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90 lines
1.8 KiB
C
90 lines
1.8 KiB
C
/*
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*
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* (c) 2005 Laurent Vivier <Laurent@Vivier.EU>
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*
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*/
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#include <sys/types.h>
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#include <string.h>
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#include <stdio.h>
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#include "libcontainer.h"
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#include "container.h"
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extern void error(char *x) __attribute__ ((noreturn));
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static unsigned long seek_block(stream_FILE *_file)
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{
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container_FILE *file = (container_FILE*)_file;
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struct emile_container *container = file->container;
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ssize_t current;
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int i;
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unsigned long offset = file->offset;
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int block_size = file->device->get_blocksize(file->device->data);
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for (i = 0, current = 0;
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container->blocks[i].offset != 0; i++)
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{
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int extent_size = block_size *
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container->blocks[i].count;
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if ( (current <= offset) && (offset < current + extent_size) )
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{
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return container->blocks[i].offset +
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(offset - current) / block_size;
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}
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current += extent_size;
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}
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return 0;
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}
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size_t container_read(stream_FILE *_file, void *ptr, size_t size)
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{
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container_FILE *file = (container_FILE*)_file;
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int err;
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ssize_t read = 0;
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int part;
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int block_size = file->device->get_blocksize(file->device->data);
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while (size != 0)
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{
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unsigned long block_nb;
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int block_offset;
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if (file->offset >= file->container->size)
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return read;
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block_nb = seek_block(_file);
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block_offset = file->offset % block_size;
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if (block_nb == 0)
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error("BUG in libcontainer !!!");
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if (block_nb != file->current_block)
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{
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err = file->device->read_sector(
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file->device->data,
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block_nb,
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file->buffer,
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block_size);
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if (err == -1)
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return -1;
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file->current_block = block_nb;
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}
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part = block_size - block_offset;
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if (part > size)
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part = size;
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memcpy(ptr, file->buffer + block_offset, part);
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size -= part;
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ptr = (char*)ptr + part;
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file->offset += 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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