/*
  * Copyright (c) 2006 Ryan Martell. (rdm4@martellventures.com)
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg 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
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 /**

  * @file

  * @brief Base64 encode/decode

  * @author Ryan Martell <rdm4@martellventures.com> (with lots of Michael)
  */
 
 #include "common.h"
 #include "base64.h"

 #include "intreadwrite.h"

 #include "timer.h"

 
 /* ---------------- private code */

 static const uint8_t map2[256] =

 {

     0xfe, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
     0xff, 0xff, 0xff,
 

     0x3e, 0xff, 0xff, 0xff, 0x3f, 0x34, 0x35, 0x36,
     0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0xff,

     0xff, 0xff, 0xfe, 0xff, 0xff, 0xff, 0x00, 0x01,

     0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
     0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11,
     0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19,
     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x1a, 0x1b,
     0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23,
     0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b,

     0x2c, 0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32, 0x33,
 
                       0xff, 0xff, 0xff, 0xff, 0xff,
     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

 };
 

 #define BASE64_DEC_STEP(i) do { \

     bits = map2[in[i]]; \
     if (bits & 0x80) \

         goto out ## i; \
     v = i ? (v << 6) + bits : bits; \

 } while(0)

 int av_base64_decode(uint8_t *out, const char *in_str, int out_size)

 {
     uint8_t *dst = out;

     uint8_t *end = out + out_size;

     // no sign extension
     const uint8_t *in = in_str;

     unsigned bits = 0xff;

     unsigned v;

     while (end - dst > 3) {

         BASE64_DEC_STEP(0);
         BASE64_DEC_STEP(1);
         BASE64_DEC_STEP(2);
         BASE64_DEC_STEP(3);

         // Using AV_WB32 directly confuses compiler

         v = av_be2ne32(v << 8);

         AV_WN32(dst, v);
         dst += 3;

         in += 4;
     }
     if (end - dst) {

         BASE64_DEC_STEP(0);
         BASE64_DEC_STEP(1);

         BASE64_DEC_STEP(2);
         BASE64_DEC_STEP(3);
         *dst++ = v >> 16;
         if (end - dst)
             *dst++ = v >> 8;
         if (end - dst)
             *dst++ = v;
         in += 4;

     }
     while (1) {

         BASE64_DEC_STEP(0);

         in++;

         BASE64_DEC_STEP(0);

         in++;

         BASE64_DEC_STEP(0);

         in++;

         BASE64_DEC_STEP(0);

         in++;

     }
 

 out3:
     *dst++ = v >> 10;
     v <<= 2;
 out2:
     *dst++ = v >> 4;
 out1:
 out0:

     return bits & 1 ? AVERROR_INVALIDDATA : dst - out;

 }
 
 /*****************************************************************************

 * b64_encode: Stolen from VLC's http.c.
 * Simplified by Michael.
 * Fixed edge cases and made it work from data (vs. strings) by Ryan.

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

 char *av_base64_encode(char *out, int out_size, const uint8_t *in, int in_size)

 {
     static const char b64[] =
         "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
     char *ret, *dst;
     unsigned i_bits = 0;
     int i_shift = 0;

     int bytes_remaining = in_size;

     if (in_size >= UINT_MAX / 4 ||

         out_size < AV_BASE64_SIZE(in_size))

         return NULL;

     ret = dst = out;

     while (bytes_remaining > 3) {
         i_bits = AV_RB32(in);
         in += 3; bytes_remaining -= 3;
         *dst++ = b64[ i_bits>>26        ];
         *dst++ = b64[(i_bits>>20) & 0x3F];
         *dst++ = b64[(i_bits>>14) & 0x3F];
         *dst++ = b64[(i_bits>>8 ) & 0x3F];
     }
     i_bits = 0;

     while (bytes_remaining) {

         i_bits = (i_bits << 8) + *in++;

         bytes_remaining--;
         i_shift += 8;
     }

     while (i_shift > 0) {

         *dst++ = b64[(i_bits << 6 >> i_shift) & 0x3f];

         i_shift -= 6;
     }

     while ((dst - ret) & 3)
         *dst++ = '=';

     *dst = '\0';
 
     return ret;
 }