Polish redbean serialization

libc/fmt/formatbinary64.c

@@ -0,0 +1,63 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2021 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/fmt/itoa.h"
+#include "libc/nexgen32e/bsr.h"
+
+static inline int PickGoodWidth(unsigned x) {
+  if (x < 16) {
+    if (x < 2) return 0;
+    if (x < 8) return 7;
+    return 15;
+  } else {
+    if (x < 32) return 31;
+    return 63;
+  }
+}
+
+/**
+ * Converts unsigned 64-bit integer to binary string.
+ *
+ * @param p needs at least 67 bytes
+ * @param z is 0 for DIGITS, 1 for 0bDIGITS, 2 for 0bDIGITS if ≠0
+ * @return pointer to nul byte
+ */
+char *FormatBinary64(char p[hasatleast 67], uint64_t x, char z) {
+  int i;
+  uint64_t b;
+  if (x) {
+    if (z) {
+      *p++ = '0';
+      *p++ = 'b';
+    }
+    i = PickGoodWidth(bsrl(x));
+    do {
+      b = 1;
+      b <<= i;
+      *p++ = '0' + !!(x & b);
+    } while (i--);
+  } else {
+    if (z == 1) {
+      *p++ = '0';
+      *p++ = 'b';
+    }
+    *p++ = '0';
+  }
+  *p = 0;
+  return p;
+}