/**
* This fills the file's currentFATData buffer with the next block of FAT data to write.
* If the next block is not the previously predicted block, then the previousFATData
* cache is modified to account for this, and the previousFATDirty byte is set to 1.
* If the cluster pointer to the beginning of the next block does not reside at
* the beginning block boundary, the entire block is read in and the relevant portions
* are updated.
*
* @param file File to fill for.
* @return Number of clusters allocated
*/
uint16_t FAT32_AllocateFATBlock(FAT32FileOpt *file) {
uint16_t clusterPointer;
uint32_t nextCluster = file->fs->mostRecentCluster + 1;
uint16_t numAllocatedClusters = 0;
// Check next cluster allocated against the last cluster link
if (FATDataToInt32(file->previousFATBlockData + file->previousFATBlockOffset) != nextCluster) {
Int32ToFATData(file->previousFATBlockData + file->previousFATBlockOffset, nextCluster);
file->previousFATDirty = 1;
}
clusterPointer = GetClusterFATOffset(file->fs, nextCluster);
file->currentFATLBA = GetClusterFATLBA(file->fs, nextCluster);
// If the next cluster pointer isn't on a block boundary, read in the current entries in the block
if (clusterPointer != 0) {
DBG_DATA_printf("Reading in FAT data at LBA=0x%08lx (cluster=0x%08lx, offset=0x%04x)",
file->currentFATLBA, nextCluster, clusterPointer);
// TODO Make this DMA Friendly
if (BLOCK_SIZE != SD_SPI_ReadSingleBlock(file->fs->card, file->currentFATLBA, file->currentFATBlockData)) {
DBG_ERR_printf("Error creating file (SD Read error on LBA = 0x%08lx).", file->currentFATLBA);
return -1; // Sanity check: Not reading the correct number of bytes
}
}
// Fill in file table data
file->nextClusterBegin = file->fs->mostRecentCluster + 1;
for (;clusterPointer<BLOCK_SIZE;clusterPointer+=file->fs->clusterPointerSize) {
nextCluster++;
Int32ToFATData(file->currentFATBlockData+clusterPointer, nextCluster);
}
file->currentFATBlockOffset = clusterPointer - file->fs->clusterPointerSize;
file->nextClusterEnd = nextCluster - 1;
// Mark as allocated
file->currentFATAllocated = 1;
file->currentFATDirty = 1;
// Compute new file size
numAllocatedClusters = (file->nextClusterEnd - file->nextClusterBegin) + 1;
file->size += (uint32_t)numAllocatedClusters * file->fs->bytesPerSector * file->fs->sectorsPerCluster;
FAT32_UpdateDirectoryTableEntry(file);
// Update FS Information sector
file->fs->mostRecentCluster = file->nextClusterEnd;
file->fs->numFreeClusters -= numAllocatedClusters;
file->fs->fsInfoDirty = 1;
DBG_DATA_printf("Allocated clusters 0x%08lx to 0x%08lx (FAT LBA=0x%08lx), file size=%lu)",
file->nextClusterBegin, file->nextClusterEnd, file->currentFATLBA, file->size);
DBG_DATA_printf("Most recent cluster=0x%08lx, num free clusters=%lu", file->fs->mostRecentCluster, file->fs->numFreeClusters);
return numAllocatedClusters;
}
void FAT32_AllocateFATBlock(FS_File *file, uint8_t *data) {
uint32_t currCluster = file->currCluster;
uint16_t pos = GetClusterFATOffset(file->fs, currCluster);
file->fs->numFreeClusters -= (file->fs->bytesPerSector - pos) /
file->fs->clusterPointerSize;
file->currFATLBA = GetClusterFATLBA(file->fs, currCluster);
for (;pos<file->fs->bytesPerSector;pos+=file->fs->clusterPointerSize) {
currCluster++;
Int32ToFATData(data+pos, currCluster);
}
currCluster--;
pos -= file->fs->clusterPointerSize;
file->currFATBlockOffset = pos;
file->currFATClusterEnd = currCluster;
file->fs->mostRecentCluster = currCluster;
file->fs->fsInfoDirty = 1;
}
void FAT32_TerminateFATBlock(FS_File *file, uint8_t *data) {
uint32_t currCluster = file->currCluster;
uint16_t pos = GetClusterFATOffset(file->fs, currCluster);
uint16_t end = GetClusterFATOffset(file->fs, file->currFATClusterEnd);
file->fs->numFreeClusters -= (end - pos) / file->fs->clusterPointerSize;
file->currFATLBA = GetClusterFATLBA(file->fs, currCluster);
Int32ToFATData(data+pos, FAT32_CLUSTER_EOC);
file->currFATClusterEnd = FAT32_CLUSTER_EOC;
file->currFATBlockOffset = pos;
file->fs->mostRecentCluster = currCluster;
file->fs->fsInfoDirty = 1;
pos += file->fs->clusterPointerSize;
for (;pos<=end;pos+=file->fs->clusterPointerSize) {
Int32ToFATData(data+pos, 0x00000000);
}
}
