1 files changed, 97 insertions, 0 deletions
diff --git a/libc/bionic/c32rtomb.cpp b/libc/bionic/c32rtomb.cpp
new file mode 100644
index 0000000..d3231c0
--- /dev/null
+++ b/libc/bionic/c32rtomb.cpp
@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <errno.h>
+#include <uchar.h>
+#include <wchar.h>
+
+#include "private/bionic_mbstate.h"
+
+size_t c32rtomb(char* s, char32_t c32, mbstate_t* ps) {
+  static mbstate_t __private_state;
+  mbstate_t* state = (ps == NULL) ? &__private_state : ps;
+
+  if (s == NULL) {
+    // Equivalent to c32rtomb(buf, U'\0', ps).
+    return reset_and_return(1, state);
+  }
+
+  // POSIX states that if char32_t is a null wide character, a null byte shall
+  // be stored, preceded by any shift sequence needed to restore the initial
+  // shift state. Since shift states are not supported, only the null byte is
+  // stored.
+  if (c32 == U'\0') {
+    *s = '\0';
+    reset_and_return(1, state);
+  }
+
+  if (!mbsinit(state)) {
+    return reset_and_return_illegal(EILSEQ, state);
+  }
+
+  if ((c32 & ~0x7f) == 0) {
+    // Fast path for plain ASCII characters.
+    *s = c32;
+    return 1;
+  }
+
+  // Determine the number of octets needed to represent this character.
+  // We always output the shortest sequence possible. Also specify the
+  // first few bits of the first octet, which contains the information
+  // about the sequence length.
+  uint8_t lead;
+  size_t length;
+  if ((c32 & ~0x7f) == 0) {
+    lead = 0;
+    length = 1;
+  } else if ((c32 & ~0x7ff) == 0) {
+    lead = 0xc0;
+    length = 2;
+  } else if ((c32 & ~0xffff) == 0) {
+    lead = 0xe0;
+    length = 3;
+  } else if ((c32 & ~0x1fffff) == 0) {
+    lead = 0xf0;
+    length = 4;
+  } else {
+    errno = EILSEQ;
+    return __MB_ERR_ILLEGAL_SEQUENCE;
+  }
+
+  // Output the octets representing the character in chunks
+  // of 6 bits, least significant last. The first octet is
+  // a special case because it contains the sequence length
+  // information.
+  for (size_t i = length - 1; i > 0; i--) {
+    s[i] = (c32 & 0x3f) | 0x80;
+    c32 >>= 6;
+  }
+  *s = (c32 & 0xff) | lead;
+
+  return length;
+}