diff --git a/inc/unicode.h b/inc/unicode.h
index c7d3318..d8c0ea6 100644
--- a/inc/unicode.h
+++ b/inc/unicode.h
@@ -14,7 +14,7 @@ typedef int32_t uchar_t;
 #define UNI_EIBYTE (-3)
 #define UNI_ETBYTE (-4)
 #define UNI_ESTRLN (-5)
-
+#define UNI_EOLONG (-6)
 
 enum {
     UCHAR_BAD,
@@ -127,15 +127,15 @@ int     uni_is_hsur(char16_t cp);
 int     uni_is_lsur(char16_t cp);
 uchar_t uni_surtoc (char16_t hsur, char16_t lsur);
 
-size_t utf16_chlen(char16_t const *str);
-size_t utf8_chlen (char     const *str);
+int utf16_chlen(char16_t const *str);
+int utf8_chlen (char     const *str);
 
-size_t utf16_dec_s(char16_t const *restrict str, size_t len, uchar_t *restrict ch);
-size_t utf8_dec_s (char     const *restrict str, size_t len, uchar_t *restrict ch);
-size_t utf16_dec  (char16_t const *restrict str,             uchar_t *restrict ch);
-size_t utf8_dec   (char     const *restrict str,             uchar_t *restrict ch);
+int utf16_dec_s(char16_t const *restrict str, size_t len, uchar_t *restrict ch);
+int utf8_dec_s (char     const *restrict str, size_t len, uchar_t *restrict ch);
+int utf16_dec  (char16_t const *restrict str,             uchar_t *restrict ch);
+int utf8_dec   (char     const *restrict str,             uchar_t *restrict ch);
 
-size_t utf16_enc_s(char16_t *str, size_t len, uchar_t ch);
-size_t utf8_enc_s (char     *str, size_t len, uchar_t ch);
-size_t utf16_enc  (char16_t *str,             uchar_t ch);
-size_t utf8_enc   (char     *str,             uchar_t ch);
+int utf16_enc_s(char16_t *str, size_t len, uchar_t ch);
+int utf8_enc_s (char     *str, size_t len, uchar_t ch);
+int utf16_enc  (char16_t *str,             uchar_t ch);
+int utf8_enc   (char     *str,             uchar_t ch);
diff --git a/src/code/unicode.c b/src/code/unicode.c
index c2008df..00d8c11 100644
--- a/src/code/unicode.c
+++ b/src/code/unicode.c
@@ -53,7 +53,7 @@ int utf16_chlen(char16_t const *str) {
     else return 1;
 }
 
-size_t utf8_chlen(char const *str) {
+int utf8_chlen(char const *str) {
     uint8_t byte0 = (uint8_t)*str;
     if(byte0 < 0x80)      return 1;
     else if(byte0 < 0xc0) return UNI_EIBYTE;
@@ -63,8 +63,8 @@ size_t utf8_chlen(char const *str) {
     return UNI_EIBYTE;
 }
 
-size_t utf16_dec(char16_t const *restrict str, uchar_t *restrict chp) {
-    size_t chlen = 0;
+int utf16_dec(char16_t const *restrict str, uchar_t *restrict chp) {
+    int chlen = 0;
     uchar_t ch;
     if(uni_is_hsur(str[0])) {
         char16_t hsur = str[0];
@@ -87,13 +87,13 @@ size_t utf16_dec(char16_t const *restrict str, uchar_t *restrict chp) {
     return chlen;
 }
 
-size_t utf16_dec_s(
+int utf16_dec_s(
     char16_t const *restrict str,
-    size_t len,
+    int len,
     uchar_t *restrict chp
 ) {
     if(len == 0) return 0;
-    size_t chlen;
+    int chlen;
     uchar_t ch;
     if(uni_is_hsur(str[0])) {
         if(len < 2) return 0;
@@ -118,10 +118,10 @@ size_t utf16_dec_s(
     return chlen;
 }
 
-size_t utf8_dec(char const *restrict str, uchar_t *restrict chp) {
+int utf8_dec(char const *restrict str, uchar_t *restrict chp) {
     uint8_t const *ustr = (uint8_t const *)str;
 
-    size_t chlen;
+    int chlen;
     uchar_t ch;
     if(ustr[0] < 0x80)      ch = ustr[0],        chlen = 1;
     else if(ustr[0] < 0xc0) ch = 0xfffd,         chlen = UNI_EIBYTE;
@@ -130,7 +130,7 @@ size_t utf8_dec(char const *restrict str, uchar_t *restrict chp) {
     else if(ustr[0] < 0xf8) ch = ustr[0] & 0x07, chlen = 4;
     else                    ch = 0xfffd,         chlen = UNI_EIBYTE;
 
-    if(chlen > 0) for(size_t i = 1; i < chlen; ++i) {
+    if(chlen > 0) for(int i = 1; i < chlen; ++i) {
         uint8_t trail = ustr[i];
         if((trail & 0xc0) != 0x80) {
             chlen = UNI_ETBYTE;
@@ -148,14 +148,14 @@ size_t utf8_dec(char const *restrict str, uchar_t *restrict chp) {
     return chlen;
 }
 
-size_t utf8_dec_s(
+int utf8_dec_s(
     char const *restrict str,
-    size_t len,
+    int len,
     uchar_t *restrict chp
 ) {
     if(len == 0) return 0;
     uint8_t const *restrict ustr = (uint8_t const *restrict)str;
-    size_t chlen;
+    int chlen;
     uchar_t ch;
     if(ustr[0] < 0x80)      ch = ustr[0],        chlen = 1;
     else if(ustr[0] < 0xc0) ch = 0xfffd,         chlen = UNI_EIBYTE;
@@ -166,7 +166,7 @@ size_t utf8_dec_s(
     if(chlen > len) {
         return UNI_ESTRLN;
     }
-    if(chlen > 0) for(size_t i = 1; i < chlen; ++i) {
+    if(chlen > 0) for(int i = 1; i < chlen; ++i) {
         uint8_t trail = ustr[i];
         if((trail & 0xc0) != 0x80) {
             chlen = UNI_ETBYTE;
@@ -184,3 +184,96 @@ size_t utf8_dec_s(
     return chlen;
 }
 
+int utf16_enc(char16_t *str, uchar_t cp) {
+    if(!is_valid(cp)) {
+        return UNI_EBADCP;
+    }
+    if(cp < 0x10000) {
+        str[0] = cp;
+        return 1;
+    }
+    else {
+        cp -= 0x10000;
+        str[0] = 0xD800 + (cp >> 10);
+        str[1] = 0xDC00 + (cp & 0x3ff);
+        return 2;
+    }
+}
+
+int utf8_enc(char *str, uchar_t ch) {
+    if(!is_valid(cp)) {
+        return UNI_EBADCP;
+    }
+    if(cp < 0x80) {
+        str[0] = ch;
+        return 1;
+    }
+    else if(cp < 0x800) {
+        str[0] = 0xc0 | (ch >> 6);
+        str[1] = 0x80 | ((ch >> 0) & 0x3f);
+        return 2;
+    }
+    else if(cp < 0x10000) {
+        str[0] = 0xe0 | (ch >> 18);
+        str[1] = 0x80 | ((ch >> 6) & 0x3f);
+        str[2] = 0x80 | ((ch >> 0) & 0x3f);
+        return 3;
+    }
+    else {
+        str[0] = 0xe0 | (ch >> 24);
+        str[1] = 0x80 | ((ch >> 18) & 0x3f);
+        str[2] = 0x80 | ((ch >> 6)  & 0x3f);
+        str[3] = 0x80 | ((ch >> 0)  & 0x3f);
+        return 4;
+    }
+}
+
+int utf16_enc_s(char16_t *str, size_t len, uchar_t ch) {
+    if(!is_valid(cp)) {
+        return UNI_EBADCP;
+    }
+    if(len == 0) return 0;
+    if(cp < 0x10000) {
+        str[0] = cp;
+        return 1;
+    }
+    else {
+        if(len < 2) return UNI_ESTRLN;
+        cp -= 0x10000;
+        str[0] = 0xD800 + (cp >> 10);
+        str[1] = 0xDC00 + (cp & 0x3ff);
+        return 2;
+    }
+}
+
+int utf8_enc_s(char *str, size_t len, uchar_t ch) {
+    if(!is_valid(cp)) {
+        return UNI_EBADCP;
+    }
+    if(len == 0) return 0;
+    if(cp < 0x80) {
+        str[0] = ch;
+        return 1;
+    }
+    else if(cp < 0x800) {
+        if(len < 2) return UNI_ESTRLN;
+        str[0] = 0xc0 | (ch >> 6);
+        str[1] = 0x80 | ((ch >> 0) & 0x3f);
+        return 2;
+    }
+    else if(cp < 0x10000) {
+        if(len < 3) return UNI_ESTRLN;
+        str[0] = 0xe0 | (ch >> 18);
+        str[1] = 0x80 | ((ch >> 6) & 0x3f);
+        str[2] = 0x80 | ((ch >> 0) & 0x3f);
+        return 3;
+    }
+    else {
+        if(len < 4) return UNI_ESTRLN;
+        str[0] = 0xe0 | (ch >> 24);
+        str[1] = 0x80 | ((ch >> 18) & 0x3f);
+        str[2] = 0x80 | ((ch >> 6)  & 0x3f);
+        str[3] = 0x80 | ((ch >> 0)  & 0x3f);
+        return 4;
+    }
+}