libdatrwxx [WP]: improve error messages in consistency checks

Let the library output a messages which should be meaningful for an end-user
of a program which uses libdatrwxx.

src/libs/libdatrwxx/mseed/mseedread_mseedrecord_read.cc

@@ -39,11 +39,13 @@
  *                          frames is guessed
  *  - 08/07/2016   V1.3   thof: 
  *                        - make correct use of new DATRW_nonfatal_assert
+ *  - 11/07/2016   V1.4   thof:
+ *                        - improve error messages in consistency checks
  * 
  * ============================================================================
  */
 #define DATRW_MSEEDREAD_MSEEDRECORD_READ_CC_VERSION \
-  "DATRW_MSEEDREAD_MSEEDRECORD_READ_CC   V1.3"
+  "DATRW_MSEEDREAD_MSEEDRECORD_READ_CC   V1.4"
 
 #include <string>
 #include <cstring>
@@ -51,6 +53,8 @@
 #include <datrwxx/mseedread.h>
 #include <datrwxx/mseed.h>
 #include <datrwxx/bytesex.h>
+#include <datrwxx/debug.h>
+#include <datrwxx/mseed_keywords.h>
 #include <aff/subarray.h>
 
 namespace datrw {
@@ -229,6 +233,16 @@ namespace datrw {
          * Check for data integrity, consistency, plausibility,...
          */
 
+        /* string constant containing hint to format modifiers 
+         * (this is a very local constant, defined here becausing being used
+         * three times)
+         */
+        const std::string CHintToFormatModifiers(
+          "consider to use format modifiers \""
+          + std::string(key::nonfatal) + "\" or \"" 
+          + std::string(key::skipcheck) + "\"\n"
+          "if you like to ignore this inconsistency");
+
         /* Check for consistent number of samples.
          * ---------------------------------------
          *
@@ -241,10 +255,13 @@ namespace datrw {
           DATRW_nonfatal_assert(Mdebug.inconsistencies_are_not_fatal
                                 || (!Mchecks.nsamples.fatal),
                                 (isample==nsamples),
-                                "ERROR (reading MiniSEED record): "
-                                "missing samples\n"
-                                "isample=" << isample << " nsamples=" <<
-                                nsamples);
+            "number of samples in MiniSEED record is inconsistent\n"
+            "consistency check \"" << key::nsamples << "\" complains:\n"
+            "number of samples announced in header: " 
+            << DATRW_value(nsamples) << "\n"
+            "number of samples actually used: " 
+            << DATRW_value(isample) << "\n"
+            << CHintToFormatModifiers);
         }
 
         /* Check for consistent data values.
@@ -267,11 +284,15 @@ namespace datrw {
           DATRW_nonfatal_assert(Mdebug.inconsistencies_are_not_fatal
                                 || (!Mchecks.data.fatal),
                                 (Mdata(isample-1)==xn),
-                                "ERROR (reading MiniSEED record): "
-                                "data is corrupt\n"
-                                "Mdata(isample-1)=" << Mdata(isample-1)
-                                << " xn=" << xn
-                                << " isample=" << isample);
+            "data in MiniSEED record are inconsistent\n"
+            "consistency check \"" << key::data << "\" complains:\n"
+            "expected value of last sample "
+            "(i.e. reverse integration constant): " 
+            << DATRW_value(xn) << "\n"
+            "value of last sample ("
+            << DATRW_value(isample) << ") actually read: " 
+            << DATRW_value(Mdata(isample-1)) << "\n"
+            << CHintToFormatModifiers);
         }
 
         /* Check for consistent number of frames.
@@ -290,11 +311,13 @@ namespace datrw {
           DATRW_nonfatal_assert(Mdebug.inconsistencies_are_not_fatal
                                 || (!Mchecks.nframes.fatal),
                                 (iframe==nframes),
-                                "ERROR (reading MiniSEED record): "
-                                "inconsistent frame count\n"
-                                "number of frames (" << iframe << ") " <<
-                                "differs from expected number (" 
-                                << nframes << ")");
+            "number of frames in MiniSEED record is inconsistent\n"
+            "consistency check \"" << key::nframes << "\" complains:\n"
+            "number of frames announced in header: " 
+            << DATRW_value(nframes) << "\n"
+            "number of frames actually used: " 
+            << DATRW_value(iframe) << "\n"
+            << CHintToFormatModifiers);
         }
 
         // finished successfully