I really hope that I haven't missed anything in this one...

From: t-ishii@sra.co.jp

Attached are patches to enhance the multi-byte support.  (patches are
against 7/18 snapshot)

* determine encoding at initdb/createdb rather than compile time

Now initdb/createdb has an option to specify the encoding. Also, I
modified the syntax of CREATE DATABASE to accept encoding option. See
README.mb for more details.

For this purpose I have added new column "encoding" to pg_database.
Also pg_attribute and pg_class are changed to catch up the
modification to pg_database.  Actually I haved added pg_database_mb.h,
pg_attribute_mb.h and pg_class_mb.h. These are used only when MB is
enabled. The reason having separate files is I couldn't find a way to
use ifdef or whatever in those files. I have to admit it looks
ugly. No way.

* support for PGCLIENTENCODING when issuing COPY command

commands/copy.c modified.

* support for SQL92 syntax "SET NAMES"

See gram.y.

* support for LATIN2-5
* add UNICODE regression test case
* new test suite for MB

New directory test/mb added.

* clean up source files

Basic idea is to have MB's own subdirectory for easier maintenance.
These are include/mb and backend/utils/mb.

src/backend/utils/mb/common.c

@@ -0,0 +1,67 @@
+/*
+ * This file contains some public functions
+ * usable for both the backend and the frontend.
+ * Tatsuo Ishii
+ * $Id: common.c,v 1.1 1998/07/24 03:31:56 scrappy Exp $ */
+
+#include <stdio.h>
+#include <string.h>
+
+#include "mb/pg_wchar.h"
+
+/*
+ * convert encoding char to encoding symbol value.
+ * case is ignored.
+ * if there's no valid encoding, returns -1
+ */
+int pg_char_to_encoding(const char *s)
+{
+  pg_encoding_conv_tbl *p = pg_conv_tbl;
+
+  for(;p->encoding >= 0;p++) {
+    if (!strcasecmp(s, p->name)) {
+      break;
+    }
+  }
+  return(p->encoding);
+}
+
+/*
+ * check to see if encoding name is valid
+ */
+int pg_valid_client_encoding(const char *name)
+{
+  return(pg_char_to_encoding(name));
+}
+
+/*
+ * find encoding table entry by encoding
+ */
+pg_encoding_conv_tbl *pg_get_encent_by_encoding(int encoding)
+{
+  pg_encoding_conv_tbl *p = pg_conv_tbl;
+  for(;p->encoding >= 0;p++) {
+    if (p->encoding == encoding) {
+      return(p);
+    }
+  }
+  return(0);
+}
+
+/*
+ * convert encoding symbol to encoding char.
+ * if there's no valid encoding symbol, returns ""
+ */
+const char *pg_encoding_to_char(int encoding)
+{
+  pg_encoding_conv_tbl *p = pg_get_encent_by_encoding(encoding);
+
+  if (!p) return("");
+  return(p->name);
+}
+
+/* returns the byte length of a multi-byte word for an encoding */
+int pg_encoding_mblen(int encoding, const unsigned char *mbstr)
+{
+  return((*pg_wchar_table[encoding].mblen)(mbstr));
+}