Bug 224: fix and improve upon the missing DNL/NEWLEN situation

diff --git a/faxd/CopyQuality.c++ b/faxd/CopyQuality.c++
index 818bc7433da3ae6c2ad097f28c0c484fc32abb4b..d31ee91f003614c2208637c9bfc713d2eeed9bdf 100644 (file)
--- a/faxd/CopyQuality.c++
+++ b/faxd/CopyQuality.c++
@@ -523,7 +523,11 @@ FaxModem::writeECMData(TIFF* tif, u_char* buf, u_int cc, const Class2Params& par
                    framelength += buf[12-1];
 
                    protoTrace("RECV: Yd field in BIH is %d", framelength);
-                   // senders commonly use 0xFFFF and 0xFFFFFFFF as empty fill - ignore such large values
+                   /*
+                    * Senders commonly use 0xFFFF and 0xFFFFFFFF as empty fill.  We ignore such large 
+                    * values because if we use them and no NEWLEN marker is received, then the page
+                    * length causes problems for viewers (specifically libtiff).
+                    */
                    if (framelength < 65535 && framelength > recvEOLCount) recvEOLCount = framelength;
                }
                break;
@@ -576,7 +580,7 @@ FaxModem::writeECMData(TIFF* tif, u_char* buf, u_int cc, const Class2Params& par
                        framelength += buf[i+5];
 
                        protoTrace("RECV: Found NEWLEN Marker Segment in BID, Yd = %d", framelength);
-                       if (framelength < 65535 && framelength > recvEOLCount) recvEOLCount = framelength;
+                       if (framelength < 65535) recvEOLCount = framelength;
                    }
                }
            }
@@ -594,14 +598,15 @@ FaxModem::writeECMData(TIFF* tif, u_char* buf, u_int cc, const Class2Params& par
                        framewidth = 256*buf[i+7];
                        framewidth += buf[i+8];
                        protoTrace("RECV: Found Start of Frame (SOF) Marker, size: %lu x %lu", framewidth, framelength);
+                       if (framelength < 65535 && framelength > recvEOLCount) recvEOLCount = framelength;
                    }
                    if (buf[i] == 0xFF && buf[i+1] == 0xDC) {
                        framelength = 256*buf[i+4];
                        framelength += buf[i+5];
                        protoTrace("RECV: Found Define Number of Lines (DNL) Marker, lines: %lu", framelength);
+                       if (framelength < 65535) recvEOLCount = framelength;
                    }
                }
-               if (framelength < 65535 && framelength > recvEOLCount) recvEOLCount = framelength;
            }
            break;
     }
@@ -611,7 +616,31 @@ FaxModem::writeECMData(TIFF* tif, u_char* buf, u_int cc, const Class2Params& par
        memcpy(recvRow, (const char*) buf, cc);
        recvRow += cc;
     }
-    if (seq & 2 && recvEOLCount && (params.df == DF_JPEG_GREY || params.df == DF_JPEG_COLOR)) {
+    if (seq & 2 && !recvEOLCount && params.df > DF_2DMMR) {
+       /*
+        * We didn't detect an image length marker (DNL/NEWLEN).  So
+        * we use the session parameters to guess at one, and we hope that
+        * the eventual viewing decoder can cope with things if the data
+        * is short.
+        */
+       u_int len, res;
+       switch (params.ln) {
+           case LN_A4: len = 297; break;
+           default:    len = 364; break;       // LN_INF, LN_B4
+       }
+       switch (params.vr) {    // values in mm/100 to avoid floats
+           case VR_NORMAL:     res = 385; break;
+           case VR_FINE:       res = 770;  break;
+           case VR_200X100:    res = 394; break;
+           case VR_200X200:    res = 787; break;
+           case VR_200X400:    res = 1575; break;
+           case VR_300X300:    res = 1181; break;
+           default:            res = 1540; break;      // VR_R16, VR_R8
+       }
+       recvEOLCount = (u_long) ((len * res) / 100);
+       protoTrace("RECV: assumed image length of %lu lines", recvEOLCount);
+    }
+    if (seq & 2 && (params.df == DF_JPEG_GREY || params.df == DF_JPEG_COLOR)) {
        /*
         * DNL markers generally are not usable in TIFF files.  Furthermore,
         * many TIFF viewers cannot use them, either.  So, we go back