//
// System.Net.ChunkStream
//
// Authors:
// Gonzalo Paniagua Javier (gonzalo@ximian.com)
//
// (C) 2003 Ximian, Inc (http://www.ximian.com)
//
//
// 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.
//
using System.Collections;
using System.Globalization;
using System.IO;
using System.Text;
namespace System.Net{
class ChunkStream
{
enum State {
None,
Body,
BodyFinished,
Trailer
}
class Chunk {
public byte [] Bytes;
public int Offset;
public Chunk (byte [] chunk)
{
this.Bytes = chunk;
}
public int Read (byte [] buffer, int offset, int size)
{
int nread = (size > Bytes.Length - Offset) ? Bytes.Length - Offset : size;
Buffer.BlockCopy (Bytes, Offset, buffer, offset, nread);
Offset += nread;
return nread;
}
}
internal WebHeaderCollection headers;
int chunkSize;
int chunkRead;
State state;
//byte [] waitBuffer;
StringBuilder saved;
bool sawCR;
bool gotit;
int trailerState;
ArrayList chunks;
public ChunkStream (byte [] buffer, int offset, int size, WebHeaderCollection headers)
: this (headers)
{
Write (buffer, offset, size);
}
public ChunkStream (WebHeaderCollection headers)
{
this.headers = headers;
saved = new StringBuilder ();
chunks = new ArrayList ();
chunkSize = -1;
}
public void ResetBuffer ()
{
chunkSize = -1;
chunkRead = 0;
chunks.Clear ();
}
public void WriteAndReadBack (byte [] buffer, int offset, int size, ref int read)
{
if (offset + read > 0)
Write (buffer, offset, offset+read);
read = Read (buffer, offset, size);
}
public int Read (byte [] buffer, int offset, int size)
{
return ReadFromChunks (buffer, offset, size);
}
int ReadFromChunks (byte [] buffer, int offset, int size)
{
int count = chunks.Count;
int nread = 0;
for (int i = 0; i < count; i++) {
Chunk chunk = (Chunk) chunks [i];
if (chunk == null)
continue;
if (chunk.Offset == chunk.Bytes.Length) {
chunks [i] = null;
continue;
}
nread += chunk.Read (buffer, offset + nread, size - nread);
if (nread == size)
break;
}
return nread;
}
public void Write (byte [] buffer, int offset, int size)
{
InternalWrite (buffer, ref offset, size);
}
void InternalWrite (byte [] buffer, ref int offset, int size)
{
if (state == State.None) {
state = GetChunkSize (buffer, ref offset, size);
if (state == State.None)
return;
saved.Length = 0;
sawCR = false;
gotit = false;
}
if (state == State.Body && offset < size) {
state = ReadBody (buffer, ref offset, size);
if (state == State.Body)
return;
}
if (state == State.BodyFinished && offset < size) {
state = ReadCRLF (buffer, ref offset, size);
if (state == State.BodyFinished)
return;
sawCR = false;
}
if (state == State.Trailer && offset < size) {
state = ReadTrailer (buffer, ref offset, size);
if (state == State.Trailer)
return;
saved.Length = 0;
sawCR = false;
gotit = false;
}
if (offset < size)
InternalWrite (buffer, ref offset, size);
}
public bool WantMore {
get { return (chunkRead != chunkSize || chunkSize != 0 || state != State.None); }
}
public int ChunkLeft {
get { return chunkSize - chunkRead; }
}
State ReadBody (byte [] buffer, ref int offset, int size)
{
if (chunkSize == 0)
return State.BodyFinished;
int diff = size - offset;
if (diff + chunkRead > chunkSize)
diff = chunkSize - chunkRead;
byte [] chunk = new byte [diff];
Buffer.BlockCopy (buffer, offset, chunk, 0, diff);
chunks.Add (new Chunk (chunk));
offset += diff;
chunkRead += diff;
return (chunkRead == chunkSize) ? State.BodyFinished : State.Body;
}
State GetChunkSize (byte [] buffer, ref int offset, int size)
{
char c = '\0';
while (offset < size) {
c = (char) buffer [offset++];
if (c == '\r') {
if (sawCR)
ThrowProtocolViolation ("2 CR found");
sawCR = true;
continue;
}
if (sawCR && c == '\n')
break;
if (c == ' ')
gotit = true;
if (!gotit)
saved.Append (c);
if (saved.Length > 20)
ThrowProtocolViolation ("chunk size too long.");
}
if (!sawCR || c != '\n') {
if (offset < size)
ThrowProtocolViolation ("Missing \\n");
try {
if (saved.Length > 0) {
chunkSize = Int32.Parse (RemoveChunkExtension (saved.ToString ()), NumberStyles.HexNumber);
}
} catch (Exception) {
ThrowProtocolViolation ("Cannot parse chunk size.");
}
return State.None;
}
chunkRead = 0;
try {
chunkSize = Int32.Parse (RemoveChunkExtension (saved.ToString ()), NumberStyles.HexNumber);
} catch (Exception) {
ThrowProtocolViolation ("Cannot parse chunk size.");
}
if (chunkSize == 0) {
trailerState = 2;
return State.Trailer;
}
return State.Body;
}
static string RemoveChunkExtension (string input)
{
int idx = input.IndexOf (';');
if (idx == -1)
return input;
return input.Substring (0, idx);
}
State ReadCRLF (byte [] buffer, ref int offset, int size)
{
if (!sawCR) {
if ((char) buffer [offset++] != '\r')
ThrowProtocolViolation ("Expecting \\r");
sawCR = true;
if (offset == size)
return State.BodyFinished;
}
if (sawCR && (char) buffer [offset++] != '\n')
ThrowProtocolViolation ("Expecting \\n");
return State.None;
}
State ReadTrailer (byte [] buffer, ref int offset, int size)
{
char c = '\0';
// short path
if (trailerState == 2 && (char) buffer [offset] == '\r' && saved.Length == 0) {
offset++;
if (offset < size && (char) buffer [offset] == '\n') {
offset++;
return State.None;
}
offset--;
}
int st = trailerState;
string stString = "\r\n\r";
while (offset < size && st < 4) {
c = (char) buffer [offset++];
if ((st == 0 || st == 2) && c == '\r') {
st++;
continue;
}
if ((st == 1 || st == 3) && c == '\n') {
st++;
continue;
}
if (st > 0) {
saved.Append (stString.Substring (0, saved.Length == 0? st-2: st));
st = 0;
if (saved.Length > 4196)
ThrowProtocolViolation ("Error reading trailer (too long).");
}
}
if (st < 4) {
trailerState = st;
if (offset < size)
ThrowProtocolViolation ("Error reading trailer.");
return State.Trailer;
}
StringReader reader = new StringReader (saved.ToString ());
string line;
while ((line = reader.ReadLine ()) != null && line != "")
headers.Add (line);
return State.None;
}
static void ThrowProtocolViolation (string message)
{
WebException we = new WebException (message, null, WebExceptionStatus.ServerProtocolViolation, null);
throw we;
}
}
}
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