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FAT32: Optimize number of dynamic allocations

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This commit is contained in:
Baptiste Wicht 2018-03-20 13:24:03 +01:00
parent 6982a98e6f
commit d0060d8607
1 changed files with 15 additions and 11 deletions
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26
kernel/src/fs/fat32.cpp
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@ -255,12 +255,13 @@ size_t fat32::fat32_file_system::read(const path& file_path, char* buffer, size_
size_t cluster_size = 512 * fat_bs->sectors_per_cluster;
// Allocate a buffer big enough to read one cluster (possibly several sectors)
std::unique_heap_array<char> cluster_buffer(cluster_size);
while(read_bytes < last){
auto cluster_last = (cluster + 1) * cluster_size;
if(first < cluster_last){
std::unique_heap_array<char> cluster_buffer(cluster_size);
if(read_sectors(cluster_lba(cluster_number), fat_bs->sectors_per_cluster, cluster_buffer.get())){
size_t i = 0;
@ -337,13 +338,15 @@ size_t fat32::fat32_file_system::write(const path& file_path, const char* buffer
size_t cluster_size = 512 * fat_bs->sectors_per_cluster;
// Allocate a buffer big enough to read one cluster (possibly several sectors)
std::unique_heap_array<char> cluster_buffer(cluster_size);
while(read_bytes < last){
auto cluster_last = (cluster + 1) * cluster_size;
if(first < cluster_last){
std::unique_heap_array<char> cluster(cluster_size);
if(read_sectors(cluster_lba(cluster_number), fat_bs->sectors_per_cluster, cluster.get())){
if(read_sectors(cluster_lba(cluster_number), fat_bs->sectors_per_cluster, cluster_buffer.get())){
size_t i = 0;
if(position == 0){
@ -351,10 +354,10 @@ size_t fat32::fat32_file_system::write(const path& file_path, const char* buffer
}
for(; i < cluster_size && read_bytes < last; ++i, ++read_bytes){
cluster[i] = buffer[position++];
cluster_buffer[i] = buffer[position++];
}
if(!write_sectors(cluster_lba(cluster_number), fat_bs->sectors_per_cluster, cluster.get())){
if(!write_sectors(cluster_lba(cluster_number), fat_bs->sectors_per_cluster, cluster_buffer.get())){
return std::ERROR_FAILED;
}
} else {
@ -420,13 +423,14 @@ size_t fat32::fat32_file_system::clear(const path& file_path, size_t count, size
size_t cluster_size = 512 * fat_bs->sectors_per_cluster;
// Allocate a buffer big enough to read one cluster (possibly several sectors)
std::unique_heap_array<char> cluster_buffer(cluster_size);
while(read_bytes < last){
auto cluster_last = (cluster + 1) * cluster_size;
if(first < cluster_last){
std::unique_heap_array<char> cluster(cluster_size);
if(read_sectors(cluster_lba(cluster_number), fat_bs->sectors_per_cluster, cluster.get())){
if(read_sectors(cluster_lba(cluster_number), fat_bs->sectors_per_cluster, cluster_buffer.get())){
size_t i = 0;
if(first_position){
@ -435,10 +439,10 @@ size_t fat32::fat32_file_system::clear(const path& file_path, size_t count, size
}
for(; i < cluster_size && read_bytes < last; ++i, ++read_bytes){
cluster[i] = 0;
cluster_buffer[i] = 0;
}
if(!write_sectors(cluster_lba(cluster_number), fat_bs->sectors_per_cluster, cluster.get())){
if(!write_sectors(cluster_lba(cluster_number), fat_bs->sectors_per_cluster, cluster_buffer.get())){
return std::ERROR_FAILED;
}
} else {