add stumpless_get_priority_string

Adds a function to print privals in a more succinct representation that
follows the priority string convention used by tools like logger, for
example "local3.info".

Co-authored-by: Jonathon Brown <[email protected]>

include/stumpless/prival.h

@@ -59,6 +59,33 @@ STUMPLESS_PUBLIC_FUNCTION
 const char *
 stumpless_get_prival_string( int prival );
 
+/** 
+ * Gets the string representation of the given prival in the format
+ * "facility.level".
+ * 
+ * The string returned must be freed by the caller when it is no longer
+ * needed to avoid memory leaks.
+ *
+ * **Thread Safety: MT-Safe**
+ * This function is thread safe.
+ *
+ * **Async Signal Safety: AS-Unsafe heap**
+ * This function is not safe to call from signal handlers due to the use of
+ * memory management functions.
+ *
+ * **Async Cancel Safety: AC-Unsafe heap**
+ * This function is not safe to call from threads that may be asynchronously
+ * cancelled due to the use of memory management functions.
+ * 
+ * @param prival int to get the string from.
+ * 
+ * @return The string representation of the given prival.
+ * 
+*/
+STUMPLESS_PUBLIC_FUNCTION
+const char *
+stumpless_get_priority_string( int prival );
+
 /**
  * Extract PRIVAL number (Facility and Severity) from the given string with
  * the direct number or with two names divided with a period in the order:

src/prival.c

@@ -58,6 +58,51 @@ stumpless_get_prival_string( int prival ) {
   return prival_string;
 }
 
+const char *
+stumpless_get_priority_string( int prival ) {
+  const char *facility;
+  const char *severity;
+
+  size_t priority_string_size;
+  char* priority_string;
+
+  if ((prival & 0xff) != prival)
+    return NULL;
+  if (facility_is_invalid(get_facility(prival)))
+    return NULL;
+
+  facility = stumpless_get_facility_string( get_facility( prival ) );
+  severity = stumpless_get_severity_string( get_severity( prival ) );
+
+  facility = strrchr(facility, '_');
+  severity = strrchr(severity, '_');
+
+  // inc by 1 to skip '_'
+  facility++; 
+  severity++;
+
+  size_t len_facility = strlen(facility);
+  size_t len_severity = strlen(severity);
+
+  // +1 for '.' formatting, +1 for termination
+  priority_string_size = ( len_facility + len_severity + 2 );
+  priority_string = alloc_mem( priority_string_size );
+
+  for (size_t idx = 0; idx < len_facility; idx++) {
+    priority_string[idx] = tolower(facility[idx]);
+  }
+
+  priority_string[len_facility] = '.';
+
+  for (size_t idx = 0; idx < len_severity; idx++) {
+    priority_string[len_facility + 1 + idx] = tolower(severity[idx]);
+  }
+
+  priority_string[priority_string_size - 1] = '\0';
+
+  return priority_string;
+}
+
 int
 stumpless_prival_from_string( const char *string ) {
   int prival;

src/windows/stumpless.def

@@ -247,7 +247,7 @@ EXPORTS
 
   stumpless_get_prival_string                   @230
   stumpless_set_severity_color                  @231
-
   stumpless_get_malloc                          @232
   stumpless_get_free                            @233
-  stumpless_get_realloc                         @234
+  stumpless_get_realloc                         @234
+  stumpless_get_priority_string                 @235

test/function/prival.cpp

@@ -121,4 +121,52 @@ namespace {
 
     free( ( void * ) result );
   }
+
+  TEST(GetPriorityString, ValidPrival) {
+    int prival;
+    const char *result;
+
+    prival = STUMPLESS_SEVERITY_ERR | STUMPLESS_FACILITY_USER;
+    result = stumpless_get_priority_string( prival );
+    EXPECT_STREQ( result, "user.err" );
+
+    free( ( void * ) result );
+  }
+
+  TEST(GetPriorityString, InvalidPrivalNegativeArgument) {
+    int prival;
+    const char *result;
+
+    // Test for negative argument (falls outside of a byte)
+    prival = -1;
+    result = stumpless_get_priority_string( prival );
+    EXPECT_STREQ( result, NULL );
+
+    free( ( void * ) result );
+  }
+
+  TEST(GetPriorityString, InvalidPrivalGreaterThanRange) {
+    int prival;
+    const char *result;
+
+    // Test for argument greater than one byte
+    prival = 0x100;
+    result = stumpless_get_priority_string( prival );
+    EXPECT_STREQ( result, NULL );
+
+    free( ( void * ) result );
+  }
+
+  TEST(GetPriorityString, InvalidPrivalFacilityGreaterThanRange) {
+    int prival;
+    const char *result;
+
+    // Test for argument that translates into an invalid facility
+    // (greater than 0xbf)
+    prival = 0xc0;
+    result = stumpless_get_priority_string( prival );
+    EXPECT_STREQ( result, NULL );
+
+    free( ( void * ) result );
+  }
 }