New modules: utf8-ucs4, utf16-ucs4, ucs4-utf8, ucs4-utf16.

[gnulib.git] / lib / ucs4-utf8.h

diff --git a/lib/ucs4-utf8.h b/lib/ucs4-utf8.h
new file mode 100644 (file)
index 0000000..0757325
--- /dev/null
+++ b/lib/ucs4-utf8.h
@@ -0,0 +1,77 @@
+/* Conversion UCS-4 to UTF-8.
+   Copyright (C) 2002 Free Software Foundation, Inc.
+   Written by Bruno Haible <haible@clisp.cons.org>, 2002.
+
+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 2, 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, write to the Free Software
+Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+
+#include <stddef.h>
+
+/* Return the length (number of units) of the UTF-8 representation of uc,
+   after storing it at S.  Return -1 upon failure, -2 if the number of
+   available units, N, is too small.  */
+static int
+u8_uctomb_aux (unsigned char *s, unsigned int uc, int n)
+{
+  int count;
+
+  if (uc < 0x80)
+    count = 1;
+  else if (uc < 0x800)
+    count = 2;
+  else if (uc < 0x10000)
+    count = 3;
+#if 0
+  else if (uc < 0x200000)
+    count = 4;
+  else if (uc < 0x4000000)
+    count = 5;
+  else if (uc <= 0x7fffffff)
+    count = 6;
+#else
+  else if (uc < 0x110000)
+    count = 4;
+#endif
+  else
+    return -1;
+
+  if (n < count)
+    return -2;
+
+  switch (count) /* note: code falls through cases! */
+    {
+#if 0
+    case 6: s[5] = 0x80 | (uc & 0x3f); uc = uc >> 6; uc |= 0x4000000;
+    case 5: s[4] = 0x80 | (uc & 0x3f); uc = uc >> 6; uc |= 0x200000;
+#endif
+    case 4: s[3] = 0x80 | (uc & 0x3f); uc = uc >> 6; uc |= 0x10000;
+    case 3: s[2] = 0x80 | (uc & 0x3f); uc = uc >> 6; uc |= 0x800;
+    case 2: s[1] = 0x80 | (uc & 0x3f); uc = uc >> 6; uc |= 0xc0;
+    case 1: s[0] = uc;
+    }
+  return count;
+}
+
+static inline int
+u8_uctomb (unsigned char *s, unsigned int uc, int n)
+{
+  if (uc < 0x80 && n > 0)
+    {
+      s[0] = uc;
+      return 1;
+    }
+  else
+    return u8_uctomb_aux (s, uc, n);
+}