better error handling in case of corrupt data

4 files changed, 21 insertions, 8 deletions

diff --git a/README b/README
index a898ca4..6984567 100644
--- a/README
+++ b/README
@@ -94,7 +94,7 @@ rsi sets the reference sample interval. A large RSI will improve
 performance and efficiency. It will also increase memory requirements
 since internal buffering is based on RSI size. A smaller RSI may be
 desirable in situations where each RSI will be packetized and possible
-error propagation has to be minimized (e.g. on board a spacecraft[2]).
+error propagation has to be minimized.
 
 Flags:
 
@@ -208,6 +208,6 @@ http://public.ccsds.org/publications/archive/121x0b2.pdf
 
 [2] Consultative Committee for Space Data Systems. Lossless Data
 Compression.  Recommendation for Space Data System Standards, CCSDS
-120.0-G-2. Green Book. Issue 2. Washington, D.C.: CCSDS, December
-2006.
-http://public.ccsds.org/publications/archive/120x0g2s.pdf
+120.0-G-3. Green Book. Issue 3. Washington, D.C.: CCSDS, April
+2013.
+http://public.ccsds.org/publications/archive/120x0g3.pdf
diff --git a/src/decode.c b/src/decode.c
index c916b41..c4464aa 100644
--- a/src/decode.c
+++ b/src/decode.c
@@ -478,7 +478,11 @@ static int m_zero_block(struct aec_stream *strm)
         i = zero_blocks * strm->block_size;
 
     zero_bytes = i * state->bytes_per_sample;
+
     if (strm->avail_out >= zero_bytes) {
+        if (state->rsi_size - (state->rsip - state->rsi_buffer) < i)
+            return M_ERROR;
+
         memset(state->rsip, 0, i * sizeof(uint32_t));
         state->rsip += i;
         strm->avail_out -= zero_bytes;
@@ -740,11 +744,18 @@ int aec_decode(struct aec_stream *strm, int flush)
     */
 
     struct internal_state *state = strm->state;
+    int status;
 
     strm->total_in += strm->avail_in;
     strm->total_out += strm->avail_out;
 
-    while (state->mode(strm) == M_CONTINUE);
+    do {
+        status = state->mode(strm);
+    } while (status == M_CONTINUE);
+
+    if (status == M_ERROR)
+        return AEC_DATA_ERROR;
+
     state->flush_output(strm);
 
     strm->total_in -= strm->avail_in;
diff --git a/src/decode.h b/src/decode.h
index db4a0a2..724e195 100644
--- a/src/decode.h
+++ b/src/decode.h
@@ -64,6 +64,7 @@
 
 #define M_CONTINUE 1
 #define M_EXIT 0
+#define M_ERROR (-1)
 
 #define MIN(a, b) (((a) < (b))? (a): (b))
 
diff --git a/src/libaec.h b/src/libaec.h
index cab1795..84ad763 100644
--- a/src/libaec.h
+++ b/src/libaec.h
@@ -72,9 +72,10 @@ struct aec_stream {
                                  * 1, ..., 32)
                                  */
     int block_size;             /* block size in samples */
-    int rsi;                    /* Reference sample interval, the number
-                                 * of _blocks_ between consecutive
-                                 * reference samples (up to 4096).
+    int rsi;                    /* Reference sample interval, the
+                                 * number of Coded Data Sets between
+                                 * consecutive reference samples (up
+                                 * to 4096).
                                  */
     int flags;