Prevent some macros from re-evaluating their arguments.

[mLib] / dstr.h

/* -*-c-*-
 *
 * $Id: dstr.h,v 1.8 1999/07/14 19:45:24 mdw Exp $
 *
 * Handle dynamically growing strings
 *
 * (c) 1998 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.
 */

/*----- Revision history --------------------------------------------------*
 *
 * $Log: dstr.h,v $
 * Revision 1.8  1999/07/14 19:45:24  mdw
 * Prevent some macros from re-evaluating their arguments.
 *
 * Revision 1.7  1999/05/21 22:12:12  mdw
 * Fix the bugs in the new macros.  (Whoops.)
 *
 * Revision 1.6  1999/05/21 08:38:14  mdw
 * Add some more macros, particularly for creation and destruction.
 *
 * Revision 1.5  1999/05/13 22:47:57  mdw
 * Misc documentation fixes.  Change `-ise' to `-ize' throughout.
 *
 * Revision 1.4  1999/05/06 19:51:35  mdw
 * Reformatted the LGPL notice a little bit.
 *
 * Revision 1.3  1999/05/05 18:50:31  mdw
 * Change licensing conditions to LGPL.
 *
 * Revision 1.2  1998/12/15 23:53:23  mdw
 * New functions `dstr_putf' and `dstr_vputf' which do `printf'-style
 * formatting in a safe way.
 *
 * Revision 1.1.1.1  1998/06/17 23:44:42  mdw
 * Initial version of mLib
 *
 */

#ifndef DSTR_H
#define DSTR_H

#ifdef __cplusplus
  extern "C" {
#endif

/*----- Rationale ---------------------------------------------------------*
 *
 * This file declares what is hopefully a fairly useful collection of
 * primitive string handling functions.  The idea is that the strings
 * allocate memory for themselves as required.  The @dstr@ routines don't
 * assume any sort of terminator character, so arbitrary binary data can
 * be stored in a dynamic string.  With luck, this should put a stop to
 * any buffer overflow problems.
 */

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

#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>

/*----- Data structures ---------------------------------------------------*/

typedef struct dstr {
  char *buf;                            /* Pointer to string buffer */
  size_t sz;                            /* Size of the buffer */
  size_t len;                           /* Length of the string */
} dstr;

#define DSTR_INIT { 0, 0, 0 }           /* How to initialize one */

/*----- Functions provided ------------------------------------------------*/

/* --- @dstr_create@ --- *
 *
 * Arguments:   @dstr *d@ = pointer to a dynamic string block
 *
 * Returns:     ---
 *
 * Use:         Initializes a dynamic string.
 */

extern void dstr_create(dstr */*d*/);

#define DCREATE(d) do {                                                 \
  dstr *_dd = (d);                                                      \
  _dd->buf = 0;                                                         \
  _dd->sz = 0;                                                          \
  _dd->len = 0;                                                         \
} while (0)

/* --- @dstr_destroy@ --- *
 *
 * Arguments:   @dstr *d@ = pointer to a dynamic string block
 *
 * Returns:     ---
 *
 * Use:         Reclaims the space used by a dynamic string.
 */

extern void dstr_destroy(dstr */*d*/);

#define DDESTROY(d) do {                                                \
  dstr *_d = (d);                                                       \
  if (_d->buf)                                                          \
    free(_d->buf);                                                      \
  DCREATE(_d);                                                          \
} while (0)

/* --- @dstr_reset@ --- *
 *
 * Arguments:   @dstr *d@ = pointer to a dynaimc string block
 *
 * Returns:     ---
 *
 * Use:         Resets a string so that new data gets put at the beginning.
 */

extern void dstr_reset(dstr */*d*/);

#define DRESET(d) ((d)->len = 0)

/* --- @dstr_ensure@ --- *
 *
 * Arguments:   @dstr *d@ = pointer to a dynamic string block
 *              @size_t sz@ = amount of free space to ensure
 *
 * Returns:     ---
 *
 * Use:         Ensures that at least @sz@ bytes are available in the
 *              given string.
 */

extern void dstr_ensure(dstr */*d*/, size_t /*sz*/);

#define DENSURE(d, rq) do {                                             \
  dstr *_dd = (d);                                                      \
  size_t _rq = (rq);                                                    \
  if (_dd->len + _rq > _dd->sz) dstr_ensure(_dd, _rq);                  \
} while (0)

/* --- @dstr_putc@ --- *
 *
 * Arguments:   @dstr *d@ = pointer to a dynamic string block
 *              @char ch@ = character to append
 *
 * Returns:     ---
 *
 * Use:         Appends a character to a string.
 */

extern void dstr_putc(dstr */*d*/, char /*ch*/);

#define DPUTC(d, ch) do {                                               \
  dstr *_d = (d);                                                       \
  DENSURE(_d, 1);                                                       \
  _d->buf[_d->len++] = (ch);                                            \
} while (0)

/* --- @dstr_putz@ --- *
 *
 * Arguments:   @dstr *d@ = pointer to a dynamic string block
 *
 * Returns:     ---
 *
 * Use:         Appends a null byte to a string.  The null byte does not
 *              contribute to the string's length, and will be overwritten
 *              by subsequent `put' operations.
 */

extern void dstr_putz(dstr */*d*/);

#define DPUTZ(d) do {                                                   \
  dstr *_d = (d);                                                       \
  DENSURE(_d, 1);                                                       \
  _d->buf[_d->len] = 0;                                         \
} while (0)

/* --- @dstr_puts@ --- *
 *
 * Arguments:   @dstr *d@ = pointer to a dynamic string block
 *              @const char *s@ = pointer to string to append
 *
 * Returns:     ---
 *
 * Use:         Appends a character string to a string.  A trailing null
 *              byte is added, as for @dstr_putz@.
 */

extern void dstr_puts(dstr */*d*/, const char */*s*/);

#define DPUTS(d, s) do {                                                \
  dstr *_d = (d);                                                       \
  const char *_s = (s);                                                 \
  size_t _sz = strlen(s);                                               \
  DENSURE(_d, _sz + 1);                                                 \
  memcpy(_d->buf + _d->len, _s, _sz + 1);                               \
  _d->len += _sz;                                                       \
} while (0)

/* --- @dstr_vputf@ --- *
 *
 * Arguments:   @dstr *d@ = pointer to a dynamic string block
 *              @const char *p@ = pointer to @printf@-style format string
 *              @va_list ap@ = argument handle
 *
 * Returns:     The number of characters written to the string.
 *
 * Use:         As for @dstr_putf@, but may be used as a back-end to user-
 *              supplied functions with @printf@-style interfaces.
 */

extern int dstr_vputf(dstr */*d*/, const char */*p*/, va_list /*ap*/);

/* --- @dstr_putf@ --- *
 *
 * Arguments:   @dstr *d@ = pointer to a dynamic string block
 *              @const char *p@ = pointer to @printf@-style format string
 *              @...@ = argument handle
 *
 * Returns:     The number of characters written to the string.
 *
 * Use:         Writes a piece of text to a dynamic string, doing @printf@-
 *              style substitutions as it goes.  Intended to be robust if
 *              faced with malicious arguments, but not if the format string
 *              itself is malicious.
 */

extern int dstr_putf(dstr */*d*/, const char */*p*/, ...);

/* --- @dstr_putd@ --- *
 *
 * Arguments:   @dstr *d@ = pointer to a dynamic string block
 *              @const dstr *s@ = pointer to a dynamic string to append
 *
 * Returns:     ---
 *
 * Use:         Appends a dynamic string to a string.  A trailing null
 *              byte is added, as for @dstr_putz@.
 */

extern void dstr_putd(dstr */*d*/, const dstr */*s*/);

#define DPUTD(d, s) do {                                                \
  dstr *_d = (d);                                                       \
  const dstr *_s = (s);                                                 \
  DENSURE(_d, _s->len + 1);                                             \
  memcpy(_d->buf + _d->len, _s->buf, _s->len);                          \
  _d->len += _s->len;                                                   \
  _d->buf[_d->len] = 0;                                                 \
} while (0)

/* --- @dstr_putm@ --- *
 *
 * Arguments:   @dstr *d@ = pointer to a dynamic string block
 *              @const void *p@ = pointer to a block to append
 *              @size_t sz@ = size of the block
 *
 * Returns:     Appends an arbitrary data block to a string.  No trailing
 *              null is appended.
 */

extern void dstr_putm(dstr */*d*/, const void */*p*/, size_t /*sz*/);

#define DPUTM(d, p, sz) do {                                            \
  dstr *_d = (d);                                                       \
  size_t _sz = (sz);                                                    \
  DENSURE(_d, _sz);                                                     \
  memcpy(_d->buf + _d->len, (p), _sz);                                  \
  _d->len += _sz;                                                       \
} while (0)

/* --- @dstr_tidy@ --- *
 *
 * Arguments:   @dstr *d@ = pointer to a dynamic string block
 *
 * Returns:     ---
 *
 * Use:         Reduces the amount of memory used by a string.  A trailing
 *              null byte is added, as for @dstr_putz@.
 */

extern void dstr_tidy(dstr */*d*/);

/* --- @dstr_putline@ --- *
 *
 * Arguments:   @dstr *d@ = pointer to a dynamic string block
 *              @FILE *fp@ = a stream to read from
 *
 * Returns:     The number of characters read into the buffer, or @EOF@ if
 *              end-of-file was reached before any characters were read.
 *
 * Use:         Appends the next line from the given input stream to the
 *              string.  A trailing newline is not added; a trailing null
 *              byte is appended, as for @dstr_putz@.
 */

extern int dstr_putline(dstr */*d*/, FILE */*fp*/);

/* --- @dstr_write@ --- *
 *
 * Arguments:   @dstr *d@ = pointer to a dynamic string block
 *              @FILE *fp@ = a stream to write on
 *
 * Returns:     The number of bytes written (as for @fwrite@).
 *
 * Use:         Writes a dynamic string to a file.
 */

extern size_t dstr_write(const dstr */*d*/, FILE */*fp*/);

#define DWRITE(d, fp) fwrite((d)->buf, 1, (d)->len, (fp))

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

#ifdef __cplusplus
  }
#endif

#endif