/*
  Copyright 2011-2021 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.
*/

#include "serd_config.h"

#include "serd/serd.h"

#include <sys/stat.h>

#if USE_POSIX_FADVISE && USE_FILENO
#  include <fcntl.h>
#endif

// IWYU pragma: no_include <features.h>

#include <assert.h>
#include <stdbool.h>
#include <stdio.h>

static size_t
serd_string_read(void* const  buf,
                 const size_t size,
                 const size_t nmemb,
                 void* const  stream)
{
  const char** position = (const char**)stream;

  size_t       n_read = 0u;
  const size_t len    = size * nmemb;
  while (n_read < len && **position) {
    ((char*)buf)[n_read++] = **position;

    ++(*position);
  }

  return n_read;
}

static int
serd_string_error(void* const stream)
{
  (void)stream;
  return 0;
}

static int
serd_string_close(void* const stream)
{
  (void)stream;
  return 0;
}

SerdInputStream
serd_open_input_stream(SerdReadFunc SERD_NONNULL         read_func,
                       SerdStreamErrorFunc SERD_NONNULL  error_func,
                       SerdStreamCloseFunc SERD_NULLABLE close_func,
                       void* const                       stream)
{
  assert(read_func);
  assert(error_func);

  SerdInputStream input = {stream, read_func, error_func, close_func};
  return input;
}

static bool
is_directory(const char* const path)
{
#ifdef _MSC_VER
  struct stat st;
  return !stat(path, &st) && (st.st_mode & _S_IFDIR);
#else
  struct stat st;
  return !stat(path, &st) && S_ISDIR(st.st_mode);
#endif
}

SerdInputStream
serd_open_input_string(const char** const position)
{
  assert(position);
  assert(*position);

  const SerdInputStream input = {
    position, serd_string_read, serd_string_error, serd_string_close};

  return input;
}

SerdInputStream
serd_open_input_file(const char* const path)
{
  assert(path);

  SerdInputStream input = {NULL, NULL, NULL, NULL};
  if (is_directory(path)) {
    return input;
  }

#ifdef __GLIBC__
  FILE* const file = fopen(path, "rbe");
#else
  FILE* const file = fopen(path, "rb");
#endif

  if (!file) {
    return input;
  }

#if USE_POSIX_FADVISE && USE_FILENO
  posix_fadvise(fileno(file), 0, 0, POSIX_FADV_SEQUENTIAL);
#endif

  input.stream = file;
  input.read   = (SerdReadFunc)fread;
  input.error  = (SerdStreamErrorFunc)ferror;
  input.close  = (SerdStreamCloseFunc)fclose;

  return input;
}

SerdStatus
serd_close_input(SerdInputStream* const input)
{
  int ret = 0;

  if (input) {
    if (input->close && input->stream) {
      ret           = input->close(input->stream);
      input->stream = NULL;
    }

    input->stream = NULL;
  }

  return ret ? SERD_BAD_READ : SERD_SUCCESS;
}