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// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.
#include "node.h"
#include "node_buffer.h"
#include "v8.h"
#include "v8-profiler.h"
#include <assert.h>
#include <string.h> // memcpy
#include <limits.h> // INT_MAX
namespace node {
using v8::Handle;
using v8::String;
// TODO: base64, hex, binary
enum StringEncoding {
kAscii,
kUtf8,
kUcs2
};
class StringDecoder {
private:
size_t len_;
char* data_;
char* storage_;
size_t GetStorageSize(Handle<String> string, enum StringEncoding encoding);
void WriteData(Handle<String> string, enum StringEncoding encoding, size_t storage_size);
public:
char* Data() {
return data_;
}
size_t Length() {
return len_;
}
StringDecoder (Handle<String> string, enum StringEncoding encoding);
~StringDecoder();
};
StringDecoder::StringDecoder (
Handle<String> string, enum StringEncoding encoding) {
// TODO If the length is really small, make data a pointer to
// a location on the stack instead of using heap allocated memory
size_t storage_size = GetStorageSize(string, encoding);
if (storage_size > INT_MAX) {
len_ = 0;
data_ = NULL;
return;
}
// always align the data to word boundary
storage_ = new char[storage_size + 15];
data_ = reinterpret_cast<char*>(ROUND_UP(
reinterpret_cast<uintptr_t>(storage_), 16));
WriteData(string, encoding, storage_size);
}
void StringDecoder::WriteData(
Handle<String> string, enum StringEncoding encoding, size_t storage_size) {
switch (encoding) {
case kAscii:
len_ = string->WriteAscii(data_, 0, -1,
String::NO_NULL_TERMINATION | String::HINT_MANY_WRITES_EXPECTED);
break;
case kUtf8:
len_ = string->WriteUtf8(data_, -1, NULL,
String::NO_NULL_TERMINATION | String::HINT_MANY_WRITES_EXPECTED);
break;
case kUcs2: {
int chars_copied = string->Write((uint16_t*) data_, 0, -1,
String::NO_NULL_TERMINATION | String::HINT_MANY_WRITES_EXPECTED);
len_ = chars_copied * sizeof(uint16_t);
break;
}
default:
// Unreachable
assert(0);
}
assert(len_ <= storage_size);
}
StringDecoder::~StringDecoder() {
if (storage_ != NULL)
delete[] storage_;
}
// Compute the size of the storage that the string will be flattened into.
size_t StringDecoder::GetStorageSize(
Handle<String> string, enum StringEncoding encoding) {
size_t storage_size;
switch (encoding) {
case kAscii:
storage_size = string->Length();
break;
case kUtf8:
if (!(string->MayContainNonAscii())) {
// If the string has only ascii characters, we know exactly how big
// the storage should be.
storage_size = string->Length();
} else if (string->Length() < 65536) {
// A single UCS2 codepoint never takes up more than 3 utf8 bytes.
// Unless the string is really long we just allocate so much space that
// we're certain the string fits in there entirely.
// TODO: maybe check handle->write_queue_size instead of string length?
storage_size = 3 * string->Length();
} else {
// The string is really long. Compute the allocation size that we
// actually need.
storage_size = string->Utf8Length();
}
break;
case kUcs2:
storage_size = string->Length() * sizeof(uint16_t);
break;
default:
// Unreachable.
assert(0);
}
return storage_size;
}
} // namespace node
@trevnorris

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commented May 1, 2013

If this is going into master then you'll need a different way to MayContainNonAscii. Comment says "This function is no longer useful." and is, or will be soon, deprecated.

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