// Input_iconv.java -- Java side of iconv() reader.

/* Copyright (C) 2000  Free Software Foundation

   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.  */

/* Author: Tom Tromey <tromey@redhat.com>.  */

#include <config.h>

#include <gcj/cni.h>
#include <jvm.h>

#include <gnu/gcj/convert/Input_iconv.h>
#include <gnu/gcj/convert/Output_iconv.h>
#include <java/io/UnsupportedEncodingException.h>

#ifdef HAVE_ICONV
#include <iconv.h>

template<typename T>
static inline size_t
iconv_adapter (size_t (*iconv_f) (iconv_t, T, size_t *, char **, size_t *),
	       iconv_t handle, char **inbuf, size_t *inavail,
	       char **outbuf, size_t *outavail)
{
  return (*iconv_f) (handle, (T) inbuf, inavail, outbuf, outavail);
}

#endif

void
gnu::gcj::convert::Input_iconv::init (jstring encoding)
{
#ifdef HAVE_ICONV
  jsize len = _Jv_GetStringUTFLength (encoding);
  char buffer[len + 1];
  _Jv_GetStringUTFRegion (encoding, 0, len, buffer);
  buffer[len] = '\0';

  iconv_t h = iconv_open ("UCS-2", buffer);
  if (h == (iconv_t) -1)
    throw new java::io::UnsupportedEncodingException (encoding);

  JvAssert (h != NULL);
  handle = reinterpret_cast<gnu::gcj::RawData *> (h);
#else /* HAVE_ICONV */
  // If no iconv, just throw an exception.
  throw new java::io::UnsupportedEncodingException (encoding);
#endif /* HAVE_ICONV */
}

void
gnu::gcj::convert::Input_iconv::finalize (void)
{
#ifdef HAVE_ICONV
  if (handle != NULL)
    {
      iconv_close ((iconv_t) handle);
      handle = NULL;
    }
#endif /* HAVE_ICONV */
}

jint
gnu::gcj::convert::Input_iconv::read (jcharArray outbuffer,
				      jint outpos, jint count)
{
#ifdef HAVE_ICONV
  jbyte *bytes = elements (inbuffer);
  jchar *out = elements (outbuffer);
  size_t inavail = inlength - inpos;
  size_t old_in = inavail;
  size_t outavail = count * sizeof (jchar);
  size_t old_out = outavail;

  char *inbuf = (char *) &bytes[inpos];
  char *outbuf = (char *) &out[outpos];

  size_t r = iconv_adapter (iconv, (iconv_t) handle,
			    &inbuf, &inavail,
			    &outbuf, &outavail);
  // FIXME: what if R==-1?

  if (iconv_byte_swap)
    {
      size_t max = (old_out - outavail) / sizeof (jchar);
      for (size_t i = 0; i < max; ++i)
	{
	  // Byte swap.
	  jchar c = (((out[outpos + i] & 0xff) << 8)
		     | ((out[outpos + i] >> 8) & 0xff));
	  outbuf[i] = c;
	}
    }

  inpos += old_in - inavail;
  return (old_out - outavail) / sizeof (jchar);
#else /* HAVE_ICONV */
  return -1;
#endif /* HAVE_ICONV */
}

void
gnu::gcj::convert::Output_iconv::init (jstring encoding)
{
#ifdef HAVE_ICONV
  jsize len = _Jv_GetStringUTFLength (encoding);
  char buffer[len + 1];
  _Jv_GetStringUTFRegion (encoding, 0, len, buffer);
  buffer[len] = '\0';

  iconv_t h = iconv_open (buffer, "UCS-2");
  if (h == (iconv_t) -1)
    throw new java::io::UnsupportedEncodingException (encoding);

  JvAssert (h != NULL);
  handle = reinterpret_cast<gnu::gcj::RawData *> (h);
#else /* HAVE_ICONV */
  // If no iconv, just throw an exception.
  throw new java::io::UnsupportedEncodingException (encoding);
#endif /* HAVE_ICONV */
}

void
gnu::gcj::convert::Output_iconv::finalize (void)
{
#ifdef HAVE_ICONV
  if (handle != NULL)
    {
      iconv_close ((iconv_t) handle);
      handle = NULL;
    }
#endif /* HAVE_ICONV */
}

jint
gnu::gcj::convert::Output_iconv::write (jcharArray inbuffer,
					jint inpos, jint inlength)
{
#ifdef HAVE_ICONV
  jchar *chars = elements (inbuffer);
  jbyte *out = elements (buf);
  jchar *temp_buffer = NULL;

  size_t inavail = inlength * sizeof (jchar);
  size_t old_in = inavail;

  size_t outavail = buf->length - count;
  size_t old_out = outavail;

  char *inbuf = (char *) &chars[inpos];
  char *outbuf = (char *) &out[count];

  if (iconv_byte_swap)
    {
      // Ugly performance penalty -- don't use losing systems!
      temp_buffer = (jchar *) _Jv_Malloc (inlength * sizeof (jchar));
      for (int i = 0; i < inlength; ++i)
	{
	  // Byte swap.
	  jchar c = (((chars[inpos + i] & 0xff) << 8)
		     | ((chars[inpos + i] >> 8) & 0xff));
	  temp_buffer[i] = c;
	}
      inbuf = (char *) temp_buffer;
    }

  // If the conversion fails on the very first character, then we
  // assume that the character can't be represented in the output
  // encoding.  There's nothing useful we can do here, so we simply
  // omit that character.  Note that we can't check `errno' because
  // glibc 2.1.3 doesn't set it correctly.  We could check it if we
  // really needed to, but we'd have to disable support for 2.1.3.
  size_t loop_old_in = old_in;
  while (1)
    {
      size_t r = iconv_adapter (iconv, (iconv_t) handle,
				&inbuf, &inavail,
				&outbuf, &outavail);
      if (r == -1 && inavail == loop_old_in)
	{
	  inavail -= 2;
	  if (inavail == 0)
	    break;
	  loop_old_in -= 2;
	  inbuf += 2;
	}
      else
	break;
    }

  if (temp_buffer != NULL)
    _Jv_Free (temp_buffer);

  count += old_out - outavail;
  return (old_in - inavail) / sizeof (jchar);
#else /* HAVE_ICONV */
  return -1;
#endif /* HAVE_ICONV */
}

jboolean
gnu::gcj::convert::IOConverter::iconv_init (void)
{
  // Some versions of iconv() always return their UCS-2 results in
  // big-endian order, and they also require UCS-2 inputs to be in
  // big-endian order.  For instance, glibc 2.1.3 does this.  If the
  // UTF-8=>UCS-2 iconv converter has this feature, then we assume
  // that all UCS-2 converters do.  (This might not be the best
  // heuristic, but is is all we've got.)
  jboolean result = false;
#ifdef HAVE_ICONV
  iconv_t handle = iconv_open ("UCS-2", "UTF-8");
  if (handle != (iconv_t) -1)
    {
      jchar c;
      unsigned char in[3];
      char *inp, *outp;
      size_t inc, outc, r;

      // This is the UTF-8 encoding of \ufeff.
      in[0] = 0xef;
      in[1] = 0xbb;
      in[2] = 0xbf;

      inp = (char *) in;
      inc = 3;
      outp = (char *) &c;
      outc = 2;

      r = iconv_adapter (iconv, handle, &inp, &inc, &outp, &outc);
      // Conversion must be complete for us to use the result.
      if (r != (size_t) -1 && inc == 0 && outc == 0)
	result = (c != 0xfeff);
    }
#endif /* HAVE_ICONV */
  return result;
}