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// SPDX-License-Identifier: GPL-2.0
/*
* The Virtual DVB test driver serves as a reference DVB driver and helps
* validate the existing APIs in the media subsystem. It can also aid
* developers working on userspace applications.
*
* Copyright (C) 2020 Daniel W. S. Almeida
*/
#define pr_fmt(fmt) KBUILD_MODNAME ":%s, %d: " fmt, __func__, __LINE__
#include <linux/printk.h>
#include <linux/ratelimit.h>
#include <linux/string.h>
#include <linux/types.h>
#include "vidtv_common.h"
/**
* vidtv_memcpy() - wrapper routine to be used by MPEG-TS
* generator, in order to avoid going past the
* output buffer.
* @to: Starting element to where a MPEG-TS packet will
* be copied.
* @to_offset: Starting position of the @to buffer to be filled.
* @to_size: Size of the @to buffer.
* @from: Starting element of the buffer to be copied.
* @len: Number of elements to be copy from @from buffer
* into @to+ @to_offset buffer.
*
* Note:
* Real digital TV demod drivers should not have memcpy
* wrappers. We use it here because emulating MPEG-TS
* generation at kernelspace requires some extra care.
*
* Return:
* Returns the number of bytes written
*/
u32 vidtv_memcpy(void *to,
size_t to_offset,
size_t to_size,
const void *from,
size_t len)
{
if (unlikely(to_offset + len > to_size)) {
pr_err_ratelimited("overflow detected, skipping. Try increasing the buffer size. Needed %zu, had %zu\n",
to_offset + len,
to_size);
return 0;
}
memcpy(to + to_offset, from, len);
return len;
}
/**
* vidtv_memset() - wrapper routine to be used by MPEG-TS
* generator, in order to avoid going past the
* output buffer.
* @to: Starting element to set
* @to_offset: Starting position of the @to buffer to be filled.
* @to_size: Size of the @to buffer.
* @c: The value to set the memory to.
* @len: Number of elements to be copy from @from buffer
* into @to+ @to_offset buffer.
*
* Note:
* Real digital TV demod drivers should not have memset
* wrappers. We use it here because emulating MPEG-TS
* generation at kernelspace requires some extra care.
*
* Return:
* Returns the number of bytes written
*/
u32 vidtv_memset(void *to,
size_t to_offset,
size_t to_size,
const int c,
size_t len)
{
if (unlikely(to_offset + len > to_size)) {
pr_err_ratelimited("overflow detected, skipping. Try increasing the buffer size. Needed %zu, had %zu\n",
to_offset + len,
to_size);
return 0;
}
memset(to + to_offset, c, len);
return len;
}
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