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util.c

/*
 * Magic Rescue misc helper code
 * Copyright (C) 2004 Jonas Jensen <jbj@knef.dk>
 * 
 * This program 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 2
 * of the License, or (at your option) any later version.
 * 
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */
#include "config.h"

#include <sys/stat.h>
#include <sys/types.h>

#include <errno.h>
#include <dirent.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "util.h"


/** Returns the value (0-15) of a single hex digit. Returns 0 on error. */
int hex2num(char c)
{
    return  (c >= '0' && c <= '9' ? c-'0' :
          (c >= 'a' && c <= 'f' ? c-'a'+10 :
          (c >= 'A' && c <= 'F' ? c-'A'+10 : 0)));
}

long long hextoll(const char *str)
{
    long long result = 0;
    size_t i, len = strlen(str);

    for (i = 0; i < len; i++) {
      result |= (long long)hex2num(str[i]) << 4*((len-1) - i);
    }
    return result;
}

long atol_calc(const char *str)
{
    if (str[0] != '\0') {
      long result = atol(str);

      switch (str[strlen(str)-1]) {
          case 'G': result *= 1024;
          case 'M': result *= 1024;
          case 'k':
          case 'K': result *= 1024;
      }
      return result;

    } else {
      return 0;
    }
}

off_t rich_seek(int fd, const char *string)
{
    off_t offset;
    int whence = SEEK_SET;

    if (string) {
      const char *stroffset = string;
      int sign = 1;

      if (strchr("=+-", stroffset[0])) {
          switch (stroffset[0]) {
            case '+': whence = SEEK_CUR; break;
            case '-': whence = SEEK_END; sign = -1; break;
          }
          stroffset++;
      }

      if (stroffset[0] == '0' && stroffset[1] == 'x') {
          offset = (off_t)hextoll(stroffset + 2);
      } else {
#ifdef HAVE_ATOLL
          offset = (off_t)atoll(stroffset);
#else
          errno = ENOSYS;
          fprintf(stderr, "Get a C99 compiler or specify offset in hex\n");
          return -1;
#endif /* not HAVE_ATOLL */
      }

      offset *= sign;

    } else {
      offset = 0;
      whence = SEEK_CUR;
    }

    return lseek(fd, offset, whence);
}

/** Initializes a struct string from a 0-terminated string, parsing escape
 * sequences. The struct string will not be 0-terminated. */
void string_init(struct string *dst, const char *src)
{
    const size_t slen = strlen(src);
    size_t i;
    dst->l = 0;
    dst->s = malloc(slen);

    for (i = 0; i < slen; i++) {
      if (src[i] == '\\') {
          if (src[i+1] == 'x' && i + 3 < slen) {
            dst->s[dst->l++] = (hex2num(src[i+2])<<4) | hex2num(src[i+3]);
            i += 3;

          } else {
            i++;
            dst->s[dst->l++] = (
                  src[i] == 'a' ? '\a' : (
                  src[i] == 'b' ? '\b' : (
                  src[i] == 'f' ? '\f' : (
                  src[i] == 'n' ? '\n' : (
                  src[i] == 'r' ? '\r' : (
                  src[i] == 't' ? '\t' : (
                  src[i] == 'v' ? '\v' : (
                  src[i] ))))))));
          }

      } else {
          dst->s[dst->l++] = src[i];
      }
    }

    /* dst->s = realloc(dst->s, dst->l); // who cares? */
}

void string_destroy(struct string *string)
{
    free(string->s);
}

/* vim: ts=8 sw=4 noet tw=80
 */

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