isdigit, libc header changes, stpcpy rename

.gitignore

@@ -36,6 +36,7 @@ u-boot/
 # Build
 bin/
 obj/
+build/
 yukari.bin
 yukari.uimg
 asagiri.img

libc/ctype/isdigit.c

@@ -0,0 +1,21 @@
+/**
+ *  isdigit implementation of Asagiri
+ *  Copyright (C) 2023 Asagiri contributors
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ * 
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+int isdigit(int c) {
+    return (unsigned)c-'0' < 10;
+}

libc/include/string.h

@@ -22,15 +22,15 @@
 #include <sys/cdefs.h>
 #include <stddef.h>
 
-char* __stpcpy(char* __restrict, const char* __restrict);
-char* strcpy(char* __restrict, const char* __restrict);
-char* strcat(char* __restrict, const char* __restrict);
-char* strtok(char* __restrict, const char* __restrict);
-int strcmp(const char* __restrict, const char* __restrict);
-char* strchr(const char* __restrict, int c);
+char* stpcpy(char* restrict, const char* restrict);
+char* strcpy(char* restrict, const char* restrict);
+char* strcat(char* restrict, const char* restrict);
+char* strtok(char* restrict, const char* restrict);
+int strcmp(const char* restrict, const char* restrict);
+char* strchr(const char* restrict, int c);
 
 int memcmp(const void*, const void*, size_t);
-void* memcpy(void* __restrict, const void* __restrict, size_t);
+void* memcpy(void* restrict, const void* restrict, size_t);
 void* memmove(void*, const void*, size_t);
 void* memset(void*, int, size_t);
 size_t strlen(const char*);

libc/string/stpcpy.c

@@ -20,12 +20,7 @@
 #include <stdint.h>
 #include <limits.h>
 
-#define ALIGN (sizeof(size_t))
-#define ONES ((size_t)-1/UCHAR_MAX)
-#define HIGHS (ONES * (UCHAR_MAX/2+1))
-#define HASZERO(x) ((x)-ONES & ~(x) & HIGHS)
-
-char* __stpcpy(char* restrict d, const char* restrict s){
+char* stpcpy(char* restrict d, const char* restrict s){
     for(;(*d=*s); s++, d++);
     return d;
 }

libc/string/strcpy.c

@@ -19,6 +19,6 @@
 #include <string.h>
 
 char* strcpy(char* restrict dest, const char* restrict src) {
-    __stpcpy(dest, src);
+    stpcpy(dest, src);
     return dest;
 }