diff --git a/build.h b/build.h
new file mode 100644
index 0000000..0d554c7
--- /dev/null
+++ b/build.h
@@ -0,0 +1,140 @@
+/* This software is licensed by the MIT License, see LICENSE file */
+/*                                Copyright © 2022 Gregory Lirent */
+
+#include <string.h>
+#include "include.h"
+
+#ifdef RARE_CASE_SWITCHING_DISABLE
+#define GREEK_EXTENDED_DISABLE              // [ 0x1f00-0x1fff ]
+#define CHEROKEE_DISABLE                    // [ 0x13a0-0x13ff ], [ 0xab70-0xabbf ]
+
+#define CYRILLIC_SUPLEMENT_DISABLE          // [ 0x0500-0x052f ]
+#define CYRILLIC_EXTENDED_C_DISABLE         // [ 0x1c80-0x1c8f ]
+#define CYRILLIC_EXTENDED_B_DISABLE         // [ 0xa640-0xa69f ]
+
+#define LATIN_EXTENDED_B_DISABLE            // [ 0x0180-0x024f ]
+#define LATIN_EXTENDED_C_DISABLE            // [ 0x2c60-0x2c7f ]
+#define LATIN_EXTENDED_D_DISABLE            // [ 0xa720-0xa7ff ]
+#define LATIN_EXTENDED_E_DISABLE            // [ 0xab30-0xab6f ]
+#define LATIN_EXTENDED_ADDITIONAL_DISABLE   // [ 0x1e00-0x1eff ]
+#define IPA_EXTENSIONS_DISABLE              // [ 0x0250-0x02af ]
+
+#define OLD_AND_RELIGION_SPECIFIC_CASE_SWITCHING_DISABLE
+#define SYNTHETIC_CASE_SWITCHING_DISABLE
+
+#endif
+
+#ifdef SYNTHETIC_CASE_SWITCHING_DISABLE
+#define PHONETIC_EXTENSIONS_DISABLE         // [ 0x1d00-0x1d7f ]
+#define DESERET_DISABLE                     // [ 0x010400-0x01044f ]
+#define WARANG_CITI_DISABLE                 // [ 0x0118a0-0x0118ff ]
+#endif
+
+#ifdef OLD_AND_RELIGION_SPECIFIC_CASE_SWITCHING_DISABLE
+#define GLAGOLITIC_DISABLE                  // [ 0x2c00-0x2c5f ]
+#define COPTIC_DISABLE                      // [ 0x2c80-0x2cff ]
+#define GEORGIAN_SUPPLEMENT_DISABLE         // [ 0x2d00-0x2d2f ]
+
+#define OSAGE_DISABLE                       // [ 0x0104b0-0x0104ff ]
+#define OLD_HUNGARIAN_DISABLE               // [ 0x010c80-0x010cff ]
+#endif
+
+
+
+
+#ifdef SYNTHETIC_CASE_SWITCHING_ENABLE
+#define PHONETIC_EXTENSIONS_ENABLE
+#define DESERET_ENABLE
+#define WARANG_CITI_ENABLE
+#endif
+
+#ifdef OLD_AND_RELIGION_SPECIFIC_CASE_SWITCHING_ENABLE
+#define GLAGOLITIC_ENABLE
+#define COPTIC_ENABLE
+#define GEORGIAN_SUPPLEMENT_ENABLE
+
+#define OLD_HUNGARIAN_DISABLE
+#endif
+
+
+
+#if defined(GREEK_EXTENDED_ENABLE) && defined(GREEK_EXTENDED_DISABLE)
+#undef GREEK_EXTENDED_DISABLE
+#endif
+
+#if defined(CHEROKEE_ENABLE) && defined(CHEROKEE_DISABLE)
+#undef CHEROKEE_DISABLE
+#endif
+
+#if defined(CYRILLIC_SUPLEMENT_ENABLE) && defined(CYRILLIC_SUPLEMENT_DISABLE)
+#undef CYRILLIC_SUPLEMENT_DISABLE
+#endif
+
+#if defined(CYRILLIC_EXTENDED_C_ENABLE) && defined(CYRILLIC_EXTENDED_C_DISABLE)
+#undef CYRILLIC_EXTENDED_C_DISABLE
+#endif
+
+#if defined(CYRILLIC_EXTENDED_B_ENABLE) && defined(CYRILLIC_EXTENDED_B_DISABLE)
+#undef CYRILLIC_EXTENDED_B_DISABLE
+#endif
+
+#if defined(LATIN_EXTENDED_B_ENABLE) && defined(LATIN_EXTENDED_B_DISABLE)
+#undef LATIN_EXTENDED_B_DISABLE
+#endif
+
+#if defined(LATIN_EXTENDED_C_ENABLE) && defined(LATIN_EXTENDED_C_DISABLE)
+#undef LATIN_EXTENDED_C_DISABLE
+#endif
+
+#if defined(LATIN_EXTENDED_D_ENABLE) && defined(LATIN_EXTENDED_D_DISABLE)
+#undef LATIN_EXTENDED_D_DISABLE
+#endif
+
+#if defined(LATIN_EXTENDED_E_ENABLE) && defined(LATIN_EXTENDED_E_DISABLE)
+#undef LATIN_EXTENDED_E_DISABLE
+#endif
+
+#if defined(LATIN_EXTENDED_ADDITIONAL_ENABLE) && defined(LATIN_EXTENDED_ADDITIONAL_DISABLE)
+#undef LATIN_EXTENDED_ADDITIONAL_DISABLE
+#endif
+
+#if defined(IPA_EXTENSIONS_ENABLE) && defined(IPA_EXTENSIONS_DISABLE)
+#undef IPA_EXTENSIONS_DISABLE
+#endif
+
+
+
+
+#if defined(PHONETIC_EXTENSIONS_ENABLE) && defined(PHONETIC_EXTENSIONS_DISABLE)
+#undef PHONETIC_EXTENSIONS_DISABLE
+#endif
+
+#if defined(DESERET_ENABLE) && defined(DESERET_DISABLE)
+#undef DESERET_DISABLE
+#endif
+
+#if defined(WARANG_CITI_ENABLE) && defined(WARANG_CITI_DISABLE)
+#undef WARANG_CITI_DISABLE
+#endif
+
+
+
+
+#if defined(GLAGOLITIC_ENABLE) && defined(GLAGOLITIC_DISABLE)
+#undef GLAGOLITIC_DISABLE
+#endif
+
+#if defined(COPTIC_ENABLE) && defined(COPTIC_DISABLE)
+#undef COPTIC_DISABLE
+#endif
+
+#if defined(GEORGIAN_SUPPLEMENT_ENABLE) && defined(GEORGIAN_SUPPLEMENT_DISABLE)
+#undef GEORGIAN_SUPPLEMENT_DISABLE
+#endif
+
+#if defined(OLD_HUNGARIAN_ENABLE) && defined(OLD_HUNGARIAN_DISABLE)
+#undef OLD_HUNGARIAN_DISABLE
+#endif
+
+
+#define IS_LITTLE_ENDIAN (*((unsigned int*)"\0\0\0\1") > (unsigned int)0xffff)
diff --git a/include.h b/include.h
new file mode 100644
index 0000000..4d72ab5
--- /dev/null
+++ b/include.h
@@ -0,0 +1,25 @@
+/* This software is licensed by the MIT License, see LICENSE file */
+/*                                Copyright © 2022 Gregory Lirent */
+
+#include <stddef.h>
+#include <uchar.h>
+
+#ifndef LIBUNIC_INCLUDE_H
+#define LIBUNIC_INCLUDE_H
+
+extern unsigned int toupper_unicode(unsigned int unicode);
+extern unsigned int tolower_unicode(unsigned int unicode);
+
+extern int charsize  (const char*     char_begin);
+extern int char16size(const char16_t* char_begin);
+extern int char32size(const char32_t* char_begin);
+
+extern const char*     fromchar_unicode  (unsigned int* unicode, const char*     char_begin);
+extern const char16_t* fromchar16_unicode(unsigned int* unicode, const char16_t* char_begin);
+extern const char32_t* fromchar32_unicode(unsigned int* unicode, const char32_t* char_begin);
+
+extern char*     tochar_unicode  (char     dest[4], unsigned int unicode);
+extern char16_t* tochar16_unicode(char16_t dest[2], unsigned int unicode);
+extern char32_t* tochar32_unicode(char32_t dest[1], unsigned int unicode);
+
+#endif /* LIBUNIC_INCLUDE_H */