[libbluray-devel] ecma167: parse AD extent type

[Petri Hintukainen]

libudfread | branch: master | Petri Hintukainen <phintuka at gmail.com> | Tue Jun 21 22:31:24 2016 +0300| [a1bb0009f3d71ad7a830a93c060c6c7ed161551a] | committer: Petri Hintukainen

ecma167: parse AD extent type

> http://git.videolan.org/gitweb.cgi/libudfread.git/?a=commit;h=a1bb0009f3d71ad7a830a93c060c6c7ed161551a
---

 src/ecma167.c |   19 ++++++++++++++-----
 src/ecma167.h |    9 +++++++++
 src/udfread.c |    8 ++++++++
 3 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/src/ecma167.c b/src/ecma167.c
index 571253d..ab7a5b9 100644
--- a/src/ecma167.c
+++ b/src/ecma167.c
@@ -72,8 +72,6 @@ void decode_entity_id(const uint8_t *p, struct entity_id *eid)
  * Part 3: Volume Structure
  */
 
-#define AD_LENGTH_MASK    0x3fffffff
-
 /* Descriptor Tag (ECMA 167, 3/7.2) */
 enum tag_identifier decode_descriptor_tag(const uint8_t *buf)
 {
@@ -197,10 +195,17 @@ static void _decode_icb_tag(const uint8_t *p, struct icb_tag *tag)
     tag->flags         = _get_u16(p + 18);
 }
 
+/* Allocation Descriptors */
+
+#define AD_LENGTH_MASK    0x3fffffff
+#define AD_TYPE(length)  ((length) >> 30)
+
 /* Short Allocation Descriptor (ECMA 167, 4/14.14.1) */
 static void _decode_short_ad(const uint8_t *buf, uint16_t partition, struct long_ad *ad)
 {
-    ad->length    = _get_u32(buf + 0) & AD_LENGTH_MASK;
+    uint32_t u32 = _get_u32(buf + 0);
+    ad->extent_type = AD_TYPE(u32);
+    ad->length    = u32 & AD_LENGTH_MASK;
     ad->lba       = _get_u32(buf + 4);
     ad->partition = partition;
 }
@@ -208,7 +213,9 @@ static void _decode_short_ad(const uint8_t *buf, uint16_t partition, struct long
 /* Long Allocation Descriptor (ECMA 167, 4/14.14.2) */
 void decode_long_ad(const uint8_t *buf, struct long_ad *ad)
 {
-    ad->length    = _get_u32(buf + 0) & AD_LENGTH_MASK;
+    uint32_t u32 = _get_u32(buf + 0);
+    ad->extent_type = AD_TYPE(u32);
+    ad->length    = u32 & AD_LENGTH_MASK;
     ad->lba       = _get_u32(buf + 4);
     ad->partition = _get_u16(buf + 8);
 }
@@ -216,7 +223,9 @@ void decode_long_ad(const uint8_t *buf, struct long_ad *ad)
 /* Exrtended Allocation Descriptor (ECMA 167, 4/14.14.3) */
 static void _decode_extended_ad(const uint8_t *buf, struct long_ad *ad)
 {
-    ad->length    = _get_u32(buf + 0) & AD_LENGTH_MASK;
+    uint32_t u32 = _get_u32(buf + 0);
+    ad->extent_type = AD_TYPE(u32);
+    ad->length    = u32 & AD_LENGTH_MASK;
     ad->lba       = _get_u32(buf + 12);
     ad->partition = _get_u16(buf + 16);
 }
diff --git a/src/ecma167.h b/src/ecma167.h
index d27710e..9300255 100644
--- a/src/ecma167.h
+++ b/src/ecma167.h
@@ -149,12 +149,21 @@ void decode_logical_volume(const uint8_t *p, struct logical_volume_descriptor *l
  * Part 4: File Structure
  */
 
+enum {
+    ECMA_AD_EXTENT_NORMAL = 0,        /* allocated and recorded file data */
+    ECMA_AD_EXTENT_NOT_RECORDED = 1,
+    ECMA_AD_EXTENT_NOT_ALLOCATED = 2,
+    ECMA_AD_EXTENT_AD = 3,            /* pointer to next extent of allocation descriptors */
+};
+
+
 /* Short/Long/Extended Allocation Descriptor (ECMA 167, 4/14.14.[1,2,3]) */
 
 struct long_ad {
     uint32_t lba;    /* start block, relative to partition start */
     uint32_t length; /* in bytes */
     uint16_t partition;
+    uint8_t  extent_type;
 };
 
 void decode_long_ad(const uint8_t *p, struct long_ad *ad);
diff --git a/src/udfread.c b/src/udfread.c
index 7b27410..4f4cb2c 100644
--- a/src/udfread.c
+++ b/src/udfread.c
@@ -1359,6 +1359,14 @@ uint32_t udfread_file_lba(UDFFILE *p, uint32_t file_block)
         const struct long_ad *ad = &fe->data.ad[0];
         ad_size = (ad[i].length + UDF_BLOCK_SIZE - 1) / UDF_BLOCK_SIZE;
         if (file_block < ad_size) {
+
+            if (ad[i].extent_type != ECMA_AD_EXTENT_NORMAL) {
+                if (ad[i].extent_type == ECMA_AD_EXTENT_AD) {
+                    udf_error("unsupported allocation desriptor: extent type %u\n", ad[i].extent_type);
+                }
+                return 0;
+            }
+
             if (!ad[i].lba) {
                 /* empty file / no allocated space */
                 return 0;