/*  tables.c - tables serialization code

 *

 *  Copyright (c) 1990 The Regents of the University of California.

 *  All rights reserved.

 *

 *  This code is derived from software contributed to Berkeley by

 *  Vern Paxson.

 *

 *  The United States Government has rights in this work pursuant

 *  to contract no. DE-AC03-76SF00098 between the United States

 *  Department of Energy and the University of California.

 *

 *  This file is part of flex.

 *

 *  Redistribution and use in source and binary forms, with or without

 *  modification, are permitted provided that the following conditions

 *  are met:

 *

 *  1. Redistributions of source code must retain the above copyright

 *     notice, this list of conditions and the following disclaimer.

 *  2. Redistributions in binary form must reproduce the above copyright

 *     notice, this list of conditions and the following disclaimer in the

 *     documentation and/or other materials provided with the distribution.

 *

 *  Neither the name of the University nor the names of its contributors

 *  may be used to endorse or promote products derived from this software

 *  without specific prior written permission.

 *

 *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR

 *  IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED

 *  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 *  PURPOSE.

 */

#include "flexdef.h"

#include "tables.h"

/** Convert size_t to t_flag.

 *  @param n in {1,2,4}

 *  @return YYTD_DATA*. 

 */

#define BYTES2TFLAG(n)\

    (((n) == sizeof(flex_int8_t))\

        ? YYTD_DATA8\

        :(((n)== sizeof(flex_int16_t))\

            ? YYTD_DATA16\

            : YYTD_DATA32))

/** Clear YYTD_DATA* bit flags

 * @return the flag with the YYTD_DATA* bits cleared

 */

#define TFLAGS_CLRDATA(flg) ((flg) & ~(YYTD_DATA8 | YYTD_DATA16 | YYTD_DATA32))

int     yytbl_write32 (struct yytbl_writer *wr, flex_uint32_t v);

int     yytbl_write16 (struct yytbl_writer *wr, flex_uint16_t v);

int     yytbl_write8 (struct yytbl_writer *wr, flex_uint8_t v);

int     yytbl_writen (struct yytbl_writer *wr, void *v, int len);

static flex_int32_t yytbl_data_geti (const struct yytbl_data *tbl, int i);

/* XXX Not used

static flex_int32_t yytbl_data_getijk (const struct yytbl_data *tbl, int i,

          int j, int k);

 */

/** Initialize the table writer.

 *  @param wr an uninitialized writer

 *  @param out the output file

 *  @return 0 on success

 */

int yytbl_writer_init (struct yytbl_writer *wr, FILE * out)

{

  wr->out = out;

  wr->total_written = 0;

  return 0;

}

/** Initialize a table header.

 *  @param th  The uninitialized structure

 *  @param version_str the  version string

 *  @param name the name of this table set

 */

int yytbl_hdr_init (struct yytbl_hdr *th, const char *version_str,

        const char *name)

{

  memset (th, 0, sizeof (struct yytbl_hdr));

  th->th_magic = YYTBL_MAGIC;

  th->th_hsize = (flex_uint32_t) (14 + strlen (version_str) + 1 + strlen (name) + 1);

  th->th_hsize += (8 - (th->th_hsize % 8)) % 8; // Pad to 64-bit boundary

  th->th_ssize = 0; // Not known at this point.

  th->th_flags = 0;

  th->th_version = xstrdup(version_str);

  th->th_name = xstrdup(name);

  return 0;

}

/** Allocate and initialize a table data structure.

 *  @param td a pointer to an uninitialized table

 *  @param id  the table identifier

 *  @return 0 on success

 */

int yytbl_data_init (struct yytbl_data *td, enum yytbl_id id)

{

  memset (td, 0, sizeof (struct yytbl_data));

  td->td_id = id;

  td->td_flags = YYTD_DATA32;

  return 0;

}

/** Clean up table and data array.

 *  @param td will be destroyed

 *  @return 0 on success

 */

int yytbl_data_destroy (struct yytbl_data *td)

{

  free(td->td_data);

  td->td_data = 0;

  free (td);

  return 0;

}

/** Write enough padding to bring the file pointer to a 64-bit boundary. */

static int yytbl_write_pad64 (struct yytbl_writer *wr)

{

  int bwritten = 0;

  while (wr->total_written % (8 * sizeof(flex_uint8_t)) > 0) {

    if (yytbl_write8 (wr, 0) < 0)

      return -1;

    else

      bwritten++;

  }

  return bwritten;

}

/** write the header.

 *  @param wr the output stream

 *  @param th table header to be written

 *  @return -1 on error, or bytes written on success.

 */

int yytbl_hdr_fwrite (struct yytbl_writer *wr, const struct yytbl_hdr *th)

{

  int  sz, rv;

  int     bwritten = 0;

  if (yytbl_write32 (wr, th->th_magic) < 0

      || yytbl_write32 (wr, th->th_hsize) < 0)

    flex_die (_("th_magic|th_hsize write32 failed"));

  bwritten += 8;

  if (fgetpos (wr->out, &(wr->th_ssize_pos)) != 0)

    flex_die (_("fgetpos failed"));

  if (yytbl_write32 (wr, th->th_ssize) < 0

      || yytbl_write16 (wr, th->th_flags) < 0)

    flex_die (_("th_ssize|th_flags write failed"));

  bwritten += 6;

  sz = (int) strlen (th->th_version) + 1;

  if ((rv = yytbl_writen (wr, th->th_version, sz)) != sz)

    flex_die (_("th_version written failed"));

  bwritten += rv;

  sz = (int) strlen (th->th_name) + 1;

  if ((rv = yytbl_writen (wr, th->th_name, sz)) != sz)

    flex_die (_("th_name written failed"));

  bwritten += rv;

  /* add padding */

  if ((rv = yytbl_write_pad64 (wr)) < 0)

    flex_die (_("pad64 failed"));

  bwritten += rv;

  /* Sanity check */

  if (bwritten != (int) th->th_hsize)

    flex_die (_("pad64 failed"));

  return bwritten;

}

/** Write this table.

 *  @param wr the file writer

 *  @param td table data to be written

 *  @return -1 on error, or bytes written on success.

 */

int yytbl_data_fwrite (struct yytbl_writer *wr, struct yytbl_data *td)

{

  int  rv;

  flex_int32_t bwritten = 0;

  flex_int32_t i, total_len;

  fpos_t  pos;

  if ((rv = yytbl_write16 (wr, td->td_id)) < 0)

    return -1;

  bwritten += rv;

  if ((rv = yytbl_write16 (wr, td->td_flags)) < 0)

    return -1;

  bwritten += rv;

  if ((rv = yytbl_write32 (wr, td->td_hilen)) < 0)

    return -1;

  bwritten += rv;

  if ((rv = yytbl_write32 (wr, td->td_lolen)) < 0)

    return -1;

  bwritten += rv;

  total_len = yytbl_calc_total_len (td);

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

    switch (YYTDFLAGS2BYTES (td->td_flags)) {

    case sizeof (flex_int8_t):

      rv = yytbl_write8 (wr, (flex_uint8_t) yytbl_data_geti (td, i));

      break;

    case sizeof (flex_int16_t):

      rv = yytbl_write16 (wr, (flex_uint16_t) yytbl_data_geti (td, i));

      break;

    case sizeof (flex_int32_t):

      rv = yytbl_write32 (wr, (flex_uint32_t) yytbl_data_geti (td, i));

      break;

    default:

      flex_die (_("invalid td_flags detected"));

    }

    if (rv < 0) {

      flex_die (_("error while writing tables"));

      return -1;

    }

    bwritten += rv;

  }

  /* Sanity check */

  if (bwritten != (12 + total_len * (int) YYTDFLAGS2BYTES (td->td_flags))) {

    flex_die (_("insanity detected"));

    return -1;

  }

  /* add padding */

  if ((rv = yytbl_write_pad64 (wr)) < 0) {

    flex_die (_("pad64 failed"));

    return -1;

  }

  bwritten += rv;

  /* Now go back and update the th_hsize member */

  if (fgetpos (wr->out, &pos) != 0

      || fsetpos (wr->out, &(wr->th_ssize_pos)) != 0

      || yytbl_write32 (wr, (flex_uint32_t) wr->total_written) < 0

      || fsetpos (wr->out, &pos)) {

    flex_die (_("get|set|fwrite32 failed"));

    return -1;

  }

  else

    /* Don't count the int we just wrote. */

    wr->total_written -= (int) sizeof (flex_int32_t);

  return bwritten;

}

/** Write n bytes.

 *  @param  wr   the table writer

 *  @param  v    data to be written

 *  @param  len  number of bytes

 *  @return  -1 on error. number of bytes written on success.

 */

int yytbl_writen (struct yytbl_writer *wr, void *v, int len)

{

  int  rv;

  rv = (int) fwrite (v, 1, (size_t) len, wr->out);

  if (rv != len)

    return -1;

  wr->total_written += len;

  return len;

}

/** Write four bytes in network byte order

 *  @param  wr  the table writer

 *  @param  v    a dword in host byte order

 *  @return  -1 on error. number of bytes written on success.

 */

int yytbl_write32 (struct yytbl_writer *wr, flex_uint32_t v)

{

  flex_uint32_t vnet;

  int  bytes, rv;

  vnet = htonl (v);

  bytes = (int) sizeof (flex_uint32_t);

  rv = (int) fwrite (&vnet, (size_t) bytes, 1, wr->out);

  if (rv != 1)

    return -1;

  wr->total_written += bytes;

  return bytes;

}

/** Write two bytes in network byte order.

 *  @param  wr  the table writer

 *  @param  v    a word in host byte order

 *  @return  -1 on error. number of bytes written on success.

 */

int yytbl_write16 (struct yytbl_writer *wr, flex_uint16_t v)

{

  flex_uint16_t vnet;

  int  bytes, rv;

  vnet = htons (v);

  bytes = (int) sizeof (flex_uint16_t);

  rv = (int) fwrite (&vnet, (size_t) bytes, 1, wr->out);

  if (rv != 1)

    return -1;

  wr->total_written += bytes;

  return bytes;

}

/** Write a byte.

 *  @param  wr  the table writer

 *  @param  v    the value to be written

 *  @return  -1 on error. number of bytes written on success.

 */

int yytbl_write8 (struct yytbl_writer *wr, flex_uint8_t v)

{

  int  bytes, rv;

  bytes = (int) sizeof (flex_uint8_t);

  rv = (int) fwrite (&v, (size_t) bytes, 1, wr->out);

  if (rv != 1)

    return -1;

  wr->total_written += bytes;

  return bytes;

}

/* XXX Not Used */

#if 0

/** Extract data element [i][j] from array data tables. 

 * @param tbl data table

 * @param i index into higher dimension array. i should be zero for one-dimensional arrays.

 * @param j index into lower dimension array.

 * @param k index into struct, must be 0 or 1. Only valid for YYTD_ID_TRANSITION table

 * @return data[i][j + k]

 */

static flex_int32_t yytbl_data_getijk (const struct yytbl_data *tbl, int i,

          int j, int k)

{

  flex_int32_t lo;

  k %= 2;

  lo = tbl->td_lolen;

  switch (YYTDFLAGS2BYTES (tbl->td_flags)) {

  case sizeof (flex_int8_t):

    return ((flex_int8_t *) (tbl->td_data))[(i * lo + j) * (k + 1) +

               k];

  case sizeof (flex_int16_t):

    return ((flex_int16_t *) (tbl->td_data))[(i * lo + j) * (k +

                    1) +

                k];

  case sizeof (flex_int32_t):

    return ((flex_int32_t *) (tbl->td_data))[(i * lo + j) * (k +

                    1) +

                k];

  default:

    flex_die (_("invalid td_flags detected"));

    break;

  }

  return 0;

}

#endif /* Not used */

/** Extract data element [i] from array data tables treated as a single flat array of integers.

 * Be careful for 2-dimensional arrays or for YYTD_ID_TRANSITION, which is an array

 * of structs. 

 * @param tbl data table

 * @param i index into array.

 * @return data[i]

 */

static flex_int32_t yytbl_data_geti (const struct yytbl_data *tbl, int i)

{

  switch (YYTDFLAGS2BYTES (tbl->td_flags)) {

  case sizeof (flex_int8_t):

    return ((flex_int8_t *) (tbl->td_data))[i];

  case sizeof (flex_int16_t):

    return ((flex_int16_t *) (tbl->td_data))[i];

  case sizeof (flex_int32_t):

    return ((flex_int32_t *) (tbl->td_data))[i];

  default:

    flex_die (_("invalid td_flags detected"));

    break;

  }

  return 0;

}

/** Set data element [i] in array data tables treated as a single flat array of integers.

 * Be careful for 2-dimensional arrays or for YYTD_ID_TRANSITION, which is an array

 * of structs. 

 * @param tbl data table

 * @param i index into array.

 * @param newval new value for data[i]

 */

static void yytbl_data_seti (const struct yytbl_data *tbl, int i,

           flex_int32_t newval)

{

  switch (YYTDFLAGS2BYTES (tbl->td_flags)) {

  case sizeof (flex_int8_t):

    ((flex_int8_t *) (tbl->td_data))[i] = (flex_int8_t) newval;

    break;

  case sizeof (flex_int16_t):

    ((flex_int16_t *) (tbl->td_data))[i] = (flex_int16_t) newval;

    break;

  case sizeof (flex_int32_t):

    ((flex_int32_t *) (tbl->td_data))[i] = (flex_int32_t) newval;

    break;

  default:

    flex_die (_("invalid td_flags detected"));

    break;

  }

}

/** Calculate the number of bytes  needed to hold the largest

 *  absolute value in this data array.

 *  @param tbl  the data table

 *  @return sizeof(n) where n in {flex_int8_t, flex_int16_t, flex_int32_t}

 */

static size_t min_int_size (struct yytbl_data *tbl)

{

  flex_int32_t i, total_len;

  flex_int32_t max = 0;

  total_len = yytbl_calc_total_len (tbl);

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

    flex_int32_t n;

    n = abs (yytbl_data_geti (tbl, i));

    if (max < n)

      max = n;

  }

  if (max <= INT8_MAX)

    return sizeof (flex_int8_t);

  else if (max <= INT16_MAX)

    return sizeof (flex_int16_t);

  else

    return sizeof (flex_int32_t);

}

/** Transform data to smallest possible of (int32, int16, int8).

 * For example, we may have generated an int32 array due to user options

 * (e.g., %option align), but if the maximum value in that array

 * is 80 (for example), then we can serialize it with only 1 byte per int.

 * This is NOT the same as compressed DFA tables. We're just trying

 * to save storage space here.

 *

 * @param tbl the table to be compressed

 */

void yytbl_data_compress (struct yytbl_data *tbl)

{

  flex_int32_t i, total_len;

  size_t newsz;

  struct yytbl_data newtbl;

  yytbl_data_init (&newtbl, tbl->td_id);

  newtbl.td_hilen = tbl->td_hilen;

  newtbl.td_lolen = tbl->td_lolen;

  newtbl.td_flags = tbl->td_flags;

  newsz = min_int_size (tbl);

  if (newsz == YYTDFLAGS2BYTES (tbl->td_flags))

    /* No change in this table needed. */

    return;

  if (newsz > YYTDFLAGS2BYTES (tbl->td_flags)) {

    flex_die (_("detected negative compression"));

    return;

  }

  total_len = yytbl_calc_total_len (tbl);

  newtbl.td_data = calloc ((size_t) total_len, newsz);

  newtbl.td_flags = (flex_uint16_t)

    (TFLAGS_CLRDATA (newtbl.td_flags) | BYTES2TFLAG (newsz));

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

    flex_int32_t g;

    g = yytbl_data_geti (tbl, i);

    yytbl_data_seti (&newtbl, i, g);

  }

  /* Now copy over the old table */

  free (tbl->td_data);

  *tbl = newtbl;

}

/* vim:set noexpandtab cindent tabstop=8 softtabstop=0 shiftwidth=8 textwidth=0: */