Add frontend helper

frontend_helper.h

@@ -0,0 +1,87 @@
+/** @file frontend_helper.h
+
+  Helper file for generic PC frontends that can use the stdio library, to avoid
+  duplication of code.
+*/
+
+// TODO: quality presets?
+
+#include <stdint.h>
+#include <stdio.h>
+
+#define DATA_FILE_NAME "data"
+
+FILE *dataFile = 0;
+
+char LCR_getNextDataFileChar(void)
+{
+#ifdef __EMSCRIPTEN__
+  return 0;
+#else
+  if (!dataFile)
+    return 0;
+
+  int c = fgetc(dataFile);
+
+  if (c == EOF)
+  {
+    rewind(dataFile);
+    return 0;
+  }
+
+  return c;
+#endif
+}
+
+void LCR_appendDataStr(const char *str)
+{
+#ifndef __EMSCRIPTEN__
+  if (!dataFile)
+    return;
+
+  if (str == 0 || *str == 0)
+    rewind(dataFile);
+  else
+  {
+#if LCR_SETTING_LOG_LEVEL > 1
+    printf("SDL: appending data \"%s\"\n",str);
+#endif 
+
+    fclose(dataFile);
+    
+    dataFile = fopen(DATA_FILE_NAME,"a");
+    
+    if (dataFile)
+    {
+      fprintf(dataFile,"%s",str);
+      fclose(dataFile);
+      dataFile = fopen(DATA_FILE_NAME,"r");
+    }
+  }
+#else
+  printf("%s",str);
+#endif
+}
+
+void LCR_log(const char *str)
+{
+  printf("%s\n",str);
+}
+
+void openDataFile(void)
+{
+#ifndef __EMSCRIPTEN__
+  dataFile = fopen(DATA_FILE_NAME,"r");
+
+  if (!dataFile)
+    puts("WARNING: couldn't open data file");
+#endif
+}
+
+void closeDataFile(void)
+{
+#ifndef __EMSCRIPTEN__
+  if (dataFile)
+    fclose(dataFile);
+#endif
+}