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Add conver/convert2 functions. They are similar to the SQL99's convert.
This commit is contained in:
Tatsuo Ishii
@ -3,7 +3,7 @@
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* client encoding and server internal encoding.
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* (currently mule internal code (mic) is used)
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* Tatsuo Ishii
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* $Id: mbutils.c,v 1.18 2001/07/15 11:07:36 ishii Exp $
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* $Id: mbutils.c,v 1.19 2001/08/15 07:07:40 ishii Exp $
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*/
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#include "postgres.h"
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@ -33,6 +33,67 @@ pg_get_enc_ent(int encoding)
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return (0);
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}
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/*
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* Find appropriate encoding conversion functions. If no such
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* functions found, returns -1.
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*
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* Arguments:
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*
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* src, dest (in): source and destination encoding ids
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*
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* src_to_mic (out): pointer to a function which converts src to
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* mic/unicode according to dest. if src == mic/unicode or no
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* appropriate function found, set to 0.
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*
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* dest_from_mic (out): pointer to a function which converts
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* mic/unicode to dest according to src. if dest == mic/unicode or no
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* appropriate function found, set to 0.
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*/
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int
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pg_find_encoding_converters(int src, int dest, void (**src_to_mic)(), void (**dest_from_mic)())
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{
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if (src == dest)
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{ /* src == dest? */
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*src_to_mic = *dest_from_mic = 0;
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}
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else if (src == MULE_INTERNAL)
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{ /* src == MULE_INETRNAL? */
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*dest_from_mic = pg_get_enc_ent(dest)->from_mic;
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if (*dest_from_mic == 0)
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return (-1);
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*src_to_mic = 0;
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}
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else if (dest == MULE_INTERNAL)
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{ /* dest == MULE_INETRNAL? */
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*src_to_mic = pg_get_enc_ent(src)->to_mic;
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if (*src_to_mic == 0)
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return (-1);
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*dest_from_mic = 0;
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}
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else if (src == UNICODE)
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{ /* src == UNICODE? */
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*dest_from_mic = pg_get_enc_ent(dest)->from_unicode;
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if (*dest_from_mic == 0)
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return (-1);
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*src_to_mic = 0;
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}
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else if (dest == UNICODE)
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{ /* dest == UNICODE? */
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*src_to_mic = pg_get_enc_ent(src)->to_unicode;
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if (*src_to_mic == 0)
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return (-1);
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*dest_from_mic = 0;
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}
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else
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{
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*src_to_mic = pg_get_enc_ent(src)->to_mic;
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*dest_from_mic = pg_get_enc_ent(dest)->from_mic;
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if (*src_to_mic == 0 || *dest_from_mic == 0)
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return (-1);
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}
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return (0);
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}
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/*
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* set the client encoding. if encoding conversion between
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* client/server encoding is not supported, returns -1
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@ -40,59 +101,15 @@ pg_get_enc_ent(int encoding)
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int
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pg_set_client_encoding(int encoding)
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{
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int current_server_encoding = GetDatabaseEncoding();
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int current_server_encoding = GetDatabaseEncoding();
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if (pg_find_encoding_converters(encoding, current_server_encoding, &client_to_mic, &server_from_mic) < 0)
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return (-1);
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client_encoding = encoding;
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if (client_encoding == current_server_encoding)
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{ /* server == client? */
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client_to_mic = client_from_mic = 0;
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server_to_mic = server_from_mic = 0;
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}
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else if (current_server_encoding == MULE_INTERNAL)
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{ /* server == MULE_INETRNAL? */
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client_to_mic = pg_get_enc_ent(encoding)->to_mic;
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client_from_mic = pg_get_enc_ent(encoding)->from_mic;
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server_to_mic = server_from_mic = 0;
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if (client_to_mic == 0 || client_from_mic == 0)
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return (-1);
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}
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else if (encoding == MULE_INTERNAL)
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{ /* client == MULE_INETRNAL? */
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client_to_mic = client_from_mic = 0;
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server_to_mic = pg_get_enc_ent(current_server_encoding)->to_mic;
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server_from_mic = pg_get_enc_ent(current_server_encoding)->from_mic;
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if (server_to_mic == 0 || server_from_mic == 0)
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return (-1);
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}
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else if (current_server_encoding == UNICODE)
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{ /* server == UNICODE? */
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client_to_mic = pg_get_enc_ent(encoding)->to_unicode;
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client_from_mic = pg_get_enc_ent(encoding)->from_unicode;
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server_to_mic = server_from_mic = 0;
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if (client_to_mic == 0 || client_from_mic == 0)
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return (-1);
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}
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else if (encoding == UNICODE)
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{ /* client == UNICODE? */
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client_to_mic = client_from_mic = 0;
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server_to_mic = pg_get_enc_ent(current_server_encoding)->to_unicode;
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server_from_mic = pg_get_enc_ent(current_server_encoding)->from_unicode;
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if (server_to_mic == 0 || server_from_mic == 0)
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return (-1);
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}
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else
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{
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client_to_mic = pg_get_enc_ent(encoding)->to_mic;
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client_from_mic = pg_get_enc_ent(encoding)->from_mic;
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server_to_mic = pg_get_enc_ent(current_server_encoding)->to_mic;
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server_from_mic = pg_get_enc_ent(current_server_encoding)->from_mic;
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if (client_to_mic == 0 || client_from_mic == 0)
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return (-1);
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if (server_to_mic == 0 || server_from_mic == 0)
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return (-1);
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}
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return (0);
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if (pg_find_encoding_converters(current_server_encoding, encoding, &server_to_mic, &client_from_mic) < 0)
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return (-1);
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return 0;
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}
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/*
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@ -109,6 +126,141 @@ pg_get_client_encoding()
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return (client_encoding);
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}
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/*
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* Convert src encoding and returns it. Actual conversion is done by
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* src_to_mic and dest_from_mic, which can be obtained by
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* pg_find_encoding_converters(). The reason we require two conversion
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* functions is that we have an intermediate encoding: MULE_INTERNAL
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* Using intermediate encodings will reduce the number of functions
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* doing encoding conversions. Special case is either src or dest is
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* the intermediate encoding itself. In this case, you don't need src
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* or dest (setting 0 will indicate there's no conversion
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* function). Another case is you have direct-conversion function from
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* src to dest. In this case either src_to_mic or dest_from_mic could
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* be set to 0 also.
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*
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* Note that If src or dest is UNICODE, we have to do
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* direct-conversion, since we don't support conversion bwteen UNICODE
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* and MULE_INTERNAL, we cannot go through MULE_INTERNAL.
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*
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* CASE 1: if no conversion is required, then the given pointer s is returned.
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*
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* CASE 2: if conversion is required, a palloc'd string is returned.
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*
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* Callers must check whether return value differs from passed value
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* to determine whether to pfree the result or not!
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*
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* Note: we assume that conversion cannot cause more than a 4-to-1 growth
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* in the length of the string --- is this enough? */
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unsigned char *
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pg_do_encoding_conversion(unsigned char *src, int len, void (*src_to_mic)(), void (*dest_from_mic)())
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{
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unsigned char *result = src;
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unsigned char *buf;
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if (src_to_mic)
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{
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buf = (unsigned char *) palloc(len * 4 + 1);
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(*src_to_mic) (result, buf, len);
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result = buf;
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len = strlen(result);
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}
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if (dest_from_mic)
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{
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buf = (unsigned char *) palloc(len * 4 + 1);
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(*dest_from_mic) (result, buf, len);
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if (result != src)
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pfree(result); /* release first buffer */
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result = buf;
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}
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return result;
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}
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/*
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* Convert string using encoding_nanme. We assume that string's
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* encoding is same as DB encoding.
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*
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* TEXT convert(TEXT string, NAME encoding_name)
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*/
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Datum
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pg_convert(PG_FUNCTION_ARGS)
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{
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text *string = PG_GETARG_TEXT_P(0);
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Name s = PG_GETARG_NAME(1);
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int encoding = pg_char_to_encoding(NameStr(*s));
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int db_encoding = GetDatabaseEncoding();
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void (*src)(), (*dest)();
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unsigned char *result;
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text *retval;
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if (encoding < 0)
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elog(ERROR, "Invalid encoding name %s", NameStr(*s));
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if (pg_find_encoding_converters(db_encoding, encoding, &src, &dest) < 0)
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{
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char *encoding_name = (char *)pg_encoding_to_char(db_encoding);
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elog(ERROR, "Conversion from %s to %s is not possible", NameStr(*s), encoding_name);
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}
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result = pg_do_encoding_conversion(VARDATA(string), VARSIZE(string)-VARHDRSZ,
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src, dest);
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if (result == NULL)
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elog(ERROR, "Encoding conversion failed");
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retval = DatumGetTextP(DirectFunctionCall1(textin, CStringGetDatum(result)));
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if (result != (unsigned char *)VARDATA(string))
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pfree(result);
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/* free memory if allocated by the toaster */
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PG_FREE_IF_COPY(string, 0);
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PG_RETURN_TEXT_P(retval);
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}
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/*
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* Convert string using encoding_nanme.
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*
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* TEXT convert(TEXT string, NAME src_encoding_name, NAME dest_encoding_name)
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*/
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Datum
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pg_convert2(PG_FUNCTION_ARGS)
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{
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text *string = PG_GETARG_TEXT_P(0);
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char *src_encoding_name = NameStr(*PG_GETARG_NAME(1));
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int src_encoding = pg_char_to_encoding(src_encoding_name);
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char *dest_encoding_name = NameStr(*PG_GETARG_NAME(2));
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int dest_encoding = pg_char_to_encoding(dest_encoding_name);
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void (*src)(), (*dest)();
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unsigned char *result;
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text *retval;
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if (src_encoding < 0)
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elog(ERROR, "Invalid source encoding name %s", src_encoding_name);
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if (dest_encoding < 0)
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elog(ERROR, "Invalid destination encoding name %s", dest_encoding_name);
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if (pg_find_encoding_converters(src_encoding, dest_encoding, &src, &dest) < 0)
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{
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elog(ERROR, "Conversion from %s to %s is not possible",
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src_encoding_name, dest_encoding_name);
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}
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result = pg_do_encoding_conversion(VARDATA(string), VARSIZE(string)-VARHDRSZ,
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src, dest);
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if (result == NULL)
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elog(ERROR, "Encoding conversion failed");
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retval = DatumGetTextP(DirectFunctionCall1(textin, CStringGetDatum(result)));
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if (result != (unsigned char *)VARDATA(string))
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pfree(result);
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/* free memory if allocated by the toaster */
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PG_FREE_IF_COPY(string, 0);
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PG_RETURN_TEXT_P(retval);
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}
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/*
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* convert client encoding to server encoding.
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*
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@ -125,27 +277,10 @@ pg_get_client_encoding()
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unsigned char *
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pg_client_to_server(unsigned char *s, int len)
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{
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unsigned char *result = s;
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unsigned char *buf;
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if (client_encoding == GetDatabaseEncoding())
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return result;
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if (client_to_mic)
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{
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buf = (unsigned char *) palloc(len * 4 + 1);
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(*client_to_mic) (result, buf, len);
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result = buf;
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len = strlen(result);
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}
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if (server_from_mic)
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{
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buf = (unsigned char *) palloc(len * 4 + 1);
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(*server_from_mic) (result, buf, len);
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if (result != s)
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pfree(result); /* release first buffer */
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result = buf;
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}
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return result;
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return s;
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return pg_do_encoding_conversion(s, len, client_to_mic, server_from_mic);
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}
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/*
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@ -164,27 +299,10 @@ pg_client_to_server(unsigned char *s, int len)
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unsigned char *
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pg_server_to_client(unsigned char *s, int len)
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{
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unsigned char *result = s;
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unsigned char *buf;
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if (client_encoding == GetDatabaseEncoding())
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return result;
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if (server_to_mic)
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{
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buf = (unsigned char *) palloc(len * 4 + 1);
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(*server_to_mic) (result, buf, len);
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result = buf;
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len = strlen(result);
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}
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if (client_from_mic)
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{
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buf = (unsigned char *) palloc(len * 4 + 1);
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(*client_from_mic) (result, buf, len);
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if (result != s)
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pfree(result); /* release first buffer */
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result = buf;
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}
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return result;
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return s;
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return pg_do_encoding_conversion(s, len, server_to_mic, client_from_mic);
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}
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/* convert a multi-byte string to a wchar */
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