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72 lines
1.3 KiB
C
72 lines
1.3 KiB
C
/*
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*
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* (c) 2005 Laurent Vivier <Laurent@lvivier.info>
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*
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*/
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#include <string.h>
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#include <stdio.h>
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#include "libiso9660.h"
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ssize_t iso9660_read(iso9660_FILE *file, void *buf, size_t count)
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{
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size_t read = 0;
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if ( count > (file->size - file->offset) )
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count = file->size - file->offset;
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while (count > 0)
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{
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size_t part;
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int offset_extent;
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int offset_index;
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offset_extent = file->base +
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(file->offset / ISO9660_EXTENT_SIZE);
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offset_index = file->offset % ISO9660_EXTENT_SIZE;
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if (file->current != offset_extent)
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{
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if ( (offset_index == 0) &&
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(count >= ISO9660_EXTENT_SIZE) )
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{
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/* direct i/o */
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int extents_nb;
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extents_nb = count / ISO9660_EXTENT_SIZE;
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part = extents_nb * ISO9660_EXTENT_SIZE;
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file->volume->device->read_sector(file->volume->device->data,
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offset_extent,
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buf + read, part);
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file->offset += part;
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count -= part;
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read += part;
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continue;
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}
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file->current = offset_extent;
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file->volume->device->read_sector(file->volume->device->data,
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offset_extent,
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file->buffer,
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ISO9660_EXTENT_SIZE);
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}
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part = ISO9660_EXTENT_SIZE - offset_index;
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if (count < part)
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part = count;
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memcpy(buf + read, file->buffer + offset_index, part);
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file->offset += part;
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count -= part;
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read += part;
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}
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return read;
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}
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