increase readability of encode.{c,h}

encode.c

@@ -33,75 +33,76 @@ unsigned char asciitob64[] = {
 
 
 int
-encode(unsigned char *op, int olen, unsigned char *sp, int url)
+encode(unsigned char *octbuf, int octbufsize, unsigned char *sxtbuf, int urlencoded)
 {
-    int tmp;
     unsigned char *table;
-    unsigned char *sbeg;
+    unsigned char *sxtbegin;
-    unsigned char *tend;
+    unsigned char *octleft;
+    int highorderbits;
 
-    table = (!url) ? b64toascii : b64urltoascii;
+    table = (!urlencoded) ? b64toascii : b64urltoascii;
 
-    sbeg = sp;
+    sxtbegin = sxtbuf;
-    tend = op + olen - (olen % 3);
+    octleft = octbuf + octbufsize - (octbufsize % 3);
-    while (op < tend) {
+    while (octbuf < octleft) {
-        *sp++ = table[(*op & ~3) >> 2];
+        *sxtbuf++ = table[(*octbuf & ~3) >> 2];
-        tmp = (*op++ & 3) << 4;
+        highorderbits = (*octbuf++ & 3) << 4;
-        *sp++ = table[tmp + ((*op & ~15) >> 4)];
+        *sxtbuf++ = table[highorderbits + ((*octbuf & ~15) >> 4)];
-        tmp = (*op++ & 15) << 2;
+        highorderbits = (*octbuf++ & 15) << 2;
-        *sp++ = table[tmp + ((*op & 192) >> 6)];
+        *sxtbuf++ = table[highorderbits + ((*octbuf & 192) >> 6)];
-        *sp++ = table[*op++ & ~192];
+        *sxtbuf++ = table[*octbuf++ & ~192];
     }
-    switch (olen % 3) {
+    switch (octbufsize % 3) {
         case 2:
-            *sp++ = table[(*op & ~3) >> 2];
+            *sxtbuf++ = table[(*octbuf & ~3) >> 2];
-            tmp = (*op++ & 3) << 4;
+            highorderbits = (*octbuf++ & 3) << 4;
-            *sp++ = table[tmp + ((*op & ~15) >> 4)];
+            *sxtbuf++ = table[highorderbits + ((*octbuf & ~15) >> 4)];
-            *sp++ = table[(*op & 15) << 2];
+            *sxtbuf++ = table[(*octbuf & 15) << 2];
-            *sp++ = PADDING;
+            *sxtbuf++ = PADDING;
             break;
         case 1:
-            *sp++ = table[(*op & ~3) >> 2];
+            *sxtbuf++ = table[(*octbuf & ~3) >> 2];
-            *sp++ = table[(*op & 3) << 4];
+            *sxtbuf++ = table[(*octbuf & 3) << 4];
-            *sp++ = PADDING;
+            *sxtbuf++ = PADDING;
-            *sp++ = PADDING;
+            *sxtbuf++ = PADDING;
             break;
     }
 
-    return sp-sbeg;
+    return sxtbuf-sxtbegin;
 }
 
 int
-decode(unsigned char *sp, int slen, unsigned char *op)
+decode(unsigned char *sxtbuf, int sxtbufsize, unsigned char *octbuf)
 {
-    int tmp, b;
+    unsigned char *octbegin;
-    unsigned char *obeg;
+    unsigned char *sxtleft;
-    unsigned char *qend;
+    int highorderbits;
+    int loworderbits;
 
-    obeg = op;
+    octbegin = octbuf;
-    qend = sp + slen - (slen % 4);
+    sxtleft = sxtbuf + sxtbufsize - (sxtbufsize % 4);
-    while (sp < qend) {
+    while (sxtbuf < sxtleft) {
-        tmp = asciitob64[*sp++] << 2;
+        highorderbits = asciitob64[*sxtbuf++] << 2;
-        b = asciitob64[*sp++];
+        loworderbits = asciitob64[*sxtbuf++];
-        *op++ = tmp + ((b & ~15) >> 4);
+        *octbuf++ = highorderbits + ((loworderbits & ~15) >> 4);
-        tmp = (b & 15) << 4;
+        highorderbits = (loworderbits & 15) << 4;
-        b = asciitob64[*sp++];
+        loworderbits = asciitob64[*sxtbuf++];
-        *op++ = tmp + ((b & ~3) >> 2);
+        *octbuf++ = highorderbits + ((loworderbits & ~3) >> 2);
-        *op++ = ((b & 3) << 6) + asciitob64[*sp++];
+        *octbuf++ = ((loworderbits & 3) << 6) + asciitob64[*sxtbuf++];
     }
-    switch (slen % 4) {
+    switch (sxtbufsize % 4) {
         case 3:
-            tmp = asciitob64[*sp++] << 2;
+            highorderbits = asciitob64[*sxtbuf++] << 2;
-            b = asciitob64[*sp++];
+            loworderbits = asciitob64[*sxtbuf++];
-            *op++ = tmp + ((b & ~15) >> 4);
+            *octbuf++ = highorderbits + ((loworderbits & ~15) >> 4);
-            tmp = (b & 15) << 4;
+            highorderbits = (loworderbits & 15) << 4;
-            *op++ = tmp + ((asciitob64[*sp++] & ~3) >> 2);
+            *octbuf++ = highorderbits + ((asciitob64[*sxtbuf++] & ~3) >> 2);
             break;
         case 2:
-            tmp = asciitob64[*sp++] << 2;
+            highorderbits = asciitob64[*sxtbuf++] << 2;
-            *op++ = tmp + ((asciitob64[*sp++] & ~15) >> 4);
+            *octbuf++ = highorderbits + ((asciitob64[*sxtbuf++] & ~15) >> 4);
             break;
     }
 
-    return op-obeg;
+    return octbuf-octbegin;
 }

encode.h

@@ -2,9 +2,9 @@
 #define ENCODE_H
 
 int
-encode(unsigned char *op, int olen, unsigned char *sp, int url);
+encode(unsigned char *octbuf, int octbufsize, unsigned char *sxtbuf, int urlencoded);
 
 int
-decode(unsigned char *sp, int slen, unsigned char *op);
+decode(unsigned char *sxtbuf, int sxtbufsize, unsigned char *octbuf);
 
 #endif