// natString.cc - Implementation of java.lang.String native methods.

/* Copyright (C) 1998, 1999  Cygnus Solutions

   This file is part of libgcj.

This software is copyrighted work licensed under the terms of the
Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
details.  */

#include <config.h>

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

#include <gcj/cni.h>
#include <java/lang/Character.h>
#include <java/lang/String.h>
#include <java/lang/IndexOutOfBoundsException.h>
#include <java/lang/ArrayIndexOutOfBoundsException.h>
#include <java/lang/StringIndexOutOfBoundsException.h>
#include <java/lang/NullPointerException.h>
#include <java/io/ByteArrayOutputStream.h>
#include <java/io/OutputStreamWriter.h>
#include <java/io/ByteArrayInputStream.h>
#include <java/io/InputStreamReader.h>
#include <gnu/gcj/convert/UnicodeToBytes.h>
#include <gnu/gcj/convert/BytesToUnicode.h>
#include <jvm.h>

static jstring* strhash = NULL;
static int strhash_count = 0;  /* Number of slots used in strhash. */
static int strhash_size = 0;  /* Number of slots available in strhash.
                               * Assumed be power of 2! */

#define DELETED_STRING ((jstring)(~0))
#define SET_STRING_IS_INTERNED(STR) /* nothing */

/* Find a slot where the string with elements DATA, length LEN,
   and hash HASH should go in the strhash table of interned strings. */
jstring*
_Jv_StringFindSlot (jchar* data, jint len, jint hash)
{
  JvSynchronize sync (&StringClass);

  int start_index = hash & (strhash_size - 1);
  int deleted_index = -1;

  register int index = start_index;
  /* step must be non-zero, and relatively prime with strhash_size. */
  int step = 8 * hash + 7;
  for (;;)
    {
      register jstring* ptr = &strhash[index];
      if (*ptr == NULL)
	{
	  if (deleted_index >= 0)
	    return (&strhash[deleted_index]);
	  else
	    return ptr;
	}
      else if (*ptr == DELETED_STRING)
	deleted_index = index;
      else if ((*ptr)->length() == len
	       && memcmp(JvGetStringChars(*ptr), data, 2*len) == 0)
	return (ptr);
      index = (index + step) & (strhash_size - 1);
      JvAssert (index != start_index);
    }
}

/* Calculate a hash code for the string starting at PTR at given LENGTH.
   This uses the same formula as specified for java.lang.String.hash. */

static jint
hashChars (jchar* ptr, jint length)
{
  register jchar* limit = ptr + length;
  jint hash = 0;
  // Updated specification from
  // http://www.javasoft.com/docs/books/jls/clarify.html.
  while (ptr < limit)
    hash = (31 * hash) + *ptr++;
  return hash;
}

jint
java::lang::String::hashCode()
{
  return hashChars(JvGetStringChars(this), length());
}

jstring*
_Jv_StringGetSlot (jstring str)
{
  jchar* data = JvGetStringChars(str);
  int length = str->length();
  return _Jv_StringFindSlot(data, length, hashChars (data, length));
}

void
java::lang::String::rehash()
{
  JvSynchronize sync (&StringClass);

  if (strhash == NULL)
    {
      strhash_size = 1024;
      strhash = (jstring *) _Jv_AllocBytes (strhash_size * sizeof (jstring));
      memset (strhash, 0, strhash_size * sizeof (jstring));
    }
  else
    {
      register int i = strhash_size;
      register jstring* ptr = strhash + i;
      strhash_size *= 2;
      strhash = (jstring *) _Jv_AllocBytes (strhash_size * sizeof (jstring));
      memset (strhash, 0, strhash_size * sizeof (jstring));

      while (--i >= 0)
	{
	  --ptr;
	  if (*ptr == NULL || *ptr == DELETED_STRING)
	    continue;

	  /* This is faster equivalent of
	   * *__JvGetInternSlot(*ptr) = *ptr; */
	  jint hash = (*ptr)->hashCode();
	  jint index = hash & (strhash_size - 1);
	  jint step = 8 * hash + 7;
	  for (;;)
	    {
	      if (strhash[index] == NULL)
		{
		  strhash[index] = *ptr;
		  break;
		}
	      index = (index + step) & (strhash_size - 1);
	    }
	}
    }
}

jstring
java::lang::String::intern()
{
  JvSynchronize sync (&StringClass);
  if (4 * strhash_count >= 3 * strhash_size)
    rehash();
  jstring* ptr = _Jv_StringGetSlot(this);
  if (*ptr != NULL && *ptr != DELETED_STRING)
    return *ptr;
  SET_STRING_IS_INTERNED(this);
  strhash_count++;
  *ptr = this;
  return this;
}

/* Called by String fake finalizer. */
void
java::lang::String::unintern()
{
  JvSynchronize sync (&StringClass);
  jstring* ptr = _Jv_StringGetSlot(this);
  if (*ptr == NULL || *ptr == DELETED_STRING)
    return;
  *ptr = DELETED_STRING;
  strhash_count--;
}

jstring
_Jv_NewStringUTF (const char *bytes)
{
  int size = strlen (bytes);
  unsigned char *p = (unsigned char *) bytes;

  int length = _Jv_strLengthUtf8 ((char *) p, size);
  if (length < 0)
    return NULL;

  jstring jstr = JvAllocString (length);
  jchar *chrs = JvGetStringChars (jstr);

  p = (unsigned char *) bytes;
  unsigned char *limit = p + size;
  while (p < limit)
    *chrs++ = UTF8_GET (p, limit);

  return jstr;
}

jstring
_Jv_NewStringUtf8Const (Utf8Const* str)
{
  jchar *chrs;
  jchar buffer[100];
  jstring jstr;
  register unsigned char* data = (unsigned char*) str->data;
  register unsigned char* limit = data + str->length;
  int length = _Jv_strLengthUtf8(str->data, str->length);

  if (length <= (int) (sizeof(buffer) / sizeof(jchar)))
    {
      jstr = NULL;
      chrs = buffer;
    }
  else
    {
      jstr = JvAllocString(length);
      chrs = JvGetStringChars(jstr);
    }

  while (data < limit)
    *chrs++ = UTF8_GET(data, limit);
  chrs -= length;

  JvSynchronize sync (&StringClass);
  if (4 * strhash_count >= 3 * strhash_size)
    java::lang::String::rehash();
  int hash = str->hash;
  jstring* ptr = _Jv_StringFindSlot (chrs, length, hash);
  if (*ptr != NULL && *ptr != DELETED_STRING)
    return *ptr;
  strhash_count++;
  if (jstr == NULL)
    {
      jstr = JvAllocString(length);
      chrs = JvGetStringChars(jstr);
      memcpy (chrs, buffer, sizeof(jchar)*length);
    }
  *ptr = jstr;
  SET_STRING_IS_INTERNED(jstr);
  return jstr;
}

jsize
_Jv_GetStringUTFLength (jstring string)
{
  register jsize len = 0;
  register jchar *ptr = JvGetStringChars (string);
  register jsize i = string->length();
  while (--i >= 0)
    {
      register jchar ch = *ptr++;
      if (ch > 0 && ch <= 0x7F)
	len += 1;
      else if (ch <= 0x7FF)
	len += 2;
      else
	len += 3;
    }
  return len;
}

// Not sure this quite matches GetStringUTFRegion.
// null-termination of result?  len?  throw exception?
jsize
_Jv_GetStringUTFRegion (jstring str, jsize start, jsize len, char *buf)
{
  register jchar *sptr = JvGetStringChars (str) + start;
  register jsize i = len;
  register char *dptr = buf;
  while (--i >= 0)
    {
      jchar ch = *sptr++;
      if (ch > 0 && ch <= 0x7F)
	*dptr++ = (char) ch;
      else if (ch <= 0x7FF)
	{
	  *dptr++ = (char) (0xC0 + ((ch >> 6) & 0x1F));
	  *dptr++ = (char) (0x80 + (ch & 0x3F));
	}
      else
	{
	  *dptr++ = (char) (0xE0 + ((ch >> 12) & 0xF));
	  *dptr++ = (char) (0x80 + ((ch >> 6) & 0x3F));
	  *dptr++ = (char) (0x80 + (ch & 0x3F));
	}
    }
  return dptr - buf;
}

jstring
_Jv_AllocString(jsize len)
{
  jsize sz = sizeof(java::lang::String) + len * sizeof(jchar);

  jstring obj = (jstring) JvAllocObject(&StringClass, sz);

  obj->data = obj;
  obj->boffset = sizeof(java::lang::String);
  obj->count = len;
  return obj;
}

jstring
_Jv_NewString(const jchar *chars, jsize len)
{
  jstring str = _Jv_AllocString(len);
  jchar* data = JvGetStringChars (str);
  while (--len >= 0)
    *data++ = *chars++;
  return str;
}

jstring
_Jv_NewStringLatin1(const char *bytes, jsize len)
{
  jstring str = JvAllocString(len);
  jchar* data = JvGetStringChars (str);
  while (--len >= 0)
    *data++ = *(unsigned char*)bytes++;
  return str;
}

void
java::lang::String::init ()
{
  count = 0;
  boffset = sizeof(java::lang::String);
  data = this;
}

void
java::lang::String::init(jcharArray chars, jint offset, jint count,
			 jboolean dont_copy)
{
  if (! chars)
    JvThrow (new NullPointerException);
  jsize data_size = JvGetArrayLength (chars);
  if (offset < 0 || count < 0 || offset + count > data_size)
    JvThrow (new StringIndexOutOfBoundsException());
  jcharArray array;
  jchar *pdst;
  if (! dont_copy)
    {
      array = JvNewCharArray(count);
      pdst = elements (array);
      memcpy (pdst, elements (chars) + offset, count * sizeof (jchar));
    }
  else
    {
      JvAssert (offset == 0);
      array = chars;
      pdst = elements (array);
    }

  data = array;
  boffset = (char *) pdst - (char *) array;
  this->count = count;
}

void
java::lang::String::init(jbyteArray ascii, jint hibyte, jint offset,
			 jint count)
{
  if (! ascii)
    JvThrow (new NullPointerException);
  jsize data_size = JvGetArrayLength (ascii);
  if (offset < 0 || count < 0 || offset + count < 0
      || offset + count > data_size)
    JvThrow (new java::lang::StringIndexOutOfBoundsException());
  jcharArray array = JvNewCharArray(count);
  jbyte *psrc = elements (ascii) + offset;
  jchar *pdst = elements (array);
  data = array;
  boffset = (char *) pdst - (char *) array;
  this->count = count;
  hibyte = (hibyte & 0xff) << 8;
  while (-- count >= 0)
    {
      *pdst++ = hibyte | (*psrc++ & 0xff);
    }
}

void
java::lang::String::init (jbyteArray bytes, jint offset, jint count,
			  jstring encoding)
{
  if (! bytes)
    JvThrow (new NullPointerException);
  jsize data_size = JvGetArrayLength (bytes);
  if (offset < 0 || count < 0 || offset + count < 0
      || offset + count > data_size)
    JvThrow (new StringIndexOutOfBoundsException);
  jcharArray array = JvNewCharArray (count);
  gnu::gcj::convert::BytesToUnicode *converter
    = gnu::gcj::convert::BytesToUnicode::getDecoder(encoding);
  jint outpos = 0;
  int avail = count;
  converter->setInput(bytes, offset, offset+count);
  while (converter->inpos < converter->inlength)
    {
      int done = converter->read(array, outpos, avail);
      if (done == 0)
	{
	  jint new_size = 2 * (outpos + avail);
	  jcharArray new_array = JvNewCharArray (new_size);
	  memcpy (elements (new_array), elements (array),
		  outpos * sizeof(jchar));
	  array = new_array;
	  avail = new_size - outpos;
	}
      else
	{
	  outpos += done;
	  avail -= done;
	}
    }
  this->data = array;
  this->boffset = (char *) elements (array) - (char *) array;
  this->count = outpos;
}

jboolean
java::lang::String::equals(jobject anObject)
{
  if (anObject == NULL)
    return false;
  if (anObject == this)
    return true;
  if (anObject->getClass() != &StringClass)
    return false;
  jstring other = (jstring) anObject;
  if (count != other->count)
    return false;
  /* if both are interned, return false. */
  register jint i = count;
  register jchar *xptr = JvGetStringChars (this);
  register jchar *yptr = JvGetStringChars (other);
  while (--i >= 0)
    {
      if (*xptr++ != *yptr++)
	return false;
    }
  return true;
}

jchar
java::lang::String::charAt(jint i)
{
  if (i < 0 || i >= count)
    JvThrow (new java::lang::StringIndexOutOfBoundsException());
  return JvGetStringChars(this)[i];
}

void
java::lang::String::getChars(jint srcBegin, jint srcEnd,
			     jcharArray dst, jint dstBegin)
{
  jint dst_length = JvGetArrayLength (dst);
  if (srcBegin < 0 || srcBegin > srcEnd || srcEnd > count
      || dstBegin < 0 || dstBegin + (srcEnd-srcBegin) > dst_length)
    JvThrow (new java::lang::ArrayIndexOutOfBoundsException());
  register jchar *dPtr = elements (dst) + dstBegin;
  register jchar *sPtr = JvGetStringChars (this) + srcBegin;
  register jint i = srcEnd-srcBegin;
  while (--i >= 0)
    *dPtr++ = *sPtr++;
}

jbyteArray
java::lang::String::getBytes (jstring enc)
{
  jint todo = length();
  jint buflen = todo;
  jbyteArray buffer = JvNewByteArray(todo);
  jint bufpos = 0;
  jint offset = 0;
  gnu::gcj::convert::UnicodeToBytes *converter
    = gnu::gcj::convert::UnicodeToBytes::getEncoder(enc);
  while (todo > 0)
    {
      converter->setOutput(buffer, bufpos);
      int converted = converter->write(this, offset, todo, NULL);
      bufpos = converter->count;
      if (converted == 0)
	{
	  buflen *= 2;
	  jbyteArray newbuffer = JvNewByteArray(buflen);
	  memcpy (elements (newbuffer), elements (buffer), bufpos);
	  buffer = newbuffer;
	}
      else
	{
	  offset += converted;
	  todo -= converted;
	}
    }
  if (bufpos == buflen)
    return buffer;
  jbyteArray result = JvNewByteArray(bufpos);
  memcpy (elements (result), elements (buffer), bufpos);
  return result;
}

void
java::lang::String::getBytes(jint srcBegin, jint srcEnd,
			     jbyteArray dst, jint dstBegin)
{
  jint dst_length = JvGetArrayLength (dst);
  if (srcBegin < 0 || srcBegin > srcEnd || srcEnd > count
      || dstBegin < 0 || dstBegin + (srcEnd-srcBegin) > dst_length)
    JvThrow (new java::lang::ArrayIndexOutOfBoundsException());
  register jbyte *dPtr = elements (dst) + dstBegin;
  register jchar *sPtr = JvGetStringChars (this) + srcBegin;
  register jint i = srcEnd-srcBegin;
  while (--i >= 0)
    *dPtr++ = (jbyte) *sPtr++;
}

jcharArray
java::lang::String::toCharArray()
{
  jcharArray array = JvNewCharArray(count);
  register jchar *dPtr = elements (array);
  register jchar *sPtr = JvGetStringChars (this);
  register jint i = count;
  while (--i >= 0)
    *dPtr++ = *sPtr++;
  return array;
}

jboolean
java::lang::String::equalsIgnoreCase (jstring anotherString)
{
  if (anotherString == NULL || count != anotherString->count)
    return false;
  register jchar *tptr = JvGetStringChars (this);
  register jchar *optr = JvGetStringChars (anotherString);
  register jint i = count;
  while (--i >= 0)
    {
      jchar tch = *tptr++;
      jchar och = *optr++;
      if (tch != och
	  && (java::lang::Character::toLowerCase (tch)
	      != java::lang::Character::toLowerCase (och))
	  && (java::lang::Character::toUpperCase (tch)
	      != java::lang::Character::toUpperCase (och)))
	return false;
    }
  return true;
}

jboolean
java::lang::String::regionMatches (jint toffset,
				   jstring other, jint ooffset, jint len)
{
  if (toffset < 0 || ooffset < 0
      || toffset + len > count
      || ooffset + len > other->count)
    return false;
  register jchar *tptr = JvGetStringChars (this) + toffset;
  register jchar *optr = JvGetStringChars (other) + ooffset;
  register jint i = len;
  while (--i >= 0)
    {
      if (*tptr++ != *optr++)
	return false;
    }
  return true;
}

jint
java::lang::String::compareTo (jstring anotherString)
{
  register jchar *tptr = JvGetStringChars (this);
  register jchar *optr = JvGetStringChars (anotherString);
  jint tlen = this->count;
  jint olen = anotherString->count;
  register jint i = tlen > olen ? olen : tlen;
  while (--i >= 0)
    {
      jchar tch = *tptr++;
      jchar och = *optr++;
      if (tch != och)
	return (jint) tch - (jint) och;
    }
  return tlen - olen;
}

jboolean
java::lang::String::regionMatches (jboolean ignoreCase, jint toffset,
				   jstring other, jint ooffset, jint len)
{
  if (toffset < 0 || ooffset < 0
      || toffset + len > count
      || ooffset + len > other->count)
    return false;
  register jchar *tptr = JvGetStringChars (this) + toffset;
  register jchar *optr = JvGetStringChars (other) + ooffset;
  register jint i = len;
  while (--i >= 0)
    {
      jchar tch = *tptr++;
      jchar och = *optr++;
      if (tch != och)
	return false;
      if (ignoreCase
	  && (java::lang::Character::toLowerCase (tch)
	      != java::lang::Character::toLowerCase (och))
	  && (java::lang::Character::toUpperCase (tch)
	      != java::lang::Character::toUpperCase (och)))
	return false;
    }
  return true;
}

jboolean
java::lang::String::startsWith (jstring prefix, jint toffset)
{
  register jint i = prefix->count;
  if (toffset < 0 || toffset + i > count)
    return false;
  register jchar *xptr = JvGetStringChars (this) + toffset;
  register jchar *yptr = JvGetStringChars (prefix);
  while (--i >= 0)
    {
      if (*xptr++ != *yptr++)
	return false;
    }
  return true;
}

jint
java::lang::String::indexOf (jint ch, jint fromIndex)
{
  if (fromIndex < 0)
    fromIndex = 0;
  register jchar *ptr = JvGetStringChars(this);
  for (;; ++fromIndex)
    {
      if (fromIndex >= count)
	return -1;
      if (ptr[fromIndex] == ch)
	return fromIndex;
    }
}

jint
java::lang::String::indexOf (jstring s, jint fromIndex)
{
  const jchar *const xchars = JvGetStringChars(s);
  const jchar *const ychars = JvGetStringChars(this) + fromIndex;
  
  const int xlength = s->length ();
  const int ylength = length () - fromIndex;
  
  int i = 0;
  int j = 0;

  while (i < ylength && j < xlength)
    {
      if (xchars[j] != ychars[i])
	{
	  i = i - j + 1;
	  j = 0;
	}
      else
	i++, j++;
    }

  if (j >= xlength)
    return fromIndex + i - xlength;
  else
    return -1;
}
    
jint
java::lang::String::lastIndexOf (jint ch, jint fromIndex)
{
  if (fromIndex >= count)
    fromIndex = count - 1;
  register jchar *ptr = JvGetStringChars(this);
  for (;; --fromIndex)
    {
      if (fromIndex < 0)
	return -1;
      if (ptr[fromIndex] == ch)
	return fromIndex;
    }
}

jstring
java::lang::String::substring (jint beginIndex, jint endIndex)
{
  if (beginIndex < 0 || endIndex > count || beginIndex > endIndex)
    JvThrow (new StringIndexOutOfBoundsException());
  if (beginIndex == 0 && endIndex == count)
    return this;
  jint newCount = endIndex - beginIndex;
  if (newCount <= 8)  // Optimization, mainly for GC.
    return JvNewString(JvGetStringChars(this) + beginIndex, newCount);
  jstring s = new String();
  s->data = data;
  s->count = newCount;
  s->boffset = boffset + sizeof(jchar) * beginIndex;
  return s;
}

jstring
java::lang::String::concat(jstring str)
{
  jint str_count = str->count;
  if (str_count == 0)
    return this;
  jstring result = JvAllocString(count + str_count);
  register jchar *dstPtr = JvGetStringChars(result);
  register jchar *srcPtr = JvGetStringChars(this);
  register jint i = count;
  while (--i >= 0)
    *dstPtr++ = *srcPtr++;
  srcPtr = JvGetStringChars(str);
  i = str->count;
  while (--i >= 0)
    *dstPtr++ = *srcPtr++;
  return result;
}

jstring
java::lang::String::replace (jchar oldChar, jchar newChar)
{
  jint i;
  jchar* chrs = JvGetStringChars (this);
  for (i = 0;  ;  i++)
    {
      if (i == count)
	return this;
      if (chrs[i] == oldChar)
	break;
    }
  jstring result = JvAllocString (count);
  jchar *dPtr = JvGetStringChars (result);
  for (int j = 0;  j < i;  j++)
    *dPtr++ = chrs[j];
  for (; i < count;  i++)
    {
      jchar ch = chrs[i];
      if (ch == oldChar)
	ch = newChar;
      *dPtr++ = ch;
    }
  return result;
}

jstring
java::lang::String::toLowerCase ()
{
  jint i;
  jchar* chrs = JvGetStringChars(this);
  jchar ch;
  for (i = 0;  ;  i++)
    {
      if (i == count)
	return this;
      jchar origChar = chrs[i];
      ch = java::lang::Character::toLowerCase(origChar);
      if (ch != origChar)
	break;
    }
  jstring result = JvAllocString(count);
  jchar *dPtr = JvGetStringChars (result);
  for (int j = 0;  j < i;  j++)
    *dPtr++ = chrs[j];
  *dPtr++ = ch;  i++;
  for (; i < count;  i++)
    {
      *dPtr++ = java::lang::Character::toLowerCase(chrs[i]);
    }
  return result;
}

jstring
java::lang::String::toUpperCase ()
{
  jint i;
  jchar* chrs = JvGetStringChars(this);
  jchar ch;
  for (i = 0;  ;  i++)
    {
      if (i == count)
	return this;
      jchar origChar = chrs[i];
      ch = java::lang::Character::toUpperCase(origChar);
      if (ch != origChar)
	break;
    }
  jstring result = JvAllocString(count);
  jchar *dPtr = JvGetStringChars (result);
  for (int j = 0;  j < i;  j++)
    *dPtr++ = chrs[j];
  *dPtr++ = ch;  i++;
  for (; i < count;  i++)
    {
      *dPtr++ = java::lang::Character::toUpperCase(chrs[i]);
    }
  return result;
}

jstring
java::lang::String::trim ()
{
  jchar* chrs = JvGetStringChars(this);
  if (count == 0 || (chrs[0] > ' ' && chrs[count-1] > ' '))
    return this;
  jint preTrim = 0;
  for (;; preTrim++)
    {
      if (preTrim == count)
	return new String();
      if (chrs[preTrim] > ' ')
	break;
    }
  jint endTrim = count;
  while (chrs[endTrim-1] <= ' ')
    endTrim--;
  return substring(preTrim, endTrim);
}

jstring
java::lang::String::valueOf(jcharArray data, jint offset, jint count)
{
  jint data_length = JvGetArrayLength (data);
  if (offset < 0 || count < 0 || offset+count > data_length)
    JvThrow (new java::lang::IndexOutOfBoundsException());
  register jstring result = JvAllocString(count);
  register jchar *sPtr = elements (data) + offset;
  register jchar *dPtr = JvGetStringChars(result);
  while (--count >= 0)
    *dPtr++ = *sPtr++;
  return result;
}

jstring
java::lang::String::valueOf(jchar c)
{
  register jstring result = JvAllocString(1);
  JvGetStringChars (result)[0] = c;
  return result;
}