/**
 * \file output.c
 * \brief Generic stdio-like output interface
 * \author Abramo Bagnara <abramo@alsa-project.org>
 * \date 2000
 *
 * Generic stdio-like output interface
 */
/*
 *  Output object
 *  Copyright (c) 2000 by Abramo Bagnara <abramo@alsa-project.org>
 *
 *
 *   This library is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Lesser General Public License as
 *   published by the Free Software Foundation; either version 2.1 of
 *   the License, 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 Lesser General Public License for more details.
 *
 *   You should have received a copy of the GNU Lesser 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
 *
 */

#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include "local.h"

#ifndef DOC_HIDDEN
typedef struct _snd_output_ops
{
  int (*close) (snd_output_t * output);
  int (*print) (snd_output_t * output, const char *format, va_list args);
  int (*puts) (snd_output_t * output, const char *str);
  int (*putch) (snd_output_t * output, int c);
  int (*flush) (snd_output_t * output);
} snd_output_ops_t;

struct _snd_output
{
  snd_output_type_t type;
  snd_output_ops_t *ops;
  void *private_data;
};
#endif

/**
 * \brief Closes an output handle.
 * \param output The output handle to be closed.
 * \return Zero if successful, otherwise a negative error code.
 */
int
snd_output_close (snd_output_t * output)
{
  int err = output->ops->close (output);
  free (output);
  return err;
}

/**
 * \brief Writes formatted output (like \c fprintf(3)) to an output handle.
 * \param output The output handle.
 * \param format Format string in \c fprintf format.
 * \param ... Other \c fprintf arguments.
 * \return The number of characters written, or a negative error code.
 */
int
snd_output_printf (snd_output_t * output, const char *format, ...)
{
  int result;
  va_list args;
  va_start (args, format);
  result = output->ops->print (output, format, args);
  va_end (args);
  return result;
}

/**
 * \brief Writes formatted output (like \c fprintf(3)) to an output handle.
 * \param output The output handle.
 * \param format Format string in \c fprintf format.
 * \param args Other \c fprintf arguments.
 * \return The number of characters written, or a negative error code.
 */
int
snd_output_vprintf (snd_output_t * output, const char *format, va_list args)
{
  return output->ops->print (output, format, args);
}

/**
 * \brief Writes a string to an output handle (like \c fputs(3)).
 * \param output The output handle.
 * \param str Pointer to the string.
 * \return Zero if successful, otherwise a negative error code or \c EOF.
 */
int
snd_output_puts (snd_output_t * output, const char *str)
{
  return output->ops->puts (output, str);
}

/**
 * \brief Writes a character to an output handle (like \c putc(3)).
 * \param output The output handle.
 * \param c The character.
 * \return Zero if successful, otherwise a negative error code or \c EOF.
 */
int
snd_output_putc (snd_output_t * output, int c)
{
  return output->ops->putch (output, c);
}

/**
 * \brief Flushes an output handle (like fflush(3)).
 * \param output The output handle.
 * \return Zero if successful, otherwise \c EOF.
 *
 * If the underlying destination is a stdio stream, this function calls
 * \c fflush. If the underlying destination is a memory buffer, the write
 * position is reset to the beginning of the buffer. \c =:-o
 */
int
snd_output_flush (snd_output_t * output)
{
  return output->ops->flush (output);
}

#ifndef DOC_HIDDEN
typedef struct _snd_output_stdio
{
  int close;
  FILE *fp;
} snd_output_stdio_t;

static int
snd_output_stdio_close (snd_output_t * output ATTRIBUTE_UNUSED)
{
  snd_output_stdio_t *stdio = output->private_data;
  if (stdio->close)
    fclose (stdio->fp);
  free (stdio);
  return 0;
}

static int
snd_output_stdio_print (snd_output_t * output, const char *format,
			va_list args)
{
  snd_output_stdio_t *stdio = output->private_data;
  return vfprintf (stdio->fp, format, args);
}

static int
snd_output_stdio_puts (snd_output_t * output, const char *str)
{
  snd_output_stdio_t *stdio = output->private_data;
  return fputs (str, stdio->fp);
}

static int
snd_output_stdio_putc (snd_output_t * output, int c)
{
  snd_output_stdio_t *stdio = output->private_data;
  return putc (c, stdio->fp);
}

static int
snd_output_stdio_flush (snd_output_t * output)
{
  snd_output_stdio_t *stdio = output->private_data;
  return fflush (stdio->fp);
}

static snd_output_ops_t snd_output_stdio_ops = {
  .close = snd_output_stdio_close,
  .print = snd_output_stdio_print,
  .puts = snd_output_stdio_puts,
  .putch = snd_output_stdio_putc,
  .flush = snd_output_stdio_flush,
};

#endif

/**
 * \brief Creates a new output object using an existing stdio \c FILE pointer.
 * \param outputp The function puts the pointer to the new output object
 *                at the address specified by \p outputp.
 * \param fp The \c FILE pointer to write to. Characters are written
 *           to the file starting at the current file position.
 * \param close Close flag. Set this to 1 if #snd_output_close should close
 *              \p fp by calling \c fclose.
 * \return Zero if successful, otherwise a negative error code.
 */
int
snd_output_stdio_attach (snd_output_t ** outputp, FILE * fp, int _close)
{
  snd_output_t *output;
  snd_output_stdio_t *stdio;
  assert (outputp && fp);
  stdio = calloc (1, sizeof (*stdio));
  if (!stdio)
    return -ENOMEM;
  output = calloc (1, sizeof (*output));
  if (!output)
    {
      free (stdio);
      return -ENOMEM;
    }
  stdio->fp = fp;
  stdio->close = _close;
  output->type = SND_OUTPUT_STDIO;
  output->ops = &snd_output_stdio_ops;
  output->private_data = stdio;
  *outputp = output;
  return 0;
}

/**
 * \brief Creates a new output object writing to a file.
 * \param outputp The function puts the pointer to the new output object
 *                at the address specified by \p outputp.
 * \param file The name of the file to open.
 * \param mode The open mode, like \c fopen(3).
 * \return Zero if successful, otherwise a negative error code.
 */
int
snd_output_stdio_open (snd_output_t ** outputp, const char *file,
		       const char *mode)
{
  int err;
  FILE *fp = fopen (file, mode);
  if (!fp)
    {
      //SYSERR("fopen");
      return -errno;
    }
  err = snd_output_stdio_attach (outputp, fp, 1);
  if (err < 0)
    fclose (fp);
  return err;
}

#ifndef DOC_HIDDEN

typedef struct _snd_output_buffer
{
  unsigned char *buf;
  size_t alloc;
  size_t size;
} snd_output_buffer_t;

static int
snd_output_buffer_close (snd_output_t * output ATTRIBUTE_UNUSED)
{
  snd_output_buffer_t *buffer = output->private_data;
  free (buffer->buf);
  free (buffer);
  return 0;
}

static int
snd_output_buffer_need (snd_output_t * output, size_t size)
{
  snd_output_buffer_t *buffer = output->private_data;
  size_t _free = buffer->alloc - buffer->size;
  size_t alloc;
  unsigned char *buf;

  if (_free >= size)
    return _free;
  if (buffer->alloc == 0)
    alloc = 256;
  else
    alloc = buffer->alloc;
  while (alloc < size)
    alloc *= 2;
  buf = realloc (buffer->buf, alloc);
  if (!buf)
    return -ENOMEM;
  buffer->buf = buf;
  buffer->alloc = alloc;
  return buffer->alloc - buffer->size;
}

static int
snd_output_buffer_print (snd_output_t * output, const char *format,
			 va_list args)
{
  snd_output_buffer_t *buffer = output->private_data;
  size_t size = 256;
  int result;
  result = snd_output_buffer_need (output, size);
  if (result < 0)
    return result;
  result = vsnprintf (buffer->buf + buffer->size, size, format, args);
  assert (result >= 0);
  if ((size_t) result <= size)
    {
      buffer->size += result;
      return result;
    }
  size = result;
  result = snd_output_buffer_need (output, size);
  if (result < 0)
    return result;
  result = vsnprintf (buffer->buf + buffer->size, result, format, args);
  assert (result == (int) size);
  buffer->size += result;
  return result;
}

static int
snd_output_buffer_puts (snd_output_t * output, const char *str)
{
  snd_output_buffer_t *buffer = output->private_data;
  size_t size = strlen (str);
  int err;
  err = snd_output_buffer_need (output, size);
  if (err < 0)
    return err;
  memcpy (buffer->buf + buffer->size, str, size);
  buffer->size += size;
  return size;
}

static int
snd_output_buffer_putc (snd_output_t * output, int c)
{
  snd_output_buffer_t *buffer = output->private_data;
  int err;
  err = snd_output_buffer_need (output, 1);
  if (err < 0)
    return err;
  buffer->buf[buffer->size++] = c;
  return 0;
}

static int
snd_output_buffer_flush (snd_output_t * output ATTRIBUTE_UNUSED)
{
  snd_output_buffer_t *buffer = output->private_data;
  buffer->size = 0;
  return 0;
}

static snd_output_ops_t snd_output_buffer_ops = {
  .close = snd_output_buffer_close,
  .print = snd_output_buffer_print,
  .puts = snd_output_buffer_puts,
  .putch = snd_output_buffer_putc,
  .flush = snd_output_buffer_flush,
};
#endif

/**
 * \brief Returns the address of the buffer of a #SND_OUTPUT_TYPE_BUFFER output handle.
 * \param output The output handle.
 * \param buf The functions puts the current address of the buffer at the
 *            address specified by \p buf.
 * \return The current size of valid data in the buffer.
 *
 * The address of the buffer may become invalid when output functions or
 * #snd_output_close are called.
 */
size_t
snd_output_buffer_string (snd_output_t * output, char **buf)
{
  snd_output_buffer_t *buffer = output->private_data;
  *buf = buffer->buf;
  return buffer->size;
}

/**
 * \brief Creates a new output object with an auto-extending memory buffer.
 * \param outputp The function puts the pointer to the new output object
 *                at the address specified by \p outputp.
 * \return Zero if successful, otherwise a negative error code.
 */
int
snd_output_buffer_open (snd_output_t ** outputp)
{
  snd_output_t *output;
  snd_output_buffer_t *buffer;
  assert (outputp);
  buffer = calloc (1, sizeof (*buffer));
  if (!buffer)
    return -ENOMEM;
  output = calloc (1, sizeof (*output));
  if (!output)
    {
      free (buffer);
      return -ENOMEM;
    }
  buffer->buf = NULL;
  buffer->alloc = 0;
  buffer->size = 0;
  output->type = SND_OUTPUT_BUFFER;
  output->ops = &snd_output_buffer_ops;
  output->private_data = buffer;
  *outputp = output;
  return 0;
}