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utils: Add helper functions to parse encoded types into regular ones

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Some virtual channels, like the location channel use encoded types to
lower the bandwidth usage.
Add common helper functions, so that each virtual channel doesn't have
to reimplement the parser functions again and again.
This commit is contained in:
Pascal Nowack 2023-10-16 17:09:09 +02:00 committed by akallabeth
parent 63e1863c9a
commit 5ec5be7ac4
3 changed files with 218 additions and 0 deletions
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40
include/freerdp/utils/encoded_types.h Normal file
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@ -0,0 +1,40 @@
/**
* FreeRDP: A Remote Desktop Protocol Implementation
*
* Helper functions to parse encoded types into regular ones
*
* Copyright 2023 Pascal Nowack <Pascal.Nowack@gmx.de>
*
* Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef FREERDP_UTILS_ENCODED_TYPES_H
#define FREERDP_UTILS_ENCODED_TYPES_H
#include <freerdp/api.h>
#include <winpr/stream.h>
#ifdef __cplusplus
extern "C"
{
#endif
FREERDP_API BOOL freerdp_read_four_byte_signed_integer(wStream* s, INT32* value);
FREERDP_API BOOL freerdp_read_four_byte_float(wStream* s, double* value);
#ifdef __cplusplus
}
#endif
#endif /* FREERDP_UTILS_ENCODED_TYPES_H */

1
libfreerdp/utils/CMakeLists.txt
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@ -19,6 +19,7 @@ set(MODULE_NAME "freerdp-utils")
set(MODULE_PREFIX "FREERDP_UTILS")
set(${MODULE_PREFIX}_SRCS
encoded_types.c
passphrase.c
cliprdr_utils.c
rdpdr_utils.c

177
libfreerdp/utils/encoded_types.c Normal file
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@ -0,0 +1,177 @@
/**
* FreeRDP: A Remote Desktop Protocol Implementation
*
* Helper functions to parse encoded types into regular ones
*
* Copyright 2023 Pascal Nowack <Pascal.Nowack@gmx.de>
*
* Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <freerdp/config.h>
#include <freerdp/channels/log.h>
#include <freerdp/utils/encoded_types.h>
#include <math.h>
#define TAG CHANNELS_TAG("encoded_types")
typedef enum
{
ONE_BYTE_VAL,
TWO_BYTE_VAL,
THREE_BYTE_VAL,
FOUR_BYTE_VAL,
FIVE_BYTE_VAL,
SIX_BYTE_VAL,
SEVEN_BYTE_VAL,
EIGHT_BYTE_VAL,
} EncodedTypeByteCount;
typedef enum
{
POSITIVE_VAL,
NEGATIVE_VAL,
} EncodedTypeSign;
typedef struct
{
EncodedTypeByteCount c;
EncodedTypeSign s;
BYTE val1;
BYTE val2;
BYTE val3;
BYTE val4;
} FOUR_BYTE_SIGNED_INTEGER;
typedef struct
{
EncodedTypeByteCount c;
EncodedTypeSign s;
BYTE e;
BYTE val1;
BYTE val2;
BYTE val3;
BYTE val4;
} FOUR_BYTE_FLOAT;
BOOL freerdp_read_four_byte_signed_integer(wStream* s, INT32* value)
{
FOUR_BYTE_SIGNED_INTEGER si = { 0 };
BYTE byte;
WINPR_ASSERT(s);
WINPR_ASSERT(value);
*value = 0;
if (!Stream_CheckAndLogRequiredLength(TAG, s, 1))
return FALSE;
Stream_Read_UINT8(s, byte);
si.c = (byte & 0xC0) >> 6;
si.s = (byte & 0x20) >> 5;
si.val1 = (byte & 0x1F);
if (!Stream_CheckAndLogRequiredLength(TAG, s, si.c))
return FALSE;
switch (si.c)
{
case ONE_BYTE_VAL:
*value = si.val1;
break;
case TWO_BYTE_VAL:
Stream_Read_UINT8(s, si.val2);
*value = si.val1 << 8 | si.val2;
break;
case THREE_BYTE_VAL:
Stream_Read_UINT8(s, si.val2);
Stream_Read_UINT8(s, si.val3);
*value = si.val1 << 16 | si.val2 << 8 | si.val3;
break;
case FOUR_BYTE_VAL:
Stream_Read_UINT8(s, si.val2);
Stream_Read_UINT8(s, si.val3);
Stream_Read_UINT8(s, si.val4);
*value = si.val1 << 24 | si.val2 << 16 | si.val3 << 8 | si.val4;
break;
default:
WLog_ERR(TAG, "Invalid byte count value in si.c: %u", si.c);
return FALSE;
}
if (si.s == NEGATIVE_VAL)
*value *= -1;
return TRUE;
}
BOOL freerdp_read_four_byte_float(wStream* s, double* value)
{
FOUR_BYTE_FLOAT f = { 0 };
UINT32 base;
BYTE byte;
WINPR_ASSERT(s);
WINPR_ASSERT(value);
*value = 0.0;
if (!Stream_CheckAndLogRequiredLength(TAG, s, 1))
return FALSE;
Stream_Read_UINT8(s, byte);
f.c = (byte & 0xC0) >> 6;
f.s = (byte & 0x20) >> 5;
f.e = (byte & 0x1C) >> 2;
f.val1 = (byte & 0x03);
if (!Stream_CheckAndLogRequiredLength(TAG, s, f.c))
return FALSE;
switch (f.c)
{
case ONE_BYTE_VAL:
base = f.val1;
break;
case TWO_BYTE_VAL:
Stream_Read_UINT8(s, f.val2);
base = f.val1 << 8 | f.val2;
break;
case THREE_BYTE_VAL:
Stream_Read_UINT8(s, f.val2);
Stream_Read_UINT8(s, f.val3);
base = f.val1 << 16 | f.val2 << 8 | f.val3;
break;
case FOUR_BYTE_VAL:
Stream_Read_UINT8(s, f.val2);
Stream_Read_UINT8(s, f.val3);
Stream_Read_UINT8(s, f.val4);
base = f.val1 << 24 | f.val2 << 16 | f.val3 << 8 | f.val4;
break;
default:
WLog_ERR(TAG, "Invalid byte count value in f.c: %u", f.c);
return FALSE;
}
*value = base;
*value /= pow(10, f.e);
if (f.s == NEGATIVE_VAL)
*value *= -1.0;
return TRUE;
}