81 lines
2.4 KiB
C
81 lines
2.4 KiB
C
#include <kernel/fs/smem.h>
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#include <kernel/fs/file.h>
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#include <kernel/util.h>
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/* casio_smem_data_base_address() - Generate the fragmented data address (0xa0000000 + offset) */
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static void *casio_smem_get_data_base_address(casio_smem_fragment_t *fragment)
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{
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extern casio_smem_block_t *casio_smem_block_table;
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casio_smem_block_t *block;
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block = casio_smem_block_table;
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while (block->magic_start == CASIO_SMEM_BLOCK_ENTRY_MAGIC &&
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block->info.id != fragment->data_block_id)
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{
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block = block + 1;
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}
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if (block->info.id != fragment->data_block_id)
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return (NULL);
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return ((void *)(block->offset + fragment->data_offset));
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}
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/* casio_smem_read() - Read the file data (based on internal cursor) */
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ssize_t casio_smem_read(FILE *file, void *buf, size_t count)
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{
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casio_smem_fragment_t *fragment;
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off_t fragment_data_offset;
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void *data_base_addr;
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ssize_t current_size;
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size_t real_size;
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// Get Check obvious error.
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if (file == NULL || buf == NULL || file->cursor > (off_t)file->size)
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return (-1);
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// Get the "real" reading size
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if (file->size - file->cursor < count)
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count = file->size - file->cursor;
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// Get the current data fragment.
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current_size = 0;
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fragment = (void *)((uint32_t)file->abstract + sizeof(casio_smem_header_t));
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while (fragment->magic == CASIO_SMEM_FRAGMENT_MAGIC &&
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file->cursor > (off_t)(current_size + fragment->data_size + 1))
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{
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current_size = current_size + fragment->data_size + 1;
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fragment = fragment + 1;
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}
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fragment_data_offset = file->cursor - current_size;
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// Read file data
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current_size = 0;
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while (current_size < (ssize_t)count &&
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fragment->magic == CASIO_SMEM_FRAGMENT_MAGIC)
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{
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// Calculate the real size to read.
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real_size = fragment->data_size + 1 - fragment_data_offset;
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if (real_size >= count - current_size)
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real_size = count - current_size;
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// Get the data address.
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data_base_addr = casio_smem_get_data_base_address(fragment);
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if (data_base_addr == NULL)
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return (current_size);
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// Handle fragment data offset.
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if (fragment_data_offset != 0){
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data_base_addr = (void *)(((uint32_t)data_base_addr) + fragment_data_offset);
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fragment_data_offset = 0;
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}
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// Fill the buffer
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memcpy((void*)(buf + current_size), (void*)(0xa0000000 + data_base_addr), real_size);
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// Update informations.
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current_size = current_size + real_size;
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file->cursor = file->cursor + real_size;
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fragment = fragment + 1;
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}
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return (current_size);
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}
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