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[mLib] / dstr.c

/* -*-c-*-
 *
 * $Id: dstr.c,v 1.3 1999/05/05 18:50:31 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.c,v $
 * Revision 1.3  1999/05/05 18:50:31  mdw
 * Change licensing conditions to LGPL.
 *
 * Revision 1.2  1998/12/15 23:53:22  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
 *
 */

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

#include <ctype.h>
#include <float.h>
#include <math.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "alloc.h"
#include "dstr.h"

/*----- Tunable constants -------------------------------------------------*/

#define DSTR_INITSZ 256			/* Initial buffer size */
#define DSTR_INCSZ 4096			/* Threshhold for doubling */
#define DSTR_PUTFSTEP 64		/* Buffer size for @putf@ */

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

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

void dstr_create(dstr *d)
{
  d->sz = 0;
  d->len = 0;
  d->buf = 0;
}

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

void dstr_destroy(dstr *d)
{
  if (d->buf)
    free(d->buf);
  d->buf = 0;
  d->len = 0;
  d->sz = 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.
 */

void dstr_reset(dstr *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.
 */

void dstr_ensure(dstr *d, size_t sz)
{
  size_t rq = d->len + sz;
  size_t nsz;

  /* --- If we have enough space, just leave it --- */

  if (rq <= d->sz)
    return;

  /* --- Grow the buffer --- *
   *
   * For small buffers, just double the size.  For big buffers, make them
   * a multiple of some suitably large chunk size.
   */

  nsz = d->sz;

  do {
    if (nsz == 0)
      nsz = DSTR_INITSZ;
    else if (d->sz < 0x1000)
      nsz <<= 1;
    else
      nsz = (rq + 0x0fff) & ~0x0fff;
  } while (rq > nsz);

  if (d->buf)
    d->buf = xrealloc(d->buf, nsz);
  else
    d->buf = xmalloc(nsz);
  d->sz = nsz;
}

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

void dstr_putc(dstr *d, char ch)
{
  DPUTC(d, ch);
}

/* --- @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.
 */

void dstr_putz(dstr *d)
{
  DPUTZ(d);
}

/* --- @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@.
 */

void dstr_puts(dstr *d, const char *s)
{
  DPUTS(d, s);
}

/* --- @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:	---
 *
 * Use:		As for @dstr_putf@, but may be used as a back-end to user-
 *		supplied functions with @printf@-style interfaces.
 */

int dstr_vputf(dstr *d, const char *p, va_list ap)
{
  const char *q = p;
  size_t n = d->len;
  size_t sz;

  while (*p) {
    unsigned f;
    int wd, prec;
    dstr dd;

    enum {
      f_short = 1,
      f_long = 2,
      f_Long = 4,
      f_wd = 8,
      f_prec = 16
    };

    /* --- Most stuff gets passed on through --- */

    if (*p != '%') {
      p++;
      continue;
    }

    /* --- Dump out what's between @q@ and @p@ --- */

    DPUTM(d, q, p - q);
    p++;

    /* --- Sort out the various silly flags and things --- */

    dstr_create(&dd);
    DPUTC(&dd, '%');
    f = 0;
    sz = DSTR_PUTFSTEP;

    for (;;) {
      switch (*p) {

	/* --- Various simple flags --- */

	case '+':
	case '-':
	case '#':
	case '0':
	  goto putch;
	case 'h':
	  f |= f_short;
	  goto putch;
	case 'l':
	  f |= f_long;
	  goto putch;
	case 'L':
	  f |= f_Long;
	  goto putch;
	case 0:
	  goto finished;

	/* --- Field widths and precision specifiers --- */

	{
	  int *ip;

	case '.':
	  DPUTC(&dd, '.');
	  ip = &prec;
	  f |= f_prec;
	  goto getnum;
	case '*':
	  ip = &wd;
	  f |= f_wd;
	  goto getnum;
	default:
	  if (isdigit((unsigned char)*p)) {
	    f |= f_prec;
	    ip = &wd;
	    goto getnum;
	  }
	  DPUTC(d, *p);
	  goto formatted;
        getnum:
	  *ip = 0;
	  if (*p == '*') {
	    *ip = va_arg(ap, int);
	    DENSURE(&dd, DSTR_PUTFSTEP);
	    dd.len += sprintf(dd.buf + dd.len, "%i", *ip);
	  } else {
	    *ip = *p + '0';
	    DPUTC(&dd, *p);
	    p++;
	    while (isdigit((unsigned char)*p)) {
	      DPUTC(&dd, *p);
	      *ip = 10 * *ip + *p++ + '0';
	    }
	  }
	  break;
	}

	/* --- Output formatting --- */

	case 'd': case 'i': case 'x': case 'X': case 'o': case 'u':
	  DPUTC(&dd, *p);
	  DPUTZ(&dd);
	  if ((f & f_prec) && prec + 16 > sz)
	    sz = prec + 16;
	  if ((f & f_wd) && wd + 1> sz)
	    sz = wd + 1;
	  DENSURE(d, sz);
	  if (f & f_long)
	    d->len += sprintf(d->buf + d->len, dd.buf,
			      va_arg(ap, unsigned long));
	  else
	    d->len += sprintf(d->buf + d->len, dd.buf,
			      va_arg(ap, unsigned int));
	  goto formatted;

	case 'e': case 'E': case 'f': case 'F': case 'g': case 'G':
	  DPUTC(&dd, *p);
	  DPUTZ(&dd);
	  if (*p == 'f') {
	    size_t mx = (f & f_Long ? LDBL_MAX_10_EXP : DBL_MAX_10_EXP) + 16;
	    if (mx > sz)
	      sz = mx;
	  }
	  if ((f & f_prec) == 0)
	    prec = 6;
	  if ((f & f_prec))
	    sz += prec + 16;	    
	  if ((f & f_wd) && wd + 1 > sz)
	    sz = wd + 1;
	  DENSURE(d, sz);
	  if (f & f_Long)
	    d->len += sprintf(d->buf + d->len, dd.buf,
			      va_arg(ap, long double));
	  else
	    d->len += sprintf(d->buf + d->len, dd.buf,
			      va_arg(ap, double));
	  goto formatted;

	case 'c':
	  DPUTC(&dd, *p);
	  DPUTZ(&dd);
	  if ((f & f_wd) && wd + 1> sz)
	    sz = wd + 1;
	  DENSURE(d, sz);
	  d->len += sprintf(d->buf + d->len, dd.buf,
			    va_arg(ap, unsigned char));
	  goto formatted;

	case 's': {
	  const char *s = va_arg(ap, const char *);
	  sz = strlen(s);
	  DPUTC(&dd, *p);
	  DPUTZ(&dd);
	  if (f & f_prec)
	    sz = prec;
	  if ((f & f_wd) && wd > sz)
	    sz = wd;
	  DENSURE(d, sz + 1);
	  d->len += sprintf(d->buf + d->len, dd.buf, s);
	  goto formatted;
	}

	case 'p':
	  DPUTC(&dd, *p);
	  DPUTZ(&dd);
	  if ((f & f_prec) && prec + 16 > sz)
	    sz = prec + 16;
	  if ((f & f_wd) && wd + 1> sz)
	    sz = wd + 1;
	  DENSURE(d, sz);
	  d->len += sprintf(d->buf + d->len, dd.buf,
			    va_arg(ap, const void *));
	  goto formatted;

	case 'n':
	  if (f & f_long)
	    *va_arg(ap, long *) = (long)(d->len - n);
	  else if (f & f_short)
	    *va_arg(ap, short *) = (short)(d->len - n);
	  else
	    *va_arg(ap, int *) = (int)(d->len - n);
	  goto formatted;

	/* --- Other random stuff --- */

	putch:
	  DPUTC(&dd, *p);
	  p++;
	  break;
      }
    }

  formatted:
    dstr_destroy(&dd);
    q = ++p;
  }

  DPUTM(d, q, p - q);
finished:
  DPUTZ(d);
  return (d->len - n);
}

/* --- @dstr_putf@ --- *
 *
 * Arguments:	@dstr *d@ = pointer to a dynamic string block
 *		@const char *p@ = pointer to @printf@-style format string
 *		@...@ = argument handle
 *
 * Returns:	---
 *
 * 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.
 */

int dstr_putf(dstr *d, const char *p, ...)
{
  int n;
  va_list ap;
  va_start(ap, p);
  n = dstr_vputf(d, p, ap);
  va_end(ap);
  return (n);
}

/* --- @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@.
 */

void dstr_putd(dstr *d, const dstr *s)
{
  DPUTD(d, s);
}

/* --- @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.
 */

void dstr_putm(dstr *d, const void *p, size_t sz)
{
  DPUTM(d, p, sz);
}

/* --- @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@.
 */

void dstr_tidy(dstr *d)
{
  dstr_putz(d);
  d->buf = xrealloc(d->buf, d->len + 1);
  d->sz = d->len + 1;
}

/* --- @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@.
 */

int dstr_putline(dstr *d, FILE *fp)
{
  size_t left = d->sz - d->len;
  size_t off = d->len;
  int rd = 0;
  int ch;

  for (;;) {

    /* --- Make sure there's some buffer space --- */

    if (!left) {
      dstr_ensure(d, 1);
      left = d->sz - off;
    }

    /* --- Read the next byte --- */

    ch = getc(fp);

    /* --- End-of-file when no characters read is special --- */

    if (ch == EOF && !rd)
      return (EOF);

    /* --- End-of-file or newline ends the loop --- */

    if (ch == EOF || ch == '\n') {
      d->buf[off] = 0;
      d->len = off;
      return rd;
    }

    /* --- Append the character and continue --- */

    d->buf[off++] = ch;
    left--; rd++;
  }
}

/* --- @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.
 */

size_t dstr_write(dstr *d, FILE *fp)
{
  return (fwrite(d->buf, 1, d->len, fp));
}

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