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common/usbx_host_classes/src/ux_host_class_hid_report_compress.c
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/**************************************************************************/
/* */
/* Copyright (c) Microsoft Corporation. All rights reserved. */
/* */
/* This software is licensed under the Microsoft Software License */
/* Terms for Microsoft Azure RTOS. Full text of the license can be */
/* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */
/* and in the root directory of this software. */
/* */
/**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/** */
/** USBX Component */
/** */
/** HID Class */
/** */
/**************************************************************************/
/**************************************************************************/
/* Include necessary system files. */
#define UX_SOURCE_CODE
#include "ux_api.h"
#include "ux_host_class_hid.h"
#include "ux_host_stack.h"
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _ux_host_class_hid_report_compress PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Chaoqiong Xiao, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function will compress a client report into a report buffer. */
/* */
/* INPUT */
/* */
/* hid Pointer to HID class */
/* client_report Pointer to client report */
/* report_buffer Pointer to report buffer */
/* report_length Length of report */
/* */
/* OUTPUT */
/* */
/* Completion Status */
/* */
/* CALLS */
/* */
/* None */
/* */
/* CALLED BY */
/* */
/* HID Class */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Chaoqiong Xiao Initial Version 6.0 */
/* 09-30-2020 Chaoqiong Xiao Modified comment(s), */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
UINT _ux_host_class_hid_report_compress(UX_HOST_CLASS_HID *hid, UX_HOST_CLASS_HID_CLIENT_REPORT *client_report,
UCHAR *report_buffer, ULONG report_length)
{
UX_HOST_CLASS_HID_REPORT *hid_report;
UX_HOST_CLASS_HID_FIELD *hid_field;
ULONG field_usage;
ULONG field_report_count;
ULONG field_report_size;
ULONG *client_buffer;
ULONG client_value;
UCHAR value;
ULONG data_offset_bit;
UCHAR is_valid_usage;
UX_PARAMETER_NOT_USED(hid);
UX_PARAMETER_NOT_USED(report_length);
/* Get the report pointer from the caller. */
hid_report = client_report -> ux_host_class_hid_client_report;
/* Get the pointer to the user buffer. */
client_buffer = client_report -> ux_host_class_hid_client_report_buffer;
/* Get the first field associated with the report. */
hid_field = hid_report -> ux_host_class_hid_report_field;
/* Set data offset bit. */
data_offset_bit = 0;
/* We need to compress each field defined in the report. */
while (hid_field != UX_NULL)
{
/* Each report field has a report count value. This count is used to extract
values from the incoming report and build each usage/value instance. */
for (field_report_count = 0; field_report_count < hid_field -> ux_host_class_hid_field_report_count; field_report_count++)
{
/* Ensure the usage in the client buffer is valid. How we determine
this depends on whether the field is VARIABLE or ARRAY. */
is_valid_usage = UX_FALSE;
if (hid_field -> ux_host_class_hid_field_value & UX_HOST_CLASS_HID_ITEM_VARIABLE)
{
/* Go through the usage array to try and find the client's usage. */
for (field_usage = 0; field_usage < hid_field -> ux_host_class_hid_field_number_usage; field_usage++)
{
/* Is this a usage we've recorded? */
if (*client_buffer == hid_field -> ux_host_class_hid_field_usages[field_usage])
{
/* Yes, this is a valid usage. */
is_valid_usage = UX_TRUE;
break;
}
}
}
else
{
/* Is the usage page valid? */
if (((*client_buffer & 0xffff0000) >> 16) == hid_field -> ux_host_class_hid_field_usage_page)
{
/* Is the usage in the min and max range? */
if ((*client_buffer & 0xffff) >= hid_field -> ux_host_class_hid_field_usage_min &&
(*client_buffer & 0xffff) <= hid_field -> ux_host_class_hid_field_usage_max)
{
/* Yes, this is a valid usage. */
is_valid_usage = UX_TRUE;
}
}
}
/* Is the usage invalid? */
if (is_valid_usage == UX_FALSE)
{
/* Error trap. */
_ux_system_error_handler(UX_SYSTEM_LEVEL_THREAD, UX_SYSTEM_CONTEXT_CLASS, UX_HOST_CLASS_HID_REPORT_ERROR);
/* If trace is enabled, insert this event into the trace buffer. */
UX_TRACE_IN_LINE_INSERT(UX_TRACE_ERROR, UX_HOST_CLASS_HID_REPORT_ERROR, hid, 0, 0, UX_TRACE_ERRORS, 0, 0)
return(UX_HOST_CLASS_HID_REPORT_ERROR);
}
/* Skip the usage and point the buffer to the value. */
client_buffer++;
/* Read the client value. */
client_value = *client_buffer++;
/* Build the value field in the report buffer bit by bit. */
for (field_report_size = hid_field -> ux_host_class_hid_field_report_size; field_report_size > 0; field_report_size--)
{
/* Isolate each bit from the report value. */
value = (UCHAR) client_value & 1;
/* Shift the isolated bit to its right space in the report byte. */
value = (UCHAR)(value << data_offset_bit);
/* Update the report with the bit value. */
*report_buffer |= value;
/* Move to next bit. */
data_offset_bit++;
/* Are we on a byte boundary. */
if ((data_offset_bit & 7) == 0)
{
/* If so increment the report address. */
report_buffer++;
/* Reset offset bit. */
data_offset_bit = 0;
}
/* Move to the next bit. */
client_value = client_value >> 1;
}
}
/* Move to the next field. */
hid_field = hid_field -> ux_host_class_hid_field_next_field;
}
/* Return successful completion. */
return(UX_SUCCESS);
}