From ab09051aaae3ae7a14a26980470860eaac128889 Mon Sep 17 00:00:00 2001
From: Dustin Oprea <doprea@magicleap.com>
Date: Sun, 16 Sep 2018 03:42:48 -0400
Subject: [PATCH] ifd_enumerate: Bugfix for incorrect read semantics.

- ...to make sure we get the right number of bytes.
---
 ifd_enumerate.go | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/ifd_enumerate.go b/ifd_enumerate.go
index 4ce1fd9..14d22f7 100644
--- a/ifd_enumerate.go
+++ b/ifd_enumerate.go
@@ -57,10 +57,16 @@ func (ife *IfdTagEnumerator) getUint16() (value uint16, raw []byte, err error) {
 		}
 	}()
 
-	raw = make([]byte, 2)
+	needBytes := 2
+	offset := 0
+	raw = make([]byte, needBytes)
 
-	_, err = ife.buffer.Read(raw)
-	log.PanicIf(err)
+	for offset < needBytes {
+		n, err := ife.buffer.Read(raw[offset:])
+		log.PanicIf(err)
+
+		offset += n
+	}
 
 	if ife.byteOrder == binary.BigEndian {
 		value = binary.BigEndian.Uint16(raw)
@@ -81,10 +87,16 @@ func (ife *IfdTagEnumerator) getUint32() (value uint32, raw []byte, err error) {
 		}
 	}()
 
-	raw = make([]byte, 4)
+	needBytes := 4
+	offset := 0
+	raw = make([]byte, needBytes)
 
-	_, err = ife.buffer.Read(raw)
-	log.PanicIf(err)
+	for offset < needBytes {
+		n, err := ife.buffer.Read(raw[offset:])
+		log.PanicIf(err)
+
+		offset += n
+	}
 
 	if ife.byteOrder == binary.BigEndian {
 		value = binary.BigEndian.Uint32(raw)