[PATCH 3/4] simfs: fix incorrect math when calculating length to copy

[Kristen Carlson Accardi <kristen@linux.intel.com>]

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---
 src/simfs.c |   21 ++++++++++++---------
 1 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/src/simfs.c b/src/simfs.c
index 5fbee8b..bfcdf23 100644
--- a/src/simfs.c
+++ b/src/simfs.c
@@ -229,14 +229,16 @@ static void sim_fs_op_read_block_cb(const struct ofono_error *error,
 	if (op->current == start_block) {
 		bufoff = 0;
 		dataoff = op->offset % 256;
-		tocopy = MIN(256 - op->offset % 256, len);
 	} else {
-		bufoff = (op->current - start_block - 1) * 256 +
-				op->offset % 256;
+		bufoff = op->current * 256;
 		dataoff = 0;
-		tocopy = len;
 	}
 
+	tocopy = op->num_bytes % 256;
+
+	if ((tocopy == 0) || (op->current != end_block))
+		tocopy = 256;
+
 	memcpy(fs->buffer + bufoff, data + dataoff, tocopy);
 	cache_block(fs, op->current, 256, data, len);
 
@@ -288,15 +290,16 @@ static gboolean sim_fs_op_read_block(gpointer user_data)
 			bufoff = 0;
 			seekoff = SIM_CACHE_HEADER_SIZE + op->current * 256 +
 				op->offset % 256;
-			toread = MIN(256 - op->offset % 256,
-					op->length - op->current * 256);
 		} else {
-			bufoff = (op->current - start_block - 1) * 256 +
-					op->offset % 256;
+			bufoff = op->current * 256;
 			seekoff = SIM_CACHE_HEADER_SIZE + op->current * 256;
-			toread = MIN(256, op->length - op->current * 256);
 		}
 
+		toread = op->num_bytes % 256;
+
+		if ((toread == 0) || (op->current != end_block))
+			toread = 256;
+
 		if (lseek(fs->fd, seekoff, SEEK_SET) == (off_t) -1)
 			break;
 
-- 
1.7.2.1