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[mLib] / struct / buf.c

/* -*-c-*-
 *
 * Buffer handling
 *
 * (c) 2001 Straylight/Edgeware
 */

/*----- Licensing notice --------------------------------------------------*
 *
 * This file is part of the mLib utilities library.
 *
 * mLib is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Library General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * mLib 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 Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with mLib; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 */

/*----- Header files ------------------------------------------------------*/

#include <assert.h>
#include <string.h>

#include "buf.h"
#include "macros.h"

/*----- Main code ---------------------------------------------------------*/

/* --- @buf_init@ --- *
 *
 * Arguments:	@buf *b@ = pointer to a buffer block
 *		@void *p@ = pointer to a buffer
 *		@size_t sz@ = size of the buffer
 *
 * Returns:	---
 *
 * Use:		Initializes the buffer block appropriately.
 */

void buf_init(buf *b, void *p, size_t sz)
{
  b->base = b->p = p;
  b->limit = b->p + sz;
  b->f = 0;
}

/* --- @dbuf_create@ --- *
 *
 * Arguments:	@dbuf *db@ = pointer to a dynamic buffer block
 *
 * Returns:	---
 *
 * Use:		Initializes a dynamic buffer.  The buffer is initially empty,
 *		and ready for writing.
 */

void dbuf_create(dbuf *db)
{
  db->_b.base = db->_b.p = db->_b.limit = 0; db->_b.f = BF_ALLOC | BF_WRITE;
  db->a = &arena_stdlib; db->sz = 0;
}

/* --- @dbuf_reset@ --- *
 *
 * Arguments:	@dbuf *db@ = pointer to a buffer block
 *
 * Returns:	---
 *
 * Use:		Resets a buffer so that it can be written again.
 */

void dbuf_reset(dbuf *db)
{
  db->_b.p = db->_b.base; db->_b.limit = db->_b.base + db->sz;
  db->_b.f = (db->_b.f&~BF_BROKEN) | BF_WRITE;
}

/* --- @dbuf_destroy@ --- *
 *
 * Arguments:	@dbuf *db@ = pointer to a buffer block
 *
 * Returns:	---
 *
 * Use:		Release all of the resources held by a dynamic buffer.
 */

void dbuf_destroy(dbuf *db)
{
  if (db->_b.base) x_free(db->a, db->_b.base);
  dbuf_create(db);
}

/* --- @buf_break@ --- *
 *
 * Arguments:	@buf *b@ = pointer to a buffer block
 *
 * Returns:	Some negative value.
 *
 * Use:		Marks a buffer as broken.
 */

int buf_break(buf *b) { b->f |= BF_BROKEN; return (-1); }

/* --- @buf_flip@ --- *
 *
 * Arguments:	@buf *b@ = pointer to a buffer block
 *
 * Returns:	---
 *
 * Use:		Flips a buffer so that if you've just been writing to it,
 *		you can now read from the bit you've written.
 */

void buf_flip(buf *b)
{
  b->limit = b->p; b->p = b->base;
  b->f &= ~BF_WRITE;
}

/* --- @buf_ensure@ --- *
 *
 * Arguments:	@buf *b@ = pointer to a buffer block
 *		@size_t sz@ = size of data wanted
 *
 * Returns:	Zero if it worked, nonzero if there wasn't enough space.
 *
 * Use:		Ensures that there are @sz@ bytes still in the buffer.
 */

int buf_ensure(buf *b, size_t sz) { return (BENSURE(b, sz)); }

/* --- @buf_tryextend@ --- *
 *
 * Arguments:	@buf *b@ = pointer to a buffer block
 *		@size_t sz@ = size of data wanted
 *
 * Returns:	Zero if it worked, nonzero if the buffer won't grow.
 *
 * Use:		Extend the buffer so that at least @sz@ bytes are available.
 *		This only works if the buffer is allocated.
 */

int buf_tryextend(buf *b, size_t sz)
{
  dbuf *db;
  size_t newsz, len;

  if (~b->f&(BF_ALLOC | BF_WRITE))
    { b->f |= BF_BROKEN; return (-1); }
  db = (dbuf *)b;
  len = BLEN(&db->_b); sz += len;
  if (db->sz >= sz)
    newsz = db->sz;
  else {
    newsz = db->sz ? 2*db->sz : 64;
    while (newsz < sz) { assert(newsz < ((size_t)-1)/2); newsz *= 2; }
    if (!db->_b.base) db->_b.base = x_alloc(db->a, newsz);
    else db->_b.base = x_realloc(db->a, db->_b.base, newsz, db->sz);
    db->_b.p = db->_b.base + len; db->sz = newsz;
  }
  db->_b.limit = db->_b.base + newsz;
  return (0);
}

/* --- @buf_get@ --- *
 *
 * Arguments:	@buf *b@ = pointer to a buffer block
 *		@size_t sz@ = size of the buffer
 *
 * Returns:	Pointer to the place in the buffer.
 *
 * Use:		Reserves a space in the buffer of the requested size, and
 *		returns its start address.
 */

void *buf_get(buf *b, size_t sz)
{
  void *p;
  if (BENSURE(b, sz))
    return (0);
  p = BCUR(b);
  BSTEP(b, sz);
  return (p);
}

/* --- @buf_put@ --- *
 *
 * Arguments:	@buf *b@ = pointer to a buffer block
 *		@const void *p@ = pointer to a buffer
 *		@size_t sz@ = size of the buffer
 *
 * Returns:	Zero if it worked, nonzero if there wasn't enough space.
 *
 * Use:		Fetches data from some place and puts it in the buffer
 */

int buf_put(buf *b, const void *p, size_t sz)
{
  if (BENSURE(b, sz))
    return (-1);
  memcpy(BCUR(b), p, sz);
  BSTEP(b, sz);
  return (0);
}

/* --- @buf_getbyte@ --- *
 *
 * Arguments:	@buf *b@ = pointer to a buffer block
 *
 * Returns:	A byte, or less than zero if there wasn't a byte there.
 *
 * Use:		Gets a single byte from a buffer.
 */

int buf_getbyte(buf *b)
{
  if (BENSURE(b, 1))
    return (-1);
  return (*b->p++);
}

/* --- @buf_putbyte@ --- *
 *
 * Arguments:	@buf *b@ = pointer to a buffer block
 *		@int ch@ = byte to write
 *
 * Returns:	Zero if OK, nonzero if there wasn't enough space.
 *
 * Use:		Puts a single byte in a buffer.
 */

int buf_putbyte(buf *b, int ch)
{
  if (BENSURE(b, 1))
    return (-1);
  *b->p++ = ch;
  return (0);
}

/* --- @buf_getu{8,{16,24,32,64}{,l,b}}@ --- *
 *
 * Arguments:	@buf *b@ = pointer to a buffer block
 *		@uintSZ *w@ = where to put the word
 *
 * Returns:	Zero if OK, or nonzero if there wasn't a word there.
 *
 * Use:		Gets a word of appropriate size and order from a buffer.
 */

#define BUF_GETU_(n, W, w)						\
  int buf_getu##w(buf *b, uint##n *ww)					\
  {									\
    if (BENSURE(b, SZ_##W)) return (-1);				\
    *ww = LOAD##W(b->p);						\
    BSTEP(b, SZ_##W);							\
    return (0);								\
  }
DOUINTCONV(BUF_GETU_)

/* --- @buf_getk64{,l,b}@ --- *
 *
 * Arguments:	@buf *b@ = pointer to a buffer block
 *		@kludge64 *w@ = where to put the word
 *
 * Returns:	Zero if OK, or nonzero if there wasn't a word there.
 *
 * Use:		Gets a word of appropriate size and order from a buffer.
 */

int buf_getk64(buf *b, kludge64 *w)
{
  if (BENSURE(b, 8)) return (-1);
  LOAD64_(*w, b->p); BSTEP(b, 8); return (0);
}

int buf_getk64l(buf *b, kludge64 *w)
{
  if (BENSURE(b, 8)) return (-1);
  LOAD64_L_(*w, b->p); BSTEP(b, 8); return (0);
}

int buf_getk64b(buf *b, kludge64 *w)
{
  if (BENSURE(b, 8)) return (-1);
  LOAD64_B_(*w, b->p); BSTEP(b, 8); return (0);
}

/* --- @buf_putu{8,{16,24,32,64}{,l,b}}@ --- *
 *
 * Arguments:	@buf *b@ = pointer to a buffer block
 *		@uintSZ w@ = word to write
 *
 * Returns:	Zero if OK, or nonzero if there wasn't enough space
 *
 * Use:		Puts a word into a buffer with appropriate size and order.
 */

#define BUF_PUTU_(n, W, w)						\
  int buf_putu##w(buf *b, uint##n ww)					\
  {									\
    if (BENSURE(b, SZ_##W)) return (-1);				\
    STORE##W(b->p, ww);							\
    BSTEP(b, SZ_##W);							\
    return (0);								\
  }
DOUINTCONV(BUF_PUTU_)

/* --- @buf_putk64{,l,b}@ --- *
 *
 * Arguments:	@buf *b@ = pointer to a buffer block
 *		@kludge64 w@ = word to write
 *
 * Returns:	Zero if OK, or nonzero if there wasn't enough space
 *
 * Use:		Gets a word of appropriate size and order from a buffer.
 */

int buf_putk64(buf *b, kludge64 w)
{
  if (BENSURE(b, 8)) return (-1);
  STORE64_(b->p, w); BSTEP(b, 8); return (0);
}

int buf_putk64l(buf *b, kludge64 w)
{
  if (BENSURE(b, 8)) return (-1);
  STORE64_L_(b->p, w); BSTEP(b, 8); return (0);
}

int buf_putk64b(buf *b, kludge64 w)
{
  if (BENSURE(b, 8)) return (-1);
  STORE64_B_(b->p, w); BSTEP(b, 8); return (0);
}

/* --- @findz@ --- *
 *
 * Arguments:	@buf *b@ = pointer to a buffer block
 *		@size_t *nn@ = where to put the length
 *
 * Returns:	Zero if OK, nonzero if there wasn't a null byte to be found.
 *
 * Use:		Finds a terminating null byte.  The length includes this
 *		terminator.
 */

static int findz(buf *b, size_t *nn)
{
  octet *p;

  if ((p = memchr(BCUR(b), 0, BLEFT(b))) == 0) {
    buf_break(b);
    return (-1);
  }
  *nn = p - BCUR(b) + 1;
  return (0);
}

/* --- @buf_getmem{8,{16,24,32,64}{,l,b},z} --- *
 *
 * Arguments:	@buf *b@ = pointer to a buffer block
 *		@size_t *nn@ = where to put the length
 *
 * Returns:	Pointer to the buffer data, or null.
 *
 * Use:		Gets a chunk of memory from a buffer.  The suffix is the
 *		width and byte order of the length; @z@ means null-
 *		terminated.
 */

#define BUF_GETMEM_(n, W, w)						\
  void *buf_getmem##w(buf *b, size_t *nn)				\
  {									\
    uint##n sz;								\
    if (buf_getu##w(b, &sz)) return (0);				\
    if (BENSURE(b, sz)) return (0);					\
    *nn = sz;								\
    return (buf_get(b, sz));						\
  }
DOUINTCONV(BUF_GETMEM_)

void *buf_getmemz(buf *b, size_t *nn)
{
  if (findz(b, nn)) return (0);
  return (buf_get(b, *nn));
}

#ifndef HAVE_UINT64

static void *getmem_k64(buf *b, size_t *nn_out, kludge64 k)
{
  kludge64 szmax;
  size_t n;

  ASSIGN64(szmax, (size_t)-1);
  if (CMP64(k, >, szmax)) { buf_break(b); return (-1); }
  n = GET64(size_t, k); *nn_out = n; return (buf_get(b, n));
}

void *buf_getmem64(buf *b, size_t *nn)
{
  kludge64 k;

  if (buf_getk64(b, &k)) return (-1);
  return (getmem_k64(b, nn, k));
}

void *buf_getmem64b(buf *b, size_t *nn)
{
  kludge64 k;

  if (buf_getk64b(b, &k)) return (-1);
  return (getmem_k64(b, nn, k));
}

void *buf_getmem64l(buf *b, size_t *nn)
{
  kludge64 k;

  if (buf_getk64l(b, &k)) return (-1);
  return (getmem_k64(b, nn, k));
}

#endif

/* --- @buf_putmem{8,{16,24,32,64}{,l,b},z} --- *
 *
 * Arguments:	@buf *b@ = pointer to a buffer block
 *		@const void *p@ = pointer to data to write
 *		@size_t n@ = length to write
 *
 * Returns:	Zero if OK, nonzero if there wasn't enough space.
 *
 * Use:		Writes a chunk of data to a buffer.  The suffix is the
 *		width and byte order of the length; @z@ means null-
 *		terminated.
 */

#define BUF_PUTMEM_(n, W, w)						\
  int buf_putmem##w(buf *b, const void *p, size_t sz)			\
  {									\
    MUFFLE_WARNINGS_STMT						\
      (CLANG_WARNING("-Wtautological-constant-out-of-range-compare"),	\
       { assert(sz <= MASK##W); });					\
    if (buf_putu##w(b, sz) || buf_put(b, p, sz))			\
      return (-1);							\
    return (0);								\
  }
DOUINTCONV(BUF_PUTMEM_)

#ifndef HAVE_UINT64

void *buf_putmem64(buf *b, const void *p, size_t n)
{
  kludge64 k;

  ASSIGN64(k, n); if (buf_putk64(b, k) || buf_put(b, p, n)) return (-1);
  return (0);
}

void *buf_putmem64b(buf *b, const void *p, size_t n)
{
  kludge64 k;

  ASSIGN64(k, n); if (buf_putk64b(b, k) || buf_put(b, p, n)) return (-1);
  return (0);
}

void *buf_putmem64l(buf *b, const void *p, size_t n)
{
  kludge64 k;

  ASSIGN64(k, n); if (buf_putk64l(b, k) || buf_put(b, p, n)) return (-1);
  return (0);
}

#endif

int buf_putmemz(buf *b, const void *p, size_t n)
{
  octet *q;

  assert(!memchr(p, 0, n));
  if ((q = buf_get(b, n + 1)) == 0)
    return (-1);
  memcpy(q, p, n);
  q[n] = 0;
  return (0);
}

/* --- @buf_getbuf{8,{16,24,32,64}{,l,b},z} --- *
 *
 * Arguments:	@buf *b@ = pointer to a buffer block
 *		@buf *bb@ = where to put the result
 *
 * Returns:	Zero if it worked, nonzero if there wasn't enough space.
 *
 * Use:		Gets a block of data from a buffer, and writes its bounds to
 *		another buffer.
 */

#define BUF_GETBUF_(n, W, w)						\
  int buf_getbuf##w(buf *b, buf *bb)					\
  {									\
    void *p;								\
    size_t sz;								\
									\
    if ((p = buf_getmem##w(b, &sz)) == 0)				\
      return (-1);							\
    buf_init(bb, p, sz);						\
    return (0);								\
  }
BUF_DOSUFFIXES(BUF_GETBUF_)

/* --- @buf_putbuf{8,{16,24,32,64}{,l,b},z} --- *
 *
 * Arguments:	@buf *b@ = pointer to a buffer block
 *		@buf *bb@ = buffer to write
 *
 * Returns:	Zero if it worked, nonzero if there wasn't enough space.
 *
 * Use:		Puts the contents of a buffer to a buffer.
 */

#define BUF_PUTBUF_(n, W, w)						\
  int buf_putbuf##w(buf *b, buf *bb)					\
    { return (buf_putmem##w(b, BBASE(bb), BLEN(bb))); }
BUF_DOSUFFIXES(BUF_PUTBUF_)

/* --- @buf_putstr{8,{16,24,32,64}{,l,b},z} --- *
 *
 * Arguments:	@buf *b@ = pointer to a buffer block
 *		@const char *p@ = string to write
 *
 * Returns:	Zero if it worked, nonzero if there wasn't enough space.
 *
 * Use:		Puts a null-terminated string to a buffer.
 */

#define BUF_PUTSTR_(n, W, w)						\
  int buf_putstr##w(buf *b, const char *p)				\
    { return (buf_putmem##w(b, p, strlen(p))); }
BUF_DOSUFFIXES(BUF_PUTSTR_)

/*----- That's all, folks -------------------------------------------------*/