/* \file simple-gettext.c
 * a simplified version of gettext.
 * Copyright (C) 1995, 1996, 1997, 1999,
 *               2005 Free Software Foundation, Inc.
 *
 * This file is part of XTrackCAD.
 *
 * GnuPG is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * GnuPG is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/* This is a simplified version of gettext written by Ulrich Drepper.
 * It is used for the Win32 version of GnuPG beucase all the overhead
 * of gettext is not needed and we have to do some special Win32 stuff.
 * I decided that this is far easier than to tweak gettext for the special
 * cases (I tried it but it is a lot of code).	wk 15.09.99
 */

/*
 * Based on the simple-gettext from GnuPG a version appropriate for the
 * needs of XTrackCAD was derived. This is a workaround for any compiler
 * specifics or runtime library dependencies. mf 26.07.09
 */

#ifdef USE_SIMPLE_GETTEXT
#if !defined (_WIN32) && !defined (__CYGWIN32__)
#error This file can only be used under Windows or Cygwin32
#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <windows.h>

#include "mswint.h"

#if _MSC_VER > 1300
#define stricmp _stricmp
#define strnicmp _strnicmp
#define strdup _strdup
#define fileno _fileno
#endif

typedef unsigned long u32;

/* The magic number of the GNU message catalog format.	*/
#define MAGIC	      0x950412de
#define MAGIC_SWAPPED 0xde120495

/* Revision number of the currently used .mo (binary) file format.  */
#define MO_REVISION_NUMBER 0


/* Header for binary .mo file format.  */
struct mo_file_header {
	/* The magic number.	*/
	u32 magic;
	/* The revision number of the file format.  */
	u32 revision;
	/* The number of strings pairs.  */
	u32 nstrings;
	/* Offset of table with start offsets of original strings.  */
	u32 orig_tab_offset;
	/* Offset of table with start offsets of translation strings.  */
	u32 trans_tab_offset;
	/* Size of hashing table.  */
	u32 hash_tab_size;
	/* Offset of first hashing entry.  */
	u32 hash_tab_offset;
};

struct string_desc {
	/* Length of addressed string.  */
	u32 length;
	/* Offset of string in file.	*/
	u32 offset;
};


struct overflow_space_s {
	struct overflow_space_s *next;
	u32 idx;
	char d[1];
};

struct loaded_domain {
	char *data;
	int must_swap;
	u32 nstrings;
	char *mapped;  /* 0 = not yet mapped, 1 = mapped,
                    2 = mapped to
                    overflow space */
	struct overflow_space_s *overflow_space;
	struct string_desc *orig_tab;
	struct string_desc *trans_tab;
	u32 hash_size;
	u32 *hash_tab;
};

static struct loaded_domain *the_domain;

/**
 *	Translate the input string from UTF8 to Windows codepage.
 *
 * \param str IN string in UTF-8 format to translate.
 * \param len IN number of chars to translate
 * \param  dummy IN ?
 * \return pointer to translated string. Free after usage
 */
char *
utf8_to_native( char *str, unsigned int len, int dummy )
{
	/* maximum output length is size of string * 2 */
	int buflen = (len + 1) * 2;
	char *buf = malloc( buflen );
	int wcharLen;
	/* maximum result size is size of UTF-8 string */
	char *resBuffer = malloc( len + 1 );

	if( !resBuffer ) {
		resBuffer = "ERROR in UTF-8 MALLOC";
	} else {
		/* as Windows has no way fo a direct translation fom UTF-8 to */
		/* the system codepage, we need to take two steps */

		/* 1. convert from UTF-8 to UTF-16 */
		wcharLen = MultiByteToWideChar(CP_UTF8, 0, (LPCSTR)str, -1, (LPWSTR)buf,
		                               buflen / 2 );

		/* 2. convert from UTF-8 to system codepage */
		WideCharToMultiByte(CP_ACP, 0, (LPWSTR)buf, wcharLen, resBuffer, len + 1, NULL,
		                    NULL );


	}
	free(buf);
	return( resBuffer );
}


static u32
do_swap_u32( u32 i )
{
	return (i << 24) | ((i & 0xff00) << 8) | ((i >> 8) & 0xff00) | (i >> 24);
}

#define SWAPIT(flag, data) ((flag) ? do_swap_u32(data) : (data) )


/* We assume to have `unsigned long int' value with at least 32 bits.  */
#define HASHWORDBITS 32

/* The so called `hashpjw' function by P.J. Weinberger
   [see Aho/Sethi/Ullman, COMPILERS: Principles, Techniques and Tools,
   1986, 1987 Bell Telephone Laboratories, Inc.]  */

static unsigned long
hash_string( const char *str_param )
{
	unsigned long int hval, g;
	const char *str = str_param;

	hval = 0;
	while (*str != '\0') {
		hval <<= 4;
		hval += (unsigned long int) *str++;
		g = hval & ((unsigned long int) 0xf << (HASHWORDBITS - 4));
		if (g != 0) {
			hval ^= g >> (HASHWORDBITS - 8);
			hval ^= g;
		}
	}
	return hval;
}


static struct loaded_domain *
load_domain( const char *filename )
{
	FILE *fp;
	size_t size;
	struct stat st;
	struct mo_file_header *data = NULL;
	struct loaded_domain *domain = NULL;
	size_t to_read;
	char *read_ptr;

	fp = fopen( filename, "rb" );
	if( !fp ) {
		return NULL;        /* can't open the file */
	}
	/* we must know about the size of the file */
	if( fstat( fileno(fp ), &st )
	    || (size = (size_t)st.st_size) != st.st_size
	    || size < sizeof (struct mo_file_header) ) {
		fclose( fp );
		return NULL;
	}

	data = malloc( size );
	if( !data ) {
		fclose( fp );
		return NULL; /* out of memory */
	}

	to_read = size;
	read_ptr = (char *) data;
	do {
		unsigned long int nb = (unsigned int)fread( read_ptr, 1, to_read, fp );
		if( nb < to_read ) {
			fclose (fp);
			free(data);
			return NULL; /* read error */
		}
		read_ptr += nb;
		to_read -= nb;
	} while( to_read > 0 );
	fclose (fp);

	/* Using the magic number we can test whether it really is a message
	 * catalog file.  */
	if( data->magic != MAGIC && data->magic != MAGIC_SWAPPED ) {
		/* The magic number is wrong: not a message catalog file.  */
		free( data );
		return NULL;
	}

	domain = calloc( 1, sizeof *domain );
	if( !domain )  {
		free( data );
		return NULL;
	}
	domain->data = (char *) data;
	domain->must_swap = data->magic != MAGIC;

	/* Fill in the information about the available tables.  */
	switch( SWAPIT(domain->must_swap, data->revision) ) {
	case 0:
		domain->nstrings = SWAPIT(domain->must_swap, data->nstrings);
		domain->orig_tab = (struct string_desc *)
		                   ((char *) data + SWAPIT(domain->must_swap, data->orig_tab_offset));
		domain->trans_tab = (struct string_desc *)
		                    ((char *) data + SWAPIT(domain->must_swap, data->trans_tab_offset));
		domain->hash_size = SWAPIT(domain->must_swap, data->hash_tab_size);
		domain->hash_tab = (u32 *)
		                   ((char *) data + SWAPIT(domain->must_swap, data->hash_tab_offset));
		break;

	default: /* This is an invalid revision.	*/
		free( data );
		free( domain );
		return NULL;
	}

	/* Allocate an array to keep track of code page mappings. */
	domain->mapped = calloc( 1, domain->nstrings );
	if( !domain->mapped ) {
		free( data );
		free( domain );
		return NULL;
	}

	return domain;
}


/**
 * Set the file used for translations. Pass a NULL to disable
 * translation.  A new filename may be set at anytime.  WARNING:
 * After changing the filename you should not access any data
 * retrieved by gettext().
 */
int
set_gettext_file ( const char *filename, const char *regkey )
{
	struct loaded_domain *domain = NULL;

	if( filename && *filename ) {
		if( filename[0] == '/'
		    || ( isalpha(filename[0])
		         && filename[1] == ':'
		         && (filename[2] == '/' || filename[2] == '\\') )
		  ) {
			/* absolute path - use it as is */
			domain = load_domain( filename );
		}
		if (!domain) {
			return -1;
		}
	}

	if( the_domain ) {
		struct overflow_space_s *os, *os2;
		free( the_domain->data );
		free( the_domain->mapped );
		for (os=the_domain->overflow_space; os; os = os2) {
			os2 = os->next;
			free (os);
		}
		free( the_domain );
		the_domain = NULL;
	}
	the_domain = domain;
	return 0;
}

/**
 * Return the required string from the message table. Before returning the result,
 * codepage translation from UTF8 to current codepage is performed.
 */

static const char*
get_string( struct loaded_domain *domain, u32 idx )
{
	struct overflow_space_s *os;
	char *p;

	p = domain->data + SWAPIT(domain->must_swap, domain->trans_tab[idx].offset);
	if (!domain->mapped[idx]) {
		size_t plen, buflen;
		char *buf;

		domain->mapped[idx] = 1;

		plen = strlen (p);
		buf = utf8_to_native (p, (unsigned int)plen, -1);
		buflen = strlen (buf);
		if (buflen <= plen) {
			strcpy (p, buf);
			free( buf );
		} else {
			/* There is not enough space for the translation - store it
			   in the overflow_space else and mark that in the mapped
			   array.  Because we expect that this won't happen too
			   often, we use a simple linked list.  */
			os = malloc (sizeof *os + buflen);
			if (os) {
				os->idx = idx;
				strcpy (os->d, buf);
				os->next = domain->overflow_space;
				domain->overflow_space = os;
				p = os->d;
			} else {
				p = "ERROR in GETTEXT MALLOC";
			}
			free (buf);
		}
	} else if (domain->mapped[idx] == 2) {
		/* We need to get the string from the overflow_space. */
		for (os=domain->overflow_space; os; os = os->next)
			if (os->idx == idx) {
				return (const char*)os->d;
			}
		p = "ERROR in GETTEXT\n";
	}
	return (const char*)p;
}

/**
 * This is the translation function itself.
 */

char *
gettext( const char *msgid )
{
	struct loaded_domain *domain;
	size_t act = 0;
	size_t top, bottom;

	if( !(domain = the_domain) ) {
		goto not_found;
	}

	/* Locate the MSGID and its translation.  */
	if( domain->hash_size > 2 && domain->hash_tab ) {
		/* Use the hashing table.  */
		u32 len = (u32)strlen (msgid);
		u32 hash_val = hash_string (msgid);
		u32 idx = hash_val % domain->hash_size;
		u32 incr = 1 + (hash_val % (domain->hash_size - 2));
		u32 nstr = SWAPIT (domain->must_swap, domain->hash_tab[idx]);

		if ( !nstr ) { /* Hash table entry is empty.  */
			goto not_found;
		}

		if( SWAPIT(domain->must_swap,
		           domain->orig_tab[nstr - 1].length) == len
		    && !strcmp( msgid,
		                domain->data + SWAPIT(domain->must_swap,
		                                      domain->orig_tab[nstr - 1].offset)) ) {
			return (char *)get_string( domain, nstr - 1 );
		}

		for(;;) {
			if (idx >= domain->hash_size - incr) {
				idx -= domain->hash_size - incr;
			} else {
				idx += incr;
			}

			nstr = SWAPIT(domain->must_swap, domain->hash_tab[idx]);
			if( !nstr ) {
				goto not_found;        /* Hash table entry is empty.  */
			}

			if ( SWAPIT(domain->must_swap,
			            domain->orig_tab[nstr - 1].length) == len
			     && !strcmp (msgid,
			                 domain->data + SWAPIT(domain->must_swap,
			                                       domain->orig_tab[nstr - 1].offset))) {
				return (char *)get_string( domain, nstr-1 );
			}
		}
		/* NOTREACHED */
	}

	/* Now we try the default method:  binary search in the sorted
	   array of messages.  */
	bottom = 0;
	top = domain->nstrings;
	while( bottom < top ) {
		int cmp_val;

		act = (bottom + top) / 2;
		cmp_val = strcmp(msgid, domain->data
		                 + SWAPIT(domain->must_swap,
		                          domain->orig_tab[act].offset));
		if (cmp_val < 0) {
			top = act;
		} else if (cmp_val > 0) {
			bottom = act + 1;
		} else {
			return (char *)get_string( domain, (int)(act) );
		}
	}

not_found:
	return (char *)msgid;
}

/**
 * This is the main initialization function for simple gettext. The message file is
 * opened and read into memory. The function must be called once before translating
 * a string.
 *
 * The message files are expected to be in a directory named in the UNIXish form en_US
 * in the path passed to this function. The filename is expected to be domainname.mo
 *
 * \param domainname IN domain
 * \param dirname IN directory for the message files
 * \return    always NULL
 */

char *
bindtextdomain( char *domainname, char *dirname )
{
	char *loc;
	char *dir;

	/* get thread's locale in UNIXish style eg. en_US */
	loc = g_win32_getlocale();

	/* make sure that path does not end with trailing slash */
	if( dirname[ strlen(dirname) ] == '/' ) {
		dirname[ strlen(dirname) ] = '\0';
	}

	/* allocate buffer for filename, 20 bytes should be enough for extension etc. */
	dir = malloc( strlen( domainname ) + strlen( dirname ) + strlen( loc ) + 20 );

	if( dir ) {
		/* create the full filename */
		sprintf( dir, "%s/%s/LC_MESSAGES/%s.mo", dirname, loc, domainname );
		/* load the file */
		set_gettext_file( dir, NULL );
		free( dir );
	}

	free( loc );
	return( NULL );
}

/**
 * This is a dummy function to maintain source code compatibility
 * with other implementations of gettext.
 * For this implementation, UTF-8 input encoding is assumed
 *
 * \param domainname IN domain
 * \param codeset In codeset
 * \return    always NULL
 */

char *
bind_textdomain_codeset(char *domainname, char *codeset )
{
	return( NULL );
}

/**
 * This is a dummy function to maintain source code compatibility
 * with other implementations of gettext.
 *
 * \param domainname IN domain
 * \return    always NULL
 */

char *
textdomain( char *domainname )
{
	return( NULL );
}
#endif /* USE_SIMPLE_GETTEXT */