> compile NEMU

221220000 张三
Linux zzy 5.15.146.1-microsoft-standard-WSL2 #1 SMP Thu Jan 11 04:09:03 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux
 09:31:07 up 21:55,  3 users,  load average: 0.09, 0.04, 0.05

abstract-machine/klib/src/stdio.c

@@ -45,36 +45,60 @@ int vsnprintf(char *out, size_t n, const char *fmt, va_list ap) {
   return rvsnprintf(out, n, fmt, ap);
 }
 
+static inline int fmt_d(char* out, size_t n, const char* fmt, va_list ap) {
+    char buf[16];
+    int in = va_arg(ap, int);
+    if (in == 0) {
+        *out = '0';
+        out ++;
+        return 1;
+    }
+
+    int i;
+    for (i = 0; in; in /= 10, i ++) {
+        buf[i] = in % 10;
+    }
+    
+    for (int j = i; j >= 0; j --) {
+        *out = buf[j];
+    }
+    return i;
+}
+
+static inline int fmt_s(char* out, size_t n, const char* fmt, va_list ap) {
+    const char* ch = va_arg(ap, const char*); 
+    size_t len = strlen(ch);
+    strncpy(out, ch, len);
+    return len;
+}
+
+static inline int fmt_match(char* out, size_t n, const char* fmt, va_list ap) {
+    int res;
+    switch(*fmt) {
+        case 'd':
+            res = fmt_d(out, n, fmt, ap);
+            break;
+        case 's':
+            res = fmt_s(out, n, fmt, ap);
+            break;
+        default:
+            res = 0;
+            break;
+    }
+    return res;
+}
+
 static int rvsnprintf(char* out, size_t n, const char* fmt, va_list ap) {
-  bool is_fmt;
-  for (is_fmt = false; n; fmt ++, out ++, n --) {
+  for (; n; fmt ++, out ++, n --) {
     switch (*fmt)
     {
     case '\0':
       *out = *fmt;
       goto END;
     case '%':
-      is_fmt = true;
-      break;
-    case 'd':
-      if (is_fmt) {
-        int va = va_arg(ap, int);
-        for (; va; va /= 10) {
-          *out = va % 10 + '0';
-          n --;
-          out ++;
-        }
-        is_fmt = false;
-      }
-      break;
-    case 's':
-      if (is_fmt) {
-        const char* va = va_arg(ap, const char*);
-        size_t len = strlen(va);
-        strncpy(out, va, len);
-        n += len;
-        is_fmt = false;
-      }
+        int len = fmt_match(out, n, fmt, ap);
+        out += len;
+        n -= len;
     default:
       *out = *fmt;
       break;