nmap/nsock/src/filespace.c

/***************************************************************************
 * filespace.c -- a simple mechanism for storing dynamic amounts of data   *
 * in a simple to use, and quick to append-to structure.                   *
 *                                                                         *
 ***********************IMPORTANT NSOCK LICENSE TERMS***********************
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 ***************************************************************************/

/* $Id$ */

#include "nsock_internal.h"
#include "filespace.h"

#include <string.h>

#define FS_INITSIZE_DEFAULT 1024


/* Assumes space for fs has already been allocated */
int filespace_init(struct filespace *fs, int initial_size) {

  memset(fs, 0, sizeof(struct filespace));
  if (initial_size == 0)
    initial_size = FS_INITSIZE_DEFAULT;

  fs->current_alloc = initial_size;
  fs->str = (char *)safe_malloc(fs->current_alloc);
  fs->str[0] = '\0';
  fs->pos = fs->str;
  return 0;
}

/* Prepend an n-char string to a filespace */
int fs_prepend(char *str, int len, struct filespace *fs){
  char *tmpstr;

  if (len < 0)
    return -1;

  if (len == 0)
    return 0;

  if (fs->current_alloc - fs->current_size < len + 2) {
    fs->current_alloc = (int)(fs->current_alloc * 1.4 + 1);
    fs->current_alloc += 100 + len;

    tmpstr = (char *)safe_malloc(fs->current_alloc);
    memcpy(tmpstr, fs->str, fs->current_size);

    fs->pos = (fs->pos - fs->str) + tmpstr;
    if (fs->str)
      free(fs->str);

    fs->str = tmpstr;
  }
  if (fs->current_size > 0)
    memmove(fs->str + len, fs->str, fs->current_size);
  memcpy(fs->str, str, len);

  fs->current_size += len;
  fs->str[fs->current_size] = '\0';
  return 0;
}

/* Used when you want to start over with a filespace you have been using (it
 * sets the length to zero and the pointers to the beginning of memory , etc */
int fs_clear(struct filespace *fs) {
  fs->current_size = 0;
  fs->pos = fs->str;
  fs->str[0] = '\0'; /* Not necessary, possible help with debugging */
  return 0;
}

int fs_free(struct filespace *fs) {
  if (fs->str)
    free(fs->str);

  fs->current_alloc = fs->current_size = 0;
  fs->pos = fs->str = NULL;
  return 0;
}