/*
** strlib.c
** String library to LUA
*/

char *rcs_strlib="$Id: strlib.c,v 1.25 1996/08/01 14:55:33 roberto Exp roberto $";

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

#include "lua.h"
#include "lualib.h"


static char *buffer = NULL;
static size_t maxbuff = 0;
static size_t buff_size = 0;


static char *lua_strbuffer (unsigned long size)
{
  if (size > maxbuff) {
    buffer = (buffer) ? realloc(buffer, maxbuff=size) : malloc(maxbuff=size);
    if (buffer == NULL)
      lua_error("memory overflow");
  }
  return buffer;
}

static char *openspace (unsigned long size)
{
  char *buff = lua_strbuffer(buff_size+size);
  return buff+buff_size;
}

void lua_arg_check(int cond, char *funcname)
{
  if (!cond) {
    char buff[100];
    sprintf(buff, "incorrect argument to function `%s'", funcname);
    lua_error(buff);
  }
}

char *lua_check_string (int numArg, char *funcname)
{
  lua_Object o = lua_getparam(numArg);
  lua_arg_check(lua_isstring(o), funcname);
  return lua_getstring(o);
}

char *lua_opt_string (int numArg, char *def, char *funcname)
{
  return (lua_getparam(numArg) == LUA_NOOBJECT) ? def :
                              lua_check_string(numArg, funcname);
}

double lua_check_number (int numArg, char *funcname)
{
  lua_Object o = lua_getparam(numArg);
  lua_arg_check(lua_isnumber(o), funcname);
  return lua_getnumber(o);
}

long lua_opt_number (int numArg, long def, char *funcname)
{
  return (lua_getparam(numArg) == LUA_NOOBJECT) ? def :
                              (long)lua_check_number(numArg, funcname);
}

char *luaI_addchar (int c)
{
  if (buff_size >= maxbuff)
    lua_strbuffer(maxbuff == 0 ? 100 : maxbuff*2);
  buffer[buff_size++] = c;
  if (c == 0)
    buff_size = 0;  /* prepare for next string */
  return buffer;
}

static void addnchar (char *s, int n)
{
  char *b = openspace(n);
  strncpy(b, s, n);
  buff_size += n;
}


/*
** Interface to strtok
*/
static void str_tok (void)
{
  char *s1 = lua_check_string(1, "strtok");
  char *del = lua_check_string(2, "strtok");
  lua_Object t = lua_createtable();
  int i = 1;
  /* As strtok changes s1, and s1 is "constant",  make a copy of it */
  s1 = strcpy(lua_strbuffer(strlen(s1+1)), s1);
  while ((s1 = strtok(s1, del)) != NULL) {
    lua_pushobject(t);
    lua_pushnumber(i++);
    lua_pushstring(s1);
    lua_storesubscript();
    s1 = NULL;  /* prepare for next strtok */
  }
  lua_pushobject(t);
  lua_pushnumber(i-1);  /* total number of tokens */
}


/*
** Return the string length
** LUA interface:
**			n = strlen (string)
*/
static void str_len (void)
{
 lua_pushnumber(strlen(lua_check_string(1, "strlen")));
}

/*
** Return the substring of a string, from start to end
** LUA interface:
**			substring = strsub (string, start, end)
*/
static void str_sub (void)
{
  char *s = lua_check_string(1, "strsub");
  long start = (long)lua_check_number(2, "strsub");
  long end = lua_opt_number(3, strlen(s), "strsub");
  if (1 <= start && start <= end && end <= strlen(s)) {
    luaI_addchar(0);
    addnchar(s+start-1, end-start+1);
    lua_pushstring(luaI_addchar(0));
  }
  else lua_pushliteral("");
}

/*
** Transliterate a string
*/
static void str_map (void)
{
  char *s = lua_check_string(1, "strmap");
  char *from = lua_check_string(2, "strmap");
  char *to = lua_opt_string(3, "", "strmap");
  long len = strlen(to);
  for (luaI_addchar(0); *s; s++) {
    char *f = strrchr(from, *s);
    if (f == NULL)
      luaI_addchar(*s);
    else {
      long pos = f-from;
      if (pos < len)
        luaI_addchar(to[pos]);
    }
  }
  lua_pushstring(luaI_addchar(0));
}

/*
** get ascii value of a character in a string
*/
static void str_ascii (void)
{
  char *s = lua_check_string(1, "ascii");
  long pos = lua_opt_number(2, 1, "ascii") - 1;
  lua_arg_check(0<=pos && pos<strlen(s), "ascii");
  lua_pushnumber((unsigned char)s[pos]);
}


/* pattern matching */

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

char *item_end (char *p)
{
  switch (*p) {
    case '\0': return p;
    case ESC:
      if (*(p+1) == 0) lua_error("incorrect pattern");
      return p+2;
    case '[': {
      char *end = (*(p+1) == 0) ? NULL : strchr(p+2, ']');
      if (end == NULL) lua_error("incorrect pattern");
      return end+1;
    }
    default:
      return p+1;
  }
}

static int matchclass (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;
    default: return (cl == c);
  }
  return (islower(cl) ? res : !res);
}

int singlematch (int c, char *p)
{
  if (c <= 0) return 0;  /* \0, EOF or other strange flags */
  switch (*p) {
    case '.': return 1;
    case ESC: return matchclass(c, *(p+1));
    case '[': {
      char *end = strchr(p+2, ']');
      int sig = *(p+1) == '^' ? (p++, 0) : 1;
      while (++p < end) {
        if (*p == ESC) {
          if (((p+1) < end) && matchclass(c, *++p)) return sig;
        }
        else if ((*(p+1) == '-') && (p+2 < end)) {
          p+=2;
          if (*(p-2) <= c && c <= *p) return sig;
        }
        else if (*p == c) return sig;
      }
      return !sig;
    }
    default: return (*p == c);
  }
}

#define MAX_CAPT 9

static struct {
  char *init;
  int len;  /* -1 signals unfinished capture */
} capture[MAX_CAPT];

static int num_captures;  /* only valid after a sucessful call to match */


static void push_captures (void)
{
  int i;
  luaI_addchar(0);
  for (i=0; i<num_captures; i++) {
    if (capture[i].len == -1) lua_error("unfinished capture");
    addnchar(capture[i].init, capture[i].len);
    lua_pushstring(luaI_addchar(0));
  }
}

static int check_cap (int l, int level)
{
  l -= '1';
  if (!(0 <= l && l < level && capture[l].len != -1))
    lua_error("invalid capture index");
  return l;
}

static void add_s (char *newp)
{
  while (*newp) {
    if (*newp != ESC || !isdigit(*++newp))
      luaI_addchar(*newp++);
    else {
      int l = check_cap(*newp++, num_captures);
      addnchar(capture[l].init, capture[l].len);
    }
  }
}

static int capture_to_close (int level)
{
  for (level--; level>=0; level--)
    if (capture[level].len == -1) return level;
  lua_error("invalid pattern capture");
  return 0;  /* to avoid warnings */
}

static char *match (char *s, char *p, int level)
{
  init: /* using goto's to optimize tail recursion */
  switch (*p) {
    case '(':  /* start capture */
      if (level >= MAX_CAPT) lua_error("too many captures");
      capture[level].init = s;
      capture[level].len = -1;
      level++; p++; goto init;  /* return match(s, p+1, level); */
    case ')': {  /* end capture */
      int l = capture_to_close(level);
      char *res;
      capture[l].len = s - capture[l].init;  /* close capture */
      if ((res = match(s, p+1, level)) == NULL) /* match failed? */
        capture[l].len = -1;  /* undo capture */
      return res;
    }
    case ESC:  /* possibly a capture (if followed by a digit) */
      if (!isdigit(*(p+1))) goto dflt;
      else {
        int l = check_cap(*(p+1), level);
        if (strncmp(capture[l].init, s, capture[l].len) == 0) {
          /* return match(p+2, s+capture[l].len, level); */
          p+=2; s+=capture[l].len; goto init;
        }
        else return NULL;
     }
    case '\0': case '$':  /* (possibly) end of pattern */
      if (*p == 0 || (*(p+1) == 0 && *s == 0)) {
        num_captures = level;
        return s;
      }
      else goto dflt;
    default: dflt: {  /* it is a pattern item */
      int m = singlematch(*s, p);
      char *ep = item_end(p);  /* get what is next */
      switch (*ep) {
        case '*': {  /* repetition */
          char *res;
          if (m && (res = match(s+1, p, level)))
            return res;
          p=ep+1; goto init;  /* else return match(s, ep+1, level); */
        }
        case '?': {  /* optional */
          char *res;
          if (m && (res = match(s+1, ep+1, level)))
            return res;
          p=ep+1; goto init;  /* else return match(s, ep+1, level); */
        }
        default:
          if (m) { s++; p=ep; goto init; }  /* return match(s+1, ep, level); */
          else return NULL;
      }
    }
  }
}

static void str_find (void)
{
  char *s = lua_check_string(1, "find");
  char *p = lua_check_string(2, "find");
  long init = lua_opt_number(3, 1, "strfind") - 1;
  lua_arg_check(0 <= init && init <= strlen(s), "find");
  if (strpbrk(p, SPECIALS) == NULL) {  /* no special caracters? */
    char *s2 = strstr(s+init, p);
    if (s2) {
      lua_pushnumber(s2-s+1);
      lua_pushnumber(s2-s+strlen(p));
    }
  }
  else {
    int anchor = (*p == '^') ? (p++, 1) : 0;
    char *s1=s+init;
    do {
      char *res;
      if ((res=match(s1, p, 0)) != NULL) {
        lua_pushnumber(s1-s+1);  /* start */
        lua_pushnumber(res-s);   /* end */
        push_captures();
        return;
      }
    } while (*s1++ && !anchor);
  }
}

static void str_s (void)
{
  char *src = lua_check_string(1, "s");
  char *p = lua_check_string(2, "s");
  char *newp = lua_check_string(3, "s");
  int max_s = lua_opt_number(4, strlen(src), "s");
  int anchor = (*p == '^') ? (p++, 1) : 0;
  int n = 0;
  luaI_addchar(0);
  while (*src && n < max_s) {
    char *e;
    if ((e=match(src, p, 0)) == NULL)
      luaI_addchar(*src++);
    else {
      if (e == src) lua_error("empty pattern in substitution");  /* ??? */
      add_s(newp);
      src = e;
      n++;
    }
    if (anchor) break;
  }
  addnchar(src, strlen(src));
  lua_pushstring(luaI_addchar(0));
  lua_pushnumber(n);  /* number of substitutions */
}

static void str_set (void)
{
  char *item = lua_check_string(1, "strset");
  int i;
  lua_arg_check(*item_end(item) == 0, "strset");
  luaI_addchar(0);
  for (i=1; i<256; i++)  /* 0 cannot be part of a set */
    if (singlematch(i, item))
      luaI_addchar(i);
  lua_pushstring(luaI_addchar(0));
}


void luaI_addquoted (char *s)
{
  luaI_addchar('"');
  for (; *s; s++) {
    if (strchr("\"\\\n", *s))
      luaI_addchar('\\');
    luaI_addchar(*s);
  }
  luaI_addchar('"');
}

#define MAX_FORMAT 200

static void str_format (void)
{
  int arg = 1;
  char *strfrmt = lua_check_string(arg++, "format");
  luaI_addchar(0);  /* initialize */
  while (*strfrmt) {
    if (*strfrmt != '%')
      luaI_addchar(*strfrmt++);
    else if (*++strfrmt == '%')
      luaI_addchar(*strfrmt++);  /* %% */
    else { /* format item */
      char form[MAX_FORMAT];      /* store the format ('%...') */
      char *buff;
      char *initf = strfrmt-1;  /* -1 to include % */
      strfrmt = match(strfrmt, "[-+ #]*(%d*)%.?(%d*)", 0);
      if (capture[0].len > 3 || capture[1].len > 3)  /* < 1000? */
        lua_error("invalid format (width/precision too long)");
      strncpy(form, initf, strfrmt-initf+1); /* +1 to include convertion */
      form[strfrmt-initf+1] = 0;
      buff = openspace(1000);  /* to store the formated value */
      switch (*strfrmt++) {
        case 'q':
          luaI_addquoted(lua_check_string(arg++, "format"));
          break;
        case 's': {
          char *s = lua_check_string(arg++, "format");
          buff = openspace(strlen(s));
          buff_size += sprintf(buff, form, s);
          break;
        }
        case 'c':  case 'd':  case 'i': case 'o':
        case 'u':  case 'x':  case 'X':
          buff_size += sprintf(buff, form,
                               (int)lua_check_number(arg++, "format"));
          break;
        case 'e':  case 'E': case 'f': case 'g':
          buff_size += sprintf(buff, form, lua_check_number(arg++, "format"));
          break;
        default:  /* also treat cases 'pnLlh' */
          lua_error("invalid format option in function `format'");
      }
    }
  }
  lua_pushstring(luaI_addchar(0));  /* push the result */
}


void luaI_openlib (struct lua_reg *l, int n)
{
  int i;
  for (i=0; i<n; i++)
    lua_register(l[i].name, l[i].func);
}


static struct lua_reg strlib[] = {
{"strtok", str_tok},
{"strlen", str_len},
{"strsub", str_sub},
{"strset", str_set},
{"strmap", str_map},
{"ascii", str_ascii},
{"format", str_format},
{"strfind", str_find},
{"gsub",    str_s}
};


/*
** Open string library
*/
void strlib_open (void)
{
  luaI_openlib(strlib, (sizeof(strlib)/sizeof(strlib[0])));
}