split encoding.h

[shyouhei]

After I organise header files, this is the largest one now. I think it's a bit too large to read through. Why not split it into files.

[nobu]

I meant

diff --git a/string.c b/string.c
index 78e2ba923f3..7c2235450d6 100644
--- a/string.c
+++ b/string.c
@@ -5706,7 +5706,7 @@ rb_str_setbyte(VALUE str, VALUE index, VALUE value)
     long pos = NUM2LONG(index);
     long len = RSTRING_LEN(str);
     char *head, *left = 0;
-    unsigned char *ptr;
+    char *ptr;
     rb_encoding *enc;
     int cr = ENC_CODERANGE_UNKNOWN, width, nlen;
 
@@ -5717,18 +5717,18 @@ rb_str_setbyte(VALUE str, VALUE index, VALUE value)
 
     VALUE v = rb_to_int(value);
     VALUE w = rb_int_and(v, INT2FIX(0xff));
-    unsigned char byte = NUM2INT(w) & 0xFF;
+    char byte = (char)(NUM2INT(w) & 0xFF);
 
     if (!str_independent(str))
 	str_make_independent(str);
     enc = STR_ENC_GET(str);
     head = RSTRING_PTR(str);
-    ptr = (unsigned char *)&head[pos];
+    ptr = &head[pos];
     if (!STR_EMBED_P(str)) {
 	cr = ENC_CODERANGE(str);
 	switch (cr) {
 	  case ENC_CODERANGE_7BIT:
-            left = (char *)ptr;
+            left = ptr;
 	    *ptr = byte;
 	    if (ISASCII(byte)) goto end;
 	    nlen = rb_enc_precise_mbclen(left, head+len, enc);

[shyouhei]

@nobu That's also okay. But ultimately, ONIGENC_LEFT_ADJUST_CHAR_HEAD operates over OnigUChar*. Using unsigned char here seems a bit more natural, to me.

[nobu]

But rb_enc_left_char_head does not use unsigned char.