// SPDX-License-Identifier: 0BSD

///////////////////////////////////////////////////////////////////////////////

//

/// \file       arm.c

/// \brief      Filter for ARM binaries

///

//  Authors:    Igor Pavlov

//              Lasse Collin

//

///////////////////////////////////////////////////////////////////////////////

#include "simple_private.h"

static size_t

arm_code(void *simple lzma_attribute((__unused__)),

    uint32_t now_pos, bool is_encoder,

    uint8_t *buffer, size_t size)

{

  size_t i;

  for (i = 0; i + 4 <= size; i += 4) {

    if (buffer[i + 3] == 0xEB) {

      uint32_t src = ((uint32_t)(buffer[i + 2]) << 16)

          | ((uint32_t)(buffer[i + 1]) << 8)

          | (uint32_t)(buffer[i + 0]);

      src <<= 2;

      uint32_t dest;

      if (is_encoder)

        dest = now_pos + (uint32_t)(i) + 8 + src;

      else

        dest = src - (now_pos + (uint32_t)(i) + 8);

      dest >>= 2;

      buffer[i + 2] = (dest >> 16);

      buffer[i + 1] = (dest >> 8);

      buffer[i + 0] = dest;

    }

  }

  return i;

}

static lzma_ret

arm_coder_init(lzma_next_coder *next, const lzma_allocator *allocator,

    const lzma_filter_info *filters, bool is_encoder)

{

  return lzma_simple_coder_init(next, allocator, filters,

      &arm_code, 0, 4, 4, is_encoder);

}

#ifdef HAVE_ENCODER_ARM

extern lzma_ret

lzma_simple_arm_encoder_init(lzma_next_coder *next,

    const lzma_allocator *allocator,

    const lzma_filter_info *filters)

{

  return arm_coder_init(next, allocator, filters, true);

}

#endif

#ifdef HAVE_DECODER_ARM

extern lzma_ret

lzma_simple_arm_decoder_init(lzma_next_coder *next,

    const lzma_allocator *allocator,

    const lzma_filter_info *filters)

{

  return arm_coder_init(next, allocator, filters, false);

}

#endif