mirror of https://github.com/pbatard/rufus.git
76 lines
2.1 KiB
C
76 lines
2.1 KiB
C
/* ----------------------------------------------------------------------- *
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*
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* Copyright 2004-2008 H. Peter Anvin - All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, Inc., 53 Temple Place Ste 330,
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* Boston MA 02111-1307, USA; either version 2 of the License, or
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* (at your option) any later version; incorporated herein by reference.
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*
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* ----------------------------------------------------------------------- */
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/*
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* cache.c
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*
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* Simple sector cache
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*/
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#include <stdlib.h>
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#include <malloc.h>
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#include "libfatint.h"
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/*
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* NB: We need to align our sector buffers to at least the 8-byte mark, as some Windows
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* disk devices, notably O2Micro PCI-E SD card readers, return ERROR_INVALID_PARAMETER
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* when attempting to use ReadFile() against a non 8-byte aligned buffer.
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* For good measure, we'll go further and align our buffers on a 16-byte boundary.
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* Also, since struct libfat_sector's data[0] is our buffer, this means we must BOTH
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* align that member in the struct declaration, and use aligned malloc/free.
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*/
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extern void _uprintf(const char *format, ...);
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void *libfat_get_sector(struct libfat_filesystem *fs, libfat_sector_t n)
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{
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struct libfat_sector *ls;
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for (ls = fs->sectors; ls; ls = ls->next) {
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if (ls->n == n)
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return ls->data; /* Found in cache */
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}
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/* Not found in cache */
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ls = _mm_malloc(sizeof(struct libfat_sector) + LIBFAT_SECTOR_SIZE, 16);
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if (!ls) {
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libfat_flush(fs);
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ls = _mm_malloc(sizeof(struct libfat_sector) + LIBFAT_SECTOR_SIZE, 16);
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if (!ls)
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return NULL; /* Can't allocate memory */
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}
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if (fs->read(fs->readptr, ls->data, LIBFAT_SECTOR_SIZE, n)
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!= LIBFAT_SECTOR_SIZE) {
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_mm_free(ls);
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return NULL; /* I/O error */
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}
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ls->n = n;
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ls->next = fs->sectors;
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fs->sectors = ls;
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return ls->data;
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}
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void libfat_flush(struct libfat_filesystem *fs)
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{
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struct libfat_sector *ls, *lsnext;
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lsnext = fs->sectors;
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fs->sectors = NULL;
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for (ls = lsnext; ls; ls = lsnext) {
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lsnext = ls->next;
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_mm_free(ls);
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}
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}
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