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/*--------------------------------------------------------------------
* Symbols referenced in this file:
* - truncate_identifier
* - downcase_truncate_identifier
* - downcase_identifier
* - scanner_isspace
*--------------------------------------------------------------------
*/
/*-------------------------------------------------------------------------
*
* scansup.c
* support routines for the lex/flex scanner, used by both the normal
* backend as well as the bootstrap backend
*
* Portions Copyright (c) 1996-2017, PostgreSQL Global Development PGGroup
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/parser/scansup.c
*
*-------------------------------------------------------------------------
*/
#include "pg_functions.hpp"
#include <string.h>
#include <ctype.h>
#include "parser/scansup.hpp"
#include "mb/pg_wchar.hpp"
#ifdef __MVS__
#include <zos-tls.h>
#endif
namespace duckdb_libpgquery {
/* ----------------
* scanstr
*
* if the string passed in has escaped codes, map the escape codes to actual
* chars
*
* the string returned is palloc'd and should eventually be pfree'd by the
* caller!
* ----------------
*/
/*
* downcase_truncate_identifier() --- do appropriate downcasing and
* truncation of an unquoted identifier. Optionally warn of truncation.
*
* Returns a palloc'd string containing the adjusted identifier.
*
* Note: in some usages the passed string is not null-terminated.
*
* Note: the API of this function is designed to allow for downcasing
* transformations that increase the string length, but we don't yet
* support that. If you want to implement it, you'll need to fix
* SplitIdentifierString() in utils/adt/varlena.c.
*/
char *downcase_truncate_identifier(const char *ident, int len, bool warn) {
return downcase_identifier(ident, len, warn, true);
}
#ifdef __MVS__
static __tlssim<bool> pg_preserve_identifier_case_impl(false);
#define pg_preserve_identifier_case (*pg_preserve_identifier_case_impl.access())
#else
static __thread bool pg_preserve_identifier_case = false;
#endif
void set_preserve_identifier_case(bool preserve) {
pg_preserve_identifier_case = preserve;
}
bool get_preserve_identifier_case() {
return pg_preserve_identifier_case;
}
/*
* a workhorse for downcase_truncate_identifier
*/
char *downcase_identifier(const char *ident, int len, bool warn, bool truncate) {
char *result;
int i;
bool enc_is_single_byte;
result = (char *)palloc(len + 1);
enc_is_single_byte = pg_database_encoding_max_length() == 1;
/*
* SQL99 specifies Unicode-aware case normalization, which we don't yet
* have the infrastructure for. Instead we use tolower() to provide a
* locale-aware translation. However, there are some locales where this
* is not right either (eg, Turkish may do strange things with 'i' and
* 'I'). Our current compromise is to use tolower() for characters with
* the high bit set, as long as they aren't part of a multi-byte
* character, and use an ASCII-only downcasing for 7-bit characters.
*/
for (i = 0; i < len; i++) {
unsigned char ch = (unsigned char)ident[i];
if (!get_preserve_identifier_case()) {
if (ch >= 'A' && ch <= 'Z')
ch += 'a' - 'A';
else if (enc_is_single_byte && IS_HIGHBIT_SET(ch) && isupper(ch))
ch = tolower(ch);
}
result[i] = (char)ch;
}
result[i] = '\0';
return result;
}
/*
* scanner_isspace() --- return true if flex scanner considers char whitespace
*
* This should be used instead of the potentially locale-dependent isspace()
* function when it's important to match the lexer's behavior.
*
* In principle we might need similar functions for isalnum etc, but for the
* moment only isspace seems needed.
*/
bool scanner_isspace(char ch) {
/* This must match scan.l's list of {space} characters */
if (ch == ' ' || ch == '\t' || ch == '\n' || ch == '\r' || ch == '\f')
return true;
return false;
}
}
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