ECC-1405: Add new function: codes_handle_new_from_samples

examples/C/new_sample.c

@@ -25,7 +25,8 @@ int main(int argc, char** argv)
         exit(1);
     }
 
-    h = codes_grib_handle_new_from_samples(NULL, "GRIB2");
+    /* h = codes_grib_handle_new_from_samples(NULL, "GRIB2"); */
+    h = codes_handle_new_from_samples(NULL, "GRIB2");
     if (!h) {
         fprintf(stderr, "Cannot create grib handle\n");
         return 1;
@@ -363,10 +364,7 @@ int main(int argc, char** argv)
 
     CODES_CHECK(codes_set_double_array(h, "values", vdouble, size), 0);
     free(vdouble);
-    CODES_CHECK(codes_set_long(h, "dirty_statistics", 1), 0);
+
-    CODES_CHECK(codes_set_long(h, "changeDecimalPrecision", 0), 0);
-    CODES_CHECK(codes_set_long(h, "decimalPrecision", 0), 0);
-    CODES_CHECK(codes_set_long(h, "setBitsPerValue", 0), 0);
     /* Save the message */
 
     f = fopen(argv[1], "wb");

src/eccodes.h

@@ -477,6 +477,17 @@ codes_handle* codes_grib_handle_new_from_samples(codes_context* c, const char* s
  */
 codes_handle* codes_bufr_handle_new_from_samples(codes_context* c, const char* sample_name);
 
+/**
+ *  Create a handle from a file contained in a samples directory.
+ *  The samples file can be GRIB, BUFR etc. Its type will be determined at runtime.
+ *  The message is copied at the creation of the handle
+ *
+ * @param c           : the context from which the handle will be created (NULL for default context)
+ * @param sample_name : the name of the sample file
+ * @return            the new handle, NULL if the resource is invalid or a problem is encountered
+ */
+codes_handle* codes_handle_new_from_samples(codes_context* c, const char* sample_name);
+
 
 /**
 *  Clone an existing handle using the context of the original handle,

src/eccodes_prototypes.h

@@ -1025,6 +1025,7 @@ void grib_empty_section(grib_context* c, grib_section* b);
 void grib_section_delete(grib_context* c, grib_section* b);
 int grib_handle_delete(grib_handle* h);
 grib_handle* grib_new_handle(grib_context* c);
+grib_handle* codes_handle_new_from_samples(grib_context* c, const char* name);
 grib_handle* grib_handle_new_from_samples(grib_context* c, const char* name);
 grib_handle* codes_bufr_handle_new_from_samples(grib_context* c, const char* name);
 int grib_write_message(const grib_handle* h, const char* file, const char* mode);
@@ -1187,6 +1188,7 @@ long grib_get_decimal_scale_fact(double max, double min, long bpval, long binary
 
 /* grib_templates.c */
 /*grib_handle *grib_internal_sample(grib_context *c, const char *name);*/
+grib_handle* codes_external_template(grib_context* c, const char* name);
 grib_handle* grib_external_template(grib_context* c, const char* name);
 grib_handle* bufr_external_template(grib_context* c, const char* name);
 char* get_external_template_path(grib_context* c, const char* name);

src/grib_handle.c

@@ -248,6 +248,29 @@ static grib_handle* grib_handle_create(grib_handle* gl, grib_context* c, const v
     return gl;
 }
 
+grib_handle* codes_handle_new_from_samples(grib_context* c, const char* name)
+{
+    grib_handle* g = 0;
+    if (c == NULL)
+        c = grib_context_get_default();
+    grib_context_set_handle_file_count(c, 0);
+    grib_context_set_handle_total_count(c, 0);
+
+    if (c->debug) {
+        fprintf(stderr, "ECCODES DEBUG codes_handle_new_from_samples '%s'\n", name);
+    }
+
+    g = codes_external_template(c, name);
+    if (!g)
+        grib_context_log(c, GRIB_LOG_ERROR,
+                         "Unable to load sample file '%s.tmpl'\n"
+                         "                   from %s\n"
+                         "                   (ecCodes Version=%s)",
+                         name, c->grib_samples_path, ECCODES_VERSION_STR);
+
+    return g;
+}
+
 grib_handle* grib_handle_new_from_samples(grib_context* c, const char* name)
 {
     grib_handle* g = 0;

src/grib_templates.c

@@ -70,6 +70,24 @@ static grib_handle* try_product_template(grib_context* c, ProductKind product_ki
             grib_context_log(c, GRIB_LOG_PERROR, "cannot open %s", path);
             return NULL;
         }
+        if (product_kind == PRODUCT_ANY)
+        {
+            /* Determine the product kind from sample file */
+            char* mesg   = NULL;
+            size_t size  = 0;
+            off_t offset = 0;
+            mesg = wmo_read_any_from_file_malloc(f, 0, &size, &offset, &err);
+            Assert(size > 4);
+            if (strncmp(mesg, "GRIB", 4) == 0 || strncmp(mesg, "DIAG", 4) == 0 || strncmp(mesg, "BUDG", 4) == 0) {
+                product_kind = PRODUCT_GRIB;
+            } else if (strncmp(mesg, "BUFR", 4) == 0) {
+                product_kind = PRODUCT_BUFR;
+            } else {
+                grib_context_log(c, GRIB_LOG_ERROR, "Could not determine product kind");
+            }
+            grib_context_free(c, mesg);
+            rewind(f);
+        }
         if (product_kind == PRODUCT_BUFR) {
             g = codes_bufr_handle_new_from_file(c, f, &err);
         } else {
@@ -77,7 +95,7 @@ static grib_handle* try_product_template(grib_context* c, ProductKind product_ki
             g = grib_handle_new_from_file(c, f, &err);
         }
         if (!g) {
-            grib_context_log(c, GRIB_LOG_ERROR, "cannot create handle from %s", path);
+            grib_context_log(c, GRIB_LOG_ERROR, "Cannot create handle from %s", path);
         }
         fclose(f);
     }
@@ -100,6 +118,37 @@ static char* try_template_path(grib_context* c, const char* dir, const char* nam
     return NULL;
 }
 
+/* TODO: The following functions should be renamed/combined: 
+ *   codes_external_template
+ *   grib_external_template
+ *   bufr_external_template
+*/
+grib_handle* codes_external_template(grib_context* c, const char* name)
+{
+    const char* base = c->grib_samples_path;
+    char buffer[1024];
+    char* p        = buffer;
+    grib_handle* g = NULL;
+
+    if (!base)
+        return NULL;
+
+    while (*base) {
+        if (*base == ECC_PATH_DELIMITER_CHAR) {
+            *p = 0;
+            g  = try_product_template(c, PRODUCT_ANY, buffer, name);
+            if (g)
+                return g;
+            p = buffer;
+            base++; /*advance past delimiter*/
+        }
+        *p++ = *base++;
+    }
+
+    *p       = 0;
+    return g = try_product_template(c, PRODUCT_ANY, buffer, name);
+}
+
 grib_handle* grib_external_template(grib_context* c, const char* name)
 {
     const char* base = c->grib_samples_path;