filemap: add parameter 'length' to sparse_copy

Added parameter 'length' to specify amount of data
to write into destination file. This is useful when only
part of source file should be written into destination file.

(From OE-Core rev: cc44e2eb3b5027a3531e6349937a23d73313b3c6)

Signed-off-by: Ed Bartosh <ed.bartosh@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 12 insertions, 3 deletions

diff --git a/scripts/lib/wic/filemap.py b/scripts/lib/wic/filemap.py
index 585b7ea84e..8fe302ab49 100644
--- a/scripts/lib/wic/filemap.py
+++ b/scripts/lib/wic/filemap.py
@@ -530,7 +530,8 @@ def filemap(image, log=None):
     except ErrorNotSupp:
         return FilemapSeek(image, log)
 
-def sparse_copy(src_fname, dst_fname, offset=0, skip=0, api=None):
+def sparse_copy(src_fname, dst_fname, offset=0, skip=0,
+                length=0, api=None):
     """Efficiently copy sparse file to or into another file."""
     if not api:
         api = filemap
@@ -541,6 +542,7 @@ def sparse_copy(src_fname, dst_fname, offset=0, skip=0, api=None):
         dst_file = open(dst_fname, 'wb')
         dst_file.truncate(os.path.getsize(src_fname))
 
+    written = 0
     for first, last in fmap.get_mapped_ranges(0, fmap.blocks_cnt):
         start = first * fmap.block_size
         end = (last + 1) * fmap.block_size
@@ -561,7 +563,14 @@ def sparse_copy(src_fname, dst_fname, offset=0, skip=0, api=None):
         while read < to_read:
             if read + chunk_size > to_read:
                 chunk_size = to_read - read
-            chunk = fmap._f_image.read(chunk_size)
+            size = chunk_size
+            if length and written + size > length:
+                size = length - written
+            chunk = fmap._f_image.read(size)
             dst_file.write(chunk)
-            read += chunk_size
+            read += size
+            written += size
+            if written == length:
+                dst_file.close()
+                return
     dst_file.close()