/***************************************************************************

 *                                  _   _ ____  _

 *  Project                     ___| | | |  _ \| |

 *                             / __| | | | |_) | |

 *                            | (__| |_| |  _ <| |___

 *                             \___|\___/|_| \_\_____|

 *

 * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.

 *

 * This software is licensed as described in the file COPYING, which

 * you should have received as part of this distribution. The terms

 * are also available at https://curl.se/docs/copyright.html.

 *

 * You may opt to use, copy, modify, merge, publish, distribute and/or sell

 * copies of the Software, and permit persons to whom the Software is

 * furnished to do so, under the terms of the COPYING file.

 *

 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY

 * KIND, either express or implied.

 *

 * SPDX-License-Identifier: curl

 *

 ***************************************************************************/

#include <errno.h>

#include "curl_setup.h"

#include "strtoofft.h"

/*

 * NOTE:

 *

 * In the ISO C standard (IEEE Std 1003.1), there is a strtoimax() function we

 * could use in case strtoll() doesn't exist...  See

 * https://www.opengroup.org/onlinepubs/009695399/functions/strtoimax.html

 */

#if (SIZEOF_CURL_OFF_T > SIZEOF_LONG)

#  ifdef HAVE_STRTOLL

#    define strtooff strtoll

#  else

#    if defined(_MSC_VER) && (_MSC_VER >= 1300) && (_INTEGRAL_MAX_BITS >= 64)

#      if defined(_SAL_VERSION)

         _Check_return_ _CRTIMP __int64 __cdecl _strtoi64(

             _In_z_ const char *_String,

             _Out_opt_ _Deref_post_z_ char **_EndPtr, _In_ int _Radix);

#      else

         _CRTIMP __int64 __cdecl _strtoi64(const char *_String,

                                           char **_EndPtr, int _Radix);

#      endif

#      define strtooff _strtoi64

#    else

#      define PRIVATE_STRTOOFF 1

#    endif

#  endif

#else

#  define strtooff strtol

#endif

#ifdef PRIVATE_STRTOOFF

/* Range tests can be used for alphanum decoding if characters are consecutive,

   like in ASCII. Else an array is scanned. Determine this condition now. */

#if('9' - '0') != 9 || ('Z' - 'A') != 25 || ('z' - 'a') != 25

#define NO_RANGE_TEST

static const char valchars[] =

            "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";

#endif

static int get_char(char c, int base);

/**

 * Custom version of the strtooff function.  This extracts a curl_off_t

 * value from the given input string and returns it.

 */

static curl_off_t strtooff(const char *nptr, char **endptr, int base)

{

  char *end;

  int is_negative = 0;

  int overflow;

  int i;

  curl_off_t value = 0;

  curl_off_t newval;

  /* Skip leading whitespace. */

  end = (char *)nptr;

  while(ISBLANK(end[0])) {

    end++;

  }

  /* Handle the sign, if any. */

  if(end[0] == '-') {

    is_negative = 1;

    end++;

  }

  else if(end[0] == '+') {

    end++;

  }

  else if(end[0] == '\0') {

    /* We had nothing but perhaps some whitespace -- there was no number. */

    if(endptr) {

      *endptr = end;

    }

    return 0;

  }

  /* Handle special beginnings, if present and allowed. */

  if(end[0] == '0' && end[1] == 'x') {

    if(base == 16 || base == 0) {

      end += 2;

      base = 16;

    }

  }

  else if(end[0] == '0') {

    if(base == 8 || base == 0) {

      end++;

      base = 8;

    }

  }

  /* Matching strtol, if the base is 0 and it doesn't look like

   * the number is octal or hex, we assume it's base 10.

   */

  if(base == 0) {

    base = 10;

  }

  /* Loop handling digits. */

  value = 0;

  overflow = 0;

  for(i = get_char(end[0], base);

      i != -1;

      end++, i = get_char(end[0], base)) {

    newval = base * value + i;

    if(newval < value) {

      /* We've overflowed. */

      overflow = 1;

      break;

    }

    else

      value = newval;

  }

  if(!overflow) {

    if(is_negative) {

      /* Fix the sign. */

      value *= -1;

    }

  }

  else {

    if(is_negative)

      value = CURL_OFF_T_MIN;

    else

      value = CURL_OFF_T_MAX;

    errno = ERANGE;

  }

  if(endptr)

    *endptr = end;

  return value;

}

/**

 * Returns the value of c in the given base, or -1 if c cannot

 * be interpreted properly in that base (i.e., is out of range,

 * is a null, etc.).

 *

 * @param c     the character to interpret according to base

 * @param base  the base in which to interpret c

 *

 * @return  the value of c in base, or -1 if c isn't in range

 */

static int get_char(char c, int base)

{

#ifndef NO_RANGE_TEST

  int value = -1;

  if(c <= '9' && c >= '0') {

    value = c - '0';

  }

  else if(c <= 'Z' && c >= 'A') {

    value = c - 'A' + 10;

  }

  else if(c <= 'z' && c >= 'a') {

    value = c - 'a' + 10;

  }

#else

  const char *cp;

  int value;

  cp = memchr(valchars, c, 10 + 26 + 26);

  if(!cp)

    return -1;

  value = cp - valchars;

  if(value >= 10 + 26)

    value -= 26;                /* Lowercase. */

#endif

  if(value >= base) {

    value = -1;

  }

  return value;

}

#endif  /* Only present if we need strtoll, but don't have it. */

/*

 * Parse a *positive* up to 64 bit number written in ascii.

 */

CURLofft curlx_strtoofft(const char *str, char **endp, int base,

                         curl_off_t *num)

{

  char *end;

  curl_off_t number;

  errno = 0;

  *num = 0; /* clear by default */

  DEBUGASSERT(base); /* starting now, avoid base zero */

  while(*str && ISBLANK(*str))

    str++;

  if(('-' == *str) || (ISSPACE(*str))) {

    if(endp)

      *endp = (char *)str; /* didn't actually move */

    return CURL_OFFT_INVAL; /* nothing parsed */

  }

  number = strtooff(str, &end, base);

  if(endp)

    *endp = end;

  if(errno == ERANGE)

    /* overflow/underflow */

    return CURL_OFFT_FLOW;

  else if(str == end)

    /* nothing parsed */

    return CURL_OFFT_INVAL;

  *num = number;

  return CURL_OFFT_OK;

}