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postgresql/src/backend/utils/mb/mbutils.c

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/*-------------------------------------------------------------------------
*
* mbutils.c
* This file contains functions for encoding conversion.
*
* The string-conversion functions in this file share some API quirks.
* Note the following:
*
* The functions return a palloc'd, null-terminated string if conversion
* is required. However, if no conversion is performed, the given source
* string pointer is returned as-is.
*
* Although the presence of a length argument means that callers can pass
* non-null-terminated strings, care is required because the same string
* will be passed back if no conversion occurs. Such callers *must* check
* whether result == src and handle that case differently.
*
* If the source and destination encodings are the same, the source string
* is returned without any verification; it's assumed to be valid data.
* If that might not be the case, the caller is responsible for validating
* the string using a separate call to pg_verify_mbstr(). Whenever the
* source and destination encodings are different, the functions ensure that
* the result is validly encoded according to the destination encoding.
*
*
* Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/utils/mb/mbutils.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/xact.h"
#include "catalog/namespace.h"
#include "mb/pg_wchar.h"
#include "utils/builtins.h"
#include "utils/memutils.h"
#include "utils/syscache.h"
#include "varatt.h"
/*
* We maintain a simple linked list caching the fmgr lookup info for the
* currently selected conversion functions, as well as any that have been
* selected previously in the current session. (We remember previous
* settings because we must be able to restore a previous setting during
* transaction rollback, without doing any fresh catalog accesses.)
*
* Since we'll never release this data, we just keep it in TopMemoryContext.
*/
typedef struct ConvProcInfo
{
int s_encoding; /* server and client encoding IDs */
int c_encoding;
FmgrInfo to_server_info; /* lookup info for conversion procs */
FmgrInfo to_client_info;
} ConvProcInfo;
static List *ConvProcList = NIL; /* List of ConvProcInfo */
/*
* These variables point to the currently active conversion functions,
* or are NULL when no conversion is needed.
*/
static FmgrInfo *ToServerConvProc = NULL;
static FmgrInfo *ToClientConvProc = NULL;
/*
* This variable stores the conversion function to convert from UTF-8
* to the server encoding. It's NULL if the server encoding *is* UTF-8,
* or if we lack a conversion function for this.
*/
static FmgrInfo *Utf8ToServerConvProc = NULL;
/*
* These variables track the currently-selected encodings.
*/
static const pg_enc2name *ClientEncoding = &pg_enc2name_tbl[PG_SQL_ASCII];
static const pg_enc2name *DatabaseEncoding = &pg_enc2name_tbl[PG_SQL_ASCII];
static const pg_enc2name *MessageEncoding = &pg_enc2name_tbl[PG_SQL_ASCII];
/*
* During backend startup we can't set client encoding because we (a)
* can't look up the conversion functions, and (b) may not know the database
* encoding yet either. So SetClientEncoding() just accepts anything and
* remembers it for InitializeClientEncoding() to apply later.
*/
static bool backend_startup_complete = false;
static int pending_client_encoding = PG_SQL_ASCII;
/* Internal functions */
static char *perform_default_encoding_conversion(const char *src,
int len, bool is_client_to_server);
static int cliplen(const char *str, int len, int limit);
/*
* Prepare for a future call to SetClientEncoding. Success should mean
* that SetClientEncoding is guaranteed to succeed for this encoding request.
*
* (But note that success before backend_startup_complete does not guarantee
* success after ...)
*
* Returns 0 if okay, -1 if not (bad encoding or can't support conversion)
*/
int
PrepareClientEncoding(int encoding)
{
int current_server_encoding;
ListCell *lc;
if (!PG_VALID_FE_ENCODING(encoding))
return -1;
/* Can't do anything during startup, per notes above */
if (!backend_startup_complete)
return 0;
current_server_encoding = GetDatabaseEncoding();
/*
* Check for cases that require no conversion function.
*/
if (current_server_encoding == encoding ||
current_server_encoding == PG_SQL_ASCII ||
encoding == PG_SQL_ASCII)
return 0;
if (IsTransactionState())
{
/*
* If we're in a live transaction, it's safe to access the catalogs,
* so look up the functions. We repeat the lookup even if the info is
* already cached, so that we can react to changes in the contents of
* pg_conversion.
*/
Oid to_server_proc,
to_client_proc;
ConvProcInfo *convinfo;
MemoryContext oldcontext;
to_server_proc = FindDefaultConversionProc(encoding,
current_server_encoding);
if (!OidIsValid(to_server_proc))
return -1;
to_client_proc = FindDefaultConversionProc(current_server_encoding,
encoding);
if (!OidIsValid(to_client_proc))
return -1;
/*
* Load the fmgr info into TopMemoryContext (could still fail here)
*/
convinfo = (ConvProcInfo *) MemoryContextAlloc(TopMemoryContext,
sizeof(ConvProcInfo));
convinfo->s_encoding = current_server_encoding;
convinfo->c_encoding = encoding;
fmgr_info_cxt(to_server_proc, &convinfo->to_server_info,
TopMemoryContext);
fmgr_info_cxt(to_client_proc, &convinfo->to_client_info,
TopMemoryContext);
/* Attach new info to head of list */
oldcontext = MemoryContextSwitchTo(TopMemoryContext);
ConvProcList = lcons(convinfo, ConvProcList);
MemoryContextSwitchTo(oldcontext);
/*
* We cannot yet remove any older entry for the same encoding pair,
* since it could still be in use. SetClientEncoding will clean up.
*/
return 0; /* success */
}
else
{
/*
* If we're not in a live transaction, the only thing we can do is
* restore a previous setting using the cache. This covers all
* transaction-rollback cases. The only case it might not work for is
* trying to change client_encoding on the fly by editing
* postgresql.conf and SIGHUP'ing. Which would probably be a stupid
* thing to do anyway.
*/
foreach(lc, ConvProcList)
{
ConvProcInfo *oldinfo = (ConvProcInfo *) lfirst(lc);
if (oldinfo->s_encoding == current_server_encoding &&
oldinfo->c_encoding == encoding)
return 0;
}
return -1; /* it's not cached, so fail */
}
}
/*
* Set the active client encoding and set up the conversion-function pointers.
* PrepareClientEncoding should have been called previously for this encoding.
*
* Returns 0 if okay, -1 if not (bad encoding or can't support conversion)
*/
int
SetClientEncoding(int encoding)
{
int current_server_encoding;
bool found;
ListCell *lc;
if (!PG_VALID_FE_ENCODING(encoding))
return -1;
/* Can't do anything during startup, per notes above */
if (!backend_startup_complete)
{
pending_client_encoding = encoding;
return 0;
}
current_server_encoding = GetDatabaseEncoding();
/*
* Check for cases that require no conversion function.
*/
if (current_server_encoding == encoding ||
current_server_encoding == PG_SQL_ASCII ||
encoding == PG_SQL_ASCII)
{
ClientEncoding = &pg_enc2name_tbl[encoding];
ToServerConvProc = NULL;
ToClientConvProc = NULL;
return 0;
}
/*
* Search the cache for the entry previously prepared by
* PrepareClientEncoding; if there isn't one, we lose. While at it,
* release any duplicate entries so that repeated Prepare/Set cycles don't
* leak memory.
*/
found = false;
foreach(lc, ConvProcList)
{
ConvProcInfo *convinfo = (ConvProcInfo *) lfirst(lc);
if (convinfo->s_encoding == current_server_encoding &&
convinfo->c_encoding == encoding)
{
if (!found)
{
/* Found newest entry, so set up */
ClientEncoding = &pg_enc2name_tbl[encoding];
ToServerConvProc = &convinfo->to_server_info;
ToClientConvProc = &convinfo->to_client_info;
found = true;
}
else
{
/* Duplicate entry, release it */
ConvProcList = foreach_delete_current(ConvProcList, lc);
pfree(convinfo);
}
}
}
if (found)
return 0; /* success */
else
return -1; /* it's not cached, so fail */
}
/*
* Initialize client encoding conversions.
* Called from InitPostgres() once during backend startup.
*/
void
InitializeClientEncoding(void)
{
int current_server_encoding;
Assert(!backend_startup_complete);
backend_startup_complete = true;
if (PrepareClientEncoding(pending_client_encoding) < 0 ||
SetClientEncoding(pending_client_encoding) < 0)
{
/*
* Oops, the requested conversion is not available. We couldn't fail
* before, but we can now.
*/
ereport(FATAL,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("conversion between %s and %s is not supported",
pg_enc2name_tbl[pending_client_encoding].name,
GetDatabaseEncodingName())));
}
/*
* Also look up the UTF8-to-server conversion function if needed. Since
* the server encoding is fixed within any one backend process, we don't
* have to do this more than once.
*/
current_server_encoding = GetDatabaseEncoding();
if (current_server_encoding != PG_UTF8 &&
current_server_encoding != PG_SQL_ASCII)
{
Oid utf8_to_server_proc;
Assert(IsTransactionState());
utf8_to_server_proc =
FindDefaultConversionProc(PG_UTF8,
current_server_encoding);
/* If there's no such conversion, just leave the pointer as NULL */
if (OidIsValid(utf8_to_server_proc))
{
FmgrInfo *finfo;
finfo = (FmgrInfo *) MemoryContextAlloc(TopMemoryContext,
sizeof(FmgrInfo));
fmgr_info_cxt(utf8_to_server_proc, finfo,
TopMemoryContext);
/* Set Utf8ToServerConvProc only after data is fully valid */
Utf8ToServerConvProc = finfo;
}
}
}
/*
* returns the current client encoding
*/
int
pg_get_client_encoding(void)
{
return ClientEncoding->encoding;
}
/*
* returns the current client encoding name
*/
const char *
pg_get_client_encoding_name(void)
{
return ClientEncoding->name;
}
/*
* Convert src string to another encoding (general case).
*
* See the notes about string conversion functions at the top of this file.
*/
unsigned char *
pg_do_encoding_conversion(unsigned char *src, int len,
int src_encoding, int dest_encoding)
{
unsigned char *result;
Oid proc;
if (len <= 0)
return src; /* empty string is always valid */
if (src_encoding == dest_encoding)
return src; /* no conversion required, assume valid */
if (dest_encoding == PG_SQL_ASCII)
return src; /* any string is valid in SQL_ASCII */
if (src_encoding == PG_SQL_ASCII)
{
/* No conversion is possible, but we must validate the result */
(void) pg_verify_mbstr(dest_encoding, (const char *) src, len, false);
return src;
}
if (!IsTransactionState()) /* shouldn't happen */
elog(ERROR, "cannot perform encoding conversion outside a transaction");
proc = FindDefaultConversionProc(src_encoding, dest_encoding);
if (!OidIsValid(proc))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_FUNCTION),
errmsg("default conversion function for encoding \"%s\" to \"%s\" does not exist",
pg_encoding_to_char(src_encoding),
pg_encoding_to_char(dest_encoding))));
/*
* Allocate space for conversion result, being wary of integer overflow.
*
* len * MAX_CONVERSION_GROWTH is typically a vast overestimate of the
* required space, so it might exceed MaxAllocSize even though the result
* would actually fit. We do not want to hand back a result string that
* exceeds MaxAllocSize, because callers might not cope gracefully --- but
* if we just allocate more than that, and don't use it, that's fine.
*/
if ((Size) len >= (MaxAllocHugeSize / (Size) MAX_CONVERSION_GROWTH))
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("out of memory"),
errdetail("String of %d bytes is too long for encoding conversion.",
len)));
result = (unsigned char *)
MemoryContextAllocHuge(CurrentMemoryContext,
(Size) len * MAX_CONVERSION_GROWTH + 1);
(void) OidFunctionCall6(proc,
Int32GetDatum(src_encoding),
Int32GetDatum(dest_encoding),
CStringGetDatum((char *) src),
CStringGetDatum((char *) result),
Int32GetDatum(len),
BoolGetDatum(false));
/*
* If the result is large, it's worth repalloc'ing to release any extra
* space we asked for. The cutoff here is somewhat arbitrary, but we
* *must* check when len * MAX_CONVERSION_GROWTH exceeds MaxAllocSize.
*/
if (len > 1000000)
{
Size resultlen = strlen((char *) result);
if (resultlen >= MaxAllocSize)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("out of memory"),
errdetail("String of %d bytes is too long for encoding conversion.",
len)));
result = (unsigned char *) repalloc(result, resultlen + 1);
}
return result;
}
/*
* Convert src string to another encoding.
*
* This function has a different API than the other conversion functions.
* The caller should've looked up the conversion function using
* FindDefaultConversionProc(). Unlike the other functions, the converted
* result is not palloc'd. It is written to the caller-supplied buffer
* instead.
*
* src_encoding - encoding to convert from
* dest_encoding - encoding to convert to
* src, srclen - input buffer and its length in bytes
* dest, destlen - destination buffer and its size in bytes
*
* The output is null-terminated.
*
* If destlen < srclen * MAX_CONVERSION_INPUT_LENGTH + 1, the converted output
* wouldn't necessarily fit in the output buffer, and the function will not
* convert the whole input.
*
* TODO: The conversion function interface is not great. Firstly, it
* would be nice to pass through the destination buffer size to the
* conversion function, so that if you pass a shorter destination buffer, it
* could still continue to fill up the whole buffer. Currently, we have to
* assume worst case expansion and stop the conversion short, even if there
* is in fact space left in the destination buffer. Secondly, it would be
* nice to return the number of bytes written to the caller, to avoid a call
* to strlen().
*/
int
pg_do_encoding_conversion_buf(Oid proc,
int src_encoding,
int dest_encoding,
unsigned char *src, int srclen,
unsigned char *dest, int destlen,
bool noError)
{
Datum result;
/*
* If the destination buffer is not large enough to hold the result in the
* worst case, limit the input size passed to the conversion function.
*/
if ((Size) srclen >= ((destlen - 1) / (Size) MAX_CONVERSION_GROWTH))
srclen = ((destlen - 1) / (Size) MAX_CONVERSION_GROWTH);
result = OidFunctionCall6(proc,
Int32GetDatum(src_encoding),
Int32GetDatum(dest_encoding),
CStringGetDatum((char *) src),
CStringGetDatum((char *) dest),
Int32GetDatum(srclen),
BoolGetDatum(noError));
return DatumGetInt32(result);
}
/*
* Convert string to encoding encoding_name. The source
* encoding is the DB encoding.
*
* BYTEA convert_to(TEXT string, NAME encoding_name) */
Datum
pg_convert_to(PG_FUNCTION_ARGS)
{
Datum string = PG_GETARG_DATUM(0);
Datum dest_encoding_name = PG_GETARG_DATUM(1);
Datum src_encoding_name = DirectFunctionCall1(namein,
CStringGetDatum(DatabaseEncoding->name));
Datum result;
/*
* pg_convert expects a bytea as its first argument. We're passing it a
* text argument here, relying on the fact that they are both in fact
* varlena types, and thus structurally identical.
*/
result = DirectFunctionCall3(pg_convert, string,
src_encoding_name, dest_encoding_name);
PG_RETURN_DATUM(result);
}
/*
* Convert string from encoding encoding_name. The destination
* encoding is the DB encoding.
*
* TEXT convert_from(BYTEA string, NAME encoding_name) */
Datum
pg_convert_from(PG_FUNCTION_ARGS)
{
Datum string = PG_GETARG_DATUM(0);
Datum src_encoding_name = PG_GETARG_DATUM(1);
Datum dest_encoding_name = DirectFunctionCall1(namein,
CStringGetDatum(DatabaseEncoding->name));
Datum result;
result = DirectFunctionCall3(pg_convert, string,
src_encoding_name, dest_encoding_name);
/*
* pg_convert returns a bytea, which we in turn return as text, relying on
* the fact that they are both in fact varlena types, and thus
* structurally identical. Although not all bytea values are valid text,
* in this case it will be because we've told pg_convert to return one
* that is valid as text in the current database encoding.
*/
PG_RETURN_DATUM(result);
}
/*
* Convert string between two arbitrary encodings.
*
* BYTEA convert(BYTEA string, NAME src_encoding_name, NAME dest_encoding_name)
*/
Datum
pg_convert(PG_FUNCTION_ARGS)
{
bytea *string = PG_GETARG_BYTEA_PP(0);
char *src_encoding_name = NameStr(*PG_GETARG_NAME(1));
int src_encoding = pg_char_to_encoding(src_encoding_name);
char *dest_encoding_name = NameStr(*PG_GETARG_NAME(2));
int dest_encoding = pg_char_to_encoding(dest_encoding_name);
const char *src_str;
char *dest_str;
bytea *retval;
int len;
if (src_encoding < 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid source encoding name \"%s\"",
src_encoding_name)));
if (dest_encoding < 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid destination encoding name \"%s\"",
dest_encoding_name)));
/* make sure that source string is valid */
len = VARSIZE_ANY_EXHDR(string);
src_str = VARDATA_ANY(string);
(void) pg_verify_mbstr(src_encoding, src_str, len, false);
/* perform conversion */
dest_str = (char *) pg_do_encoding_conversion((unsigned char *) unconstify(char *, src_str),
len,
src_encoding,
dest_encoding);
/* update len if conversion actually happened */
if (dest_str != src_str)
len = strlen(dest_str);
/*
* build bytea data type structure.
*/
retval = (bytea *) palloc(len + VARHDRSZ);
SET_VARSIZE(retval, len + VARHDRSZ);
memcpy(VARDATA(retval), dest_str, len);
if (dest_str != src_str)
pfree(dest_str);
/* free memory if allocated by the toaster */
PG_FREE_IF_COPY(string, 0);
PG_RETURN_BYTEA_P(retval);
}
/*
* get the length of the string considered as text in the specified
* encoding. Raises an error if the data is not valid in that
* encoding.
*
* INT4 length (BYTEA string, NAME src_encoding_name)
*/
Datum
length_in_encoding(PG_FUNCTION_ARGS)
{
bytea *string = PG_GETARG_BYTEA_PP(0);
char *src_encoding_name = NameStr(*PG_GETARG_NAME(1));
int src_encoding = pg_char_to_encoding(src_encoding_name);
const char *src_str;
int len;
int retval;
if (src_encoding < 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid encoding name \"%s\"",
src_encoding_name)));
len = VARSIZE_ANY_EXHDR(string);
src_str = VARDATA_ANY(string);
retval = pg_verify_mbstr_len(src_encoding, src_str, len, false);
PG_RETURN_INT32(retval);
}
/*
* Get maximum multibyte character length in the specified encoding.
*
* Note encoding is specified numerically, not by name as above.
*/
Datum
pg_encoding_max_length_sql(PG_FUNCTION_ARGS)
{
int encoding = PG_GETARG_INT32(0);
if (PG_VALID_ENCODING(encoding))
PG_RETURN_INT32(pg_wchar_table[encoding].maxmblen);
else
PG_RETURN_NULL();
}
/*
* Convert client encoding to server encoding.
*
* See the notes about string conversion functions at the top of this file.
*/
char *
pg_client_to_server(const char *s, int len)
{
return pg_any_to_server(s, len, ClientEncoding->encoding);
}
/*
* Convert any encoding to server encoding.
*
* See the notes about string conversion functions at the top of this file.
*
* Unlike the other string conversion functions, this will apply validation
* even if encoding == DatabaseEncoding->encoding. This is because this is
* used to process data coming in from outside the database, and we never
* want to just assume validity.
*/
char *
pg_any_to_server(const char *s, int len, int encoding)
{
if (len <= 0)
return unconstify(char *, s); /* empty string is always valid */
if (encoding == DatabaseEncoding->encoding ||
encoding == PG_SQL_ASCII)
{
/*
* No conversion is needed, but we must still validate the data.
*/
(void) pg_verify_mbstr(DatabaseEncoding->encoding, s, len, false);
return unconstify(char *, s);
}
if (DatabaseEncoding->encoding == PG_SQL_ASCII)
{
/*
* No conversion is possible, but we must still validate the data,
* because the client-side code might have done string escaping using
* the selected client_encoding. If the client encoding is ASCII-safe
* then we just do a straight validation under that encoding. For an
* ASCII-unsafe encoding we have a problem: we dare not pass such data
* to the parser but we have no way to convert it. We compromise by
* rejecting the data if it contains any non-ASCII characters.
*/
if (PG_VALID_BE_ENCODING(encoding))
(void) pg_verify_mbstr(encoding, s, len, false);
else
{
int i;
for (i = 0; i < len; i++)
{
if (s[i] == '\0' || IS_HIGHBIT_SET(s[i]))
ereport(ERROR,
(errcode(ERRCODE_CHARACTER_NOT_IN_REPERTOIRE),
errmsg("invalid byte value for encoding \"%s\": 0x%02x",
pg_enc2name_tbl[PG_SQL_ASCII].name,
(unsigned char) s[i])));
}
}
return unconstify(char *, s);
}
/* Fast path if we can use cached conversion function */
if (encoding == ClientEncoding->encoding)
return perform_default_encoding_conversion(s, len, true);
/* General case ... will not work outside transactions */
return (char *) pg_do_encoding_conversion((unsigned char *) unconstify(char *, s),
len,
encoding,
DatabaseEncoding->encoding);
}
/*
* Convert server encoding to client encoding.
*
* See the notes about string conversion functions at the top of this file.
*/
char *
pg_server_to_client(const char *s, int len)
{
return pg_server_to_any(s, len, ClientEncoding->encoding);
}
/*
* Convert server encoding to any encoding.
*
* See the notes about string conversion functions at the top of this file.
*/
char *
pg_server_to_any(const char *s, int len, int encoding)
{
if (len <= 0)
return unconstify(char *, s); /* empty string is always valid */
if (encoding == DatabaseEncoding->encoding ||
encoding == PG_SQL_ASCII)
return unconstify(char *, s); /* assume data is valid */
if (DatabaseEncoding->encoding == PG_SQL_ASCII)
{
/* No conversion is possible, but we must validate the result */
(void) pg_verify_mbstr(encoding, s, len, false);
return unconstify(char *, s);
}
/* Fast path if we can use cached conversion function */
if (encoding == ClientEncoding->encoding)
return perform_default_encoding_conversion(s, len, false);
/* General case ... will not work outside transactions */
return (char *) pg_do_encoding_conversion((unsigned char *) unconstify(char *, s),
len,
DatabaseEncoding->encoding,
encoding);
}
/*
* Perform default encoding conversion using cached FmgrInfo. Since
* this function does not access database at all, it is safe to call
* outside transactions. If the conversion has not been set up by
* SetClientEncoding(), no conversion is performed.
*/
static char *
perform_default_encoding_conversion(const char *src, int len,
bool is_client_to_server)
{
char *result;
int src_encoding,
dest_encoding;
FmgrInfo *flinfo;
if (is_client_to_server)
{
src_encoding = ClientEncoding->encoding;
dest_encoding = DatabaseEncoding->encoding;
flinfo = ToServerConvProc;
}
else
{
src_encoding = DatabaseEncoding->encoding;
dest_encoding = ClientEncoding->encoding;
flinfo = ToClientConvProc;
}
if (flinfo == NULL)
return unconstify(char *, src);
/*
* Allocate space for conversion result, being wary of integer overflow.
* See comments in pg_do_encoding_conversion.
*/
if ((Size) len >= (MaxAllocHugeSize / (Size) MAX_CONVERSION_GROWTH))
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("out of memory"),
errdetail("String of %d bytes is too long for encoding conversion.",
len)));
result = (char *)
MemoryContextAllocHuge(CurrentMemoryContext,
(Size) len * MAX_CONVERSION_GROWTH + 1);
FunctionCall6(flinfo,
Int32GetDatum(src_encoding),
Int32GetDatum(dest_encoding),
CStringGetDatum(src),
CStringGetDatum(result),
Int32GetDatum(len),
BoolGetDatum(false));
/*
* Release extra space if there might be a lot --- see comments in
* pg_do_encoding_conversion.
*/
if (len > 1000000)
{
Size resultlen = strlen(result);
if (resultlen >= MaxAllocSize)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("out of memory"),
errdetail("String of %d bytes is too long for encoding conversion.",
len)));
result = (char *) repalloc(result, resultlen + 1);
}
return result;
}
/*
* Convert a single Unicode code point into a string in the server encoding.
*
* The code point given by "c" is converted and stored at *s, which must
* have at least MAX_UNICODE_EQUIVALENT_STRING+1 bytes available.
* The output will have a trailing '\0'. Throws error if the conversion
* cannot be performed.
*
* Note that this relies on having previously looked up any required
* conversion function. That's partly for speed but mostly because the parser
* may call this outside any transaction, or in an aborted transaction.
*/
void
pg_unicode_to_server(pg_wchar c, unsigned char *s)
{
unsigned char c_as_utf8[MAX_MULTIBYTE_CHAR_LEN + 1];
int c_as_utf8_len;
int server_encoding;
/*
* Complain if invalid Unicode code point. The choice of errcode here is
* debatable, but really our caller should have checked this anyway.
*/
if (!is_valid_unicode_codepoint(c))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("invalid Unicode code point")));
/* Otherwise, if it's in ASCII range, conversion is trivial */
if (c <= 0x7F)
{
s[0] = (unsigned char) c;
s[1] = '\0';
return;
}
/* If the server encoding is UTF-8, we just need to reformat the code */
server_encoding = GetDatabaseEncoding();
if (server_encoding == PG_UTF8)
{
unicode_to_utf8(c, s);
s[pg_utf_mblen(s)] = '\0';
return;
}
/* For all other cases, we must have a conversion function available */
if (Utf8ToServerConvProc == NULL)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("conversion between %s and %s is not supported",
pg_enc2name_tbl[PG_UTF8].name,
GetDatabaseEncodingName())));
/* Construct UTF-8 source string */
unicode_to_utf8(c, c_as_utf8);
c_as_utf8_len = pg_utf_mblen(c_as_utf8);
c_as_utf8[c_as_utf8_len] = '\0';
/* Convert, or throw error if we can't */
FunctionCall6(Utf8ToServerConvProc,
Int32GetDatum(PG_UTF8),
Int32GetDatum(server_encoding),
CStringGetDatum((char *) c_as_utf8),
CStringGetDatum((char *) s),
Int32GetDatum(c_as_utf8_len),
BoolGetDatum(false));
}
/*
* Convert a single Unicode code point into a string in the server encoding.
*
* Same as pg_unicode_to_server(), except that we don't throw errors,
* but simply return false on conversion failure.
*/
bool
pg_unicode_to_server_noerror(pg_wchar c, unsigned char *s)
{
unsigned char c_as_utf8[MAX_MULTIBYTE_CHAR_LEN + 1];
int c_as_utf8_len;
int converted_len;
int server_encoding;
/* Fail if invalid Unicode code point */
if (!is_valid_unicode_codepoint(c))
return false;
/* Otherwise, if it's in ASCII range, conversion is trivial */
if (c <= 0x7F)
{
s[0] = (unsigned char) c;
s[1] = '\0';
return true;
}
/* If the server encoding is UTF-8, we just need to reformat the code */
server_encoding = GetDatabaseEncoding();
if (server_encoding == PG_UTF8)
{
unicode_to_utf8(c, s);
s[pg_utf_mblen(s)] = '\0';
return true;
}
/* For all other cases, we must have a conversion function available */
if (Utf8ToServerConvProc == NULL)
return false;
/* Construct UTF-8 source string */
unicode_to_utf8(c, c_as_utf8);
c_as_utf8_len = pg_utf_mblen(c_as_utf8);
c_as_utf8[c_as_utf8_len] = '\0';
/* Convert, but without throwing error if we can't */
converted_len = DatumGetInt32(FunctionCall6(Utf8ToServerConvProc,
Int32GetDatum(PG_UTF8),
Int32GetDatum(server_encoding),
CStringGetDatum((char *) c_as_utf8),
CStringGetDatum((char *) s),
Int32GetDatum(c_as_utf8_len),
BoolGetDatum(true)));
/* Conversion was successful iff it consumed the whole input */
return (converted_len == c_as_utf8_len);
}
/* convert a multibyte string to a wchar */
int
pg_mb2wchar(const char *from, pg_wchar *to)
{
return pg_wchar_table[DatabaseEncoding->encoding].mb2wchar_with_len((const unsigned char *) from, to, strlen(from));
}
/* convert a multibyte string to a wchar with a limited length */
int
pg_mb2wchar_with_len(const char *from, pg_wchar *to, int len)
{
return pg_wchar_table[DatabaseEncoding->encoding].mb2wchar_with_len((const unsigned char *) from, to, len);
}
/* same, with any encoding */
int
pg_encoding_mb2wchar_with_len(int encoding,
const char *from, pg_wchar *to, int len)
{
return pg_wchar_table[encoding].mb2wchar_with_len((const unsigned char *) from, to, len);
}
/* convert a wchar string to a multibyte */
int
pg_wchar2mb(const pg_wchar *from, char *to)
{
return pg_wchar_table[DatabaseEncoding->encoding].wchar2mb_with_len(from, (unsigned char *) to, pg_wchar_strlen(from));
}
/* convert a wchar string to a multibyte with a limited length */
int
pg_wchar2mb_with_len(const pg_wchar *from, char *to, int len)
{
return pg_wchar_table[DatabaseEncoding->encoding].wchar2mb_with_len(from, (unsigned char *) to, len);
}
/* same, with any encoding */
int
pg_encoding_wchar2mb_with_len(int encoding,
const pg_wchar *from, char *to, int len)
{
return pg_wchar_table[encoding].wchar2mb_with_len(from, (unsigned char *) to, len);
}
/* returns the byte length of a multibyte character */
int
pg_mblen(const char *mbstr)
{
return pg_wchar_table[DatabaseEncoding->encoding].mblen((const unsigned char *) mbstr);
}
/* returns the display length of a multibyte character */
int
pg_dsplen(const char *mbstr)
{
return pg_wchar_table[DatabaseEncoding->encoding].dsplen((const unsigned char *) mbstr);
}
/* returns the length (counted in wchars) of a multibyte string */
int
pg_mbstrlen(const char *mbstr)
{
int len = 0;
/* optimization for single byte encoding */
if (pg_database_encoding_max_length() == 1)
return strlen(mbstr);
while (*mbstr)
{
mbstr += pg_mblen(mbstr);
len++;
}
return len;
}
/* returns the length (counted in wchars) of a multibyte string
* (not necessarily NULL terminated)
*/
int
pg_mbstrlen_with_len(const char *mbstr, int limit)
{
int len = 0;
/* optimization for single byte encoding */
if (pg_database_encoding_max_length() == 1)
return limit;
while (limit > 0 && *mbstr)
{
int l = pg_mblen(mbstr);
limit -= l;
mbstr += l;
len++;
}
return len;
}
/*
* returns the byte length of a multibyte string
* (not necessarily NULL terminated)
* that is no longer than limit.
* this function does not break multibyte character boundary.
*/
int
pg_mbcliplen(const char *mbstr, int len, int limit)
{
return pg_encoding_mbcliplen(DatabaseEncoding->encoding, mbstr,
len, limit);
}
/*
* pg_mbcliplen with specified encoding
*/
int
pg_encoding_mbcliplen(int encoding, const char *mbstr,
int len, int limit)
{
mblen_converter mblen_fn;
int clen = 0;
int l;
/* optimization for single byte encoding */
if (pg_encoding_max_length(encoding) == 1)
return cliplen(mbstr, len, limit);
mblen_fn = pg_wchar_table[encoding].mblen;
while (len > 0 && *mbstr)
{
l = (*mblen_fn) ((const unsigned char *) mbstr);
if ((clen + l) > limit)
break;
clen += l;
if (clen == limit)
break;
len -= l;
mbstr += l;
}
return clen;
}
/*
* Similar to pg_mbcliplen except the limit parameter specifies the
* character length, not the byte length.
*/
int
pg_mbcharcliplen(const char *mbstr, int len, int limit)
{
int clen = 0;
int nch = 0;
int l;
/* optimization for single byte encoding */
if (pg_database_encoding_max_length() == 1)
return cliplen(mbstr, len, limit);
while (len > 0 && *mbstr)
{
l = pg_mblen(mbstr);
nch++;
if (nch > limit)
break;
clen += l;
len -= l;
mbstr += l;
}
return clen;
}
/* mbcliplen for any single-byte encoding */
static int
cliplen(const char *str, int len, int limit)
{
int l = 0;
len = Min(len, limit);
while (l < len && str[l])
l++;
return l;
}
void
SetDatabaseEncoding(int encoding)
{
if (!PG_VALID_BE_ENCODING(encoding))
elog(ERROR, "invalid database encoding: %d", encoding);
DatabaseEncoding = &pg_enc2name_tbl[encoding];
Assert(DatabaseEncoding->encoding == encoding);
}
void
SetMessageEncoding(int encoding)
{
/* Some calls happen before we can elog()! */
Assert(PG_VALID_ENCODING(encoding));
MessageEncoding = &pg_enc2name_tbl[encoding];
Assert(MessageEncoding->encoding == encoding);
}
#ifdef ENABLE_NLS
/*
* Make one bind_textdomain_codeset() call, translating a pg_enc to a gettext
* codeset. Fails for MULE_INTERNAL, an encoding unknown to gettext; can also
* fail for gettext-internal causes like out-of-memory.
*/
static bool
raw_pg_bind_textdomain_codeset(const char *domainname, int encoding)
{
bool elog_ok = (CurrentMemoryContext != NULL);
int i;
for (i = 0; pg_enc2gettext_tbl[i].name != NULL; i++)
{
if (pg_enc2gettext_tbl[i].encoding == encoding)
{
if (bind_textdomain_codeset(domainname,
pg_enc2gettext_tbl[i].name) != NULL)
return true;
if (elog_ok)
elog(LOG, "bind_textdomain_codeset failed");
else
write_stderr("bind_textdomain_codeset failed");
break;
}
}
return false;
}
/*
* Bind a gettext message domain to the codeset corresponding to the database
* encoding. For SQL_ASCII, instead bind to the codeset implied by LC_CTYPE.
* Return the MessageEncoding implied by the new settings.
*
* On most platforms, gettext defaults to the codeset implied by LC_CTYPE.
* When that matches the database encoding, we don't need to do anything. In
* CREATE DATABASE, we enforce or trust that the locale's codeset matches the
* database encoding, except for the C locale. (On Windows, we also permit a
* discrepancy under the UTF8 encoding.) For the C locale, explicitly bind
* gettext to the right codeset.
*
* On Windows, gettext defaults to the Windows ANSI code page. This is a
* convenient departure for software that passes the strings to Windows ANSI
* APIs, but we don't do that. Compel gettext to use database encoding or,
* failing that, the LC_CTYPE encoding as it would on other platforms.
*
* This function is called before elog() and palloc() are usable.
*/
int
pg_bind_textdomain_codeset(const char *domainname)
{
bool elog_ok = (CurrentMemoryContext != NULL);
int encoding = GetDatabaseEncoding();
int new_msgenc;
#ifndef WIN32
const char *ctype = setlocale(LC_CTYPE, NULL);
if (pg_strcasecmp(ctype, "C") == 0 || pg_strcasecmp(ctype, "POSIX") == 0)
#endif
if (encoding != PG_SQL_ASCII &&
raw_pg_bind_textdomain_codeset(domainname, encoding))
return encoding;
new_msgenc = pg_get_encoding_from_locale(NULL, elog_ok);
if (new_msgenc < 0)
new_msgenc = PG_SQL_ASCII;
#ifdef WIN32
if (!raw_pg_bind_textdomain_codeset(domainname, new_msgenc))
/* On failure, the old message encoding remains valid. */
return GetMessageEncoding();
#endif
return new_msgenc;
}
#endif
/*
* The database encoding, also called the server encoding, represents the
* encoding of data stored in text-like data types. Affected types include
* cstring, text, varchar, name, xml, and json.
*/
int
GetDatabaseEncoding(void)
{
return DatabaseEncoding->encoding;
}
const char *
GetDatabaseEncodingName(void)
{
return DatabaseEncoding->name;
}
Datum
getdatabaseencoding(PG_FUNCTION_ARGS)
{
return DirectFunctionCall1(namein, CStringGetDatum(DatabaseEncoding->name));
}
Datum
pg_client_encoding(PG_FUNCTION_ARGS)
{
return DirectFunctionCall1(namein, CStringGetDatum(ClientEncoding->name));
}
Datum
PG_char_to_encoding(PG_FUNCTION_ARGS)
{
Name s = PG_GETARG_NAME(0);
PG_RETURN_INT32(pg_char_to_encoding(NameStr(*s)));
}
Datum
PG_encoding_to_char(PG_FUNCTION_ARGS)
{
int32 encoding = PG_GETARG_INT32(0);
const char *encoding_name = pg_encoding_to_char(encoding);
return DirectFunctionCall1(namein, CStringGetDatum(encoding_name));
}
/*
* gettext() returns messages in this encoding. This often matches the
* database encoding, but it differs for SQL_ASCII databases, for processes
* not attached to a database, and under a database encoding lacking iconv
* support (MULE_INTERNAL).
*/
int
GetMessageEncoding(void)
{
return MessageEncoding->encoding;
}
/*
* Generic character incrementer function.
*
* Not knowing anything about the properties of the encoding in use, we just
* keep incrementing the last byte until we get a validly-encoded result,
* or we run out of values to try. We don't bother to try incrementing
* higher-order bytes, so there's no growth in runtime for wider characters.
* (If we did try to do that, we'd need to consider the likelihood that 255
* is not a valid final byte in the encoding.)
*/
static bool
pg_generic_charinc(unsigned char *charptr, int len)
{
unsigned char *lastbyte = charptr + len - 1;
mbchar_verifier mbverify;
/* We can just invoke the character verifier directly. */
mbverify = pg_wchar_table[GetDatabaseEncoding()].mbverifychar;
while (*lastbyte < (unsigned char) 255)
{
(*lastbyte)++;
if ((*mbverify) (charptr, len) == len)
return true;
}
return false;
}
/*
* UTF-8 character incrementer function.
*
* For a one-byte character less than 0x7F, we just increment the byte.
*
* For a multibyte character, every byte but the first must fall between 0x80
* and 0xBF; and the first byte must be between 0xC0 and 0xF4. We increment
* the last byte that's not already at its maximum value. If we can't find a
* byte that's less than the maximum allowable value, we simply fail. We also
* need some special-case logic to skip regions used for surrogate pair
* handling, as those should not occur in valid UTF-8.
*
* Note that we don't reset lower-order bytes back to their minimums, since
* we can't afford to make an exhaustive search (see make_greater_string).
*/
static bool
pg_utf8_increment(unsigned char *charptr, int length)
{
unsigned char a;
unsigned char limit;
switch (length)
{
default:
/* reject lengths 5 and 6 for now */
return false;
case 4:
a = charptr[3];
if (a < 0xBF)
{
charptr[3]++;
break;
}
/* FALL THRU */
case 3:
a = charptr[2];
if (a < 0xBF)
{
charptr[2]++;
break;
}
/* FALL THRU */
case 2:
a = charptr[1];
switch (*charptr)
{
case 0xED:
limit = 0x9F;
break;
case 0xF4:
limit = 0x8F;
break;
default:
limit = 0xBF;
break;
}
if (a < limit)
{
charptr[1]++;
break;
}
/* FALL THRU */
case 1:
a = *charptr;
if (a == 0x7F || a == 0xDF || a == 0xEF || a == 0xF4)
return false;
charptr[0]++;
break;
}
return true;
}
/*
* EUC-JP character incrementer function.
*
* If the sequence starts with SS2 (0x8e), it must be a two-byte sequence
* representing JIS X 0201 characters with the second byte ranging between
* 0xa1 and 0xdf. We just increment the last byte if it's less than 0xdf,
* and otherwise rewrite the whole sequence to 0xa1 0xa1.
*
* If the sequence starts with SS3 (0x8f), it must be a three-byte sequence
* in which the last two bytes range between 0xa1 and 0xfe. The last byte
* is incremented if possible, otherwise the second-to-last byte.
*
* If the sequence starts with a value other than the above and its MSB
* is set, it must be a two-byte sequence representing JIS X 0208 characters
* with both bytes ranging between 0xa1 and 0xfe. The last byte is
* incremented if possible, otherwise the second-to-last byte.
*
* Otherwise, the sequence is a single-byte ASCII character. It is
* incremented up to 0x7f.
*/
static bool
pg_eucjp_increment(unsigned char *charptr, int length)
{
unsigned char c1,
c2;
int i;
c1 = *charptr;
switch (c1)
{
case SS2: /* JIS X 0201 */
if (length != 2)
return false;
c2 = charptr[1];
if (c2 >= 0xdf)
charptr[0] = charptr[1] = 0xa1;
else if (c2 < 0xa1)
charptr[1] = 0xa1;
else
charptr[1]++;
break;
case SS3: /* JIS X 0212 */
if (length != 3)
return false;
for (i = 2; i > 0; i--)
{
c2 = charptr[i];
if (c2 < 0xa1)
{
charptr[i] = 0xa1;
return true;
}
else if (c2 < 0xfe)
{
charptr[i]++;
return true;
}
}
/* Out of 3-byte code region */
return false;
default:
if (IS_HIGHBIT_SET(c1)) /* JIS X 0208? */
{
if (length != 2)
return false;
for (i = 1; i >= 0; i--)
{
c2 = charptr[i];
if (c2 < 0xa1)
{
charptr[i] = 0xa1;
return true;
}
else if (c2 < 0xfe)
{
charptr[i]++;
return true;
}
}
/* Out of 2 byte code region */
return false;
}
else
{ /* ASCII, single byte */
if (c1 > 0x7e)
return false;
(*charptr)++;
}
break;
}
return true;
}
/*
* get the character incrementer for the encoding for the current database
*/
mbcharacter_incrementer
pg_database_encoding_character_incrementer(void)
{
/*
* Eventually it might be best to add a field to pg_wchar_table[], but for
* now we just use a switch.
*/
switch (GetDatabaseEncoding())
{
case PG_UTF8:
return pg_utf8_increment;
case PG_EUC_JP:
return pg_eucjp_increment;
default:
return pg_generic_charinc;
}
}
/*
* fetch maximum length of the encoding for the current database
*/
int
pg_database_encoding_max_length(void)
{
return pg_wchar_table[GetDatabaseEncoding()].maxmblen;
}
/*
* Verify mbstr to make sure that it is validly encoded in the current
* database encoding. Otherwise same as pg_verify_mbstr().
*/
bool
pg_verifymbstr(const char *mbstr, int len, bool noError)
{
return pg_verify_mbstr(GetDatabaseEncoding(), mbstr, len, noError);
}
/*
* Verify mbstr to make sure that it is validly encoded in the specified
* encoding.
*/
bool
pg_verify_mbstr(int encoding, const char *mbstr, int len, bool noError)
{
int oklen;
Assert(PG_VALID_ENCODING(encoding));
oklen = pg_wchar_table[encoding].mbverifystr((const unsigned char *) mbstr, len);
if (oklen != len)
{
if (noError)
return false;
report_invalid_encoding(encoding, mbstr + oklen, len - oklen);
}
return true;
}
/*
* Verify mbstr to make sure that it is validly encoded in the specified
* encoding.
*
* mbstr is not necessarily zero terminated; length of mbstr is
* specified by len.
*
* If OK, return length of string in the encoding.
* If a problem is found, return -1 when noError is
* true; when noError is false, ereport() a descriptive message.
*
* Note: We cannot use the faster encoding-specific mbverifystr() function
* here, because we need to count the number of characters in the string.
*/
int
pg_verify_mbstr_len(int encoding, const char *mbstr, int len, bool noError)
{
mbchar_verifier mbverifychar;
int mb_len;
Assert(PG_VALID_ENCODING(encoding));
/*
* In single-byte encodings, we need only reject nulls (\0).
*/
if (pg_encoding_max_length(encoding) <= 1)
{
const char *nullpos = memchr(mbstr, 0, len);
if (nullpos == NULL)
return len;
if (noError)
return -1;
report_invalid_encoding(encoding, nullpos, 1);
}
/* fetch function pointer just once */
mbverifychar = pg_wchar_table[encoding].mbverifychar;
mb_len = 0;
while (len > 0)
{
int l;
/* fast path for ASCII-subset characters */
if (!IS_HIGHBIT_SET(*mbstr))
{
if (*mbstr != '\0')
{
mb_len++;
mbstr++;
len--;
continue;
}
if (noError)
return -1;
report_invalid_encoding(encoding, mbstr, len);
}
l = (*mbverifychar) ((const unsigned char *) mbstr, len);
if (l < 0)
{
if (noError)
return -1;
report_invalid_encoding(encoding, mbstr, len);
}
mbstr += l;
len -= l;
mb_len++;
}
return mb_len;
}
/*
* check_encoding_conversion_args: check arguments of a conversion function
*
* "expected" arguments can be either an encoding ID or -1 to indicate that
* the caller will check whether it accepts the ID.
*
* Note: the errors here are not really user-facing, so elog instead of
* ereport seems sufficient. Also, we trust that the "expected" encoding
* arguments are valid encoding IDs, but we don't trust the actuals.
*/
void
check_encoding_conversion_args(int src_encoding,
int dest_encoding,
int len,
int expected_src_encoding,
int expected_dest_encoding)
{
if (!PG_VALID_ENCODING(src_encoding))
elog(ERROR, "invalid source encoding ID: %d", src_encoding);
if (src_encoding != expected_src_encoding && expected_src_encoding >= 0)
elog(ERROR, "expected source encoding \"%s\", but got \"%s\"",
pg_enc2name_tbl[expected_src_encoding].name,
pg_enc2name_tbl[src_encoding].name);
if (!PG_VALID_ENCODING(dest_encoding))
elog(ERROR, "invalid destination encoding ID: %d", dest_encoding);
if (dest_encoding != expected_dest_encoding && expected_dest_encoding >= 0)
elog(ERROR, "expected destination encoding \"%s\", but got \"%s\"",
pg_enc2name_tbl[expected_dest_encoding].name,
pg_enc2name_tbl[dest_encoding].name);
if (len < 0)
elog(ERROR, "encoding conversion length must not be negative");
}
/*
* report_invalid_encoding: complain about invalid multibyte character
*
* note: len is remaining length of string, not length of character;
* len must be greater than zero, as we always examine the first byte.
*/
void
report_invalid_encoding(int encoding, const char *mbstr, int len)
{
int l = pg_encoding_mblen(encoding, mbstr);
char buf[8 * 5 + 1];
char *p = buf;
int j,
jlimit;
jlimit = Min(l, len);
jlimit = Min(jlimit, 8); /* prevent buffer overrun */
for (j = 0; j < jlimit; j++)
{
p += sprintf(p, "0x%02x", (unsigned char) mbstr[j]);
if (j < jlimit - 1)
p += sprintf(p, " ");
}
ereport(ERROR,
(errcode(ERRCODE_CHARACTER_NOT_IN_REPERTOIRE),
errmsg("invalid byte sequence for encoding \"%s\": %s",
pg_enc2name_tbl[encoding].name,
buf)));
}
/*
* report_untranslatable_char: complain about untranslatable character
*
* note: len is remaining length of string, not length of character;
* len must be greater than zero, as we always examine the first byte.
*/
void
report_untranslatable_char(int src_encoding, int dest_encoding,
const char *mbstr, int len)
{
int l = pg_encoding_mblen(src_encoding, mbstr);
char buf[8 * 5 + 1];
char *p = buf;
int j,
jlimit;
jlimit = Min(l, len);
jlimit = Min(jlimit, 8); /* prevent buffer overrun */
for (j = 0; j < jlimit; j++)
{
p += sprintf(p, "0x%02x", (unsigned char) mbstr[j]);
if (j < jlimit - 1)
p += sprintf(p, " ");
}
ereport(ERROR,
(errcode(ERRCODE_UNTRANSLATABLE_CHARACTER),
errmsg("character with byte sequence %s in encoding \"%s\" has no equivalent in encoding \"%s\"",
buf,
pg_enc2name_tbl[src_encoding].name,
pg_enc2name_tbl[dest_encoding].name)));
}
#ifdef WIN32
/*
* Convert from MessageEncoding to a palloc'ed, null-terminated utf16
* string. The character length is also passed to utf16len if not
* null. Returns NULL iff failed. Before MessageEncoding initialization, "str"
* should be ASCII-only; this will function as though MessageEncoding is UTF8.
*/
WCHAR *
pgwin32_message_to_UTF16(const char *str, int len, int *utf16len)
{
int msgenc = GetMessageEncoding();
WCHAR *utf16;
int dstlen;
UINT codepage;
if (msgenc == PG_SQL_ASCII)
/* No conversion is possible, and SQL_ASCII is never utf16. */
return NULL;
codepage = pg_enc2name_tbl[msgenc].codepage;
/*
* Use MultiByteToWideChar directly if there is a corresponding codepage,
* or double conversion through UTF8 if not. Double conversion is needed,
* for example, in an ENCODING=LATIN8, LC_CTYPE=C database.
*/
if (codepage != 0)
{
utf16 = (WCHAR *) palloc(sizeof(WCHAR) * (len + 1));
dstlen = MultiByteToWideChar(codepage, 0, str, len, utf16, len);
utf16[dstlen] = (WCHAR) 0;
}
else
{
char *utf8;
/*
* XXX pg_do_encoding_conversion() requires a transaction. In the
* absence of one, hope for the input to be valid UTF8.
*/
if (IsTransactionState())
{
utf8 = (char *) pg_do_encoding_conversion((unsigned char *) str,
len,
msgenc,
PG_UTF8);
if (utf8 != str)
len = strlen(utf8);
}
else
utf8 = (char *) str;
utf16 = (WCHAR *) palloc(sizeof(WCHAR) * (len + 1));
dstlen = MultiByteToWideChar(CP_UTF8, 0, utf8, len, utf16, len);
utf16[dstlen] = (WCHAR) 0;
if (utf8 != str)
pfree(utf8);
}
if (dstlen == 0 && len > 0)
{
pfree(utf16);
return NULL; /* error */
}
if (utf16len)
*utf16len = dstlen;
return utf16;
}
#endif /* WIN32 */
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