/* Copyright (c) 2002-2018 Pigeonhole authors, see the included COPYING file

 */

#include "lib.h"

#include "str.h"

#include "str-sanitize.h"

#include "mempool.h"

#include "buffer.h"

#include "hash.h"

#include "array.h"

#include "ostream.h"

#include "sieve-common.h"

#include "sieve-error.h"

#include "sieve-extensions.h"

#include "sieve-code.h"

#include "sieve-script.h"

#include "sieve-binary-private.h"

/*

 * Forward declarations

 */

static inline sieve_size_t

sieve_binary_emit_dynamic_data(struct sieve_binary_block *sblock,

             const void *data, size_t size);

/*

 * Emission functions

 */

/* Low-level emission functions */

static inline void

_sieve_binary_emit_data(struct sieve_binary_block *sblock,

      const void *data, sieve_size_t size)

{

  buffer_append(sblock->data, data, size);

}

static inline void

_sieve_binary_emit_byte(struct sieve_binary_block *sblock, uint8_t byte)

{

  _sieve_binary_emit_data(sblock, &byte, 1);

}

static inline void

_sieve_binary_update_data(struct sieve_binary_block *sblock,

        sieve_size_t address, const void *data,

        sieve_size_t size)

{

  buffer_write(sblock->data, address, data, size);

}

sieve_size_t sieve_binary_emit_data(struct sieve_binary_block *sblock,

            const void *data, sieve_size_t size)

{

  sieve_size_t address = _sieve_binary_block_get_size(sblock);

  _sieve_binary_emit_data(sblock, data, size);

  return address;

}

sieve_size_t sieve_binary_emit_byte(struct sieve_binary_block *sblock,

            uint8_t byte)

{

  sieve_size_t address = _sieve_binary_block_get_size(sblock);

  _sieve_binary_emit_data(sblock, &byte, 1);

  return address;

}

void sieve_binary_update_data(struct sieve_binary_block *sblock,

            sieve_size_t address, const void *data,

            sieve_size_t size)

{

  _sieve_binary_update_data(sblock, address, data, size);

}

/* Offset emission functions */

sieve_size_t sieve_binary_emit_offset(struct sieve_binary_block *sblock,

              sieve_offset_t offset)

{

  sieve_size_t address = _sieve_binary_block_get_size(sblock);

  uint8_t encoded[sizeof(offset)];

  int i;

  for (i = sizeof(offset)-1; i >= 0; i--) {

    encoded[i] = (uint8_t)offset;

    offset >>= 8;

  }

  _sieve_binary_emit_data(sblock, encoded, sizeof(offset));

  return address;

}

void sieve_binary_resolve_offset(struct sieve_binary_block *sblock,

         sieve_size_t address)

{

  sieve_size_t cur_address = _sieve_binary_block_get_size(sblock);

  sieve_offset_t offset;

  uint8_t encoded[sizeof(offset)];

  int i;

  i_assert(cur_address > address);

  i_assert((cur_address - address) <= (sieve_offset_t)-1);

  offset = cur_address - address;

  for (i = sizeof(offset)-1; i >= 0; i--) {

    encoded[i] = (uint8_t)offset;

    offset >>= 8;

  }

  _sieve_binary_update_data(sblock, address, encoded, sizeof(offset));

}

/* Literal emission */

sieve_size_t sieve_binary_emit_integer(struct sieve_binary_block *sblock,

               sieve_number_t integer)

{

  sieve_size_t address = _sieve_binary_block_get_size(sblock);

  uint8_t buffer[sizeof(sieve_number_t) + 1];

  int bufpos = sizeof(buffer) - 1;

  /* Encode last byte [0xxxxxxx]; msb == 0 marks the last byte */

  buffer[bufpos] = integer & 0x7F;

  bufpos--;

  /* Encode first bytes [1xxxxxxx] */

  integer >>= 7;

  while (integer > 0) {

    buffer[bufpos] = (integer & 0x7F) | 0x80;

    bufpos--;

    integer >>= 7;

  }

  /* Emit encoded integer */

  bufpos++;

  _sieve_binary_emit_data(sblock, buffer + bufpos, sizeof(buffer) - bufpos);

  return address;

}

static inline sieve_size_t

sieve_binary_emit_dynamic_data(struct sieve_binary_block *sblock,

             const void *data, sieve_size_t size)

{

  sieve_size_t address =

    sieve_binary_emit_integer(sblock, (sieve_number_t)size);

  _sieve_binary_emit_data(sblock, data, size);

  return address;

}

sieve_size_t sieve_binary_emit_cstring(struct sieve_binary_block *sblock,

               const char *str)

{

  sieve_size_t address =

    sieve_binary_emit_dynamic_data(sblock, str,

                 (sieve_size_t)strlen(str));

  _sieve_binary_emit_byte(sblock, 0);

  return address;

}

sieve_size_t sieve_binary_emit_string(struct sieve_binary_block *sblock,

              const string_t *str)

{

  sieve_size_t address =

    sieve_binary_emit_dynamic_data(sblock, str_data(str),

                 (sieve_size_t)str_len(str));

  _sieve_binary_emit_byte(sblock, 0);

  return address;

}

/*

 * Extension emission

 */

sieve_size_t sieve_binary_emit_extension(struct sieve_binary_block *sblock,

           const struct sieve_extension *ext,

           unsigned int offset)

{

  sieve_size_t address = _sieve_binary_block_get_size(sblock);

  struct sieve_binary_extension_reg *ereg = NULL;

  (void)sieve_binary_extension_register(sblock->sbin, ext, &ereg);

  i_assert(ereg != NULL);

  _sieve_binary_emit_byte(sblock, offset + ereg->index);

  return address;

}

void sieve_binary_emit_extension_object(

  struct sieve_binary_block *sblock,

  const struct sieve_extension_objects *objs, unsigned int code)

{

  if (objs->count > 1)

    _sieve_binary_emit_byte(sblock, code);

}

/*

 * Code retrieval

 */

#define ADDR_CODE_READ(block) \

  size_t _code_size; \

  const int8_t *_code = buffer_get_data((block)->data, &_code_size)

#define ADDR_CODE_AT(address) \

  ((int8_t)(_code[*address]))

#define ADDR_DATA_AT(address) \

  ((uint8_t)(_code[*address]))

#define ADDR_POINTER(address) \

  ((const int8_t *)(&_code[*address]))

#define ADDR_BYTES_LEFT(address) \

  ((*address) > _code_size ? 0 : ((_code_size) - (*address)))

#define ADDR_JUMP(address, offset) \

  (*address) += offset

/* Literals */

bool sieve_binary_read_byte(struct sieve_binary_block *sblock,

          sieve_size_t *address, unsigned int *byte_r)

{

  ADDR_CODE_READ(sblock);

  if (ADDR_BYTES_LEFT(address) >= 1) {

    if (byte_r != NULL)

      *byte_r = ADDR_DATA_AT(address);

    ADDR_JUMP(address, 1);

    return TRUE;

  }

  if (byte_r != NULL)

    *byte_r = 0;

  return FALSE;

}

bool sieve_binary_read_code(struct sieve_binary_block *sblock,

          sieve_size_t *address, signed int *code_r)

{

  ADDR_CODE_READ(sblock);

  if (ADDR_BYTES_LEFT(address) >= 1) {

    if (code_r != NULL)

      *code_r = ADDR_CODE_AT(address);

    ADDR_JUMP(address, 1);

    return TRUE;

  }

  if (code_r != NULL)

    *code_r = 0;

  return FALSE;

}

bool sieve_binary_read_offset(struct sieve_binary_block *sblock,

            sieve_size_t *address, sieve_offset_t *offset_r)

{

  sieve_offset_t offs = 0;

  ADDR_CODE_READ(sblock);

  if (ADDR_BYTES_LEFT(address) >= 4) {

    int i;

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

      offs = (offs << 8) + ADDR_DATA_AT(address);

      ADDR_JUMP(address, 1);

    }

    if (offset_r != NULL)

      *offset_r = offs;

    return TRUE;

  }

  return FALSE;

}

/* FIXME: might need negative numbers in the future */

bool sieve_binary_read_integer(struct sieve_binary_block *sblock,

             sieve_size_t *address, sieve_number_t *int_r)

{

  int bits = sizeof(sieve_number_t) * 8;

  sieve_number_t integer = 0;

  ADDR_CODE_READ(sblock);

  if (ADDR_BYTES_LEFT(address) == 0)

    return FALSE;

  /* Read first integer bytes [1xxxxxxx] */

  while ((ADDR_DATA_AT(address) & 0x80) > 0) {

    if (ADDR_BYTES_LEFT(address) > 0 && bits > 0) {

      integer |= ADDR_DATA_AT(address) & 0x7F;

      ADDR_JUMP(address, 1);

      /* Each byte encodes 7 bits of the integer */

      integer <<= 7;

      bits -= 7;

    } else {

      /* This is an error */

      return FALSE;

    }

  }

  /* Read last byte [0xxxxxxx] */

  integer |= ADDR_DATA_AT(address) & 0x7F;

  ADDR_JUMP(address, 1);

  if (int_r != NULL)

    *int_r = integer;

  return TRUE;

}

bool sieve_binary_read_string(struct sieve_binary_block *sblock,

            sieve_size_t *address, string_t **str_r)

{

  unsigned int strlen = 0;

  const char *strdata;

  ADDR_CODE_READ(sblock);

  if (!sieve_binary_read_unsigned(sblock, address, &strlen))

    return FALSE;

  if (strlen > ADDR_BYTES_LEFT(address))

    return FALSE;

  strdata = (const char *)ADDR_POINTER(address);

  ADDR_JUMP(address, strlen);

  if (ADDR_CODE_AT(address) != 0)

    return FALSE;

  if (str_r != NULL)

    *str_r = t_str_new_const(strdata, strlen);

  ADDR_JUMP(address, 1);

  return TRUE;

}

bool sieve_binary_read_extension(struct sieve_binary_block *sblock,

         sieve_size_t *address, unsigned int *offset_r,

         const struct sieve_extension **ext_r)

{

  unsigned int code;

  unsigned int offset = *offset_r;

  const struct sieve_extension *ext = NULL;

  ADDR_CODE_READ(sblock);

  if (ADDR_BYTES_LEFT(address) == 0)

    return FALSE;

  *offset_r = code = ADDR_DATA_AT(address);

  ADDR_JUMP(address, 1);

  if (code >= offset) {

    ext = sieve_binary_extension_get_by_index(sblock->sbin,

                (code - offset));

    if (ext == NULL)

      return FALSE;

  }

  if (ext_r != NULL)

    *ext_r = ext;

  return TRUE;

}

const void *

sieve_binary_read_extension_object(struct sieve_binary_block *sblock,

           sieve_size_t *address,

           const struct sieve_extension_objects *objs)

{

  unsigned int code;

  ADDR_CODE_READ(sblock);

  if (objs->count == 0)

    return NULL;

  if (objs->count == 1)

    return objs->objects;

  if (ADDR_BYTES_LEFT(address) == 0)

    return NULL;

  code = ADDR_DATA_AT(address);

  ADDR_JUMP(address, 1);

  if (code >= objs->count)

    return NULL;

  return ((const void *const *)objs->objects)[code];

}