/*** $Id: lstrlib.c,v 1.1 2002/02/14 10:46:59 jcatki Exp $** 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 */#endifstruct 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;