#include "hb-fuzzer.hh"

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <assert.h>

#include "hb-subset-repacker.h"

typedef struct

{

  uint16_t parent;

  uint16_t child;

  uint16_t position;

  uint8_t width;

} link_t;

/* The fuzzer seed contains a serialized representation of a object graph which forms

 * the input graph to the repacker call. The binary format is:

 *

 * table tag: 4 bytes

 * number of objects: 2 bytes

 * objects[number of objects]:

 *   blob size: 2 bytes

 *   blob: blob size bytes

 * num of real links: 2 bytes

 * links[number of real links]: link_t struct

 *

 * TODO(garretrieger): add optional virtual links

 */

template <typename T>

bool read(const uint8_t** data, size_t* size, T* out)

{

  if (*size < sizeof (T)) return false;

  memcpy(out, *data, sizeof (T));

  *data += sizeof (T);

  *size -= sizeof (T);

  return true;

}

bool read<unsigned int>(unsigned char const**, unsigned long*, unsigned int*)

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2.81k

{

35

2.81k

  if (*size < sizeof (T)) return false;

36

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2.80k

  memcpy(out, *data, sizeof (T));

38

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2.80k

  *data += sizeof (T);

40

2.80k

  *size -= sizeof (T);

41

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2.80k

  return true;

43

2.81k

}

bool read<unsigned short>(unsigned char const**, unsigned long*, unsigned short*)

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34

10.4M

{

35

10.4M

  if (*size < sizeof (T)) return false;

36

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10.4M

  memcpy(out, *data, sizeof (T));

38

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10.4M

  *data += sizeof (T);

40

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  *size -= sizeof (T);

41

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10.4M

  return true;

43

10.4M

}

bool read<link_t>(unsigned char const**, unsigned long*, link_t*)

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34

15.1M

{

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  if (*size < sizeof (T)) return false;

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15.1M

  memcpy(out, *data, sizeof (T));

38

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15.1M

  *data += sizeof (T);

40

15.1M

  *size -= sizeof (T);

41

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15.1M

  return true;

43

15.1M

}

void cleanup (hb_object_t* objects, uint16_t num_objects)

{

  for (uint32_t i = 0; i < num_objects; i++)

  {

    free (objects[i].head);

    free (objects[i].real_links);

  }

}

void add_links_to_objects (hb_object_t* objects, uint16_t num_objects,

                           link_t* links, uint16_t num_links)

{

  unsigned* link_count = (unsigned*) calloc (num_objects, sizeof (unsigned));

  for (uint32_t i = 0; i < num_links; i++)

  {

    uint16_t parent_idx = links[i].parent;

    link_count[parent_idx]++;

  }

  for (uint32_t i = 0; i < num_objects; i++)

  {

    objects[i].num_real_links = link_count[i];

    objects[i].real_links = (hb_link_t*) calloc (link_count[i], sizeof (hb_link_t));

    objects[i].num_virtual_links = 0;

    objects[i].virtual_links = nullptr;

  }

  for (uint32_t i = 0; i < num_links; i++)

  {

    uint16_t parent_idx = links[i].parent;

    uint16_t child_idx = links[i].child + 1; // All indices are shifted by 1 by the null object.

    hb_link_t* link = &(objects[parent_idx].real_links[link_count[parent_idx] - 1]);

    link->width = links[i].width;

    link->position = links[i].position;

    link->objidx = child_idx;

    link_count[parent_idx]--;

  }

  free (link_count);

}

extern "C" int LLVMFuzzerTestOneInput (const uint8_t *data, size_t size)

{

  // TODO(garretrieger): move graph validity checks into repacker graph creation.

  alloc_state = _fuzzing_alloc_state (data, size);

  uint16_t num_objects = 0;

  hb_object_t* objects = nullptr;

  uint16_t num_real_links = 0;

  link_t* links = nullptr;

  hb_tag_t table_tag;

  if (!read<hb_tag_t> (&data, &size, &table_tag)) goto end;

  if (!read<uint16_t> (&data, &size, &num_objects)) goto end;

  objects = (hb_object_t*) calloc (num_objects, sizeof (hb_object_t));

  for (uint32_t i = 0; i < num_objects; i++)

  {

    uint16_t blob_size;

    if (!read<uint16_t> (&data, &size, &blob_size)) goto end;

    if (size < blob_size) goto end;

    char* copy = (char*) calloc (1, blob_size);

    memcpy (copy, data, blob_size);

    objects[i].head = (char*) copy;

    objects[i].tail = (char*) (copy + blob_size);

    size -= blob_size;

    data += blob_size;

  }

  if (!read<uint16_t> (&data, &size, &num_real_links)) goto end;

  links = (link_t*) calloc (num_real_links, sizeof (link_t));

  for (uint32_t i = 0; i < num_real_links; i++)

  {

    if (!read<link_t> (&data, &size, &links[i])) goto end;

    if (links[i].parent >= num_objects)

      goto end;

  }

  add_links_to_objects (objects, num_objects,

                        links, num_real_links);

  hb_blob_destroy (hb_subset_repack_or_fail (table_tag,

                                             objects,

                                             num_objects));

end:

  if (objects)

  {

    cleanup (objects, num_objects);

    free (objects);

  }

  free (links);

  return 0;

}