/* Copyright (c) Dovecot authors, see top-level COPYING file */

#include "lib.h"

#include "str.h"

#include "istream.h"

#include "istream-private.h"

#include "test-common.h"

#include "fuzzer.h"

#include "istream-json-string.h"

/*

 * Feed arbitrary bytes into i_stream_create_json_string() and:

 *   1. Drain the decoded output completely.

 *   2. If the stream is seekable, seek back to 0 and drain again,

 *      verifying both reads produce identical output.

 */

FUZZ_BEGIN_DATA(const unsigned char *data, size_t size)

{

  struct istream *raw, *jstr;

  const unsigned char *buf;

  size_t buf_size;

  string_t *first, *second;

  ssize_t ret;

  raw = i_stream_create_from_data(data, size);

  jstr = i_stream_create_json_string(raw);

  i_stream_unref(&raw);

  /* First pass: decode everything */

  first = str_new(default_pool, 64);

  while ((ret = i_stream_read_more(jstr, &buf, &buf_size)) > 0) {

    str_append_data(first, buf, buf_size);

    i_stream_skip(jstr, buf_size);

  }

  /* ret == -1 on EOF or error; either is acceptable for fuzz input */

  /* Second pass: seek back and verify output is identical.

     Only meaningful when the first pass completed without error;

     i_stream_seek() is a no-op when stream_errno != 0. */

  if (jstr->seekable && jstr->stream_errno == 0) {

    i_stream_seek(jstr, 0);

    second = str_new(default_pool, 64);

    while ((ret = i_stream_read_more(jstr, &buf, &buf_size)) > 0) {

      str_append_data(second, buf, buf_size);

      i_stream_skip(jstr, buf_size);

    }

    /* Both reads must produce the same bytes */

    i_assert(str_len(first) == str_len(second) &&

       memcmp(str_data(first), str_data(second),

        str_len(first)) == 0);

    str_free(&second);

  }

  str_free(&first);

  i_stream_unref(&jstr);

}

FUZZ_END