gecko-dev/xpcom/io/Base64.cpp

360 строки
9.1 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "Base64.h"
#include "nsIInputStream.h"
#include "nsString.h"
#include "plbase64.h"
namespace {
// BEGIN base64 encode code copied and modified from NSPR
const unsigned char* base =
(unsigned char*)"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz"
"0123456789+/";
template<typename T>
static void
Encode3to4(const unsigned char* aSrc, T* aDest)
{
uint32_t b32 = (uint32_t)0;
int i, j = 18;
for (i = 0; i < 3; ++i) {
b32 <<= 8;
b32 |= (uint32_t)aSrc[i];
}
for (i = 0; i < 4; ++i) {
aDest[i] = base[(uint32_t)((b32 >> j) & 0x3F)];
j -= 6;
}
}
template<typename T>
static void
Encode2to4(const unsigned char* aSrc, T* aDest)
{
aDest[0] = base[(uint32_t)((aSrc[0] >> 2) & 0x3F)];
aDest[1] = base[(uint32_t)(((aSrc[0] & 0x03) << 4) | ((aSrc[1] >> 4) & 0x0F))];
aDest[2] = base[(uint32_t)((aSrc[1] & 0x0F) << 2)];
aDest[3] = (unsigned char)'=';
}
template<typename T>
static void
Encode1to4(const unsigned char* aSrc, T* aDest)
{
aDest[0] = base[(uint32_t)((aSrc[0] >> 2) & 0x3F)];
aDest[1] = base[(uint32_t)((aSrc[0] & 0x03) << 4)];
aDest[2] = (unsigned char)'=';
aDest[3] = (unsigned char)'=';
}
template<typename T>
static void
Encode(const unsigned char* aSrc, uint32_t aSrcLen, T* aDest)
{
while (aSrcLen >= 3) {
Encode3to4(aSrc, aDest);
aSrc += 3;
aDest += 4;
aSrcLen -= 3;
}
switch (aSrcLen) {
case 2:
Encode2to4(aSrc, aDest);
break;
case 1:
Encode1to4(aSrc, aDest);
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];
uint8_t charsOnStack;
typename T::char_type* buffer;
};
template<typename T>
NS_METHOD
EncodeInputStream_Encoder(nsIInputStream* aStream,
void* aClosure,
const char* aFromSegment,
uint32_t aToOffset,
uint32_t aCount,
uint32_t* 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.
uint32_t 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
uint32_t 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,
uint32_t aCount,
uint32_t aOffset)
{
nsresult rv;
uint64_t count64 = aCount;
if (!aCount) {
rv = aInputStream->Available(&count64);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
// if count64 is over 4GB, it will be failed at the below condition,
// then will return NS_ERROR_OUT_OF_MEMORY
aCount = (uint32_t)count64;
}
uint64_t countlong =
(count64 + 2) / 3 * 4; // +2 due to integer math.
if (countlong + aOffset > UINT32_MAX) {
return NS_ERROR_OUT_OF_MEMORY;
}
uint32_t count = uint32_t(countlong);
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) {
uint32_t 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);
}
if (aDest.Length()) {
// May belong to an nsCString with an unallocated buffer, so only null
// terminate if there is a need to.
*aDest.EndWriting() = '\0';
}
return NS_OK;
}
} // namespace (anonymous)
namespace mozilla {
nsresult
Base64EncodeInputStream(nsIInputStream* aInputStream,
nsACString& aDest,
uint32_t aCount,
uint32_t aOffset)
{
return EncodeInputStream<nsACString>(aInputStream, aDest, aCount, aOffset);
}
nsresult
Base64EncodeInputStream(nsIInputStream* aInputStream,
nsAString& aDest,
uint32_t aCount,
uint32_t aOffset)
{
return EncodeInputStream<nsAString>(aInputStream, aDest, aCount, aOffset);
}
nsresult
Base64Encode(const nsACString& aBinaryData, nsACString& aString)
{
// Check for overflow.
if (aBinaryData.Length() > (UINT32_MAX / 4) * 3) {
return NS_ERROR_FAILURE;
}
// Don't ask PR_Base64Encode to encode empty strings
if (aBinaryData.IsEmpty()) {
aString.Truncate();
return NS_OK;
}
uint32_t stringLen = ((aBinaryData.Length() + 2) / 3) * 4;
char* buffer;
// Add one byte for null termination.
if (aString.SetCapacity(stringLen + 1, fallible_t()) &&
(buffer = aString.BeginWriting()) &&
PL_Base64Encode(aBinaryData.BeginReading(), aBinaryData.Length(), buffer)) {
// PL_Base64Encode doesn't null terminate the buffer for us when we pass
// the buffer in. Do that manually.
buffer[stringLen] = '\0';
aString.SetLength(stringLen);
return NS_OK;
}
aString.Truncate();
return NS_ERROR_INVALID_ARG;
}
nsresult
Base64Encode(const nsAString& aString, nsAString& aBinaryData)
{
NS_LossyConvertUTF16toASCII string(aString);
nsAutoCString binaryData;
nsresult rv = Base64Encode(string, binaryData);
if (NS_SUCCEEDED(rv)) {
CopyASCIItoUTF16(binaryData, aBinaryData);
} else {
aBinaryData.Truncate();
}
return rv;
}
nsresult
Base64Decode(const nsACString& aString, nsACString& aBinaryData)
{
// Check for overflow.
if (aString.Length() > UINT32_MAX / 3) {
return NS_ERROR_FAILURE;
}
// Don't ask PR_Base64Decode to decode the empty string
if (aString.IsEmpty()) {
aBinaryData.Truncate();
return NS_OK;
}
uint32_t binaryDataLen = ((aString.Length() * 3) / 4);
char* buffer;
// Add one byte for null termination.
if (aBinaryData.SetCapacity(binaryDataLen + 1, fallible_t()) &&
(buffer = aBinaryData.BeginWriting()) &&
PL_Base64Decode(aString.BeginReading(), aString.Length(), buffer)) {
// PL_Base64Decode doesn't null terminate the buffer for us when we pass
// the buffer in. Do that manually, taking into account the number of '='
// characters we were passed.
if (!aString.IsEmpty() && aString[aString.Length() - 1] == '=') {
if (aString.Length() > 1 && aString[aString.Length() - 2] == '=') {
binaryDataLen -= 2;
} else {
binaryDataLen -= 1;
}
}
buffer[binaryDataLen] = '\0';
aBinaryData.SetLength(binaryDataLen);
return NS_OK;
}
aBinaryData.Truncate();
return NS_ERROR_INVALID_ARG;
}
nsresult
Base64Decode(const nsAString& aBinaryData, nsAString& aString)
{
NS_LossyConvertUTF16toASCII binaryData(aBinaryData);
nsAutoCString string;
nsresult rv = Base64Decode(binaryData, string);
if (NS_SUCCEEDED(rv)) {
CopyASCIItoUTF16(string, aString);
} else {
aString.Truncate();
}
return rv;
}
} // namespace mozilla