/* base32.c

 * Base-32 conversion

 *

 * Wireshark - Network traffic analyzer

 * By Gerald Combs <gerald@wireshark.org>

 * Copyright 1998 Gerald Combs

 *

 * SPDX-License-Identifier: GPL-2.0-or-later

 */

#include "config.h"

#include "base32.h"

#include <string.h>

/*

 * Cjdns style base32 encoding

 */

/** Returned by ws_base32_encode() if the input is not valid base32. */

#define Base32_BAD_INPUT -1

/** Returned by ws_base32_encode() if the output buffer is too small. */

#define Base32_TOO_BIG -2

int ws_base32_decode(uint8_t* output, const uint32_t outputLength,

            const uint8_t* in, const uint32_t inputLength)

{

  uint32_t outIndex = 0;

  uint32_t inIndex = 0;

  uint32_t work = 0;

  uint32_t bits = 0;

  static const uint8_t* kChars = (uint8_t*) "0123456789bcdfghjklmnpqrstuvwxyz";

  while (inIndex < inputLength) {

    work |= ((unsigned) in[inIndex++]) << bits;

    bits += 8;

    while (bits >= 5) {

      if (outIndex >= outputLength) {

        return Base32_TOO_BIG;

      }

      output[outIndex++] = kChars[work & 31];

      bits -= 5;

      work >>= 5;

    }

  }

  if (bits) {

    if (outIndex >= outputLength) {

      return Base32_TOO_BIG;

    }

    output[outIndex++] = kChars[work & 31];

  }

  if (outIndex < outputLength) {

    output[outIndex] = '\0';

  }

  return outIndex;

}

/*

 * Editor modelines  -  https://www.wireshark.org/tools/modelines.html

 *

 * Local variables:

 * c-basic-offset: 8

 * tab-width: 8

 * indent-tabs-mode: t

 * End:

 *

 * vi: set shiftwidth=8 tabstop=8 noexpandtab:

 * :indentSize=8:tabSize=8:noTabs=false:

 */