start implementing data representation parsing

lib/parser.js

@@ -171,6 +171,20 @@ var sectionParsers = {
 
     return rv;
   },
+  5: function(binary) {
+    var rv = {};
+    rv.dataPointCount = binary.read('uint32');
+    rv.templateNumber = binary.read('uint16');
+
+    // Parse representation
+    var dataReprParser = dataRepresentationParsers[rv.templateNumber];
+    if(!dataReprParser) {
+      // console.warn('Unknown data representation template: ' + rv.templateNumber);
+      return rv;
+    }
+    rv.representation = dataReprParser(binary);
+    return rv;
+  },
 };
 
 // Parser for scale factor / scaled value. See 92.1.12
@@ -319,3 +333,23 @@ var gridParsers = {
     return rv;
   },
 };
+
+var dataRepresentationParsers = {
+  // Grid point data - simple packing
+  0: function(binary) {
+    var rv = {};
+    rv.name = 'Grid point data - simple packing';
+    rv.referenceValue = binary.read('float32');
+    rv.binaryScale = binary.read('uint16');
+    rv.decimalScale = binary.read('uint16');
+    rv.bitCount = binary.read('uint8');
+    rv.dataType = tables.lookup(tables.tables.OriginalFieldType, binary.read('uint8'));
+    return rv;
+  },
+  // Grid point data - complex packing and spatial differencing
+  3: function(binary) {
+    var rv = {};
+    // FIXME: stub
+    return rv;
+  },
+};

lib/tables.js

@@ -55,6 +55,13 @@ exports.tables = {
     MISSING:            { name: 'Missing', value: 255 },
   }),
 
+  // Code Table 5.1
+  OriginalFieldType: Object.freeze({
+    FLOAT:              { name: 'Floating point', value: 0 },
+    INTEGER:            { name: 'Integer', value: 1 },
+    MISSING:            { name: 'Missing', value: 255 },
+  }),
+
   // Code Table 6.0
   BitMapIndicator: Object.freeze({
     SPECIFIED:          { name: 'Use specified bit-map', value: 0 },

test/dataRepresentationTemplates.js

@@ -0,0 +1,30 @@
+var assert = require('assert');
+var grib = require('../index');
+var files = require('./lib/fixtures').files;
+
+describe('data representation template', function() {
+  var msgs = null;
+
+  describe('of ngm.grb', function() {
+    before(function(done) {
+      msgs = null;
+      grib.readUrl(files['ngm.grb'].url, function(err, msgs_) {
+        if(err) return done(err);
+        msgs = msgs_;
+        done();
+      });
+    });
+
+    it('should be template 0', function() {
+      var msg, field;
+      for(var m_idx in msgs) {
+        msg = msgs[m_idx];
+        for(var f_idx in msg.fields) {
+          field = msg.fields[f_idx];
+          assert.ok(field.representation.representation);
+          assert.strictEqual(0, field.representation.representation.templateNumber);
+        }
+      }
+    });
+  });
+});