Refactor charset plugins a bit and add CP437 module.

Now all 8-bit charsets with gaps (not all symbols defined) could be produced through
one macro -- SMB_GENERATE_CHARSET_MODULE_8_BIT_GAP(CHARSETNAME) within source file
with three charset tables. Full source code for such modules can be generated by
source/script/gen-8bit-gap.sh script which was taken from GNU libc and changed slightly
to follow our data types and structure.
(This used to be commit 37042c7bc0f349370e93e4bed37d8fa371013247)

9 files changed, 597 insertions, 75 deletions

diff --git a/source3/Makefile.in b/source3/Makefile.in
index 2f88142ff2..bb5a1656d6 100644
--- a/source3/Makefile.in
+++ b/source3/Makefile.in
@@ -288,6 +288,7 @@ XML_OBJ = passdb/pdb_xml.o
 MYSQL_OBJ = passdb/pdb_mysql.o
 DEVEL_HELP_WEIRD_OBJ = modules/weird.o
 DEVEL_HELP_CP850_OBJ = modules/CP850.o
+DEVEL_HELP_CP437_OBJ = modules/CP437.o
 
 GROUPDB_OBJ = groupdb/mapping.o
 
@@ -1071,6 +1072,11 @@ bin/CP850.@SHLIBEXT@: $(DEVEL_HELP_CP850_OBJ:.o=.po)
 	@$(SHLD) $(LDSHFLAGS) -o $@ $(DEVEL_HELP_CP850_OBJ:.o=.po) \
 		@SONAMEFLAG@`basename $@`
 
+bin/CP437.@SHLIBEXT@: $(DEVEL_HELP_CP437_OBJ:.o=.po)
+	@echo "Building plugin $@"
+	@$(SHLD) $(LDSHFLAGS) -o $@ $(DEVEL_HELP_CP437_OBJ:.o=.po) \
+		@SONAMEFLAG@`basename $@`
+
 bin/xml.@SHLIBEXT@: $(XML_OBJ:.o=.po)
 	@echo "Building plugin $@"
 	@$(SHLD) $(LDSHFLAGS) -o $@ $(XML_OBJ:.o=.po) @XML_LIBS@ \
diff --git a/source3/configure.in b/source3/configure.in
index c8b5aa4b2d..9998d3a235 100644
--- a/source3/configure.in
+++ b/source3/configure.in
@@ -288,7 +288,7 @@ dnl These have to be built static:
 default_static_modules="pdb_smbpasswd pdb_tdbsam rpc_lsa rpc_samr rpc_reg rpc_lsa_ds rpc_wks rpc_net rpc_dfs rpc_srv rpc_spoolss auth_rhosts auth_sam auth_unix auth_winbind auth_server auth_domain auth_builtin"
 
 dnl These are preferably build shared, and static if dlopen() is not available
-default_shared_modules="vfs_recycle vfs_audit vfs_extd_audit vfs_netatalk vfs_fake_perms vfs_default_quota vfs_readonly vfs_cap charset_CP850"
+default_shared_modules="vfs_recycle vfs_audit vfs_extd_audit vfs_netatalk vfs_fake_perms vfs_default_quota vfs_readonly vfs_cap charset_CP850 charset_CP437"
 
 if test "x$developer" = xyes; then
    default_static_modules="$default_static_modules rpc_echo"
@@ -4027,6 +4027,7 @@ SMB_SUBSYSTEM(IDMAP,sam/idmap.c)
 
 SMB_MODULE(charset_weird, modules/weird.o, "bin/weird.$SHLIBEXT", CHARSET)
 SMB_MODULE(charset_CP850, modules/CP850.o, "bin/CP850.$SHLIBEXT", CHARSET)
+SMB_MODULE(charset_CP437, modules/CP437.o, "bin/CP437.$SHLIBEXT", CHARSET)
 SMB_SUBSYSTEM(CHARSET,lib/iconv.c)
 
 SMB_MODULE(auth_rhosts, \$(AUTH_RHOSTS_OBJ), "bin/rhosts.$SHLIBEXT", AUTH)
@@ -4089,7 +4090,7 @@ dnl Remove -I/usr/include/? from CFLAGS and CPPFLAGS
 CFLAGS_REMOVE_USR_INCLUDE(CFLAGS)
 CFLAGS_REMOVE_USR_INCLUDE(CPPFLAGS)
 
-AC_OUTPUT(include/stamp-h Makefile script/findsmb smbadduser)
+AC_OUTPUT(include/stamp-h Makefile script/findsmb smbadduser script/gen-8bit-gap.sh)
 
 #################################################
 # Print very concise instructions on building/use
diff --git a/source3/include/charset.h b/source3/include/charset.h
index f999a9cf72..7a9b12ef55 100644
--- a/source3/include/charset.h
+++ b/source3/include/charset.h
@@ -38,3 +38,90 @@ struct charset_functions {
 	struct charset_functions *prev, *next;
 };
 
+/*
+ * This is auxiliary struct used by source/script/gen-8-bit-gap.sh script
+ * during generation of an encoding table for charset module
+ *     */
+
+struct charset_gap_table {
+  uint16 start;
+  uint16 end;
+  int32 idx;
+};
+
+/*
+ *   Define stub for charset module which implements 8-bit encoding with gaps.
+ *   Encoding tables for such module should be produced from glibc's CHARMAPs
+ *   using script source/script/gen-8bit-gap.sh
+ *   CHARSETNAME is CAPITALIZED charset name
+ *
+ *     */
+#define SMB_GENERATE_CHARSET_MODULE_8_BIT_GAP(CHARSETNAME) 					\
+static size_t CHARSETNAME ## _push(void *cd, char **inbuf, size_t *inbytesleft,			\
+			 char **outbuf, size_t *outbytesleft) 					\
+{ 												\
+	while (*inbytesleft >= 2 && *outbytesleft >= 1) { 					\
+		int i; 										\
+		int done = 0; 									\
+												\
+		uint16 ch = SVAL(*inbuf,0); 							\
+												\
+		for (i=0; from_idx[i].start != 0xffff; i++) {					\
+			if ((from_idx[i].start <= ch) && (from_idx[i].end >= ch)) {		\
+				((unsigned char*)(*outbuf))[0] = from_ucs2[from_idx[i].idx+ch];	\
+				(*inbytesleft) -= 2;						\
+				(*outbytesleft) -= 1;						\
+				(*inbuf)  += 2;							\
+				(*outbuf) += 1;							\
+				done = 1;							\
+				break;								\
+			}									\
+		}										\
+		if (!done) {									\
+			errno = EINVAL;								\
+			return -1;								\
+		}										\
+												\
+	}											\
+												\
+	if (*inbytesleft == 1) {								\
+		errno = EINVAL;									\
+		return -1;									\
+	}											\
+												\
+	if (*inbytesleft > 1) {									\
+		errno = E2BIG;									\
+		return -1;									\
+	}											\
+												\
+	return 0;										\
+}												\
+												\
+static size_t CHARSETNAME ## _pull(void *cd, char **inbuf, size_t *inbytesleft,				\
+			 char **outbuf, size_t *outbytesleft)					\
+{												\
+	while (*inbytesleft >= 1 && *outbytesleft >= 2) {					\
+		*(uint16*)(*outbuf) = to_ucs2[((unsigned char*)(*inbuf))[0]];			\
+		(*inbytesleft)  -= 1;								\
+		(*outbytesleft) -= 2;								\
+		(*inbuf)  += 1;									\
+		(*outbuf) += 2;									\
+	}											\
+												\
+	if (*inbytesleft > 0) {									\
+		errno = E2BIG;									\
+		return -1;									\
+	}											\
+												\
+	return 0;										\
+}												\
+												\
+struct charset_functions CHARSETNAME ## _functions = 						\
+		{#CHARSETNAME, CHARSETNAME ## _pull, CHARSETNAME ## _push};			\
+												\
+NTSTATUS charset_ ## CHARSETNAME ## _init(void)							\
+{												\
+	return smb_register_charset(& CHARSETNAME ## _functions);				\
+}												\
+
+
diff --git a/source3/modules/CP437.c b/source3/modules/CP437.c
new file mode 100644
index 0000000000..954104265e
--- /dev/null
+++ b/source3/modules/CP437.c
@@ -0,0 +1,359 @@
+/* 
+ * Conversion table for CP437 charset also known as IBM437
+ *
+ * Copyright (C) Alexander Bokovoy		2003
+ *
+ * Conversion tables are generated using GNU libc 2.2.5's 
+ * localedata/charmaps/IBM437 table and source/script/gen-8bit-gap.sh script
+ *
+ * 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 of the License, 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include "includes.h"
+
+static const uint16 to_ucs2[256] = {
+  [0x01] = 0x0001,
+  [0x02] = 0x0002,
+  [0x03] = 0x0003,
+  [0x04] = 0x0004,
+  [0x05] = 0x0005,
+  [0x06] = 0x0006,
+  [0x07] = 0x0007,
+  [0x08] = 0x0008,
+  [0x09] = 0x0009,
+  [0x0a] = 0x000A,
+  [0x0b] = 0x000B,
+  [0x0c] = 0x000C,
+  [0x0d] = 0x000D,
+  [0x0e] = 0x000E,
+  [0x0f] = 0x000F,
+  [0x10] = 0x0010,
+  [0x11] = 0x0011,
+  [0x12] = 0x0012,
+  [0x13] = 0x0013,
+  [0x14] = 0x0014,
+  [0x15] = 0x0015,
+  [0x16] = 0x0016,
+  [0x17] = 0x0017,
+  [0x18] = 0x0018,
+  [0x19] = 0x0019,
+  [0x1a] = 0x001A,
+  [0x1b] = 0x001B,
+  [0x1c] = 0x001C,
+  [0x1d] = 0x001D,
+  [0x1e] = 0x001E,
+  [0x1f] = 0x001F,
+  [0x20] = 0x0020,
+  [0x21] = 0x0021,
+  [0x22] = 0x0022,
+  [0x23] = 0x0023,
+  [0x24] = 0x0024,
+  [0x25] = 0x0025,
+  [0x26] = 0x0026,
+  [0x27] = 0x0027,
+  [0x28] = 0x0028,
+  [0x29] = 0x0029,
+  [0x2a] = 0x002A,
+  [0x2b] = 0x002B,
+  [0x2c] = 0x002C,
+  [0x2d] = 0x002D,
+  [0x2e] = 0x002E,
+  [0x2f] = 0x002F,
+  [0x30] = 0x0030,
+  [0x31] = 0x0031,
+  [0x32] = 0x0032,
+  [0x33] = 0x0033,
+  [0x34] = 0x0034,
+  [0x35] = 0x0035,
+  [0x36] = 0x0036,
+  [0x37] = 0x0037,
+  [0x38] = 0x0038,
+  [0x39] = 0x0039,
+  [0x3a] = 0x003A,
+  [0x3b] = 0x003B,
+  [0x3c] = 0x003C,
+  [0x3d] = 0x003D,
+  [0x3e] = 0x003E,
+  [0x3f] = 0x003F,
+  [0x40] = 0x0040,
+  [0x41] = 0x0041,
+  [0x42] = 0x0042,
+  [0x43] = 0x0043,
+  [0x44] = 0x0044,
+  [0x45] = 0x0045,
+  [0x46] = 0x0046,
+  [0x47] = 0x0047,
+  [0x48] = 0x0048,
+  [0x49] = 0x0049,
+  [0x4a] = 0x004A,
+  [0x4b] = 0x004B,
+  [0x4c] = 0x004C,
+  [0x4d] = 0x004D,
+  [0x4e] = 0x004E,
+  [0x4f] = 0x004F,
+  [0x50] = 0x0050,
+  [0x51] = 0x0051,
+  [0x52] = 0x0052,
+  [0x53] = 0x0053,
+  [0x54] = 0x0054,
+  [0x55] = 0x0055,
+  [0x56] = 0x0056,
+  [0x57] = 0x0057,
+  [0x58] = 0x0058,
+  [0x59] = 0x0059,
+  [0x5a] = 0x005A,
+  [0x5b] = 0x005B,
+  [0x5c] = 0x005C,
+  [0x5d] = 0x005D,
+  [0x5e] = 0x005E,
+  [0x5f] = 0x005F,
+  [0x60] = 0x0060,
+  [0x61] = 0x0061,
+  [0x62] = 0x0062,
+  [0x63] = 0x0063,
+  [0x64] = 0x0064,
+  [0x65] = 0x0065,
+  [0x66] = 0x0066,
+  [0x67] = 0x0067,
+  [0x68] = 0x0068,
+  [0x69] = 0x0069,
+  [0x6a] = 0x006A,
+  [0x6b] = 0x006B,
+  [0x6c] = 0x006C,
+  [0x6d] = 0x006D,
+  [0x6e] = 0x006E,
+  [0x6f] = 0x006F,
+  [0x70] = 0x0070,
+  [0x71] = 0x0071,
+  [0x72] = 0x0072,
+  [0x73] = 0x0073,
+  [0x74] = 0x0074,
+  [0x75] = 0x0075,
+  [0x76] = 0x0076,
+  [0x77] = 0x0077,
+  [0x78] = 0x0078,
+  [0x79] = 0x0079,
+  [0x7a] = 0x007A,
+  [0x7b] = 0x007B,
+  [0x7c] = 0x007C,
+  [0x7d] = 0x007D,
+  [0x7e] = 0x007E,
+  [0x7f] = 0x007F,
+  [0x80] = 0x00C7,
+  [0x81] = 0x00FC,
+  [0x82] = 0x00E9,
+  [0x83] = 0x00E2,
+  [0x84] = 0x00E4,
+  [0x85] = 0x00E0,
+  [0x86] = 0x00E5,
+  [0x87] = 0x00E7,
+  [0x88] = 0x00EA,
+  [0x89] = 0x00EB,
+  [0x8a] = 0x00E8,
+  [0x8b] = 0x00EF,
+  [0x8c] = 0x00EE,
+  [0x8d] = 0x00EC,
+  [0x8e] = 0x00C4,
+  [0x8f] = 0x00C5,
+  [0x90] = 0x00C9,
+  [0x91] = 0x00E6,
+  [0x92] = 0x00C6,
+  [0x93] = 0x00F4,
+  [0x94] = 0x00F6,
+  [0x95] = 0x00F2,
+  [0x96] = 0x00FB,
+  [0x97] = 0x00F9,
+  [0x98] = 0x00FF,
+  [0x99] = 0x00D6,
+  [0x9a] = 0x00DC,
+  [0x9b] = 0x00A2,
+  [0x9c] = 0x00A3,
+  [0x9d] = 0x00A5,
+  [0x9e] = 0x20A7,
+  [0x9f] = 0x0192,
+  [0xa0] = 0x00E1,
+  [0xa1] = 0x00ED,
+  [0xa2] = 0x00F3,
+  [0xa3] = 0x00FA,
+  [0xa4] = 0x00F1,
+  [0xa5] = 0x00D1,
+  [0xa6] = 0x00AA,
+  [0xa7] = 0x00BA,
+  [0xa8] = 0x00BF,
+  [0xa9] = 0x2310,
+  [0xaa] = 0x00AC,
+  [0xab] = 0x00BD,
+  [0xac] = 0x00BC,
+  [0xad] = 0x00A1,
+  [0xae] = 0x00AB,
+  [0xaf] = 0x00BB,
+  [0xb0] = 0x2591,
+  [0xb1] = 0x2592,
+  [0xb2] = 0x2593,
+  [0xb3] = 0x2502,
+  [0xb4] = 0x2524,
+  [0xb5] = 0x2561,
+  [0xb6] = 0x2562,
+  [0xb7] = 0x2556,
+  [0xb8] = 0x2555,
+  [0xb9] = 0x2563,
+  [0xba] = 0x2551,
+  [0xbb] = 0x2557,
+  [0xbc] = 0x255D,
+  [0xbd] = 0x255C,
+  [0xbe] = 0x255B,
+  [0xbf] = 0x2510,
+  [0xc0] = 0x2514,
+  [0xc1] = 0x2534,
+  [0xc2] = 0x252C,
+  [0xc3] = 0x251C,
+  [0xc4] = 0x2500,
+  [0xc5] = 0x253C,
+  [0xc6] = 0x255E,
+  [0xc7] = 0x255F,
+  [0xc8] = 0x255A,
+  [0xc9] = 0x2554,
+  [0xca] = 0x2569,
+  [0xcb] = 0x2566,
+  [0xcc] = 0x2560,
+  [0xcd] = 0x2550,
+  [0xce] = 0x256C,
+  [0xcf] = 0x2567,
+  [0xd0] = 0x2568,
+  [0xd1] = 0x2564,
+  [0xd2] = 0x2565,
+  [0xd3] = 0x2559,
+  [0xd4] = 0x2558,
+  [0xd5] = 0x2552,
+  [0xd6] = 0x2553,
+  [0xd7] = 0x256B,
+  [0xd8] = 0x256A,
+  [0xd9] = 0x2518,
+  [0xda] = 0x250C,
+  [0xdb] = 0x2588,
+  [0xdc] = 0x2584,
+  [0xdd] = 0x258C,
+  [0xde] = 0x2590,
+  [0xdf] = 0x2580,
+  [0xe0] = 0x03B1,
+  [0xe1] = 0x00DF,
+  [0xe2] = 0x0393,
+  [0xe3] = 0x03C0,
+  [0xe4] = 0x03A3,
+  [0xe5] = 0x03C3,
+  [0xe6] = 0x00B5,
+  [0xe7] = 0x03C4,
+  [0xe8] = 0x03A6,
+  [0xe9] = 0x0398,
+  [0xea] = 0x03A9,
+  [0xeb] = 0x03B4,
+  [0xec] = 0x221E,
+  [0xed] = 0x03C6,
+  [0xee] = 0x03B5,
+  [0xef] = 0x2229,
+  [0xf0] = 0x2261,
+  [0xf1] = 0x00B1,
+  [0xf2] = 0x2265,
+  [0xf3] = 0x2264,
+  [0xf4] = 0x2320,
+  [0xf5] = 0x2321,
+  [0xf6] = 0x00F7,
+  [0xf7] = 0x2248,
+  [0xf8] = 0x00B0,
+  [0xf9] = 0x2219,
+  [0xfa] = 0x00B7,
+  [0xfb] = 0x221A,
+  [0xfc] = 0x207F,
+  [0xfd] = 0x00B2,
+  [0xfe] = 0x25A0,
+  [0xff] = 0x00A0,
+};
+
+static const struct charset_gap_table from_idx[] = {
+  { 0x0000, 0x007f,     0 },
+  { 0x00a0, 0x00c9,   -32 },
+  { 0x00d1, 0x00ff,   -39 },
+  { 0x0192, 0x0192,  -185 },
+  { 0x0393, 0x0398,  -697 },
+  { 0x03a3, 0x03a9,  -707 },
+  { 0x03b1, 0x03b5,  -714 },
+  { 0x03c0, 0x03c6,  -724 },
+  { 0x207f, 0x207f, -8076 },
+  { 0x20a7, 0x20a7, -8115 },
+  { 0x2219, 0x221e, -8484 },
+  { 0x2229, 0x2229, -8494 },
+  { 0x2248, 0x2248, -8524 },
+  { 0x2261, 0x2265, -8548 },
+  { 0x2310, 0x2310, -8718 },
+  { 0x2320, 0x2321, -8733 },
+  { 0x2500, 0x2502, -9211 },
+  { 0x250c, 0x251c, -9220 },
+  { 0x2524, 0x2524, -9227 },
+  { 0x252c, 0x252c, -9234 },
+  { 0x2534, 0x2534, -9241 },
+  { 0x253c, 0x253c, -9248 },
+  { 0x2550, 0x256c, -9267 },
+  { 0x2580, 0x2593, -9286 },
+  { 0x25a0, 0x25a0, -9298 },
+  { 0xffff, 0xffff,     0 }
+};
+
+static const unsigned char from_ucs2[] = {
+
+  '\x00', '\x01', '\x02', '\x03', '\x04', '\x05', '\x06', '\x07',
+  '\x08', '\x09', '\x0a', '\x0b', '\x0c', '\x0d', '\x0e', '\x0f',
+  '\x10', '\x11', '\x12', '\x13', '\x14', '\x15', '\x16', '\x17',
+  '\x18', '\x19', '\x1a', '\x1b', '\x1c', '\x1d', '\x1e', '\x1f',
+  '\x20', '\x21', '\x22', '\x23', '\x24', '\x25', '\x26', '\x27',
+  '\x28', '\x29', '\x2a', '\x2b', '\x2c', '\x2d', '\x2e', '\x2f',
+  '\x30', '\x31', '\x32', '\x33', '\x34', '\x35', '\x36', '\x37',
+  '\x38', '\x39', '\x3a', '\x3b', '\x3c', '\x3d', '\x3e', '\x3f',
+  '\x40', '\x41', '\x42', '\x43', '\x44', '\x45', '\x46', '\x47',
+  '\x48', '\x49', '\x4a', '\x4b', '\x4c', '\x4d', '\x4e', '\x4f',
+  '\x50', '\x51', '\x52', '\x53', '\x54', '\x55', '\x56', '\x57',
+  '\x58', '\x59', '\x5a', '\x5b', '\x5c', '\x5d', '\x5e', '\x5f',
+  '\x60', '\x61', '\x62', '\x63', '\x64', '\x65', '\x66', '\x67',
+  '\x68', '\x69', '\x6a', '\x6b', '\x6c', '\x6d', '\x6e', '\x6f',
+  '\x70', '\x71', '\x72', '\x73', '\x74', '\x75', '\x76', '\x77',
+  '\x78', '\x79', '\x7a', '\x7b', '\x7c', '\x7d', '\x7e', '\x7f',
+  '\xff', '\xad', '\x9b', '\x9c', '\x00', '\x9d', '\x00', '\x00',
+  '\x00', '\x00', '\xa6', '\xae', '\xaa', '\x00', '\x00', '\x00',
+  '\xf8', '\xf1', '\xfd', '\x00', '\x00', '\xe6', '\x00', '\xfa',
+  '\x00', '\x00', '\xa7', '\xaf', '\xac', '\xab', '\x00', '\xa8',
+  '\x00', '\x00', '\x00', '\x00', '\x8e', '\x8f', '\x92', '\x80',
+  '\x00', '\x90', '\xa5', '\x00', '\x00', '\x00', '\x00', '\x99',
+  '\x00', '\x00', '\x00', '\x00', '\x00', '\x9a', '\x00', '\x00',
+  '\xe1', '\x85', '\xa0', '\x83', '\x00', '\x84', '\x86', '\x91',
+  '\x87', '\x8a', '\x82', '\x88', '\x89', '\x8d', '\xa1', '\x8c',
+  '\x8b', '\x00', '\xa4', '\x95', '\xa2', '\x93', '\x00', '\x94',
+  '\xf6', '\x00', '\x97', '\xa3', '\x96', '\x81', '\x00', '\x00',
+  '\x98', '\x9f', '\xe2', '\x00', '\x00', '\x00', '\x00', '\xe9',
+  '\xe4', '\x00', '\x00', '\xe8', '\x00', '\x00', '\xea', '\xe0',
+  '\x00', '\x00', '\xeb', '\xee', '\xe3', '\x00', '\x00', '\xe5',
+  '\xe7', '\x00', '\xed', '\xfc', '\x9e', '\xf9', '\xfb', '\x00',
+  '\x00', '\x00', '\xec', '\xef', '\xf7', '\xf0', '\x00', '\x00',
+  '\xf3', '\xf2', '\xa9', '\xf4', '\xf5', '\xc4', '\x00', '\xb3',
+  '\xda', '\x00', '\x00', '\x00', '\xbf', '\x00', '\x00', '\x00',
+  '\xc0', '\x00', '\x00', '\x00', '\xd9', '\x00', '\x00', '\x00',
+  '\xc3', '\xb4', '\xc2', '\xc1', '\xc5', '\xcd', '\xba', '\xd5',
+  '\xd6', '\xc9', '\xb8', '\xb7', '\xbb', '\xd4', '\xd3', '\xc8',
+  '\xbe', '\xbd', '\xbc', '\xc6', '\xc7', '\xcc', '\xb5', '\xb6',
+  '\xb9', '\xd1', '\xd2', '\xcb', '\xcf', '\xd0', '\xca', '\xd8',
+  '\xd7', '\xce', '\xdf', '\x00', '\x00', '\x00', '\xdc', '\x00',
+  '\x00', '\x00', '\xdb', '\x00', '\x00', '\x00', '\xdd', '\x00',
+  '\x00', '\x00', '\xde', '\xb0', '\xb1', '\xb2', '\xfe',
+};
+
+SMB_GENERATE_CHARSET_MODULE_8_BIT_GAP(CP437)
diff --git a/source3/modules/CP850.c b/source3/modules/CP850.c
index 1805a1e11b..0adfd24def 100644
--- a/source3/modules/CP850.c
+++ b/source3/modules/CP850.c
@@ -2,8 +2,9 @@
  * Conversion table for CP850 charset also known as IBM850.
  *
  * Copyright (C) Alexander Bokovoy		2003
+ *
  * Conversion tables are generated using GNU libc 2.2.5's 
- * localedata/charmaps/IBM850 table and iconvdata/gen-8bit-gap.sh script
+ * localedata/charmaps/IBM850 table and source/script/gen-8bit-gap.sh script
  *
  * 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
@@ -22,13 +23,6 @@
 
 #include "includes.h"
 
-struct gap
-{
-  uint16 start;
-  uint16 end;
-  int32 idx;
-};
-
 static const uint16 to_ucs2[256] = {
   [0x01] = 0x0001,
   [0x02] = 0x0002,
@@ -347,69 +341,5 @@ static const unsigned char from_ucs2[] = {
   '\xdb', '\xb0', '\xb1', '\xb2', '\xfe',
 };
 
+SMB_GENERATE_CHARSET_MODULE_8_BIT_GAP(CP850)
 
-static size_t CP850_push(void *cd, char **inbuf, size_t *inbytesleft,
-			 char **outbuf, size_t *outbytesleft)
-{
-	while (*inbytesleft >= 2 && *outbytesleft >= 1) {
-		int i;
-		int done = 0;
-		
-		uint16 ch = SVAL(*inbuf,0);
-		
-		for (i=0; from_idx[i].start != 0xffff; i++) {
-			if ((from_idx[i].start <= ch) && (from_idx[i].end >= ch)) {
-				((unsigned char*)(*outbuf))[0] = from_ucs2[from_idx[i].idx+ch];
-				(*inbytesleft) -= 2;
-				(*outbytesleft) -= 1;
-				(*inbuf)  += 2;
-				(*outbuf) += 1;
-				done = 1;
-				break;
-			}
-		}
-		if (!done) {
-			errno = EINVAL;
-			return -1;
-		}
-		
-	}
-
-	if (*inbytesleft == 1) {
-		errno = EINVAL;
-		return -1;
-	}
-
-	if (*inbytesleft > 1) {
-		errno = E2BIG;
-		return -1;
-	}
-	
-	return 0;
-}
-
-static size_t CP850_pull(void *cd, char **inbuf, size_t *inbytesleft,
-			 char **outbuf, size_t *outbytesleft)
-{
-	while (*inbytesleft >= 1 && *outbytesleft >= 2) {
-		*(uint16*)(*outbuf) = to_ucs2[((unsigned char*)(*inbuf))[0]];
-		(*inbytesleft)  -= 1;
-		(*outbytesleft) -= 2;
-		(*inbuf)  += 1;
-		(*outbuf) += 2;
-	}
-
-	if (*inbytesleft > 0) {
-		errno = E2BIG;
-		return -1;
-	}
-	
-	return 0;
-}
-
-struct charset_functions CP850_functions = {"CP850", CP850_pull, CP850_push};
-
-NTSTATUS charset_CP850_init(void)
-{
-	return smb_register_charset(&CP850_functions);
-}
diff --git a/source3/script/.cvsignore b/source3/script/.cvsignore
index 7a8114ecd7..0464ca2335 100644
--- a/source3/script/.cvsignore
+++ b/source3/script/.cvsignore
@@ -1 +1,2 @@
 findsmb
+gen-8bit-gap.sh
diff --git a/source3/script/gap.awk b/source3/script/gap.awk
new file mode 100644
index 0000000000..11680d10f9
--- /dev/null
+++ b/source3/script/gap.awk
@@ -0,0 +1,39 @@
+BEGIN { hv["0"] =  0; hv["1"] =  1; hv["2"] =  2; hv["3"] =  3;
+	hv["4"] =  4; hv["5"] =  5; hv["6"] =  6; hv["7"] =  7;
+	hv["8"] =  8; hv["9"] =  9; hv["A"] = 10; hv["B"] = 11;
+	hv["C"] = 12; hv["D"] = 13; hv["E"] = 14; hv["F"] = 15;
+	hv["a"] = 10; hv["b"] = 11; hv["c"] = 12; hv["d"] = 13;
+	hv["e"] = 14; hv["f"] = 15;
+
+	first = 0; last = 0; idx = 0;
+}
+
+function tonum(str)
+{
+  num=0;
+  cnt=1;
+  while (cnt <= length(str)) {
+    num *= 16;
+    num += hv[substr(str,cnt,1)];
+    ++cnt;
+  }
+  return num;
+}
+
+{
+  u = tonum($1);
+  if (u - last > 6)
+    {
+      if (last)
+	{
+	  printf ("  { 0x%04x, 0x%04x, %5d },\n",
+		  first, last, idx);
+	  idx -= u - last - 1;
+	}
+      first = u;
+    }
+  last = u;
+}
+
+END { printf ("  { 0x%04x, 0x%04x, %5d },\n",
+	      first, last, idx); }
diff --git a/source3/script/gaptab.awk b/source3/script/gaptab.awk
new file mode 100644
index 0000000000..f9d1526361
--- /dev/null
+++ b/source3/script/gaptab.awk
@@ -0,0 +1,48 @@
+BEGIN { hv["0"] =  0; hv["1"] =  1; hv["2"] =  2; hv["3"] =  3;
+	hv["4"] =  4; hv["5"] =  5; hv["6"] =  6; hv["7"] =  7;
+	hv["8"] =  8; hv["9"] =  9; hv["A"] = 10; hv["B"] = 11;
+	hv["C"] = 12; hv["D"] = 13; hv["E"] = 14; hv["F"] = 15;
+	hv["a"] = 10; hv["b"] = 11; hv["c"] = 12; hv["d"] = 13;
+	hv["e"] = 14; hv["f"] = 15;
+
+	first = 0; last = 0; idx = 0; f = 0;
+}
+
+function tonum(str)
+{
+  num=0;
+  cnt=1;
+  while (cnt <= length(str)) {
+    num *= 16;
+    num += hv[substr(str,cnt,1)];
+    ++cnt;
+  }
+  return num;
+}
+
+function fmt(val)
+{
+  if (f++ % 8 == 0)
+    { printf ("\n  '\\x%02x',", val); }
+  else
+    { printf (" '\\x%02x',", val); }
+}
+
+{
+  u = tonum($1); c = tonum($2);
+
+  if (u - last > 6)
+    {
+      if (last) { idx += last - first + 1; }
+      first = u;
+    }
+  else
+    {
+      for (m = last+1; m < u; m++) { fmt(0); }
+    }
+
+  fmt(c);
+  last = u;
+}
+
+END { print "" }
diff --git a/source3/script/gen-8bit-gap.sh.in b/source3/script/gen-8bit-gap.sh.in
new file mode 100755
index 0000000000..e66c654c22
--- /dev/null
+++ b/source3/script/gen-8bit-gap.sh.in
@@ -0,0 +1,51 @@
+#!/bin/sh
+if test $# -ne 2 ; then
+	echo "Usage: $0 <charmap file> <CHARSET NAME>"
+	exit 1
+fi
+
+CHARMAP=$1
+CHARSETNAME=$2
+
+echo "/* "
+echo " * Conversion table for $CHARSETNAME charset "
+echo " * "
+echo " * Conversion tables are generated using $CHARMAP table "
+echo " * and source/script/gen-8bit-gap.sh script "
+echo " * "
+echo " * This program is free software; you can redistribute it and/or modify "
+echo " * it under the terms of the GNU General Public License as published by "
+echo " * the Free Software Foundation; either version 2 of the License, or "
+echo " * (at your option) any later version. "
+echo " *  "
+echo " * This program is distributed in the hope that it will be useful,"
+echo " * but WITHOUT ANY WARRANTY; without even the implied warranty of "
+echo " * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the "
+echo " * GNU General Public License for more details. "
+echo " *  "
+echo " * You should have received a copy of the GNU General Public License "
+echo " * along with this program; if not, write to the Free Software "
+echo " * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. "
+echo " */"
+
+echo '#include "includes.h"'
+echo
+echo "static const uint16 to_ucs2[256] = {"
+sed -ne '/^[^[:space:]]*[[:space:]]*.x00/d' \
+    -e 's/^<U\(....\)>[[:space:]]*.x\(..\).*/  [0x\2] = 0x\1,/p' \
+    "$CHARMAP" | sort -u
+echo "};"
+echo
+echo "static const struct charset_gap_table from_idx[] = {"
+sed -ne 's/^<U\(....\).*/\1/p' \
+    "$CHARMAP" | sort -u | @AWK@ -f @srcdir@/script/gap.awk
+echo "  { 0xffff, 0xffff, 0 }"
+echo "};"
+echo
+echo "static const unsigned char from_ucs2[] = {"
+sed -ne 's/^<U\(....\)>[[:space:]]*.x\(..\).*/\1 \2/p' \
+    "$CHARMAP" | sort -u | @AWK@ -f @srcdir@/script/gaptab.awk
+echo "};"
+echo 
+echo "SMB_GENERATE_CHARSET_MODULE_8_BIT_GAP($CHARSETNAME)"
+echo