/* sb.c - string buffer manipulation routines

   Copyright (C) 1994-2025 Free Software Foundation, Inc.

   Written by Steve and Judy Chamberlain of Cygnus Support,

      sac@cygnus.com

   This file is part of GAS, the GNU Assembler.

   GAS is free software; you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 3, or (at your option)

   any later version.

   GAS is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License

   along with GAS; see the file COPYING.  If not, write to the Free

   Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA

   02110-1301, USA.  */

#include "as.h"

#include "sb.h"

#include <limits.h>

#ifndef CHAR_BIT

#define CHAR_BIT 8

#endif

/* These routines are about manipulating strings.

   They are managed in things called `sb's which is an abbreviation

   for string buffers.  An sb has to be created, things can be glued

   on to it, and at the end of it's life it should be freed.  The

   contents should never be pointed at whilst it is still growing,

   since it could be moved at any time

   eg:

   sb_new (&foo);

   sb_grow... (&foo,...);

   use foo->ptr[*];

   sb_kill (&foo);  */

/* Buffers start at INIT_ALLOC size, and roughly double each time we

   go over the current allocation.  MALLOC_OVERHEAD is a guess at the

   system malloc overhead.  We aim to not waste any memory in the

   underlying page/chunk allocated by the system malloc.  */

#define MALLOC_OVERHEAD (2 * sizeof (size_t))

#define INIT_ALLOC (64 - MALLOC_OVERHEAD - 1)

static void sb_check (sb *, size_t);

/* Initializes an sb.  */

void

sb_build (sb *ptr, size_t size)

{

  ptr->ptr = XNEWVEC (char, size + 1);

  ptr->max = size;

  ptr->len = 0;

}

void

sb_new (sb *ptr)

{

  sb_build (ptr, INIT_ALLOC);

}

/* Deallocate the sb at ptr.  */

void

sb_kill (sb *ptr)

{

  free (ptr->ptr);

}

/* Add the sb at s to the end of the sb at ptr.  */

void

sb_add_sb (sb *ptr, sb *s)

{

  sb_check (ptr, s->len);

  memcpy (ptr->ptr + ptr->len, s->ptr, s->len);

  ptr->len += s->len;

}

/* Helper for sb_scrub_and_add_sb.  */

static sb *sb_to_scrub;

static char *scrub_position;

static size_t

scrub_from_sb (char *buf, size_t buflen)

{

  size_t copy;

  copy = sb_to_scrub->len - (scrub_position - sb_to_scrub->ptr);

  if (copy > buflen)

    copy = buflen;

  memcpy (buf, scrub_position, copy);

  scrub_position += copy;

  return copy;

}

/* Run the sb at s through do_scrub_chars and add the result to the sb

   at ptr.  */

void

sb_scrub_and_add_sb (sb *ptr, sb *s)

{

  sb_to_scrub = s;

  scrub_position = s->ptr;

  /* do_scrub_chars can expand text, for example when replacing

     # 123 "filename"

     with

     \t.linefile 123 "filename"

     or when replacing a 'c with the decimal ascii number for c.

     So we loop until the input S is consumed.  */

  while (1)

    {

      size_t copy = s->len - (scrub_position - s->ptr) + do_scrub_pending ();

      if (copy == 0)

  break;

      sb_check (ptr, copy);

      ptr->len += do_scrub_chars (scrub_from_sb, ptr->ptr + ptr->len,

          ptr->max - ptr->len, false);

    }

  sb_to_scrub = 0;

  scrub_position = 0;

}

/* Make sure that the sb at ptr has room for another len characters,

   and grow it if it doesn't.  */

static void

sb_check (sb *ptr, size_t len)

{

  size_t want = ptr->len + len;

  if (want > ptr->max)

    {

      size_t max;

      want += MALLOC_OVERHEAD + 1;

      if ((ssize_t) want < 0)

  as_fatal ("string buffer overflow");

#if GCC_VERSION >= 3004

      max = (size_t) 1 << (CHAR_BIT * sizeof (want)

         - (sizeof (want) <= sizeof (long)

            ? __builtin_clzl ((long) want)

            : __builtin_clzll ((long long) want)));

#else

      max = 128;

      while (want > max)

  max <<= 1;

#endif

      max -= MALLOC_OVERHEAD + 1;

      ptr->max = max;

      ptr->ptr = XRESIZEVEC (char, ptr->ptr, max + 1);

    }

}

/* Make the sb at ptr point back to the beginning.  */

void

sb_reset (sb *ptr)

{

  ptr->len = 0;

}

/* Add character c to the end of the sb at ptr.  */

void

sb_add_char (sb *ptr, char c)

{

  sb_check (ptr, 1);

  ptr->ptr[ptr->len++] = c;

}

/* Add null terminated string s to the end of sb at ptr.  */

void

sb_add_string (sb *ptr, const char *s)

{

  size_t len = strlen (s);

  sb_check (ptr, len);

  memcpy (ptr->ptr + ptr->len, s, len);

  ptr->len += len;

}

/* Add string at s of length len to sb at ptr */

void

sb_add_buffer (sb *ptr, const char *s, size_t len)

{

  sb_check (ptr, len);

  memcpy (ptr->ptr + ptr->len, s, len);

  ptr->len += len;

}

/* Write terminating NUL and return string.  */

char *

sb_terminate (sb *in)

{

  in->ptr[in->len] = 0;

  return in->ptr;

}

/* Start at the index idx into the string in sb at ptr and skip

   whitespace. return the index of the first non whitespace character.  */

size_t

sb_skip_white (size_t idx, sb *ptr)

{

  while (idx < ptr->len && is_whitespace (ptr->ptr[idx]))

    idx++;

  return idx;

}

/* Start at the index idx into the sb at ptr. skips whitespace,

   a comma and any following whitespace. returns the index of the

   next character.  */

size_t

sb_skip_comma (size_t idx, sb *ptr)

{

  while (idx < ptr->len && is_whitespace (ptr->ptr[idx]))

    idx++;

  if (idx < ptr->len

      && ptr->ptr[idx] == ',')

    idx++;

  while (idx < ptr->len && is_whitespace (ptr->ptr[idx]))

    idx++;

  return idx;

}