Minor refactoring and renames, implementation of disk_xor

1 files changed, 65 insertions, 45 deletions

diff --git a/myraid.py b/myraid.py
index 785b514..c7dbf31 100644
--- a/myraid.py
+++ b/myraid.py
@@ -32,18 +32,6 @@ class MyRaid():
         self.raid_disk_count = 0
         self.raid_types = [ '0', '1', '5', '5+0' ]
 
-    def get_raid_size(self, raid_type):
-        size = self.raid_end - self.raid_start
-        if size <= 0:
-            return 0
-        else:
-            return {
-                '0': size * self.raid_disk_count,
-                '1': size,
-                '5': size * (self.raid_disk_count - 1) if self.raid_disk_count >= 3 else 0,
-                '5+0': size * (self.raid_disk_count - 2) if self.raid_disk_count >= 6 and self.raid_disk_count % 2 == 0 else 0 ,
-                }[raid_type]
-
     def get_raid_start(self):
         return self.raid_start
 
@@ -84,34 +72,32 @@ class MyRaid():
         self.raid_disk_order = new_raid_disk_order
         self.raid_disk_count = len(new_raid_disk_order)
 
+    def sizeof_raid_result(self, raid_type):
+        size = self.raid_end - self.raid_start
+        if size <= 0 :
+            return 0
+        else:
+            return {
+                '0'  : size * self.raid_disk_count,
+                '1'  : size,
+                '5'  : size * (self.raid_disk_count - 1) if self.raid_disk_count >= 3 else 0,
+                '5+0': size * (self.raid_disk_count - 2) if self.raid_disk_count >= 6 and self.raid_disk_count % 2 == 0 else 0,
+                }[raid_type]
 
-    def read_data(self,raid_type,disks,offset,size):
-        """TODO"""
-        disk_count = len(self.raid_disk_order)
-
-        # This code is RAID 5 only
-
-        slice_no = offset / self.raid_chunk_size
-        slice_off = offset % self.raid_chunk_size 
-        segment=slice_no/(disk_count-1)
-        par_disk=(disk_count-1) - (segment % disk_count) # TODO : equivalent a : segment-1 % disk_count ?
-        data_disk=( par_disk + 1 + (slice_no % (disk_count-1)) ) % disk_count
-        off_disk = self.raid_start + segment * self.raid_chunk_size + slice_off
-
-        size2 = min(size, (slice_no+1) * self.raid_chunk_size - offset)
-
-        logging.info("raid.read_data(%s): offset=%d,slice_no=%d,slice_off=%d,segment=%d,par_disk=%d,data_disk=%d,off_disk=%d,size2=%d,slice_off+size2=%d" 
-        % (raid_type,offset,slice_no,slice_off,segment,par_disk,data_disk,off_disk,size2,slice_off+size2) )
+    def sizeof_disk_parity(self, raid_type):
+        return self.sizeof_disk_xor(raid_type) / self.raid_sector_size * 16
 
-        data_fd = disks[self.raid_disk_order[data_disk]]
-        data_fd.seek(off_disk)
-        data = data_fd.read(size2)
-        
-        # This kills performance but don't make short reads before EOF
-        #if size2 < size:
-        #    data += self.read_data(self,raid_type,disks,offset+size2,size-size2)
-
-        return data
+    def sizeof_disk_xor(self, raid_type):
+        size = self.raid_end - self.raid_start
+        if size <= 0:
+            return 0
+        else:
+            return {
+                '0'  : 0, # TODO Could contain some plain text error message
+                '1'  : size,
+                '5'  : size if self.raid_disk_count >= 3 else 0,
+                '5+0': size if self.raid_disk_count >= 6 and self.raid_disk_count % 2 == 0 else 0,
+                }[raid_type]
 
     def xor_blocks(self,fd_list, offset, size):
         """TODO"""
@@ -149,22 +135,56 @@ class MyRaid():
             result = 'b'
 
         logging.info("Exit. xor_blocks(fd_list,%d,%d)"%(offset, size))
-        return result
-
-    def check_data(self,raid_type,disks,offset,size):
-        """TODO"""
-        logging.warn("Enter check_data(%s,disks,%d,%d)"%(raid_type,offset,size))
         #import binascii
         #logging.warn(binascii.hexlify(numpy_b1))
+        return (result,numpy_b1)
 
-        #result = ''.join([ self.xor_blocks(disks, (offset+i)*self.raid_sector_size, self.raid_sector_size) for i in range(size)])
-        result = ''.join([ '0x%011x %c\n'%( (offset/16+i)*self.raid_sector_size, self.xor_blocks(disks, (offset/16+i)*self.raid_sector_size, self.raid_sector_size)) for i in range(size/16) ])
+    def read_disk_parity(self,raid_type,disks,offset,size):
+        """TODO"""
+        logging.warn("Enter check_data(%s,disks,%d,%d)"%(raid_type,offset,size))
         # TODO donner des offests RAID et pas disques 
+        #result = ''.join([ '0x%011x %c\n'%( (offset/16+i)*self.raid_sector_size, self.xor_blocks(disks, (offset/16+i)*self.raid_sector_size, self.raid_sector_size)) for i in range(size/16) ])
+        start = self.raid_start + offset * self.raid_sector_size / 16
+        end = start + size * self.raid_sector_size / 16
+        result = ''.join(
+                [ '0x%011x %c\n'%( addr, self.xor_blocks(disks, addr, self.raid_sector_size)[0])
+                        for addr in range(start, end, self.raid_sector_size)
+                ])
         
         logging.warn("Exit. check_data(%s,disks,%d,%d)"%(raid_type,offset,size))
 
         return result
 
+    def read_disk_xor(self,raid_type,disks,offset,size):
+        return self.xor_blocks(disks,offset,size)[1].tostring()
+
 
+    def read_raid_result(self,raid_type,disks,offset,size):
+        """TODO"""
+        disk_count = len(self.raid_disk_order)
+
+        # This code is RAID 5 only (left-assymetric)
+
+        slice_no = offset / self.raid_chunk_size
+        slice_off = offset % self.raid_chunk_size 
+        segment=slice_no/(disk_count-1)
+        par_disk=(disk_count-1) - (segment % disk_count) # TODO : equivalent a : segment-1 % disk_count ?
+        data_disk=( par_disk + 1 + (slice_no % (disk_count-1)) ) % disk_count
+        off_disk = self.raid_start + segment * self.raid_chunk_size + slice_off
+
+        size2 = min(size, (slice_no+1) * self.raid_chunk_size - offset)
+
+        logging.info("raid.read_result(%s): offset=%d,slice_no=%d,slice_off=%d,segment=%d,par_disk=%d,data_disk=%d,off_disk=%d,size2=%d,slice_off+size2=%d" 
+        % (raid_type,offset,slice_no,slice_off,segment,par_disk,data_disk,off_disk,size2,slice_off+size2) )
+
+        data_fd = disks[self.raid_disk_order[data_disk]]
+        data_fd.seek(off_disk)
+        data = data_fd.read(size2)
+        
+        # This kills performance but don't make short reads before EOF
+        #if size2 < size:
+        #    data += self.read_result(self,raid_type,disks,offset+size2,size-size2)
+
+        return data