pnm: Handle ASCII encoded PNM data that is split over multiple buffers

Also:
- unref buffers after gst_buffer_span
- fix scanning of header if header data is split over several buffers

Fixes bug #595700.

gst/pnm/gstpnmdec.c

@@ -95,6 +95,7 @@ static GstFlowReturn
 gst_pnmdec_chain_raw (GstPnmdec * s, GstPad * src, GstBuffer * buf)
 {
   GstFlowReturn r = GST_FLOW_OK;
+  GstBuffer *out;
 
   /* If we got the whole image, just push the buffer. */
   if (GST_BUFFER_SIZE (buf) == s->size) {
@@ -108,10 +109,11 @@ gst_pnmdec_chain_raw (GstPnmdec * s, GstPad * src, GstBuffer * buf)
   if (!s->buf) {
     s->buf = buf;
   } else {
-    buf = gst_buffer_span (s->buf, 0, buf,
+    out = gst_buffer_span (s->buf, 0, buf,
         GST_BUFFER_SIZE (s->buf) + GST_BUFFER_SIZE (buf));
+    gst_buffer_unref (buf);
     gst_buffer_unref (s->buf);
-    s->buf = buf;
+    s->buf = out;
   }
   if (!s->buf)
     return GST_FLOW_ERROR;
@@ -132,16 +134,46 @@ static GstFlowReturn
 gst_pnmdec_chain_ascii (GstPnmdec * s, GstPad * src, GstBuffer * buf)
 {
   GScanner *scanner;
-  GstBuffer *out = gst_buffer_new_and_alloc (s->size);
+  GstBuffer *out;
   guint i = 0;
+  gchar *b = (gchar *) GST_BUFFER_DATA (buf);
+  guint bs = GST_BUFFER_SIZE (buf);
+  guint target = s->size - (s->buf ? GST_BUFFER_SIZE (s->buf) : 0);
+
+  if (!bs) {
+    gst_buffer_unref (buf);
+    return GST_FLOW_OK;
+  }
+
+  if (s->last_byte) {
+    while (*b >= '0' && *b <= '9') {
+      s->last_byte = 10 * s->last_byte + *b - '0';
+      b++;
+      if (!--bs) {
+        gst_buffer_unref (buf);
+        return GST_FLOW_OK;
+      }
+    }
+    if (s->last_byte > 255) {
+      gst_buffer_unref (buf);
+      GST_DEBUG_OBJECT (s, "Corrupt ASCII encoded PNM file.");
+      return GST_FLOW_ERROR;
+    }
+  }
+
+  out = gst_buffer_new_and_alloc (target);
+
+  if (s->last_byte) {
+    GST_BUFFER_DATA (out)[i++] = s->last_byte;
+    s->last_byte = 0;
+  }
 
   scanner = g_scanner_new (NULL);
-  g_scanner_input_text (scanner, (gchar *) GST_BUFFER_DATA (buf),
+  g_scanner_input_text (scanner, b, bs);
-      GST_BUFFER_SIZE (buf));
   while (!g_scanner_eof (scanner)) {
     switch (g_scanner_get_next_token (scanner)) {
       case G_TOKEN_INT:
-        if (i == s->size) {
+        if (i == target) {
           GST_DEBUG_OBJECT (s, "PNM file contains too much data.");
           gst_buffer_unref (buf);
           gst_buffer_unref (out);
@@ -154,15 +186,18 @@ gst_pnmdec_chain_ascii (GstPnmdec * s, GstPad * src, GstBuffer * buf)
     }
   }
   g_scanner_destroy (scanner);
-  gst_buffer_unref (buf);
 
-  if (i < s->size) {
+  /* If we didn't get the whole image, handle the last byte with care. */
-    GST_DEBUG_OBJECT (s, "FIXME: Decoding of ASCII encoded files split "
+  if (i < target && b[bs - 1] > '0' && b[bs - 1] <= '9')
-        "over several buffers is not implemented!");
+    s->last_byte = GST_BUFFER_DATA (out)[--i];
+
+  gst_buffer_unref (buf);
+  if (!i) {
     gst_buffer_unref (out);
-    return GST_FLOW_ERROR;
+    return GST_FLOW_OK;
   }
 
+  GST_BUFFER_SIZE (out) = i;
   return gst_pnmdec_chain_raw (s, src, out);
 }
 
@@ -175,7 +210,7 @@ gst_pnmdec_chain (GstPad * pad, GstBuffer * data)
   GstFlowReturn r = GST_FLOW_OK;
   guint offset = 0;
 
-  if (!(s->mngr.info.fields & GST_PNM_INFO_FIELDS_ALL)) {
+  if (s->mngr.info.fields != GST_PNM_INFO_FIELDS_ALL) {
     switch (gst_pnm_info_mngr_scan (&s->mngr, GST_BUFFER_DATA (data),
             GST_BUFFER_SIZE (data))) {
       case GST_PNM_INFO_MNGR_RESULT_FAILED:

gst/pnm/gstpnmdec.h

@@ -39,7 +39,7 @@ struct _GstPnmdec
   GstElement element;
 
   GstPnmInfoMngr mngr;
-  guint size;
+  guint size, last_byte;
   GstBuffer *buf;
 };
 

gst/pnm/gstpnmutils.c

@@ -134,6 +134,7 @@ gst_pnm_info_mngr_scan (GstPnmInfoMngr * mngr, const guint8 * buf,
           case '\n':
           case '\t':
           case ' ':
+            mngr->info.fields |= GST_PNM_INFO_FIELDS_WIDTH;
             mngr->state = GST_PNM_INFO_MNGR_STATE_WHITE_SPACE;
             mngr->data_offset += i;
             return gst_pnm_info_mngr_scan (mngr, buf + i, buf_len - i);
@@ -143,7 +144,6 @@ gst_pnm_info_mngr_scan (GstPnmInfoMngr * mngr, const guint8 * buf,
       }
       mngr->info.width *= 10;
       mngr->info.width += buf[i++] - 0x030;
-      mngr->info.fields |= GST_PNM_INFO_FIELDS_WIDTH;
       mngr->data_offset += i;
       return gst_pnm_info_mngr_scan (mngr, buf + i, buf_len - i);
     case GST_PNM_INFO_MNGR_STATE_DATA_HEIGHT:
@@ -152,6 +152,7 @@ gst_pnm_info_mngr_scan (GstPnmInfoMngr * mngr, const guint8 * buf,
           case '\n':
           case '\t':
           case ' ':
+            mngr->info.fields |= GST_PNM_INFO_FIELDS_HEIGHT;
             mngr->state = GST_PNM_INFO_MNGR_STATE_WHITE_SPACE;
             mngr->data_offset += i;
             return gst_pnm_info_mngr_scan (mngr, buf + i, buf_len - i);
@@ -161,7 +162,6 @@ gst_pnm_info_mngr_scan (GstPnmInfoMngr * mngr, const guint8 * buf,
       }
       mngr->info.height *= 10;
       mngr->info.height += buf[i++] - 0x030;
-      mngr->info.fields |= GST_PNM_INFO_FIELDS_HEIGHT;
       mngr->data_offset += i;
       return gst_pnm_info_mngr_scan (mngr, buf + i, buf_len - i);
     case GST_PNM_INFO_MNGR_STATE_DATA_MAX:
@@ -170,6 +170,7 @@ gst_pnm_info_mngr_scan (GstPnmInfoMngr * mngr, const guint8 * buf,
           case '\n':
           case '\t':
           case ' ':
+            mngr->info.fields |= GST_PNM_INFO_FIELDS_MAX;
             mngr->data_offset += i + 1;
             return GST_PNM_INFO_MNGR_RESULT_FINISHED;
           default:
@@ -178,7 +179,6 @@ gst_pnm_info_mngr_scan (GstPnmInfoMngr * mngr, const guint8 * buf,
       }
       mngr->info.max *= 10;
       mngr->info.max += buf[i++] - 0x030;
-      mngr->info.fields |= GST_PNM_INFO_FIELDS_MAX;
       mngr->data_offset += i;
       return gst_pnm_info_mngr_scan (mngr, buf + i, buf_len - i);
   }