Add inline documentation for bdc109b.

This commit simply adds some additional comments to the commit provided
by sasha-s that fixes the "slice out of bounds" errors.

1 files changed, 12 insertions, 0 deletions

diff --git a/tx.go b/tx.go
index 9ffceaf..3fef4b4 100644
--- a/tx.go
+++ b/tx.go
@@ -422,26 +422,38 @@ func (tx *Tx) write() error {
 	for _, p := range pages {
 		size := (int(p.overflow) + 1) * tx.db.pageSize
 		offset := int64(p.id) * int64(tx.db.pageSize)
+
+		// Write out page in "max allocation" sized chunks.
 		ptr := (*[maxAllocSize]byte)(unsafe.Pointer(p))
 		for {
+			// Limit our write to our max allocation size.
 			sz := size
 			if sz > maxAllocSize-1 {
 				sz = maxAllocSize - 1
 			}
+
+			// Write chunk to disk.
 			buf := ptr[:sz]
 			if _, err := tx.db.ops.writeAt(buf, offset); err != nil {
 				return err
 			}
+
 			// Update statistics.
 			tx.stats.Write++
+
+			// Exit inner for loop if we've written all the chunks.
 			size -= sz
 			if size == 0 {
 				break
 			}
+
+			// Otherwise move offset forward and move pointer to next chunk.
 			offset += int64(sz)
 			ptr = (*[maxAllocSize]byte)(unsafe.Pointer(&ptr[sz]))
 		}
 	}
+
+	// Ignore file sync if flag is set on DB.
 	if !tx.db.NoSync || IgnoreNoSync {
 		if err := fdatasync(tx.db); err != nil {
 			return err