gecko-dev/xpcom/io/Base64.cpp

259 строки
7.4 KiB
C++

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is the Netscape Portable Runtime (NSPR).
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998-2000
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Kyle Huey <me@kylehuey.com>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#include "Base64.h"
#include "nsIInputStream.h"
namespace {
// BEGIN base64 encode code copied and modified from NSPR
const unsigned char *base = (unsigned char *)"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
template <typename T>
static void
Encode3to4(const unsigned char *src, T *dest)
{
PRUint32 b32 = (PRUint32)0;
PRIntn i, j = 18;
for( i = 0; i < 3; i++ )
{
b32 <<= 8;
b32 |= (PRUint32)src[i];
}
for( i = 0; i < 4; i++ )
{
dest[i] = base[ (PRUint32)((b32>>j) & 0x3F) ];
j -= 6;
}
}
template <typename T>
static void
Encode2to4(const unsigned char *src, T *dest)
{
dest[0] = base[ (PRUint32)((src[0]>>2) & 0x3F) ];
dest[1] = base[ (PRUint32)(((src[0] & 0x03) << 4) | ((src[1] >> 4) & 0x0F)) ];
dest[2] = base[ (PRUint32)((src[1] & 0x0F) << 2) ];
dest[3] = (unsigned char)'=';
}
template <typename T>
static void
Encode1to4(const unsigned char *src, T *dest)
{
dest[0] = base[ (PRUint32)((src[0]>>2) & 0x3F) ];
dest[1] = base[ (PRUint32)((src[0] & 0x03) << 4) ];
dest[2] = (unsigned char)'=';
dest[3] = (unsigned char)'=';
}
template <typename T>
static void
Encode(const unsigned char *src, PRUint32 srclen, T *dest)
{
while( srclen >= 3 )
{
Encode3to4(src, dest);
src += 3;
dest += 4;
srclen -= 3;
}
switch( srclen )
{
case 2:
Encode2to4(src, dest);
break;
case 1:
Encode1to4(src, dest);
break;
case 0:
break;
default:
NS_NOTREACHED("coding error");
}
}
// END base64 encode code copied and modified from NSPR.
template <typename T>
struct EncodeInputStream_State {
unsigned char c[3];
PRUint8 charsOnStack;
typename T::char_type* buffer;
};
template <typename T>
NS_METHOD
EncodeInputStream_Encoder(nsIInputStream *aStream,
void *aClosure,
const char *aFromSegment,
PRUint32 aToOffset,
PRUint32 aCount,
PRUint32 *aWriteCount)
{
NS_ASSERTION(aCount > 0, "Er, what?");
EncodeInputStream_State<T>* state =
static_cast<EncodeInputStream_State<T>*>(aClosure);
// If we have any data left from last time, encode it now.
PRUint32 countRemaining = aCount;
const unsigned char *src = (const unsigned char*)aFromSegment;
if (state->charsOnStack) {
unsigned char firstSet[4];
if (state->charsOnStack == 1) {
firstSet[0] = state->c[0];
firstSet[1] = src[0];
firstSet[2] = (countRemaining > 1) ? src[1] : '\0';
firstSet[3] = '\0';
} else /* state->charsOnStack == 2 */ {
firstSet[0] = state->c[0];
firstSet[1] = state->c[1];
firstSet[2] = src[0];
firstSet[3] = '\0';
}
Encode(firstSet, 3, state->buffer);
state->buffer += 4;
countRemaining -= (3 - state->charsOnStack);
src += (3 - state->charsOnStack);
state->charsOnStack = 0;
}
// Encode the bulk of the
PRUint32 encodeLength = countRemaining - countRemaining % 3;
NS_ABORT_IF_FALSE(encodeLength % 3 == 0,
"Should have an exact number of triplets!");
Encode(src, encodeLength, state->buffer);
state->buffer += (encodeLength / 3) * 4;
src += encodeLength;
countRemaining -= encodeLength;
// We must consume all data, so if there's some data left stash it
*aWriteCount = aCount;
if (countRemaining) {
// We should never have a full triplet left at this point.
NS_ABORT_IF_FALSE(countRemaining < 3, "We should have encoded more!");
state->c[0] = src[0];
state->c[1] = (countRemaining == 2) ? src[1] : '\0';
state->charsOnStack = countRemaining;
}
return NS_OK;
}
template <typename T>
nsresult
EncodeInputStream(nsIInputStream *aInputStream,
T &aDest,
PRUint32 aCount,
PRUint32 aOffset)
{
nsresult rv;
if (!aCount) {
rv = aInputStream->Available(&aCount);
NS_ENSURE_SUCCESS(rv, rv);
}
PRUint32 count = (aCount + 2) / 3 * 4; // +2 due to integer math.
aDest.SetLength(count + aOffset);
if (aDest.Length() != count + aOffset)
return NS_ERROR_OUT_OF_MEMORY;
EncodeInputStream_State<T> state;
state.charsOnStack = 0;
state.c[2] = '\0';
state.buffer = aOffset + aDest.BeginWriting();
while (1) {
PRUint32 read = 0;
rv = aInputStream->ReadSegments(&EncodeInputStream_Encoder<T>,
(void*)&state,
aCount,
&read);
if (NS_FAILED(rv)) {
if (rv == NS_BASE_STREAM_WOULD_BLOCK)
NS_RUNTIMEABORT("Not implemented for async streams!");
if (rv == NS_ERROR_NOT_IMPLEMENTED)
NS_RUNTIMEABORT("Requires a stream that implements ReadSegments!");
return rv;
}
if (!read)
break;
}
// Finish encoding if anything is left
if (state.charsOnStack)
Encode(state.c, state.charsOnStack, state.buffer);
*aDest.EndWriting() = '\0';
return NS_OK;
}
} // namespace (anonymous)
namespace mozilla {
nsresult
Base64EncodeInputStream(nsIInputStream *aInputStream,
nsACString &aDest,
PRUint32 aCount,
PRUint32 aOffset)
{
return EncodeInputStream<nsACString>(aInputStream, aDest, aCount, aOffset);
}
nsresult
Base64EncodeInputStream(nsIInputStream *aInputStream,
nsAString &aDest,
PRUint32 aCount,
PRUint32 aOffset)
{
return EncodeInputStream<nsAString>(aInputStream, aDest, aCount, aOffset);
}
} // namespace mozilla