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/*
* Copyright 2009, Google Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
// This file contains the declaration of functions for dealing with base64
// encoding and decoding
#include "utils/cross/base64.h"
#include "core/cross/types.h"
namespace o3d {
namespace base64 {
size_t GetEncodeLength(size_t length) {
return (length + 2) / 3 * 4;
}
void Encode(const void* src_ptr, size_t length, void* dst_ptr) {
const int kEncodePad = 64;
static const char kEncode[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz"
"0123456789+/=";
const uint8* src = reinterpret_cast<const uint8*>(src_ptr);
uint8* dst = reinterpret_cast<uint8*>(dst_ptr);
if (dst) {
size_t remainder = length % 3;
const uint8* end = &src[length - remainder];
while (src < end) {
unsigned a = *src++;
unsigned b = *src++;
unsigned c = *src++;
unsigned d = c & 0x3F;
c = (c >> 6 | b << 2) & 0x3F;
b = (b >> 4 | a << 4) & 0x3F;
a = a >> 2;
*dst++ = kEncode[a];
*dst++ = kEncode[b];
*dst++ = kEncode[c];
*dst++ = kEncode[d];
}
if (remainder > 0) {
unsigned k1 = 0;
unsigned k2 = kEncodePad;
unsigned a = *src++;
if (remainder == 2) {
int b = *src++;
k1 = b >> 4;
k2 = (b << 2) & 0x3F;
}
*dst++ = kEncode[a >> 2];
*dst++ = kEncode[(k1 | a << 4) & 0x3F];
*dst++ = kEncode[k2];
*dst++ = kEncode[kEncodePad];
}
}
}
// This function actually does the decoding.
// Parameters:
// src_ptr: pointer to the source data
// input_length: The length in bytes of the source data.
// dst_ptr: pointer to where the output data should be stored.
// dst_buffer_length: the size in bytes of the dst_ptr buffer. This
// is used to check for overflow. Not used if write_destination is
// false.
// output_length: The output length (in bytes) will be stored here if
// it is not null.
// write_destination: If true, actually write to the output. Otherwise,
// the length of the output will be determined only.
DecodeStatus PerformDecode(const void* src_ptr,
size_t input_length,
void* dst_ptr,
size_t dst_buffer_length,
size_t* output_length,
bool write_destination) {
const int kDecodePad = -2;
static const int8 kDecodeData[] = {
62, -1, -1, -1, 63,
52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, kDecodePad, -1, -1,
-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,
-1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51
};
uint8* dst = reinterpret_cast<uint8*>(dst_ptr);
const uint8* dst_start = reinterpret_cast<const uint8*>(dst_ptr);
const uint8* dst_end = dst_start + dst_buffer_length;
const uint8* src = reinterpret_cast<const uint8*>(src_ptr);
bool pad_two = false;
bool pad_three = false;
const uint8* end = src + input_length;
while (src < end) {
uint8 bytes[4];
int byte = 0;
do {
uint8 src_byte = *src++;
if (src_byte == 0)
goto goHome;
if (src_byte <= ' ')
continue; // treat as white space
if (src_byte < '+' || src_byte > 'z')
return kBadCharError;
int8 decoded = kDecodeData[src_byte - '+'];
bytes[byte] = decoded;
if (decoded < 0) {
if (decoded == kDecodePad)
goto handlePad;
return kBadCharError;
} else {
byte++;
}
if (*src)
continue;
if (byte == 0)
goto goHome;
if (byte == 4)
break;
handlePad:
if (byte < 2)
return kPadError;
pad_three = true;
if (byte == 2)
pad_two = true;
break;
} while (byte < 4);
int two, three;
if (write_destination) {
int one = (bytes[0] << 2) & 0xFF;
two = bytes[1];
one |= two >> 4;
two = (two << 4) & 0xFF;
three = bytes[2];
two |= three >> 2;
three = (three << 6) & 0xFF;
three |= bytes[3];
O3D_ASSERT(one < 256 && two < 256 && three < 256);
if (dst >= dst_end) {
return kOutputOverflowError;
}
*dst = one;
}
dst++;
if (pad_two)
break;
if (write_destination) {
if (dst >= dst_end) {
return kOutputOverflowError;
}
*dst = two;
}
dst++;
if (pad_three)
break;
if (write_destination) {
if (dst >= dst_end) {
return kOutputOverflowError;
}
*dst = three;
}
dst++;
}
goHome:
if (output_length) {
*output_length = dst - dst_start;
}
return kSuccess;
}
// Returns the number of bytes of output data after decoding from base64.
DecodeStatus GetDecodeLength(const void* src,
size_t input_length,
size_t* decode_length) {
return PerformDecode(src, input_length, NULL, 0, decode_length, false);
}
// Decodes the src data from base64 and stores the result in dst.
DecodeStatus Decode(const void* src,
size_t input_length,
void* dst,
size_t dst_buffer_length) {
return PerformDecode(src, input_length, dst, dst_buffer_length, NULL, true);
}
} // namespace base64
} // namespace o3d
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