From a13536d0c7dbec8fd3daccd783c877d9cf6a48ae Mon Sep 17 00:00:00 2001
From: Chewing_Bever <roosensjef@gmail.com>
Date: Wed, 2 Dec 2020 14:26:01 +0100
Subject: [PATCH] Some refactoring

---
 src/st/st.c | 69 ++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 44 insertions(+), 25 deletions(-)

diff --git a/src/st/st.c b/src/st/st.c
index 8d2a202..c39ffa9 100644
--- a/src/st/st.c
+++ b/src/st/st.c
@@ -308,67 +308,86 @@ char *safe_strdup(char *p_str) {
  * @return size of the decoded rune
  */
 size_t utf8decode(const char *p_char, Rune *p_rune, size_t p_char_len) {
-    size_t decoded_len, type;
-    Rune rune_decoded;
+    size_t decoded_len, type, i;
+    Rune decoded_rune;
 
     *p_rune = UTF_INVALID;
-    if (!p_char_len) // chr_len is 0, so just return 0
+    if (!p_char_len) // p_char_len is 0, so just return 0
         return 0;
 
-    rune_decoded = utf8decodebyte(p_char[0], &decoded_len);
+    decoded_rune = utf8decodebyte(p_char[0], &decoded_len);
     if (!BETWEEN(decoded_len, 1, UTF_SIZE))
         return 1;
 
-    size_t i, j;
-    for (i = 1, j = 1; i < p_char_len && j < decoded_len; ++i, ++j) {
-        rune_decoded = (rune_decoded << 6) | utf8decodebyte(p_char[i], &type);
+    for (i = 1; i < p_char_len && i < decoded_len; ++i) {
+        decoded_rune = (decoded_rune << 6) | utf8decodebyte(p_char[i], &type);
 
         if (type != 0)
-            return j;
+            return i;
     }
 
-    if (j < decoded_len)
+    if (i < decoded_len)
         return 0;
 
-    *p_rune = rune_decoded;
+    *p_rune = decoded_rune;
     utf8validate(p_rune, decoded_len);
 
     return decoded_len;
 }
 
-Rune utf8decodebyte(char p_char, size_t *i) {
-
-    for (*i = 0; *i < LEN(utfmask); ++(*i)) {
-        if (((uchar)p_char & utfmask[*i]) == utfbyte[*i])
-            return (uchar)p_char & ~utfmask[*i];
+/**
+ * Decode a single byte to UTF-8
+ *
+ * @param p_char char to decode
+ * @param p_i counter used in internal for loop
+ * @return decoded rune
+ */
+Rune utf8decodebyte(char p_char, size_t *p_i) {
+    for (*p_i = 0; *p_i < LEN(utfmask); ++(*p_i)) {
+        if (((uchar)p_char & utfmask[*p_i]) == utfbyte[*p_i])
+            return (uchar)p_char & ~utfmask[*p_i];
     }
 
     return 0;
 }
 
-size_t utf8encode(Rune u, char *c) {
+/**
+ * Encode a UTF-8 rune
+ *
+ * @param p_rune rune to encode
+ * @param p_char char array to encode to
+ * @return 
+ */
+size_t utf8encode(Rune p_rune, char *p_char) {
     size_t len, i;
 
-    len = utf8validate(&u, 0);
+    len = utf8validate(&p_rune, 0);
     if (len > UTF_SIZE)
         return 0;
 
     for (i = len - 1; i != 0; --i) {
-        c[i] = utf8encodebyte(u, 0);
-        u >>= 6;
+        p_char[i] = utf8encodebyte(p_rune, 0);
+        p_rune >>= 6;
     }
-    c[0] = utf8encodebyte(u, len);
+    p_char[0] = utf8encodebyte(p_rune, len);
 
     return len;
 }
 
 char utf8encodebyte(Rune u, size_t i) { return utfbyte[i] | (u & ~utfmask[i]); }
 
-size_t utf8validate(Rune *u, size_t i) {
-    if (!BETWEEN(*u, utfmin[i], utfmax[i]) || BETWEEN(*u, 0xD800, 0xDFFF))
-        *u = UTF_INVALID;
-    for (i = 1; *u > utfmax[i]; ++i)
-        ;
+/**
+ * Check if a given rune is a valid UTF-8 rune
+ *
+ * @param p_rune rune to validate
+ * @param i 
+ */
+size_t utf8validate(Rune *p_rune, size_t i) {
+    if (!BETWEEN(*p_rune, utfmin[i], utfmax[i]) || BETWEEN(*p_rune, 0xD800, 0xDFFF))
+        *p_rune = UTF_INVALID;
+
+    // Count up i until you find a utfmax entry that's greater than *p_rune
+    for (i = 1; *p_rune > utfmax[i]; ++i);
 
     return i;
 }