GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: fx_utility_FAT_sector_get.c Lines: 9 9 100.0 %
Date: 2024-03-11 05:15:45 Branches: 4 4 100.0 %

Line Branch Exec Source
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/***************************************************************************
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 * Copyright (c) 2024 Microsoft Corporation
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 *
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 * This program and the accompanying materials are made available under the
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 * terms of the MIT License which is available at
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 * https://opensource.org/licenses/MIT.
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 *
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 * SPDX-License-Identifier: MIT
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 **************************************************************************/
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/**************************************************************************/
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/**************************************************************************/
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/**                                                                       */
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/** FileX Component                                                       */
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/**                                                                       */
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/**   Utility                                                             */
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/**                                                                       */
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/**************************************************************************/
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/**************************************************************************/
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#define FX_SOURCE_CODE
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/* Include necessary system files.  */
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#include "fx_api.h"
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#include "fx_utility.h"
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/**************************************************************************/
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/*                                                                        */
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/*  FUNCTION                                               RELEASE        */
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/*                                                                        */
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/*    _fx_utility_FAT_sector_get                          PORTABLE C      */
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/*                                                           6.1          */
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/*  AUTHOR                                                                */
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/*                                                                        */
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/*    William E. Lamie, Microsoft Corporation                             */
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/*                                                                        */
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/*  DESCRIPTION                                                           */
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/*                                                                        */
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/*    This function gets the sector of supplied FAT entry.                */
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/*                                                                        */
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/*  INPUT                                                                 */
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/*                                                                        */
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/*    media_ptr                             Media control block pointer   */
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/*    cluster                               Cluster entry number          */
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/*                                                                        */
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/*  OUTPUT                                                                */
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/*                                                                        */
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/*    return sector of FAT entry                                          */
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/*                                                                        */
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/*  CALLS                                                                 */
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/*                                                                        */
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/*                                                                        */
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/*  CALLED BY                                                             */
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/*                                                                        */
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/*    FileX System Functions                                              */
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/*                                                                        */
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/*  RELEASE HISTORY                                                       */
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/*                                                                        */
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/*    DATE              NAME                      DESCRIPTION             */
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/*                                                                        */
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/*  05-19-2020     William E. Lamie         Initial Version 6.0           */
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/*  09-30-2020     William E. Lamie         Modified comment(s),          */
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/*                                            resulting in version 6.1    */
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/*                                                                        */
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/**************************************************************************/
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ULONG  _fx_utility_FAT_sector_get(FX_MEDIA *media_ptr, ULONG cluster)
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{
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ULONG FAT_sector;
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ULONG byte_offset;
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    /* Determine which type of FAT is present.  */
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    if (media_ptr -> fx_media_12_bit_FAT)
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    {
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        /* 12-bit FAT is present.  */
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        /* Calculate the byte offset to the cluster entry.  */
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        byte_offset =  (((ULONG)cluster << 1) + cluster) >> 1;
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    }
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    else if (!media_ptr -> fx_media_32_bit_FAT)
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    {
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        /* 16-bit FAT is present.  */
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        /* Calculate the byte offset to the cluster entry.  */
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        byte_offset =  (((ULONG)cluster) << 1);
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    }
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    else
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    {
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        /* 32-bit FAT is present.  */
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        /* Calculate the byte offset to the cluster entry.  */
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        byte_offset =  (((ULONG)cluster) * 4);
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    }
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    /* Calculate the FAT sector the requested FAT entry resides in.  */
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    FAT_sector =  (byte_offset / media_ptr -> fx_media_bytes_per_sector) +
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        (ULONG)media_ptr -> fx_media_reserved_sectors;
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    /* Return successful status.  */
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    return(FAT_sector);
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}
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