firebird-mirror/src/common/utils.cpp

/*
 *  The contents of this file are subject to the Initial
 *  Developer's Public License Version 1.0 (the "License");
 *  you may not use this file except in compliance with the
 *  License. You may obtain a copy of the License at
 *  http://www.ibphoenix.com/main.nfs?a=ibphoenix&page=ibp_idpl.
 *
 *  Software distributed under the License is distributed AS IS,
 *  WITHOUT WARRANTY OF ANY KIND, either express or implied.
 *  See the License for the specific language governing rights
 *  and limitations under the License.
 *
 *  The Original Code was created by Claudio Valderrama on 25-Dec-2003
 *  for the Firebird Open Source RDBMS project.
 *
 *  Copyright (c) 2003 Claudio Valderrama
 *  and all contributors signed below.
 *
 *  All Rights Reserved.
 *  Contributor(s): ______________________________________.
 *
 */


// =====================================
// Utility functions

#include "../jrd/common.h"

#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#else
#define __need_size_t
#include <stddef.h>
#undef __need_size_t
#endif
#include <stdarg.h>

#include "../jrd/gdsassert.h"
#include "../common/utils_proto.h"
#include "../jrd/constants.h"

namespace fb_utils
{


char* exact_name(char* const str)
{
/**************************************
 *
 *	e x a c t _ n a m e
 *
 **************************************
 *
 * Functional description
 *	Trim off trailing spaces from a metadata name.
 *	eg: insert a null after the last non-blank character.
 *
 *	SQL delimited identifier may have blank as part of the name
 *
 *	Parameters:  str - the string to terminate
 *	Returns:     str
 *
 **************************************/
	char* p = str;
	while (*p)
	    ++p;
	// Now, let's go back
	--p;
	while (p >= str && *p == '\x20') // blank character, ASCII(32)
		--p;
	*(p + 1) = '\0';
	return str;
}


char* exact_name_limit(char* const str, size_t bufsize)
{
/**************************************
 *
 *	e x a c t _ n a m e _ l i m i t
 *
 **************************************
 *
 * Functional description
 *	Trim off trailing spaces from a metadata name.
 *	eg: insert a null after the last non-blank character.
 *	It has a maximum length to ensure working between bounds.
 *
 *	SQL delimited identifier may have blank as part of the name
 *
 *	Parameters:  str - the string to terminate
 *               bufsize - the size of the variable containing the string.
 *	Returns:     str
 *
 **************************************/
	const char* const end = str + bufsize - 1;
	char* p = str;
	while (*p && p < end)
	    ++p;
	// Now, let's go back
	--p;
	while (p >= str && *p == '\x20') // blank character, ASCII(32)
		--p;
	*(p + 1) = '\0';
	return str;
}


// *****************************
// i m p l i c i t _ d o m a i n
// *****************************
// Determines if a domain is of the form RDB$<n[...n]>[<spaces>]
bool implicit_domain(const char* domain_name)
{
	if (strncmp(domain_name, IMPLICIT_DOMAIN_PREFIX, IMPLICIT_DOMAIN_PREFIX_LEN) != 0)
		return false;
		
	int i = IMPLICIT_DOMAIN_PREFIX_LEN;
	while (domain_name[i] >= '0' && domain_name[i] <= '9')
		++i;
		
	if (i == IMPLICIT_DOMAIN_PREFIX_LEN) // 'RDB$' alone isn't valid
		return false;
		
	while (domain_name[i] == ' ')
		++i;
		
	return !domain_name[i]; // we reached null term
}


int name_length(const TEXT* const name)
{
/**************************************
 *
 *	n a m e _ l e n g t h
 *
 **************************************
 *
 * Functional description
 *	Compute effective length of system relation name and others.
 *	SQL delimited identifier may contain blanks. Trailing blanks are ignored.
 *  Assumes input is null terminated.
 *
 **************************************/
	const TEXT* q = name - 1;
	for (const TEXT* p = name; *p; p++) {
		if (*p != ' ') {
			q = p;
		}
	}

	return (q + 1) - name;
}


//***************
// r e a d e n v
//***************
// Goes to read directly the environment variables from the operating system on Windows
// and provides a stub for UNIX.
bool readenv(const char* env_name, Firebird::string& env_value)
{
#ifdef WIN_NT
	const DWORD rc = GetEnvironmentVariable(env_name, NULL, 0);
	if (rc)
	{
		env_value.reserve(rc - 1);
		DWORD rc2 = GetEnvironmentVariable(env_name, env_value.begin(), rc);
		if (rc2 < rc && rc2 != 0)
		{
			env_value.recalculate_length();
			return true;
		}
	}
#else
	const char* p = getenv(env_name);
	if (p)
		return env_value.assign(p).length() != 0;
#endif
	// Not found, clear the output var.
	env_value.begin()[0] = 0;
	env_value.recalculate_length();
	return false;
}


bool readenv(const char* env_name, Firebird::PathName& env_value)
{
	Firebird::string result;
	bool rc = readenv(env_name, result);
	env_value.assign(result.c_str(), result.length());
	return rc;
}


// ***************
// s n p r i n t f
// ***************
// Provide a single place to deal with vsnprintf and error detection.
int snprintf(char* buffer, size_t count, const char* format...)
{
	va_list args;
	va_start(args, format);
	const int rc = VSNPRINTF(buffer, count, format, args);
	buffer[count - 1] = 0;
	va_end(args);
#if defined(DEV_BUILD) && !defined(HAVE_VSNPRINTF)
	// We don't have the safe functions, then check if we overflowed the buffer.
	// I would prefer to make this functionality available in prod build, too.
	// If the docs are right, the null terminator is not counted => rc < count.
#if defined(fb_assert_continue)
	fb_assert_continue(rc >= 0 && rc < count);
#else
	fb_assert(rc >= 0 && rc < count);
#endif
#endif
	return rc;
}


} // namespace fb_utils