mirror of https://gitee.com/openkylin/linux.git
26 lines
596 B
C
26 lines
596 B
C
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/*
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* linux/fs/ext2/bitmap.c
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*
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* Copyright (C) 1992, 1993, 1994, 1995
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* Remy Card (card@masi.ibp.fr)
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* Laboratoire MASI - Institut Blaise Pascal
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* Universite Pierre et Marie Curie (Paris VI)
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*/
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#include <linux/buffer_head.h>
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static int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};
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unsigned long ext2_count_free (struct buffer_head * map, unsigned int numchars)
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{
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unsigned int i;
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unsigned long sum = 0;
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if (!map)
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return (0);
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for (i = 0; i < numchars; i++)
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sum += nibblemap[map->b_data[i] & 0xf] +
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nibblemap[(map->b_data[i] >> 4) & 0xf];
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return (sum);
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}
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