/* src/vm/string.c - java.lang.String related functions

   Copyright (C) 1996-2005, 2006, 2007, 2008
   CACAOVM - Verein zur Foerderung der freien virtuellen Maschine CACAO

   This file is part of CACAO.

   This program 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, or (at
   your option) any later version.

   This program 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.

*/


#include "config.h"

#include <assert.h>

#include "vmcore/system.h"

#include "vm/types.h"

#include "vm/global.h"

#include "mm/memory.h"

#include "native/jni.h"
#include "native/llni.h"

#include "native/include/java_lang_String.h"

#include "threads/lock-common.h"

#include "vm/array.h"
#include "vm/builtin.h"
#include "vm/exceptions.h"
#include "vm/primitive.hpp"
#include "vm/stringlocal.h"
#include "vm/vm.hpp"

#include "vmcore/options.h"
#include "vmcore/statistics.h"
#include "vmcore/utf8.h"


/* global variables ***********************************************************/

/* hashsize must be power of 2 */

#define HASHTABLE_STRING_SIZE    2048   /* initial size of javastring-hash    */

hashtable hashtable_string;             /* hashtable for javastrings          */

#if defined(ENABLE_THREADS)
static java_object_t *lock_hashtable_string;
#endif


/* XXX preliminary typedef, will be removed once string.c and utf8.c are
   unified. */

#if defined(ENABLE_HANDLES)
typedef heap_java_lang_String heapstring_t;
#else
typedef java_lang_String heapstring_t;
#endif


/* string_init *****************************************************************

   Initialize the string hashtable lock.

*******************************************************************************/

bool string_init(void)
{
	TRACESUBSYSTEMINITIALIZATION("string_init");

	/* create string (javastring) hashtable */

	hashtable_create(&hashtable_string, HASHTABLE_STRING_SIZE);

#if defined(ENABLE_THREADS)
	/* create string hashtable lock object */

	lock_hashtable_string = NEW(java_object_t);

	LOCK_INIT_OBJECT_LOCK(lock_hashtable_string);
#endif

	/* everything's ok */

	return true;
}


/* stringtable_update **********************************************************

   Traverses the javastring hashtable and sets the vftbl-entries of
   javastrings which were temporarily set to NULL, because
   java.lang.Object was not yet loaded.

*******************************************************************************/
 
void stringtable_update(void)
{
	heapstring_t     *js;
	java_chararray_t *a;
	literalstring    *s;       /* hashtable entry */
	int i;

	for (i = 0; i < hashtable_string.size; i++) {
		s = hashtable_string.ptr[i];
		if (s) {
			while (s) {
				js = (heapstring_t *) s->string;
                               
				if ((js == NULL) || (js->value == NULL)) {
					/* error in hashtable found */

					vm_abort("stringtable_update: invalid literalstring in hashtable");
				}

				a = js->value;

				if (!js->header.vftbl) 
					/* vftbl of javastring is NULL */ 
					js->header.vftbl = class_java_lang_String->vftbl;

				if (!a->header.objheader.vftbl) 
					/* vftbl of character-array is NULL */ 
					a->header.objheader.vftbl =
						Primitive_get_arrayclass_by_type(ARRAYTYPE_CHAR)->vftbl;

				/* follow link in external hash chain */
				s = s->hashlink;
			}       
		}               
	}
}


/* javastring_new_from_utf_buffer **********************************************

   Create a new object of type java/lang/String with the text from
   the specified utf8 buffer.

   IN:
      buffer.......points to first char in the buffer
	  blength......number of bytes to read from the buffer

   RETURN VALUE:
      the java.lang.String object, or
      NULL if an exception has been thrown

*******************************************************************************/

static java_handle_t *javastring_new_from_utf_buffer(const char *buffer,
														 u4 blength)
{
	const char *utf_ptr;            /* current utf character in utf string    */
	u4 utflength;                   /* length of utf-string if uncompressed   */
	java_handle_t     *o;
	java_lang_String  *s;           /* result-string                          */
	java_handle_chararray_t *a;
	u4 i;

	assert(buffer);

	utflength = utf_get_number_of_u2s_for_buffer(buffer,blength);

	o = builtin_new(class_java_lang_String);
	a = builtin_newarray_char(utflength);

	/* javastring or character-array could not be created */

	if ((o == NULL) || (a == NULL))
		return NULL;

	/* decompress utf-string */

	utf_ptr = buffer;

	for (i = 0; i < utflength; i++)
		LLNI_array_direct(a, i) = utf_nextu2((char **) &utf_ptr);
	
	/* set fields of the javastring-object */

	s = (java_lang_String *) o;

	LLNI_field_set_ref(s, value , a);
	LLNI_field_set_val(s, offset, 0);
	LLNI_field_set_val(s, count , utflength);

	return o;
}


/* javastring_safe_new_from_utf8 ***********************************************

   Create a new object of type java/lang/String with the text from
   the specified UTF-8 string. This function is safe for invalid UTF-8.
   (Invalid characters will be replaced by U+fffd.)

   IN:
      text.........the UTF-8 string, zero-terminated.

   RETURN VALUE:
      the java.lang.String object, or
      NULL if an exception has been thrown

*******************************************************************************/

java_handle_t *javastring_safe_new_from_utf8(const char *text)
{
	java_handle_t           *o;
	java_handle_chararray_t *a;
	java_lang_String        *s;
	s4 nbytes;
	s4 len;

	if (text == NULL)
		return NULL;

	/* Get number of bytes. We need this to completely emulate the messy */
	/* behaviour of the RI. :(                                           */

	nbytes = strlen(text);

	/* calculate number of Java characters */

	len = utf8_safe_number_of_u2s(text, nbytes);

	/* allocate the String object and the char array */

	o = builtin_new(class_java_lang_String);
	a = builtin_newarray_char(len);

	/* javastring or character-array could not be created? */

	if ((o == NULL) || (a == NULL))
		return NULL;

	/* decompress UTF-8 string */

	utf8_safe_convert_to_u2s(text, nbytes, LLNI_array_data(a));

	/* set fields of the String object */

	s = (java_lang_String *) o;

	LLNI_field_set_ref(s, value , a);
	LLNI_field_set_val(s, offset, 0);
	LLNI_field_set_val(s, count , len);

	return o;
}


/* javastring_new_from_utf_string **********************************************

   Create a new object of type java/lang/String with the text from
   the specified zero-terminated utf8 string.

   IN:
      buffer.......points to first char in the buffer
	  blength......number of bytes to read from the buffer

   RETURN VALUE:
      the java.lang.String object, or
      NULL if an exception has been thrown

*******************************************************************************/

java_handle_t *javastring_new_from_utf_string(const char *utfstr)
{
	assert(utfstr);

	return javastring_new_from_utf_buffer(utfstr, strlen(utfstr));
}


/* javastring_new **************************************************************

   creates a new object of type java/lang/String with the text of 
   the specified utf8-string

   return: pointer to the string or NULL if memory is exhausted.	

*******************************************************************************/

java_handle_t *javastring_new(utf *u)
{
	char *utf_ptr;                  /* current utf character in utf string    */
	u4 utflength;                   /* length of utf-string if uncompressed   */
	java_handle_t           *o;
	java_handle_chararray_t *a;
	java_lang_String        *s;
	s4 i;

	if (u == NULL) {
		exceptions_throw_nullpointerexception();
		return NULL;
	}

	utf_ptr = u->text;
	utflength = utf_get_number_of_u2s(u);

	o = builtin_new(class_java_lang_String);
	a = builtin_newarray_char(utflength);

	/* javastring or character-array could not be created */

	if ((o == NULL) || (a == NULL))
		return NULL;

	/* decompress utf-string */

	for (i = 0; i < utflength; i++)
		LLNI_array_direct(a, i) = utf_nextu2(&utf_ptr);
	
	/* set fields of the javastring-object */

	s = (java_lang_String *) o;

	LLNI_field_set_ref(s, value , a);
	LLNI_field_set_val(s, offset, 0);
	LLNI_field_set_val(s, count , utflength);

	return o;
}


/* javastring_new_slash_to_dot *************************************************

   creates a new object of type java/lang/String with the text of 
   the specified utf8-string with slashes changed to dots

   return: pointer to the string or NULL if memory is exhausted.	

*******************************************************************************/

java_handle_t *javastring_new_slash_to_dot(utf *u)
{
	char *utf_ptr;                  /* current utf character in utf string    */
	u4 utflength;                   /* length of utf-string if uncompressed   */
	java_handle_t           *o;
	java_handle_chararray_t *a;
	java_lang_String        *s;
	s4 i;
	u2 ch;

	if (u == NULL) {
		exceptions_throw_nullpointerexception();
		return NULL;
	}

	utf_ptr = u->text;
	utflength = utf_get_number_of_u2s(u);

	o = builtin_new(class_java_lang_String);
	a = builtin_newarray_char(utflength);

	/* javastring or character-array could not be created */
	if ((o == NULL) || (a == NULL))
		return NULL;

	/* decompress utf-string */

	for (i = 0; i < utflength; i++) {
		ch = utf_nextu2(&utf_ptr);
		if (ch == '/')
			ch = '.';
		LLNI_array_direct(a, i) = ch;
	}
	
	/* set fields of the javastring-object */

	s = (java_lang_String *) o;

	LLNI_field_set_ref(s, value , a);
	LLNI_field_set_val(s, offset, 0);
	LLNI_field_set_val(s, count , utflength);

	return o;
}


/* javastring_new_from_ascii ***************************************************

   creates a new java/lang/String object which contains the given ASCII
   C-string converted to UTF-16.

   IN:
      text.........string of ASCII characters

   RETURN VALUE:
      the java.lang.String object, or 
      NULL if an exception has been thrown.

*******************************************************************************/

java_handle_t *javastring_new_from_ascii(const char *text)
{
	s4 i;
	s4 len;                             /* length of the string               */
	java_handle_t           *o;
	java_lang_String        *s;
	java_handle_chararray_t *a;

	if (text == NULL) {
		exceptions_throw_nullpointerexception();
		return NULL;
	}

	len = strlen(text);

	o = builtin_new(class_java_lang_String);
	a = builtin_newarray_char(len);

	/* javastring or character-array could not be created */

	if ((o == NULL) || (a == NULL))
		return NULL;

	/* copy text */

	for (i = 0; i < len; i++)
		LLNI_array_direct(a, i) = text[i];
	
	/* set fields of the javastring-object */

	s = (java_lang_String *) o;

	LLNI_field_set_ref(s, value , a);
	LLNI_field_set_val(s, offset, 0);
	LLNI_field_set_val(s, count , len);

	return o;
}


/* javastring_tochar ***********************************************************

   converts a Java string into a C string.
	
   return: pointer to C string
	
   Caution: calling method MUST release the allocated memory!
	
*******************************************************************************/

char *javastring_tochar(java_handle_t *so) 
{
	java_lang_String        *s = (java_lang_String *) so;
	java_handle_chararray_t *a;
	int32_t                  count;
	int32_t                  offset;
	char *buf;
	s4 i;
	
	if (!s)
		return "";

	LLNI_field_get_ref(s, value, a);

	if (!a)
		return "";

	LLNI_field_get_val(s, count, count);
	LLNI_field_get_val(s, offset, offset);

	buf = MNEW(char, count + 1);

	for (i = 0; i < count; i++)
		buf[i] = LLNI_array_direct(a, offset + i);

	buf[i] = '\0';

	return buf;
}


/* javastring_toutf ************************************************************

   Make utf symbol from javastring.

*******************************************************************************/

utf *javastring_toutf(java_handle_t *string, bool isclassname)
{
	java_lang_String        *s;
	java_handle_chararray_t *value;
	int32_t                  count;
	int32_t                  offset;

	s = (java_lang_String *) string;

	if (s == NULL)
		return utf_null;

	LLNI_field_get_ref(s, value, value);

	if (value == NULL)
		return utf_null;

	LLNI_field_get_val(s, count, count);
	LLNI_field_get_val(s, offset, offset);

	return utf_new_u2(LLNI_array_data(value) + offset, count, isclassname);
}


/* literalstring_u2 ************************************************************

   Searches for the literalstring with the specified u2-array in the
   string hashtable, if there is no such string a new one is created.

   If copymode is true a copy of the u2-array is made.

*******************************************************************************/

static java_object_t *literalstring_u2(java_chararray_t *a, u4 length,
									   u4 offset, bool copymode)
{
    literalstring    *s;                /* hashtable element                  */
    heapstring_t     *js;               /* u2-array wrapped in javastring     */
    java_chararray_t *ca;               /* copy of u2-array                   */
    u4                key;
    u4                slot;
    u2                i;

	LOCK_MONITOR_ENTER(lock_hashtable_string);

    /* find location in hashtable */

    key  = unicode_hashkey(a->data + offset, length);
    slot = key & (hashtable_string.size - 1);
    s    = hashtable_string.ptr[slot];

    while (s) {
		js = (heapstring_t *) s->string;

		if (length == js->count) {
			/* compare text */

			for (i = 0; i < length; i++)
				if (a->data[offset + i] != js->value->data[i])
					goto nomatch;

			/* string already in hashtable, free memory */

			if (!copymode)
				mem_free(a, sizeof(java_chararray_t) + sizeof(u2) * (length - 1) + 10);

			LOCK_MONITOR_EXIT(lock_hashtable_string);

			return (java_object_t *) js;
		}

	nomatch:
		/* follow link in external hash chain */
		s = s->hashlink;
    }

    if (copymode) {
		/* create copy of u2-array for new javastring */
		u4 arraysize = sizeof(java_chararray_t) + sizeof(u2) * (length - 1) + 10;
		ca = mem_alloc(arraysize);
/*    		memcpy(ca, a, arraysize); */
  		memcpy(&(ca->header), &(a->header), sizeof(java_array_t));
  		memcpy(&(ca->data), &(a->data) + offset, sizeof(u2) * (length - 1) + 10);

    } else {
		ca = a;
	}

    /* location in hashtable found, complete arrayheader */

    ca->header.objheader.vftbl =
		Primitive_get_arrayclass_by_type(ARRAYTYPE_CHAR)->vftbl;
    ca->header.size            = length;

	assert(class_java_lang_String);
	assert(class_java_lang_String->state & CLASS_LOADED);

	/* create new javastring */

	js = NEW(heapstring_t);

#if defined(ENABLE_STATISTICS)
	if (opt_stat)
		size_string += sizeof(heapstring_t);
#endif

#if defined(ENABLE_THREADS)
	lock_init_object_lock(&js->header);
#endif

	js->header.vftbl = class_java_lang_String->vftbl;
	js->value  = ca;
	js->offset = 0;
	js->count  = length;

	/* create new literalstring */

	s = NEW(literalstring);

#if defined(ENABLE_STATISTICS)
	if (opt_stat)
		size_string += sizeof(literalstring);
#endif

	s->hashlink = hashtable_string.ptr[slot];
	s->string   = (java_object_t *) js;
	hashtable_string.ptr[slot] = s;

	/* update number of hashtable entries */

	hashtable_string.entries++;

	/* reorganization of hashtable */       

	if (hashtable_string.entries > (hashtable_string.size * 2)) {
		/* reorganization of hashtable, average length of the external
		   chains is approx. 2 */

		u4             i;
		literalstring *s;
		literalstring *nexts;
		heapstring_t  *tmpjs;
		hashtable      newhash;                          /* the new hashtable */
      
		/* create new hashtable, double the size */

		hashtable_create(&newhash, hashtable_string.size * 2);
		newhash.entries = hashtable_string.entries;
      
		/* transfer elements to new hashtable */

		for (i = 0; i < hashtable_string.size; i++) {
			s = hashtable_string.ptr[i];

			while (s) {
				nexts = s->hashlink;
				tmpjs = (heapstring_t *) s->string;
				slot  = unicode_hashkey(tmpjs->value->data, tmpjs->count) & (newhash.size - 1);
	  
				s->hashlink = newhash.ptr[slot];
				newhash.ptr[slot] = s;
	
				/* follow link in external hash chain */
				s = nexts;
			}
		}
	
		/* dispose old table */

		MFREE(hashtable_string.ptr, void*, hashtable_string.size);
		hashtable_string = newhash;
	}

	LOCK_MONITOR_EXIT(lock_hashtable_string);

	return (java_object_t *) js;
}


/* literalstring_new ***********************************************************

   Creates a new literalstring with the text of the utf-symbol and inserts
   it into the string hashtable.

*******************************************************************************/

java_object_t *literalstring_new(utf *u)
{
    char             *utf_ptr;       /* pointer to current unicode character  */
	                                 /* utf string                            */
    u4                utflength;     /* length of utf-string if uncompressed  */
    java_chararray_t *a;             /* u2-array constructed from utf string  */
    u4                i;

	utf_ptr = u->text;
	utflength = utf_get_number_of_u2s(u);

    /* allocate memory */ 
    a = mem_alloc(sizeof(java_chararray_t) + sizeof(u2) * (utflength - 1) + 10);

    /* convert utf-string to u2-array */
    for (i = 0; i < utflength; i++)
		a->data[i] = utf_nextu2(&utf_ptr);

    return literalstring_u2(a, utflength, 0, false);
}


/* literalstring_free **********************************************************

   Removes a literalstring from memory.

*******************************************************************************/

#if 0
/* TWISTI This one is currently not used. */

static void literalstring_free(java_object_t* string)
{
	heapstring_t     *s;
	java_chararray_t *a;

	s = (heapstring_t *) string;
	a = s->value;

	/* dispose memory of java.lang.String object */
	FREE(s, heapstring_t);

	/* dispose memory of java-characterarray */
	FREE(a, sizeof(java_chararray_t) + sizeof(u2) * (a->header.size - 1)); /* +10 ?? */
}
#endif


/* javastring_intern ***********************************************************

   Intern the given Java string.

   XXX NOTE: Literal Strings are direct references since they are not placed
   onto the GC-Heap. That's why this function looks so "different".

*******************************************************************************/

java_handle_t *javastring_intern(java_handle_t *s)
{
	java_lang_String *so;
	java_chararray_t *value;
	int32_t           count;
	int32_t           offset;
/* 	java_lang_String *o; */
	java_object_t    *o; /* XXX see note above */

	so = (java_lang_String *) s;

	value  = LLNI_field_direct(so, value); /* XXX see note above */
	LLNI_field_get_val(so, count, count);
	LLNI_field_get_val(so, offset, offset);

	o = literalstring_u2(value, count, offset, true);

	return LLNI_WRAP(o); /* XXX see note above */
}


/* javastring_fprint ***********************************************************

   Print the given Java string to the given stream.

*******************************************************************************/

void javastring_fprint(java_handle_t *s, FILE *stream)
{
	java_lang_String        *so;
	java_handle_chararray_t *value;
	int32_t                  count;
	int32_t                  offset;
	uint16_t                 c;
	int                      i;

	so = (java_lang_String *) s;

	LLNI_field_get_ref(so, value, value);
	LLNI_field_get_val(so, count, count);
	LLNI_field_get_val(so, offset, offset);

	for (i = offset; i < offset + count; i++) {
		c = LLNI_array_direct(value, i);
		fputc(c, stream);
	}
}


/*
 * These are local overrides for various environment variables in Emacs.
 * Please do not remove this and leave it at the end of the file, where
 * Emacs will automagically detect them.
 * ---------------------------------------------------------------------
 * Local variables:
 * mode: c
 * indent-tabs-mode: t
 * c-basic-offset: 4
 * tab-width: 4
 * End:
 * vim:noexpandtab:sw=4:ts=4:
 */