLS);
  656.     if ((e = match(&ms, src, p)) != NULL) {
  657.       lua_Integer newstart = e-s;
  658.       if (e == src) newstart++;  /* empty match? go at least one position */
  659.       lua_pushinteger(L, newstart);
  660.       lua_replace(L, lua_upvalueindex(3));
  661.       return push_captures(&ms, src, e);
  662.     }
  663.   }
  664.   return 0;  /* not found */
  665. }
  666.  
  667.  
  668. static int gmatch (lua_State *L) {
  669.   luaL_checkstring(L, 1);
  670.   luaL_checkstring(L, 2);
  671.   lua_settop(L, 2);
  672.   lua_pushinteger(L, 0);
  673.   lua_pushcclosure(L, gmatch_aux, 3);
  674.   return 1;
  675. }
  676.  
  677.  
  678. static void add_s (MatchState *ms, luaL_Buffer *b, const char *s,
  679.                                                    const char *e) {
  680.   size_t l, i;
  681.   const char *news = lua_tolstring(ms->L, 3, &l);
  682.   for (i = 0; i < l; i++) {
  683.     if (news[i] != L_ESC)
  684.       luaL_addchar(b, news[i]);
  685.     else {
  686.       i++;  /* skip ESC */
  687.       if (!isdigit(uchar(news[i]))) {
  688.         if (news[i] != L_ESC)
  689.           luaL_error(ms->L, "invalid use of " LUA_QL("%c")
  690.                            " in replacement string", L_ESC);
  691.         luaL_addchar(b, news[i]);
  692.       }
  693.       else if (news[i] == '0')
  694.           luaL_addlstring(b, s, e - s);
  695.       else {
  696.         push_onecapture(ms, news[i] - '1', s, e);
  697.         luaL_addvalue(b);  /* add capture to accumulated result */
  698.       }
  699.     }
  700.   }
  701. }
  702.  
  703.  
  704. static void add_value (MatchState *ms, luaL_Buffer *b, const char *s,
  705.                                        const char *e, int tr) {
  706.   lua_State *L = ms->L;
  707.   switch (tr) {
  708.     case LUA_TFUNCTION: {
  709.       int n;
  710.       lua_pushvalue(L, 3);
  711.       n = push_captures(ms, s, e);
  712.       lua_call(L, n, 1);
  713.       break;
  714.     }
  715.     case LUA_TTABLE: {
  716.       push_onecapture(ms, 0, s, e);
  717.       lua_gettable(L, 3);
  718.       break;
  719.     }
  720.     default: {  /* LUA_TNUMBER or LUA_TSTRING */
  721.       add_s(ms, b, s, e);
  722.       return;
  723.     }
  724.   }
  725.   if (!lua_toboolean(L, -1)) {  /* nil or false? */
  726.     lua_pop(L, 1);
  727.     lua_pushlstring(L, s, e - s);  /* keep original text */
  728.   }
  729.   else if (!lua_isstring(L, -1))
  730.     luaL_error(L, "invalid replacement value (a %s)", luaL_typename(L, -1));
  731.   luaL_addvalue(b);  /* add result to accumulator */
  732. }
  733.  
  734.  
  735. static int str_gsub (lua_State *L) {
  736.   size_t srcl, lp;
  737.   const char *src = luaL_checklstring(L, 1, &srcl);
  738.   const char *p = luaL_checklstring(L, 2, &lp);
  739.   int tr = lua_type(L, 3);
  740.   size_t max_s = luaL_optinteger(L, 4, srcl+1);
  741.   int anchor = (*p == '^');
  742.   size_t n = 0;
  743.   MatchState ms;
  744.   luaL_Buffer b;
  745.   luaL_argcheck(L, tr == LUA_TNUMBER || tr == LUA_TSTRING ||
  746.                    tr == LUA_TFUNCTION || tr == LUA_TTABLE, 3,
  747.                       "string/function/table expected");
  748.   luaL_buffinit(L, &b);
  749.   if (anchor) {
  750.     p++; lp--;  /* skip anchor character */
  751.   }
  752.   ms.L = L;
  753.   ms.matchdepth = MAXCCALLS;
  754.   ms.src_init = src;
  755.   ms.src_end = src+srcl;
  756.   ms.p_end = p + lp;
  757.   while (n < max_s) {
  758.     const char *e;
  759.     ms.level = 0;
  760.     lua_assert(ms.matchdepth == MAXCCALLS);
  761.     e = match(&ms, src, p);
  762.     if (e) {
  763.       n++;
  764.       add_value(&ms, &b, src, e, tr);
  765.     }
  766.     if (e && e>src) /* non empty match? */
  767.       src = e;  /* skip it */
  768.     else if (src < ms.src_end)
  769.       luaL_addchar(&b, *src++);
  770.     else break;
  771.     if (anchor) break;
  772.   }
  773.   luaL_addlstring(&b, src, ms.src_end-src);
  774.   luaL_pushresult(&b);
  775.   lua_pushinteger(L, n);  /* number of substitutions */
  776.   return 2;
  777. }
  778.  
  779. /* }====================================================== */
  780.  
  781.  
  782.  
  783. /*
  784. ** {======================================================
  785. ** STRING FORMAT
  786. ** =======================================================
  787. */
  788.  
  789. /*
  790. ** LUA_INTFRMLEN is the length modifier for integer conversions in
  791. ** 'string.format'; LUA_INTFRM_T is the integer type corresponding to
  792. ** the previous length
  793. */
  794. #if !defined(LUA_INTFRMLEN)     /* { */
  795. #if defined(LUA_USE_LONGLONG)
  796.  
  797. #define LUA_INTFRMLEN           "ll"
  798. #define LUA_INTFRM_T            long long
  799.  
  800. #else
  801.  
  802. #define LUA_INTFRMLEN           "l"
  803. #define LUA_INTFRM_T            long
  804.  
  805. #endif
  806. #endif                          /* } */
  807.  
  808.  
  809. /*
  810. ** LUA_FLTFRMLEN is the length modifier for float conversions in
  811. ** 'string.format'; LUA_FLTFRM_T is the float type corresponding to
  812. ** the previous length
  813. */
  814. #if !defined(LUA_FLTFRMLEN)
  815.  
  816. #define LUA_FLTFRMLEN           ""
  817. #define LUA_FLTFRM_T            double
  818.  
  819. #endif
  820.  
  821.  
  822. /* maximum size of each formatted item (> len(format('%99.99f', -1e308))) */
  823. #define MAX_ITEM        512
  824. /* valid flags in a format specification */
  825. #define FLAGS   "-+ #0"
  826. /*
  827. ** maximum size of each format specification (such as '%-099.99d')
  828. ** (+10 accounts for %99.99x plus margin of error)
  829. */
  830. #define MAX_FORMAT      (sizeof(FLAGS) + sizeof(LUA_INTFRMLEN) + 10)
  831.  
  832.  
  833. static void addquoted (lua_State *L, luaL_Buffer *b, int arg) {
  834.   size_t l;
  835.   const char *s = luaL_checklstring(L, arg, &l);
  836.   luaL_addchar(b, '"');
  837.   while (l--) {
  838.     if (*s == '"' || *s == '\\' || *s == '\n') {
  839.       luaL_addchar(b, '\\');
  840.       luaL_addchar(b, *s);
  841.     }
  842.     else if (*s == '\0' || iscntrl(uchar(*s))) {
  843.       char buff[10];
  844.       if (!isdigit(uchar(*(s+1))))
  845.         sprintf(buff, "\\%d", (int)uchar(*s));
  846.       else
  847.         sprintf(buff, "\\%03d", (int)uchar(*s));
  848.       luaL_addstring(b, buff);
  849.     }
  850.     else
  851.       luaL_addchar(b, *s);
  852.     s++;
  853.   }
  854.   luaL_addchar(b, '"');
  855. }
  856.  
  857. static const char *scanformat (lua_State *L, const char *strfrmt, char *form) {
  858.   const char *p = strfrmt;
  859.   while (*p != '\0' && strchr(FLAGS, *p) != NULL) p++;  /* skip flags */
  860.   if ((size_t)(p - strfrmt) >= sizeof(FLAGS)/sizeof(char))
  861.     luaL_error(L, "invalid format (repeated flags)");
  862.   if (isdigit(uchar(*p))) p++;  /* skip width */
  863.   if (isdigit(uchar(*p))) p++;  /* (2 digits at most) */
  864.   if (*p == '.') {
  865.     p++;
  866.     if (isdigit(uchar(*p))) p++;  /* skip precision */
  867.     if (isdigit(uchar(*p))) p++;  /* (2 digits at most) */
  868.   }
  869.   if (isdigit(uchar(*p)))
  870.     luaL_error(L, "invalid format (width or precision too long)");
  871.   *(form++) = '%';
  872.   memcpy(form, strfrmt, (p - strfrmt + 1) * sizeof(char));
  873.   form += p - strfrmt + 1;
  874.   *form = '\0';
  875.   return p;
  876. }
  877.  
  878.  
  879. /*
  880. ** add length modifier into formats
  881. */
  882. static void addlenmod (char *form, const char *lenmod) {
  883.   size_t l = strlen(form);
  884.   size_t lm = strlen(lenmod);
  885.   char spec = form[l - 1];
  886.   strcpy(form + l - 1, lenmod);
  887.   form[l + lm - 1] = spec;
  888.   form[l + lm] = '\0';
  889. }
  890.  
  891.  
  892. static int str_format (lua_State *L) {
  893.   int top = lua_gettop(L);
  894.   int arg = 1;
  895.   size_t sfl;
  896.   const char *strfrmt = luaL_checklstring(L, arg, &sfl);
  897.   const char *strfrmt_end = strfrmt+sfl;
  898.   luaL_Buffer b;
  899.   luaL_buffinit(L, &b);
  900.   while (strfrmt < strfrmt_end) {
  901.     if (*strfrmt != L_ESC)
  902.       luaL_addchar(&b, *strfrmt++);
  903.     else if (*++strfrmt == L_ESC)
  904.       luaL_addchar(&b, *strfrmt++);  /* %% */
  905.     else { /* format item */
  906.       char form[MAX_FORMAT];  /* to store the format (`%...') */
  907.       char *buff = luaL_prepbuffsize(&b, MAX_ITEM);  /* to put formatted item */
  908.       int nb = 0;  /* number of bytes in added item */
  909.       if (++arg > top)
  910.         luaL_argerror(L, arg, "no value");
  911.       strfrmt = scanformat(L, strfrmt, form);
  912.       switch (*strfrmt++) {
  913.         case 'c': {
  914.           nb = sprintf(buff, form, luaL_checkint(L, arg));
  915.           break;
  916.         }
  917.         case 'd': case 'i': {
  918.           lua_Number n = luaL_checknumber(L, arg);
  919.           LUA_INTFRM_T ni = (LUA_INTFRM_T)n;
  920.           lua_Number diff = n - (lua_Number)ni;
  921.           luaL_argcheck(L, -1 < diff && diff < 1, arg,
  922.                         "not a number in proper range");
  923.           addlenmod(form, LUA_INTFRMLEN);
  924.           nb = sprintf(buff, form, ni);
  925.           break;
  926.         }
  927.         case 'o': case 'u': case 'x': case 'X': {
  928.           lua_Number n = luaL_checknumber(L, arg);
  929.           unsigned LUA_INTFRM_T ni = (unsigned LUA_INTFRM_T)n;
  930.           lua_Number diff = n - (lua_Number)ni;
  931.           luaL_argcheck(L, -1 < diff && diff < 1, arg,
  932.                         "not a non-negative number in proper range");
  933.           addlenmod(form, LUA_INTFRMLEN);
  934.           nb = sprintf(buff, form, ni);
  935.           break;
  936.         }
  937.         case 'e': case 'E': case 'f':
  938. #if defined(LUA_USE_AFORMAT)
  939.         case 'a': case 'A':
  940. #endif
  941.         case 'g': case 'G': {
  942.           addlenmod(form, LUA_FLTFRMLEN);
  943.           nb = sprintf(buff, form, (LUA_FLTFRM_T)luaL_checknumber(L, arg));
  944.           break;
  945.         }
  946.         case 'q': {
  947.           addquoted(L, &b, arg);
  948.           break;
  949.         }
  950.         case 's': {
  951.           size_t l;
  952.           const char *s = luaL_tolstring(L, arg, &l);
  953.           if (!strchr(form, '.') && l >= 100) {
  954.             /* no precision and string is too long to be formatted;
  955.                keep original string */
  956.             luaL_addvalue(&b);
  957.             break;
  958.           }
  959.           else {
  960.             nb = sprintf(buff, form, s);
  961.             lua_pop(L, 1);  /* remove result from 'luaL_tolstring' */
  962.             break;
  963.           }
  964.         }
  965.         default: {  /* also treat cases `pnLlh' */
  966.           return luaL_error(L, "invalid option " LUA_QL("%%%c") " to "
  967.                                LUA_QL("format"), *(strfrmt - 1));
  968.         }
  969.       }
  970.       luaL_addsize(&b, nb);
  971.     }
  972.   }
  973.   luaL_pushresult(&b);
  974.   return 1;
  975. }
  976.  
  977. /* }====================================================== */
  978.  
  979.  
  980. static const luaL_Reg strlib[] = {
  981.   {"byte", str_byte},
  982.   {"char", str_char},
  983.   {"dump", str_dump},
  984.   {"find", str_find},
  985.   {"format", str_format},
  986.   {"gmatch", gmatch},
  987.   {"gsub", str_gsub},
  988.   {"len", str_len},
  989.   {"lower", str_lower},
  990.   {"match", str_match},
  991.   {"rep", str_rep},
  992.   {"reverse", str_reverse},
  993.   {"sub", str_sub},
  994.   {"upper", str_upper},
  995.   {NULL, NULL}
  996. };
  997.  
  998.  
  999. static void createmetatable (lua_State *L) {
  1000.   lua_createtable(L, 0, 1);  /* table to be metatable for strings */
  1001.   lua_pushliteral(L, "");  /* dummy string */
  1002.   lua_pushvalue(L, -2);  /* copy table */
  1003.   lua_setmetatable(L, -2);  /* set table as metatable for strings */
  1004.   lua_pop(L, 1);  /* pop dummy string */
  1005.   lua_pushvalue(L, -2);  /* get string library */
  1006.   lua_setfield(L, -2, "__index");  /* metatable.__index = string */
  1007.   lua_pop(L, 1);  /* pop metatable */
  1008. }
  1009.  
  1010.  
  1011. /*
  1012. ** Open string library
  1013. */
  1014. LUAMOD_API int luaopen_string (lua_State *L) {
  1015.   luaL_newlib(L, strlib);
  1016.   createmetatable(L);
  1017.   return 1;
  1018. }
  1019.  
  1020.