1 files changed, 41 insertions, 0 deletions
diff --git a/pkg/blockchain/chainwriter/readwrite.go b/pkg/blockchain/chainwriter/readwrite.go
new file mode 100644
index 0000000..32944a4
--- /dev/null
+++ b/pkg/blockchain/chainwriter/readwrite.go
@@ -0,0 +1,41 @@
+package chainwriter
+
+import (
+	"log"
+	"os"
+)
+
+// writeToDisk appends a slice of bytes to a file.
+func writeToDisk(fileName string, data []byte) {
+	file, err := os.OpenFile(fileName, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
+	if err != nil {
+		log.Fatalf("Unable to open file {%v}", fileName)
+	}
+	if _, err := file.Write(data); err != nil {
+		file.Close() // ignore error; Write error takes precedence
+		log.Fatalf("Failed to write to file {%v}", fileName)
+	}
+	if err := file.Close(); err != nil {
+		log.Fatalf("Failed to close file {%v}", fileName)
+	}
+}
+
+// readFromDisk return a slice of bytes from a file, given a FileInfo.
+func readFromDisk(info *FileInfo) []byte {
+	file, err := os.Open(info.FileName)
+	if err != nil {
+		log.Fatalf("Unable to open file {%v}", info.FileName)
+	}
+	if _, err2 := file.Seek(int64(info.StartOffset), 0); err2 != nil {
+		log.Fatalf("Failed to seek to {%v} in file {%v}", info.StartOffset, info.FileName)
+	}
+	numBytes := info.EndOffset - info.StartOffset
+	buf := make([]byte, numBytes)
+	if n, err3 := file.Read(buf); uint32(n) != info.EndOffset-info.StartOffset || err3 != nil {
+		log.Fatalf("Failed to read {%v} bytes from file {%v}", numBytes, info.FileName)
+	}
+	if err4 := file.Close(); err4 != nil {
+		log.Fatalf("Failed to close file {%v}", info.FileName)
+	}
+	return buf
+}