/*
  Copyright 2011-2020 David Robillard <d@drobilla.net>

  Permission to use, copy, modify, and/or distribute this software for any
  purpose with or without fee is hereby granted, provided that the above
  copyright notice and this permission notice appear in all copies.

  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/

#ifndef SERD_BYTE_SINK_H
#define SERD_BYTE_SINK_H

#include "serd/serd.h"

#include <stddef.h>
#include <string.h>

typedef enum {
  TO_BUFFER,   ///< Writing to a user-provided buffer
  TO_FILENAME, ///< Writing to a file we opened
  TO_FUNCTION, ///< Writing to a user-provided function
} SerdByteSinkType;

struct SerdByteSinkImpl {
  SerdWriteFunc    write_func; ///< User sink for TO_FUNCTION
  void*            stream;     ///< User data for write_func
  char*            buf;        ///< Local buffer iff block_size > 1
  size_t           size;       ///< Bytes written so far in this chunk
  size_t           block_size; ///< Size of chunks to write
  SerdByteSinkType type;       ///< Type of output
};

static inline size_t
serd_byte_sink_write(const void* buf, size_t len, SerdByteSink* const sink)
{
  if (len == 0) {
    return 0;
  }

  if (sink->block_size == 1) {
    return sink->write_func(buf, 1, len, sink->stream);
  }

  const size_t orig_len = len;
  while (len) {
    const size_t space = sink->block_size - sink->size;
    const size_t n     = space < len ? space : len;

    // Write as much as possible into the remaining buffer space
    memcpy(sink->buf + sink->size, buf, n);
    sink->size += n;
    buf = (const char*)buf + n;
    len -= n;

    // Flush page if buffer is full
    if (sink->size == sink->block_size) {
      sink->write_func(sink->buf, 1, sink->block_size, sink->stream);
      sink->size = 0;
    }
  }

  return orig_len;
}

#endif // SERD_BYTE_SINK_H