/* GStreamer byte writer
 *
 * Copyright (C) 2009 Sebastian Dröge <sebastian.droege@collabora.co.uk>.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "gstbytewriter.h"
#include <string.h>

/**
 * SECTION:gstbytewriter
 * @short_description: Writes different integer, string and floating point
 *     types to a memory buffer and allows reading
 *
 * #GstByteWriter provides a byte writer and reader that can write/read different
 * integer and floating point types to/from a memory buffer. It provides functions
 * for writing/reading signed/unsigned, little/big endian integers of 8, 16, 24,
 * 32 and 64 bits and functions for reading little/big endian floating points numbers of
 * 32 and 64 bits. It also provides functions to write/read NUL-terminated strings
 * in various character encodings.
 */

/**
 * gst_byte_writer_new:
 *
 * Creates a new, empty #GstByteWriter instance
 *
 * Returns: a new, empty #GstByteWriter instance
 *
 * Since: 0.10.26
 */
GstByteWriter *
gst_byte_writer_new (void)
{
  GstByteWriter *ret = g_slice_new0 (GstByteWriter);

  ret->owned = TRUE;
  return ret;
}

/**
 * gst_byte_writer_new_with_size:
 * @size: Initial size of data
 * @fixed: If %TRUE the data can't be reallocated
 *
 * Creates a new #GstByteWriter instance with the given
 * initial data size.
 *
 * Returns: a new #GstByteWriter instance
 *
 * Since: 0.10.26
 */
GstByteWriter *
gst_byte_writer_new_with_size (guint size, gboolean fixed)
{
  GstByteWriter *ret = gst_byte_writer_new ();

  ret->alloc_size = size;
  ret->parent.data = g_malloc (ret->alloc_size);
  ret->fixed = fixed;
  ret->owned = TRUE;

  return ret;
}

/**
 * gst_byte_writer_new_with_data:
 * @data: Memory area for writing
 * @size: Size of @data in bytes
 * @initialized: If %TRUE the complete data can be read from the beginning
 *
 * Creates a new #GstByteWriter instance with the given
 * memory area. If @initialized is %TRUE it is possible to
 * read @size bytes from the #GstByteWriter from the beginning.
 *
 * Returns: a new #GstByteWriter instance
 *
 * Since: 0.10.26
 */
GstByteWriter *
gst_byte_writer_new_with_data (guint8 * data, guint size, gboolean initialized)
{
  GstByteWriter *ret = gst_byte_writer_new ();

  ret->parent.data = data;
  ret->parent.size = (initialized) ? size : 0;
  ret->alloc_size = size;
  ret->fixed = TRUE;
  ret->owned = FALSE;

  return ret;
}

/**
 * gst_byte_writer_new_with_buffer:
 * @buffer: Buffer used for writing
 * @initialized: If %TRUE the complete data can be read from the beginning
 *
 * Creates a new #GstByteWriter instance with the given
 * buffer. If @initialized is %TRUE it is possible to
 * read the complete buffer from the #GstByteWriter from the beginning.
 *
 * <note>@buffer must be writable</note>
 *
 * Returns: a new #GstByteWriter instance
 *
 * Since: 0.10.26
 */
GstByteWriter *
gst_byte_writer_new_with_buffer (GstBuffer * buffer, gboolean initialized)
{
  g_return_val_if_fail (GST_IS_BUFFER (buffer)
      && gst_buffer_is_writable (buffer), NULL);

  return gst_byte_writer_new_with_data (GST_BUFFER_DATA (buffer),
      GST_BUFFER_SIZE (buffer), initialized);
}

/**
 * gst_byte_writer_init:
 * @writer: #GstByteWriter instance
 *
 * Initializes @writer to an empty instance
 *
 * Since: 0.10.26
 */
void
gst_byte_writer_init (GstByteWriter * writer)
{
  g_return_if_fail (writer != NULL);

  memset (writer, 0, sizeof (GstByteWriter));

  writer->owned = TRUE;
}

/**
 * gst_byte_writer_init_with_size:
 * @writer: #GstByteWriter instance
 * @size: Initial size of data
 * @fixed: If %TRUE the data can't be reallocated
 *
 * Initializes @writer with the given initial data size.
 *
 * Since: 0.10.26
 */
void
gst_byte_writer_init_with_size (GstByteWriter * writer, guint size,
    gboolean fixed)
{
  g_return_if_fail (writer != NULL);

  gst_byte_writer_init (writer);

  writer->parent.data = g_malloc (size);
  writer->alloc_size = size;
  writer->fixed = fixed;
  writer->owned = TRUE;
}

/**
 * gst_byte_writer_init_with_data:
 * @writer: #GstByteWriter instance
 * @data: Memory area for writing
 * @size: Size of @data in bytes
 * @initialized: If %TRUE the complete data can be read from the beginning
 *
 * Initializes @writer with the given
 * memory area. If @initialized is %TRUE it is possible to
 * read @size bytes from the #GstByteWriter from the beginning.
 *
 * Since: 0.10.26
 */
void
gst_byte_writer_init_with_data (GstByteWriter * writer, guint8 * data,
    guint size, gboolean initialized)
{
  g_return_if_fail (writer != NULL);

  gst_byte_writer_init (writer);

  writer->parent.data = data;
  writer->parent.size = (initialized) ? size : 0;
  writer->alloc_size = size;
  writer->fixed = TRUE;
  writer->owned = FALSE;
}

/**
 * gst_byte_writer_init_with_buffer:
 * @writer: #GstByteWriter instance
 * @buffer: Buffer used for writing
 * @initialized: If %TRUE the complete data can be read from the beginning
 *
 * Initializes @writer with the given
 * buffer. If @initialized is %TRUE it is possible to
 * read the complete buffer from the #GstByteWriter from the beginning.
 *
 * <note>@buffer must be writable</note>
 *
 * Since: 0.10.26
 */
void
gst_byte_writer_init_with_buffer (GstByteWriter * writer, GstBuffer * buffer,
    gboolean initialized)
{
  g_return_if_fail (GST_IS_BUFFER (buffer) && gst_buffer_is_writable (buffer));

  gst_byte_writer_init_with_data (writer, GST_BUFFER_DATA (buffer),
      GST_BUFFER_SIZE (buffer), initialized);
}

/**
 * gst_byte_writer_reset:
 * @writer: #GstByteWriter instance
 *
 * Resets @writer and frees the data if it's
 * owned by @writer.
 *
 * Since: 0.10.26
 */
void
gst_byte_writer_reset (GstByteWriter * writer)
{
  g_return_if_fail (writer != NULL);

  if (writer->owned)
    g_free ((guint8 *) writer->parent.data);
  memset (writer, 0, sizeof (GstByteWriter));
}

/**
 * gst_byte_writer_reset_and_get_data:
 * @writer: #GstByteWriter instance
 *
 * Resets @writer and returns the current data.
 *
 * Returns: the current data. g_free() after usage.
 *
 * Since: 0.10.26
 */
guint8 *
gst_byte_writer_reset_and_get_data (GstByteWriter * writer)
{
  guint8 *data;

  g_return_val_if_fail (writer != NULL, NULL);

  data = (guint8 *) writer->parent.data;
  if (!writer->owned)
    data = g_memdup (data, writer->parent.size);
  writer->parent.data = NULL;
  gst_byte_writer_reset (writer);

  return data;
}

/**
 * gst_byte_writer_reset_and_get_buffer:
 * @writer: #GstByteWriter instance
 *
 * Resets @writer and returns the current data as buffer.
 *
 * Returns: the current data as buffer. gst_buffer_unref() after usage.
 *
 * Since: 0.10.26
 */
GstBuffer *
gst_byte_writer_reset_and_get_buffer (GstByteWriter * writer)
{
  GstBuffer *buffer;

  g_return_val_if_fail (writer != NULL, NULL);

  buffer = gst_buffer_new ();
  GST_BUFFER_SIZE (buffer) = writer->parent.size;
  GST_BUFFER_MALLOCDATA (buffer) = gst_byte_writer_reset_and_get_data (writer);
  GST_BUFFER_DATA (buffer) = GST_BUFFER_MALLOCDATA (buffer);

  return buffer;
}

/**
 * gst_byte_writer_free:
 * @writer: #GstByteWriter instance
 *
 * Frees @writer and all memory allocated by it.
 *
 * Since: 0.10.26
 */
void
gst_byte_writer_free (GstByteWriter * writer)
{
  g_return_if_fail (writer != NULL);

  gst_byte_writer_reset (writer);
  g_slice_free (GstByteWriter, writer);
}

/**
 * gst_byte_writer_free_and_get_data:
 * @writer: #GstByteWriter instance
 *
 * Frees @writer and all memory allocated by it except
 * the current data, which is returned.
 *
 * Returns: the current data. g_free() after usage.
 *
 * Since: 0.10.26
 */
guint8 *
gst_byte_writer_free_and_get_data (GstByteWriter * writer)
{
  guint8 *data;

  g_return_val_if_fail (writer != NULL, NULL);

  data = gst_byte_writer_reset_and_get_data (writer);
  g_slice_free (GstByteWriter, writer);

  return data;
}

/**
 * gst_byte_writer_free_and_get_buffer:
 * @writer: #GstByteWriter instance
 *
 * Frees @writer and all memory allocated by it except
 * the current data, which is returned as #GstBuffer.
 *
 * Returns: the current data as buffer. gst_buffer_unref() after usage.
 *
 * Since: 0.10.26
 */
GstBuffer *
gst_byte_writer_free_and_get_buffer (GstByteWriter * writer)
{
  GstBuffer *buffer;

  g_return_val_if_fail (writer != NULL, NULL);

  buffer = gst_byte_writer_reset_and_get_buffer (writer);
  g_slice_free (GstByteWriter, writer);

  return buffer;
}

/**
 * gst_byte_writer_get_remaining:
 * @writer: #GstByteWriter instance
 *
 * Returns the remaining size of data that can still be written. If
 * -1 is returned the remaining size is only limited by system resources.
 *
 * Returns: the remaining size of data that can still be written
 *
 * Since: 0.10.26
 */
guint
gst_byte_writer_get_remaining (const GstByteWriter * writer)
{
  g_return_val_if_fail (writer != NULL, -1);

  if (!writer->fixed)
    return -1;
  else
    return writer->alloc_size - writer->parent.byte;
}

static guint
_next_pow2 (guint n)
{
  guint ret = 16;

  /* We start with 16, smaller allocations make no sense */

  while (ret < n)
    ret <<= 1;

  return ret;
}

/**
 * gst_byte_writer_ensure_free_space:
 * @writer: #GstByteWriter instance
 * @size: Number of bytes that should be available
 *
 * Checks if enough free space from the current write cursor is
 * available and reallocates if necessary.
 *
 * Returns: %TRUE if at least @size bytes are still available
 *
 * Since: 0.10.26
 */
gboolean
gst_byte_writer_ensure_free_space (GstByteWriter * writer, guint size)
{
  guint8 *data;

  if (G_UNLIKELY (size <= writer->alloc_size - writer->parent.byte))
    return TRUE;
  if (G_UNLIKELY (writer->fixed || !writer->owned))
    return FALSE;
  if (G_UNLIKELY (writer->parent.byte > G_MAXUINT - size))
    return FALSE;

  writer->alloc_size = _next_pow2 (writer->parent.byte + size);
  data = g_try_realloc ((guint8 *) writer->parent.data, writer->alloc_size);
  if (G_UNLIKELY (data == NULL))
    return FALSE;

  writer->parent.data = data;

  return TRUE;
}


#define CREATE_WRITE_FUNC(bits,type,name,write_func) \
gboolean \
gst_byte_writer_put_##name (GstByteWriter *writer, type val) \
{ \
  g_return_val_if_fail (writer != NULL, FALSE); \
  \
  if (G_UNLIKELY (!gst_byte_writer_ensure_free_space(writer, bits/8))) \
    return FALSE; \
  \
  write_func ((guint8 *) &writer->parent.data[writer->parent.byte], val); \
  writer->parent.byte += bits/8; \
  writer->parent.size = MAX (writer->parent.size, writer->parent.byte); \
  \
  return TRUE; \
}

CREATE_WRITE_FUNC (8, guint8, uint8, GST_WRITE_UINT8);
CREATE_WRITE_FUNC (8, gint8, int8, GST_WRITE_UINT8);
CREATE_WRITE_FUNC (16, guint16, uint16_le, GST_WRITE_UINT16_LE);
CREATE_WRITE_FUNC (16, guint16, uint16_be, GST_WRITE_UINT16_BE);
CREATE_WRITE_FUNC (16, gint16, int16_le, GST_WRITE_UINT16_LE);
CREATE_WRITE_FUNC (16, gint16, int16_be, GST_WRITE_UINT16_BE);
CREATE_WRITE_FUNC (24, guint32, uint24_le, GST_WRITE_UINT24_LE);
CREATE_WRITE_FUNC (24, guint32, uint24_be, GST_WRITE_UINT24_BE);
CREATE_WRITE_FUNC (24, gint32, int24_le, GST_WRITE_UINT24_LE);
CREATE_WRITE_FUNC (24, gint32, int24_be, GST_WRITE_UINT24_BE);
CREATE_WRITE_FUNC (32, guint32, uint32_le, GST_WRITE_UINT32_LE);
CREATE_WRITE_FUNC (32, guint32, uint32_be, GST_WRITE_UINT32_BE);
CREATE_WRITE_FUNC (32, gint32, int32_le, GST_WRITE_UINT32_LE);
CREATE_WRITE_FUNC (32, gint32, int32_be, GST_WRITE_UINT32_BE);
CREATE_WRITE_FUNC (64, guint64, uint64_le, GST_WRITE_UINT64_LE);
CREATE_WRITE_FUNC (64, guint64, uint64_be, GST_WRITE_UINT64_BE);
CREATE_WRITE_FUNC (64, gint64, int64_le, GST_WRITE_UINT64_LE);
CREATE_WRITE_FUNC (64, gint64, int64_be, GST_WRITE_UINT64_BE);

CREATE_WRITE_FUNC (32, gfloat, float32_be, GST_WRITE_FLOAT_BE);
CREATE_WRITE_FUNC (32, gfloat, float32_le, GST_WRITE_FLOAT_LE);
CREATE_WRITE_FUNC (64, gdouble, float64_be, GST_WRITE_DOUBLE_BE);
CREATE_WRITE_FUNC (64, gdouble, float64_le, GST_WRITE_DOUBLE_LE);

gboolean
gst_byte_writer_put_data (GstByteWriter * writer, const guint8 * data,
    guint size)
{
  g_return_val_if_fail (writer != NULL, FALSE);

  if (G_UNLIKELY (!gst_byte_writer_ensure_free_space (writer, size)))
    return FALSE;

  memcpy ((guint8 *) & writer->parent.data[writer->parent.byte], data, size);
  writer->parent.byte += size;
  writer->parent.size = MAX (writer->parent.size, writer->parent.byte);

  return TRUE;
}

#define CREATE_WRITE_STRING_FUNC(bits,type) \
gboolean \
gst_byte_writer_put_string_utf##bits (GstByteWriter *writer, const type * data) \
{ \
  guint size = 0; \
  g_return_val_if_fail (writer != NULL, FALSE); \
  \
  /* endianness does not matter if we are looking for a NUL terminator */ \
  while (data[size] != 0) { \
    /* have prevent overflow */ \
    if (G_UNLIKELY (size == G_MAXUINT)) \
      return FALSE; \
    ++size; \
  } \
  ++size; \
  \
  if (G_UNLIKELY (!gst_byte_writer_ensure_free_space(writer, size * (bits / 8)))) \
    return FALSE; \
  \
  gst_byte_writer_put_data (writer, (const guint8 *) data, size * (bits / 8)); \
  \
  return TRUE; \
}

CREATE_WRITE_STRING_FUNC (8, gchar);
CREATE_WRITE_STRING_FUNC (16, guint16);
CREATE_WRITE_STRING_FUNC (32, guint32);
/**
 * gst_byte_writer_put_uint8:
 * @writer: #GstByteWriter instance
 * @val: Value to write
 *
 * Writes a unsigned 8 bit integer to @writer.
 *
 * Returns: %TRUE if the value could be written
 *
 * Since: 0.10.26
 */
/**
 * gst_byte_writer_put_uint16_be:
 * @writer: #GstByteWriter instance
 * @val: Value to write
 *
 * Writes a unsigned big endian 16 bit integer to @writer.
 *
 * Returns: %TRUE if the value could be written
 *
 * Since: 0.10.26
 */
/**
 * gst_byte_writer_put_uint24_be:
 * @writer: #GstByteWriter instance
 * @val: Value to write
 *
 * Writes a unsigned big endian 24 bit integer to @writer.
 *
 * Returns: %TRUE if the value could be written
 *
 * Since: 0.10.26
 */
/**
 * gst_byte_writer_put_uint32_be:
 * @writer: #GstByteWriter instance
 * @val: Value to write
 *
 * Writes a unsigned big endian 32 bit integer to @writer.
 *
 * Returns: %TRUE if the value could be written
 *
 * Since: 0.10.26
 */
/**
 * gst_byte_writer_put_uint64_be:
 * @writer: #GstByteWriter instance
 * @val: Value to write
 *
 * Writes a unsigned big endian 64 bit integer to @writer.
 *
 * Returns: %TRUE if the value could be written
 *
 * Since: 0.10.26
 */
/**
 * gst_byte_writer_put_uint16_le:
 * @writer: #GstByteWriter instance
 * @val: Value to write
 *
 * Writes a unsigned little endian 16 bit integer to @writer.
 *
 * Returns: %TRUE if the value could be written
 *
 * Since: 0.10.26
 */
/**
 * gst_byte_writer_put_uint24_le:
 * @writer: #GstByteWriter instance
 * @val: Value to write
 *
 * Writes a unsigned little endian 24 bit integer to @writer.
 *
 * Returns: %TRUE if the value could be written
 *
 * Since: 0.10.26
 */
/**
 * gst_byte_writer_put_uint32_le:
 * @writer: #GstByteWriter instance
 * @val: Value to write
 *
 * Writes a unsigned little endian 32 bit integer to @writer.
 *
 * Returns: %TRUE if the value could be written
 *
 * Since: 0.10.26
 */
/**
 * gst_byte_writer_put_uint64_le:
 * @writer: #GstByteWriter instance
 * @val: Value to write
 *
 * Writes a unsigned little endian 64 bit integer to @writer.
 *
 * Returns: %TRUE if the value could be written
 *
 * Since: 0.10.26
 */
/**
 * gst_byte_writer_put_int8:
 * @writer: #GstByteWriter instance
 * @val: Value to write
 *
 * Writes a signed 8 bit integer to @writer.
 *
 * Returns: %TRUE if the value could be written
 *
 * Since: 0.10.26
 */
/**
 * gst_byte_writer_put_int16_be:
 * @writer: #GstByteWriter instance
 * @val: Value to write
 *
 * Writes a signed big endian 16 bit integer to @writer.
 *
 * Returns: %TRUE if the value could be written
 *
 * Since: 0.10.26
 */
/**
 * gst_byte_writer_put_int24_be:
 * @writer: #GstByteWriter instance
 * @val: Value to write
 *
 * Writes a signed big endian 24 bit integer to @writer.
 *
 * Returns: %TRUE if the value could be written
 *
 * Since: 0.10.26
 */
/**
 * gst_byte_writer_put_int32_be:
 * @writer: #GstByteWriter instance
 * @val: Value to write
 *
 * Writes a signed big endian 32 bit integer to @writer.
 *
 * Returns: %TRUE if the value could be written
 *
 * Since: 0.10.26
 */
/**
 * gst_byte_writer_put_int64_be:
 * @writer: #GstByteWriter instance
 * @val: Value to write
 *
 * Writes a signed big endian 64 bit integer to @writer.
 *
 * Returns: %TRUE if the value could be written
 *
 * Since: 0.10.26
 */
/**
 * gst_byte_writer_put_int16_le:
 * @writer: #GstByteWriter instance
 * @val: Value to write
 *
 * Writes a signed little endian 16 bit integer to @writer.
 *
 * Returns: %TRUE if the value could be written
 *
 * Since: 0.10.26
 */
/**
 * gst_byte_writer_put_int24_le:
 * @writer: #GstByteWriter instance
 * @val: Value to write
 *
 * Writes a signed little endian 24 bit integer to @writer.
 *
 * Returns: %TRUE if the value could be written
 *
 * Since: 0.10.26
 */
/**
 * gst_byte_writer_put_int32_le:
 * @writer: #GstByteWriter instance
 * @val: Value to write
 *
 * Writes a signed little endian 32 bit integer to @writer.
 *
 * Returns: %TRUE if the value could be written
 *
 * Since: 0.10.26
 */
/**
 * gst_byte_writer_put_int64_le:
 * @writer: #GstByteWriter instance
 * @val: Value to write
 *
 * Writes a signed little endian 64 bit integer to @writer.
 *
 * Returns: %TRUE if the value could be written
 *
 * Since: 0.10.26
 */
/**
 * gst_byte_writer_put_float_be:
 * @writer: #GstByteWriter instance
 * @val: Value to write
 *
 * Writes a big endian 32 bit float to @writer.
 *
 * Returns: %TRUE if the value could be written
 *
 * Since: 0.10.26
 */
/**
 * gst_byte_writer_put_double_be:
 * @writer: #GstByteWriter instance
 * @val: Value to write
 *
 * Writes a big endian 64 bit float to @writer.
 *
 * Returns: %TRUE if the value could be written
 *
 * Since: 0.10.26
 */
/**
 * gst_byte_writer_put_float_le:
 * @writer: #GstByteWriter instance
 * @val: Value to write
 *
 * Writes a little endian 32 bit float to @writer.
 *
 * Returns: %TRUE if the value could be written
 *
 * Since: 0.10.26
 */
/**
 * gst_byte_writer_put_double_le:
 * @writer: #GstByteWriter instance
 * @val: Value to write
 *
 * Writes a little endian 64 bit float to @writer.
 *
 * Returns: %TRUE if the value could be written
 *
 * Since: 0.10.26
 */
/**
 * gst_byte_writer_put_string_utf8:
 * @writer: #GstByteWriter instance
 * @data: UTF8 string to write
 *
 * Writes a null-terminated UTF8 string to @writer.
 *
 * Returns: %TRUE if the value could be written
 *
 * Since: 0.10.26
 */
/**
 * gst_byte_writer_put_string_utf16:
 * @writer: #GstByteWriter instance
 * @data: UTF16 string to write
 *
 * Writes a null-terminated UTF16 string to @writer.
 *
 * Returns: %TRUE if the value could be written
 *
 * Since: 0.10.26
 */
/**
 * gst_byte_writer_put_string_utf32:
 * @writer: #GstByteWriter instance
 * @data: UTF32 string to write
 *
 * Writes a null-terminated UTF32 string to @writer.
 *
 * Returns: %TRUE if the value could be written
 *
 * Since: 0.10.26
 */
/**
 * gst_byte_writer_put_data:
 * @writer: #GstByteWriter instance
 * @data: Data to write
 * @size: Size of @data in bytes
 *
 * Writes @size bytes of @data to @writer.
 *
 * Returns: %TRUE if the value could be written
 *
 * Since: 0.10.26
 */