/trunk/IronHells/src/lua/lstrlib.c

/*
** $Id: lstrlib.c 124 2003-04-09 00:19:02Z cipher $
** Standard library for string operations and pattern-matching
** See Copyright Notice in lua.h
*/

#include <ctype.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "lua.h"

#include "lauxlib.h"
#include "lualib.h"

static int
str_len(lua_State * L)
{
     size_t          l;

     luaL_check_lstr(L, 1, &l);
     lua_pushnumber(L, l);
     return 1;
}

static long
posrelat(long pos,
         size_t len)
{
     /* relative string position: negative means back from end */
     return (pos >= 0) ? pos : (long) len + pos + 1;
}

static int
str_sub(lua_State * L)
{
     size_t          l;
     const char     *s = luaL_check_lstr(L, 1, &l);
     long            start = posrelat(luaL_check_long(L, 2), l);
     long            end = posrelat(luaL_opt_long(L, 3, -1), l);

     if(start < 1)
          start = 1;
     if(end > (long) l)
          end = l;
     if(start <= end)
          lua_pushlstring(L, s + start - 1, end - start + 1);
     else
          lua_pushstring(L, "");
     return 1;
}

static int
str_lower(lua_State * L)
{
     size_t          l;
     size_t          i;
     luaL_Buffer     b;
     const char     *s = luaL_check_lstr(L, 1, &l);

     luaL_buffinit(L, &b);
     for(i = 0; i < l; i++)
          luaL_putchar(&b, tolower((unsigned char) (s[i])));
     luaL_pushresult(&b);
     return 1;
}

static int
str_upper(lua_State * L)
{
     size_t          l;
     size_t          i;
     luaL_Buffer     b;
     const char     *s = luaL_check_lstr(L, 1, &l);

     luaL_buffinit(L, &b);
     for(i = 0; i < l; i++)
          luaL_putchar(&b, toupper((unsigned char) (s[i])));
     luaL_pushresult(&b);
     return 1;
}

static int
str_rep(lua_State * L)
{
     size_t          l;
     luaL_Buffer     b;
     const char     *s = luaL_check_lstr(L, 1, &l);
     int             n = luaL_check_int(L, 2);

     luaL_buffinit(L, &b);
     while(n-- > 0)
          luaL_addlstring(&b, s, l);
     luaL_pushresult(&b);
     return 1;
}

static int
str_byte(lua_State * L)
{
     size_t          l;
     const char     *s = luaL_check_lstr(L, 1, &l);
     long            pos = posrelat(luaL_opt_long(L, 2, 1), l);

     luaL_arg_check(L, 0 < pos && (size_t) pos <= l, 2, "out of range");
     lua_pushnumber(L, (unsigned char) s[pos - 1]);
     return 1;
}

static int
str_char(lua_State * L)
{
     int             n = lua_gettop(L); /* number of arguments */
     int             i;
     luaL_Buffer     b;

     luaL_buffinit(L, &b);
     for(i = 1; i <= n; i++)
     {
          int             c = luaL_check_int(L, i);

          luaL_arg_check(L, (unsigned char) c == c, i, "invalid value");
          luaL_putchar(&b, (unsigned char) c);
     }
     luaL_pushresult(&b);
     return 1;
}

/*
** {======================================================
** PATTERN MATCHING
** =======================================================
*/

#ifndef MAX_CAPTURES
#define MAX_CAPTURES 32         /* arbitrary limit */
#endif

struct Capture
{
     const char     *src_end;   /* end ('\0') of source string */
     int             level;     /* total number of captures (finished or unfinished) */
     struct
     {
          const char     *init;
          long            len;  /* -1 signals unfinished capture */
     }
     capture[MAX_CAPTURES];
};

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

static int
check_capture(lua_State * L,
              int l,
              struct Capture *cap)
{
     l -= '1';
     if(!(0 <= l && l < cap->level && cap->capture[l].len != -1))
          lua_error(L, "invalid capture index");
     return l;
}

static int
capture_to_close(lua_State * L,
                 struct Capture *cap)
{
     int             level = cap->level;

     for(level--; level >= 0; level--)
          if(cap->capture[level].len == -1)
               return level;
     lua_error(L, "invalid pattern capture");
     return 0;                  /* to avoid warnings */
}

const char     *
luaI_classend(lua_State * L,
              const char *p)
{
     switch (*p++)
     {
          case ESC:
               if(*p == '\0')
                    lua_error(L, "malformed pattern (ends with `%')");
               return p + 1;
          case '[':
               if(*p == '^')
                    p++;
               do
               {                /* look for a ']' */
                    if(*p == '\0')
                         lua_error(L, "malformed pattern (missing `]')");
                    if(*(p++) == ESC && *p != '\0')
                         p++;   /* skip escapes (e.g. '%]') */
               } while(*p != ']');
               return p + 1;
          default:
               return p;
     }
}

static int
match_class(int c,
            int cl)
{
     int             res;

     switch (tolower(cl))
     {
          case 'a':
               res = isalpha(c);
               break;
          case 'c':
               res = iscntrl(c);
               break;
          case 'd':
               res = isdigit(c);
               break;
          case 'l':
               res = islower(c);
               break;
          case 'p':
               res = ispunct(c);
               break;
          case 's':
               res = isspace(c);
               break;
          case 'u':
               res = isupper(c);
               break;
          case 'w':
               res = isalnum(c);
               break;
          case 'x':
               res = isxdigit(c);
               break;
          case 'z':
               res = (c == '\0');
               break;
          default:
               return (cl == c);
     }
     return (islower(cl) ? res : !res);
}

static int
matchbracketclass(int c,
                  const char *p,
                  const char *endclass)
{
     int             sig = 1;

     if(*(p + 1) == '^')
     {
          sig = 0;
          p++;                  /* skip the '^' */
     }
     while(++p < endclass)
     {
          if(*p == ESC)
          {
               p++;
               if(match_class(c, (unsigned char) *p))
                    return sig;
          }
          else if((*(p + 1) == '-') && (p + 2 < endclass))
          {
               p += 2;
               if((int) (unsigned char) *(p - 2) <= c &&
                  c <= (int) (unsigned char) *p)
                    return sig;
          }
          else if((int) (unsigned char) *p == c)
               return sig;
     }
     return !sig;
}

int
luaI_singlematch(int c,
                 const char *p,
                 const char *ep)
{
     switch (*p)
     {
          case '.':            /* matches any char */
               return 1;
          case ESC:
               return match_class(c, (unsigned char) *(p + 1));
          case '[':
               return matchbracketclass(c, p, ep - 1);
          default:
               return ((unsigned char) *p == c);
     }
}

static const char *match(lua_State * L,
                         const char *s,
                         const char *p,
                         struct Capture *cap);

static const char *
matchbalance(lua_State * L,
             const char *s,
             const char *p,
             struct Capture *cap)
{
     if(*p == 0 || *(p + 1) == 0)
          lua_error(L, "unbalanced pattern");
     if(*s != *p)
          return NULL;
     else
     {
          int             b = *p;
          int             e = *(p + 1);
          int             cont = 1;

          while(++s < cap->src_end)
          {
               if(*s == e)
               {
                    if(--cont == 0)
                         return s + 1;
               }
               else if(*s == b)
                    cont++;
          }
     }
     return NULL;               /* string ends out of balance */
}

static const char *
max_expand(lua_State * L,
           const char *s,
           const char *p,
           const char *ep,
           struct Capture *cap)
{
     long            i = 0;     /* counts maximum expand for item */

     while((s + i) < cap->src_end &&
           luaI_singlematch((unsigned char) *(s + i), p, ep))
          i++;
     /* keeps trying to match with the maximum repetitions */
     while(i >= 0)
     {
          const char     *res = match(L, (s + i), ep + 1, cap);

          if(res)
               return res;
          i--;                  /* else didn't match; reduce 1 repetition to try again */
     }
     return NULL;
}

static const char *
min_expand(lua_State * L,
           const char *s,
           const char *p,
           const char *ep,
           struct Capture *cap)
{
     for(;;)
     {
          const char     *res = match(L, s, ep + 1, cap);

          if(res != NULL)
               return res;
          else if(s < cap->src_end &&
                  luaI_singlematch((unsigned char) *s, p, ep))
               s++;             /* try with one more repetition */
          else
               return NULL;
     }
}

static const char *
start_capture(lua_State * L,
              const char *s,
              const char *p,
              struct Capture *cap)
{
     const char     *res;
     int             level = cap->level;

     if(level >= MAX_CAPTURES)
          lua_error(L, "too many captures");
     cap->capture[level].init = s;
     cap->capture[level].len = -1;
     cap->level = level + 1;
     if((res = match(L, s, p + 1, cap)) == NULL) /* match failed? */
          cap->level--;         /* undo capture */
     return res;
}

static const char *
end_capture(lua_State * L,
            const char *s,
            const char *p,
            struct Capture *cap)
{
     int             l = capture_to_close(L, cap);
     const char     *res;

     cap->capture[l].len = s - cap->capture[l].init; /* close capture */
     if((res = match(L, s, p + 1, cap)) == NULL) /* match failed? */
          cap->capture[l].len = -1; /* undo capture */
     return res;
}

static const char *
match_capture(lua_State * L,
              const char *s,
              int level,
              struct Capture *cap)
{
     int             l = check_capture(L, level, cap);
     size_t          len = cap->capture[l].len;

     if((size_t) (cap->src_end - s) >= len &&
        memcmp(cap->capture[l].init, s, len) == 0)
          return s + len;
     else
          return NULL;
}

static const char *
match(lua_State * L,
      const char *s,
      const char *p,
      struct Capture *cap)
{
   init:                       /* using goto's to optimize tail recursion */
     switch (*p)
     {
          case '(':            /* start capture */
               return start_capture(L, s, p, cap);
          case ')':            /* end capture */
               return end_capture(L, s, p, cap);
          case ESC:            /* may be %[0-9] or %b */
               if(isdigit((unsigned char) (*(p + 1))))
               {                /* capture? */
                    s = match_capture(L, s, *(p + 1), cap);
                    if(s == NULL)
                         return NULL;
                    p += 2;
                    goto init;  /* else return match(L, s, p+2, cap) */
               }
               else if(*(p + 1) == 'b')
               {                /* balanced string? */
                    s = matchbalance(L, s, p + 2, cap);
                    if(s == NULL)
                         return NULL;
                    p += 4;
                    goto init;  /* else return match(L, s, p+4, cap); */
               }
               else
                    goto dflt;  /* case default */
          case '\0':           /* end of pattern */
               return s;        /* match succeeded */
          case '$':
               if(*(p + 1) == '\0') /* is the '$' the last char in pattern? */
                    return (s == cap->src_end) ? s : NULL; /* check end of string */
               else
                    goto dflt;
          default:
             dflt:{            /* it is a pattern item */
                    const char     *ep = luaI_classend(L, p); /* points to what is next */
                    int             m = s < cap->src_end &&
                        luaI_singlematch((unsigned char) *s, p, ep);
                    switch (*ep)
                    {
                         case '?':
                              { /* optional */
                                   const char     *res;

                                   if(m &&
                                      ((res =
                                        match(L, s + 1, ep + 1,
                                              cap)) != NULL))
                                        return res;
                                   p = ep + 1;
                                   goto init; /* else return match(L, s, ep+1, cap); */
                              }
                         case '*': /* 0 or more repetitions */
                              return max_expand(L, s, p, ep, cap);
                         case '+': /* 1 or more repetitions */
                              return (m ? max_expand(L, s + 1, p, ep, cap)
                                      : NULL);
                         case '-': /* 0 or more repetitions (minimum) */
                              return min_expand(L, s, p, ep, cap);
                         default:
                              if(!m)
                                   return NULL;
                              s++;
                              p = ep;
                              goto init; /* else return match(L, s+1, ep, cap); */
                    }
               }
     }
}

static const char *
lmemfind(const char *s1,
         size_t l1,
         const char *s2,
         size_t l2)
{
     if(l2 == 0)
          return s1;            /* empty strings are everywhere */
     else if(l2 > l1)
          return NULL;          /* avoids a negative `l1' */
     else
     {
          const char     *init; /* to search for a `*s2' inside `s1' */

          l2--;                 /* 1st char will be checked by `memchr' */
          l1 = l1 - l2;         /* `s2' cannot be found after that */
          while(l1 > 0 &&
                (init = (const char *) memchr(s1, *s2, l1)) != NULL)
          {
               init++;          /* 1st char is already checked */
               if(memcmp(init, s2 + 1, l2) == 0)
                    return init - 1;
               else
               {                /* correct `l1' and `s1' to try again */
                    l1 -= init - s1;
                    s1 = init;
               }
          }
          return NULL;          /* not found */
     }
}

static int
push_captures(lua_State * L,
              struct Capture *cap)
{
     int             i;

     luaL_checkstack(L, cap->level, "too many captures");
     for(i = 0; i < cap->level; i++)
     {
          int             l = cap->capture[i].len;

          if(l == -1)
               lua_error(L, "unfinished capture");
          lua_pushlstring(L, cap->capture[i].init, l);
     }
     return cap->level;         /* number of strings pushed */
}

static int
str_find(lua_State * L)
{
     size_t          l1, l2;
     const char     *s = luaL_check_lstr(L, 1, &l1);
     const char     *p = luaL_check_lstr(L, 2, &l2);
     long            init = posrelat(luaL_opt_long(L, 3, 1), l1) - 1;
     struct Capture  cap;

     luaL_arg_check(L, 0 <= init &&
                    (size_t) init <= l1, 3, "out of range");
     if(lua_gettop(L) > 3 ||    /* extra argument? */
        strpbrk(p, SPECIALS) == NULL)
     {                          /* or no special characters? */
          const char     *s2 = lmemfind(s + init, l1 - init, p, l2);

          if(s2)
          {
               lua_pushnumber(L, s2 - s + 1);
               lua_pushnumber(L, s2 - s + l2);
               return 2;
          }
     }
     else
     {
          int             anchor = (*p == '^') ? (p++, 1) : 0;
          const char     *s1 = s + init;

          cap.src_end = s + l1;
          do
          {
               const char     *res;

               cap.level = 0;
               if((res = match(L, s1, p, &cap)) != NULL)
               {
                    lua_pushnumber(L, s1 - s + 1); /* start */
                    lua_pushnumber(L, res - s); /* end */
                    return push_captures(L, &cap) + 2;
               }
          } while(s1++ < cap.src_end && !anchor);
     }
     lua_pushnil(L);            /* not found */
     return 1;
}

static void
add_s(lua_State * L,
      luaL_Buffer * b,
      struct Capture *cap)
{
     if(lua_isstring(L, 3))
     {
          const char     *news = lua_tostring(L, 3);
          size_t          l = lua_strlen(L, 3);
          size_t          i;

          for(i = 0; i < l; i++)
          {
               if(news[i] != ESC)
                    luaL_putchar(b, news[i]);
               else
               {
                    i++;        /* skip ESC */
                    if(!isdigit((unsigned char) news[i]))
                         luaL_putchar(b, news[i]);
                    else
                    {
                         int             level =
                             check_capture(L, news[i], cap);
                         luaL_addlstring(b, cap->capture[level].init,
                                         cap->capture[level].len);
                    }
               }
          }
     }
     else
     {                          /* is a function */
          int             n;

          lua_pushvalue(L, 3);
          n = push_captures(L, cap);
          lua_rawcall(L, n, 1);
          if(lua_isstring(L, -1))
               luaL_addvalue(b); /* add return to accumulated result */
          else
               lua_pop(L, 1);   /* function result is not a string: pop it */
     }
}

static int
str_gsub(lua_State * L)
{
     size_t          srcl;
     const char     *src = luaL_check_lstr(L, 1, &srcl);
     const char     *p = luaL_check_string(L, 2);
     int             max_s = luaL_opt_int(L, 4, srcl + 1);
     int             anchor = (*p == '^') ? (p++, 1) : 0;
     int             n = 0;
     struct Capture  cap;
     luaL_Buffer     b;

     luaL_arg_check(L,
                    lua_gettop(L) >= 3 && (lua_isstring(L, 3) ||
                                           lua_isfunction(L, 3)), 3,
                    "string or function expected");
     luaL_buffinit(L, &b);
     cap.src_end = src + srcl;
     while(n < max_s)
     {
          const char     *e;

          cap.level = 0;
          e = match(L, src, p, &cap);
          if(e)
          {
               n++;
               add_s(L, &b, &cap);
          }
          if(e && e > src)      /* non empty match? */
               src = e;         /* skip it */
          else if(src < cap.src_end)
               luaL_putchar(&b, *src++);
          else
               break;
          if(anchor)
               break;
     }
     luaL_addlstring(&b, src, cap.src_end - src);
     luaL_pushresult(&b);
     lua_pushnumber(L, n);      /* number of substitutions */
     return 2;
}

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

static void
luaI_addquoted(lua_State * L,
               luaL_Buffer * b,
               int arg)
{
     size_t          l;
     const char     *s = luaL_check_lstr(L, arg, &l);

     luaL_putchar(b, '"');
     while(l--)
     {
          switch (*s)
          {
               case '"':
               case '\\':
               case '\n':
                    luaL_putchar(b, '\\');
                    luaL_putchar(b, *s);
                    break;
               case '\0':
                    luaL_addlstring(b, "\\000", 4);
                    break;
               default:
                    luaL_putchar(b, *s);
          }
          s++;
     }
     luaL_putchar(b, '"');
}

/* maximum size of each formatted item (> len(format('%99.99f', -1e308))) */
#define MAX_ITEM	512

/* maximum size of each format specification (such as '%-099.99d') */
#define MAX_FORMAT	20

static int
str_format(lua_State * L)
{
     int             arg = 1;
     const char     *strfrmt = luaL_check_string(L, arg);
     luaL_Buffer     b;

     luaL_buffinit(L, &b);
     while(*strfrmt)
     {
          if(*strfrmt != '%')
               luaL_putchar(&b, *strfrmt++);
          else if(*++strfrmt == '%')
               luaL_putchar(&b, *strfrmt++); /* %% */
          else
          {                     /* format item */
               struct Capture  cap;
               char            form[MAX_FORMAT]; /* to store the format ('%...') */
               char            buff[MAX_ITEM]; /* to store the formatted item */
               const char     *initf = strfrmt;

               form[0] = '%';
               if(isdigit((unsigned char) *initf) && *(initf + 1) == '$')
               {
                    arg = *initf - '0';
                    initf += 2; /* skip the 'n$' */
               }
               arg++;
               cap.src_end = strfrmt + strlen(strfrmt) + 1;
               cap.level = 0;
               strfrmt = match(L, initf, "[-+ #0]*(%d*)%.?(%d*)", &cap);
               if(cap.capture[0].len > 2 || cap.capture[1].len > 2 || /* < 100? */
                  strfrmt - initf > MAX_FORMAT - 2)
                    lua_error(L,
                              "invalid format (width or precision too long)");
               strncpy(form + 1, initf, strfrmt - initf + 1); /* +1 to include conversion */
               form[strfrmt - initf + 2] = 0;
               switch (*strfrmt++)
               {
                    case 'c':
                    case 'd':
                    case 'i':
                         sprintf(buff, form, luaL_check_int(L, arg));
                         break;
                    case 'o':
                    case 'u':
                    case 'x':
                    case 'X':
                         sprintf(buff, form,
                                 (unsigned int) luaL_check_number(L, arg));
                         break;
                    case 'e':
                    case 'E':
                    case 'f':
                    case 'g':
                    case 'G':
                         sprintf(buff, form, luaL_check_number(L, arg));
                         break;
                    case 'q':
                         luaI_addquoted(L, &b, arg);
                         continue; /* skip the "addsize" at the end */
                    case 's':
                         {
                              size_t          l;
                              const char     *s =
                                  luaL_check_lstr(L, arg, &l);
                              if(cap.capture[1].len == 0 && l >= 100)
                              {
                                   /* no precision and string is too long to be formatted;
                                    * keep original string */
                                   lua_pushvalue(L, arg);
                                   luaL_addvalue(&b);
                                   continue; /* skip the "addsize" at the end */
                              }
                              else
                              {
                                   sprintf(buff, form, s);
                                   break;
                              }
                         }
                    default:   /* also treat cases 'pnLlh' */
                         lua_error(L, "invalid option in `format'");
               }
               luaL_addlstring(&b, buff, strlen(buff));
          }
     }
     luaL_pushresult(&b);
     return 1;
}

static const struct luaL_reg strlib[] = {
     {"strlen", str_len},
     {"strsub", str_sub},
     {"strlower", str_lower},
     {"strupper", str_upper},
     {"strchar", str_char},
     {"strrep", str_rep},
     {"ascii", str_byte},       /* for compatibility with 3.0 and earlier */
     {"strbyte", str_byte},
     {"format", str_format},
     {"strfind", str_find},
     {"gsub", str_gsub}
};

/*
** Open string library
*/
LUALIB_API void
lua_strlibopen(lua_State * L)
{
     luaL_openl(L, strlib);
}