Code:
/ Dotnetfx_Vista_SP2 / Dotnetfx_Vista_SP2 / 8.0.50727.4016 / DEVDIV / depot / DevDiv / releases / whidbey / NetFxQFE / ndp / fx / src / Net / System / Net / _ChunkParse.cs / 1 / _ChunkParse.cs
//------------------------------------------------------------------------------
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
//-----------------------------------------------------------------------------
namespace System.Net {
/*++
IReadChunkBytes - An interface for reading chunk streams.
An interface implemented by objects that read from chuked
streams. This interface is used by the chunk parsing
utility functions.
--*/
internal interface IReadChunkBytes {
int NextByte {get; set;}
} // interface IReadChunkBytes
internal static class ChunkParse {
/*++
SkipPastCRLF - Skip past the terminating CRLF.
An internal utility function. This is used to skip over any chunk
extensions or footers in a chunked response. We look through the
source bytes looking for the terminating CRLF, honoring any quoted
strings we see in the process.
Input:
Source - An IReadChunkBytes interface which we can
use to read the bytes from.
Returns:
The number of bytes we consumed, or -1 if there wasn't enough
in the buffer. We'll return a 0 if there's some sort of syntax
error.
--*/
internal static int
SkipPastCRLF(IReadChunkBytes Source) {
int BytesRead;
int Current;
bool Escape;
bool InQS;
bool HaveCR;
bool HaveLF;
BytesRead = 0;
Escape = false;
InQS = false;
HaveCR = false;
HaveLF = false;
GlobalLog.Enter("SkipPastCRLF");
// Loop through the buffer, looking at each byte. We have a
// pseudo state machine going here, and the action we take
// with each byte depends on the state.
Current = Source.NextByte;
BytesRead++;
while (Current != -1) {
// If we saw a CR last time, it must be followed by an unescaped
// LF, otherwise it's an error. If it is followed by a LF, and
// we're not in a quoted string, then we've found our termination.
// If we are in a quoted string, this could be the start of a LWS
// production. Remember that, and next time through we'll
// check to make sure that this is an LWS production.
if (HaveCR) {
if (Current != '\n') {
// CR w/o a trailing LF is an error.
GlobalLog.Leave("SkipPastCRLF", 0);
return 0;
}
else {
if (Escape) {
// We have an CR, but they're trying to escape the
// LF. This is an error.
GlobalLog.Leave("SkipPastCRLF", 0);
return 0;
}
// If we're not in a quoted string, we're done.
if (!InQS) {
// We've found the terminating CRLF pair.
GlobalLog.Leave("SkipPastCRLF", 0);
return BytesRead;
}
else {
// We're in a quoted string, so set HaveLF
// so we remember to check for a LWS production next
// time.
HaveLF = true;
// We've proceessed this byte, set Escape so we don't
// do it again.
Escape = true;
}
}
// We're past the CR now, don't remember it any more.
HaveCR = false;
}
else {
// If HaveLF is set, we must be in a quoted string and have
// seen a CRLF pair. Make sure this character is a space or
// tab.
if (HaveLF) {
// We have a LF. For this to be valid, we have to have a
// space or tab be the next character.
if (Current != ' ' && Current != '\t') {
// Not a continuation, so return an error.
GlobalLog.Leave("SkipPastCRLF", 0);
return 0;
}
Escape = true; // Don't process this byte again.
HaveLF = false;
}
}
// If we're escaping, just skip the next character.
if (!Escape) {
switch (Current) {
case '"':
if (InQS) {
InQS = false;
}
else {
InQS = true;
}
break;
case '\\':
if (InQS) {
Escape = true;
}
break;
case '\r':
HaveCR = true;
break;
case '\n':
// If we get here, we have a LF without a preceding CR.
// This is an error.
GlobalLog.Leave("SkipPastCRLF", 0);
return 0;
default:
break;
}
}
else {
// We're escaping, do nothing but rest the Escape flag.
Escape = false;
}
Current = Source.NextByte;
BytesRead++;
}
// If we get here, we never saw the terminating CRLF, so return -1.
GlobalLog.Leave("SkipPastCRLF", -1);
return -1;
}
/*++
GetChunkSize - Read the chunk size.
An internal utility function. Reads the chunk size from a
byte soruce, and returns the size or -1 if there isn't enough data.
Input:
Source - An IReadChunkBytes interface which we can
use to read the bytes from.
chunkSize - Out parameter for chunk size.
Returns:
The number of bytes we consumed, or -1 if there wasn't enough
in the buffer. We'll also return 0 if we have some sort of
syntax error.
--*/
internal static int
GetChunkSize(IReadChunkBytes Source, out int chunkSize) {
int BytesRead;
int Size;
int Current;
GlobalLog.Enter("GetChunkSize");
Size = 0;
//
// Loop while we have data. If we run out of data and exit the loop
// at the bottom, then we've run out of data and haven't found the
// length.
Current = Source.NextByte;
BytesRead = 0;
if (Current == 10 || Current == 13) {
GlobalLog.Print(" Got Char: " + Current.ToString("X"));
BytesRead++;
Current = Source.NextByte;
}
while (Current != -1) {
// Get the next byte, and decode it.
if (Current >= '0' && Current <= '9') {
// Normalize it to 0 based.
Current -= '0';
}
else {
// If we're here, this might be a hex digit.
// If it is, normalize it to 10 based.
if (Current >= 'a' && Current <= 'f') {
Current -= 'a';
}
else {
if (Current >= 'A' && Current <= 'F') {
Current -= 'A';
}
else {
// Done with the decoding. If we haven't actually
// decoded a digit yet, we'll end up returning
// 0, which will signal the error.
// Push back the byte we read and didn't use.
Source.NextByte = Current;
chunkSize = Size;
// Return how many bytes we took.
GlobalLog.Print("Chunk Size = " + Size.ToString());
GlobalLog.Leave("GetChunkSize", BytesRead);
return BytesRead;
}
}
// If we get here we've had an A-F digit, add 10
// to it to normalize it.
Current += 10;
}
// Update the size and our state.
Size *= 16;
Size += Current;
BytesRead++;
Current = Source.NextByte;
}
chunkSize = Size;
GlobalLog.Print("*Chunk Size* = " + Size.ToString());
GlobalLog.Leave("GetChunkSize", -1);
return -1;
}
} // ChunkParse
} // namespace System.Net
// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
//------------------------------------------------------------------------------
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
//-----------------------------------------------------------------------------
namespace System.Net {
/*++
IReadChunkBytes - An interface for reading chunk streams.
An interface implemented by objects that read from chuked
streams. This interface is used by the chunk parsing
utility functions.
--*/
internal interface IReadChunkBytes {
int NextByte {get; set;}
} // interface IReadChunkBytes
internal static class ChunkParse {
/*++
SkipPastCRLF - Skip past the terminating CRLF.
An internal utility function. This is used to skip over any chunk
extensions or footers in a chunked response. We look through the
source bytes looking for the terminating CRLF, honoring any quoted
strings we see in the process.
Input:
Source - An IReadChunkBytes interface which we can
use to read the bytes from.
Returns:
The number of bytes we consumed, or -1 if there wasn't enough
in the buffer. We'll return a 0 if there's some sort of syntax
error.
--*/
internal static int
SkipPastCRLF(IReadChunkBytes Source) {
int BytesRead;
int Current;
bool Escape;
bool InQS;
bool HaveCR;
bool HaveLF;
BytesRead = 0;
Escape = false;
InQS = false;
HaveCR = false;
HaveLF = false;
GlobalLog.Enter("SkipPastCRLF");
// Loop through the buffer, looking at each byte. We have a
// pseudo state machine going here, and the action we take
// with each byte depends on the state.
Current = Source.NextByte;
BytesRead++;
while (Current != -1) {
// If we saw a CR last time, it must be followed by an unescaped
// LF, otherwise it's an error. If it is followed by a LF, and
// we're not in a quoted string, then we've found our termination.
// If we are in a quoted string, this could be the start of a LWS
// production. Remember that, and next time through we'll
// check to make sure that this is an LWS production.
if (HaveCR) {
if (Current != '\n') {
// CR w/o a trailing LF is an error.
GlobalLog.Leave("SkipPastCRLF", 0);
return 0;
}
else {
if (Escape) {
// We have an CR, but they're trying to escape the
// LF. This is an error.
GlobalLog.Leave("SkipPastCRLF", 0);
return 0;
}
// If we're not in a quoted string, we're done.
if (!InQS) {
// We've found the terminating CRLF pair.
GlobalLog.Leave("SkipPastCRLF", 0);
return BytesRead;
}
else {
// We're in a quoted string, so set HaveLF
// so we remember to check for a LWS production next
// time.
HaveLF = true;
// We've proceessed this byte, set Escape so we don't
// do it again.
Escape = true;
}
}
// We're past the CR now, don't remember it any more.
HaveCR = false;
}
else {
// If HaveLF is set, we must be in a quoted string and have
// seen a CRLF pair. Make sure this character is a space or
// tab.
if (HaveLF) {
// We have a LF. For this to be valid, we have to have a
// space or tab be the next character.
if (Current != ' ' && Current != '\t') {
// Not a continuation, so return an error.
GlobalLog.Leave("SkipPastCRLF", 0);
return 0;
}
Escape = true; // Don't process this byte again.
HaveLF = false;
}
}
// If we're escaping, just skip the next character.
if (!Escape) {
switch (Current) {
case '"':
if (InQS) {
InQS = false;
}
else {
InQS = true;
}
break;
case '\\':
if (InQS) {
Escape = true;
}
break;
case '\r':
HaveCR = true;
break;
case '\n':
// If we get here, we have a LF without a preceding CR.
// This is an error.
GlobalLog.Leave("SkipPastCRLF", 0);
return 0;
default:
break;
}
}
else {
// We're escaping, do nothing but rest the Escape flag.
Escape = false;
}
Current = Source.NextByte;
BytesRead++;
}
// If we get here, we never saw the terminating CRLF, so return -1.
GlobalLog.Leave("SkipPastCRLF", -1);
return -1;
}
/*++
GetChunkSize - Read the chunk size.
An internal utility function. Reads the chunk size from a
byte soruce, and returns the size or -1 if there isn't enough data.
Input:
Source - An IReadChunkBytes interface which we can
use to read the bytes from.
chunkSize - Out parameter for chunk size.
Returns:
The number of bytes we consumed, or -1 if there wasn't enough
in the buffer. We'll also return 0 if we have some sort of
syntax error.
--*/
internal static int
GetChunkSize(IReadChunkBytes Source, out int chunkSize) {
int BytesRead;
int Size;
int Current;
GlobalLog.Enter("GetChunkSize");
Size = 0;
//
// Loop while we have data. If we run out of data and exit the loop
// at the bottom, then we've run out of data and haven't found the
// length.
Current = Source.NextByte;
BytesRead = 0;
if (Current == 10 || Current == 13) {
GlobalLog.Print(" Got Char: " + Current.ToString("X"));
BytesRead++;
Current = Source.NextByte;
}
while (Current != -1) {
// Get the next byte, and decode it.
if (Current >= '0' && Current <= '9') {
// Normalize it to 0 based.
Current -= '0';
}
else {
// If we're here, this might be a hex digit.
// If it is, normalize it to 10 based.
if (Current >= 'a' && Current <= 'f') {
Current -= 'a';
}
else {
if (Current >= 'A' && Current <= 'F') {
Current -= 'A';
}
else {
// Done with the decoding. If we haven't actually
// decoded a digit yet, we'll end up returning
// 0, which will signal the error.
// Push back the byte we read and didn't use.
Source.NextByte = Current;
chunkSize = Size;
// Return how many bytes we took.
GlobalLog.Print("Chunk Size = " + Size.ToString());
GlobalLog.Leave("GetChunkSize", BytesRead);
return BytesRead;
}
}
// If we get here we've had an A-F digit, add 10
// to it to normalize it.
Current += 10;
}
// Update the size and our state.
Size *= 16;
Size += Current;
BytesRead++;
Current = Source.NextByte;
}
chunkSize = Size;
GlobalLog.Print("*Chunk Size* = " + Size.ToString());
GlobalLog.Leave("GetChunkSize", -1);
return -1;
}
} // ChunkParse
} // namespace System.Net
// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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