ddnet/src/base/system.h

/* (c) Magnus Auvinen. See licence.txt in the root of the distribution for more information. */
/* If you are missing that file, acquire a complete release at teeworlds.com.                */

/*
	Title: OS Abstraction
*/

#ifndef BASE_SYSTEM_H
#define BASE_SYSTEM_H

#include "detect.h"

#ifdef __cplusplus
extern "C" {
#endif

/* Group: Debug */
/*
	Function: dbg_assert
		Breaks into the debugger based on a test.
	
	Parameters:
		test - Result of the test.
		msg - Message that should be printed if the test fails.
	
	Remarks:
		Does nothing in release version of the library.
	
	See Also:
		<dbg_break>
*/
void dbg_assert(int test, const char *msg);
#define dbg_assert(test,msg) dbg_assert_imp(__FILE__, __LINE__, test,  msg)
void dbg_assert_imp(const char *filename, int line, int test, const char *msg);

/*
	Function: dbg_break
		Breaks into the debugger.
	
	Remarks:
		Does nothing in release version of the library.
	
	See Also:
		<dbg_assert>
*/
void dbg_break();

/*
	Function: dbg_msg
	
	Prints a debug message.
	
	Parameters:
		sys - A string that describes what system the message belongs to
		fmt - A printf styled format string.
	
	Remarks:
		Does nothing in release version of the library.
		
	See Also:
		<dbg_assert>
*/
void dbg_msg(const char *sys, const char *fmt, ...);

/* Group: Memory */

/*
	Function: mem_alloc
		Allocates memory.
	
	Parameters:
		size - Size of the needed block.
		alignment - Alignment for the block.
	
	Returns:
		Returns a pointer to the newly allocated block. Returns a
		null pointer if the memory couldn't be allocated.
		
	Remarks:
		- Passing 0 to size will allocated the smallest amount possible
		and return a unique pointer.

	See Also:
		<mem_free>
*/
void *mem_alloc_debug(const char *filename, int line, unsigned size, unsigned alignment);
#define mem_alloc(s,a) mem_alloc_debug(__FILE__, __LINE__, (s), (a))

/*
	Function: mem_free
		Frees a block allocated through <mem_alloc>.
	
	Remarks:
		- In the debug version of the library the function will assert if
		a non-valid block is passed, like a null pointer or a block that
		isn't allocated.
	
	See Also:
		<mem_alloc>
*/
void mem_free(void *block);

/*
	Function: mem_copy
		Copies a a memory block.
	
	Parameters:
		dest - Destination.
		source - Source to copy.
		size - Size of the block to copy.
	
	Remarks:
		- This functions DOES NOT handles cases where source and
		destination is overlapping.
	
	See Also:
		<mem_move>
*/
void mem_copy(void *dest, const void *source, unsigned size);

/*
	Function: mem_move
		Copies a a memory block
	
	Parameters:
		dest - Destination
		source - Source to copy
		size - Size of the block to copy
	
	Remarks:
		- This functions handles cases where source and destination
		is overlapping
	
	See Also:
		<mem_copy>
*/
void mem_move(void *dest, const void *source, unsigned size);

/*
	Function: mem_zero
		Sets a complete memory block to 0
	
	Parameters:
		block - Pointer to the block to zero out
		size - Size of the block
*/
void mem_zero(void *block, unsigned size);

/*
	Function: mem_comp
		Compares two blocks of memory
	
	Parameters:
		a - First block of data
		b - Second block of data
		size - Size of the data to compare
		
	Returns:
		<0 - Block a is lesser then block b
		0 - Block a is equal to block b
		>0 - Block a is greater then block b
*/
int mem_comp(const void *a, const void *b, int size);

/*
	Function: mem_check
		Validates the heap
		Will trigger a assert if memory has failed.
*/
int mem_check_imp();
#define mem_check() dbg_assert_imp(__FILE__, __LINE__, mem_check_imp(),  "Memory check failed")

/* Group: File IO */
enum {
	IOFLAG_READ = 1,
	IOFLAG_WRITE = 2,
	IOFLAG_RANDOM = 4,

	IOSEEK_START = 0,
	IOSEEK_CUR = 1,
	IOSEEK_END = 2
};

typedef struct IOINTERNAL *IOHANDLE;

/*
	Function: io_open
		Opens a file.

	Parameters:
		filename - File to open.
		flags - A set of flags. IOFLAG_READ, IOFLAG_WRITE, IOFLAG_RANDOM.

	Returns:
		Returns a handle to the file on success and 0 on failure.

*/
IOHANDLE io_open(const char *filename, int flags);

/*
	Function: io_read
		Reads data into a buffer from a file.

	Parameters:
		io - Handle to the file to read data from.
		buffer - Pointer to the buffer that will recive the data.
		size - Number of bytes to read from the file.
		
	Returns:
		Number of bytes read.

*/
unsigned io_read(IOHANDLE io, void *buffer, unsigned size);

/*
	Function: io_skip
		Skips data in a file.
	
	Parameters:
		io - Handle to the file.
		size - Number of bytes to skip.
		
	Returns:
		Number of bytes skipped.
*/
unsigned io_skip(IOHANDLE io, int size);

/*
	Function: io_write
		Writes data from a buffer to file.
	
	Parameters:
		io - Handle to the file.
		buffer - Pointer to the data that should be written.
		size - Number of bytes to write.
		
	Returns:
		Number of bytes written.
*/
unsigned io_write(IOHANDLE io, const void *buffer, unsigned size);

/*
	Function: io_seek
		Seeks to a specified offset in the file.
	
	Parameters:
		io - Handle to the file.
		offset - Offset from pos to stop.
		origin - Position to start searching from.
		
	Returns:
		Returns 0 on success.
*/
int io_seek(IOHANDLE io, int offset, int origin);

/*
	Function: io_tell
		Gets the current position in the file.
	
	Parameters:
		io - Handle to the file.
		
	Returns:
		Returns the current position. -1L if an error occured.
*/
long int io_tell(IOHANDLE io);

/*
	Function: io_length
		Gets the total length of the file. Resetting cursor to the beginning
	
	Parameters:
		io - Handle to the file.
		
	Returns:
		Returns the total size. -1L if an error occured.
*/
long int io_length(IOHANDLE io);

/*
	Function: io_close
		Closes a file.
	
	Parameters:
		io - Handle to the file.
		
	Returns:
		Returns 0 on success.
*/
int io_close(IOHANDLE io);

/*
	Function: io_flush
		Empties all buffers and writes all pending data.
	
	Parameters:
		io - Handle to the file.
		
	Returns:
		Returns 0 on success.
*/
int io_flush(IOHANDLE io);


/*
	Function: io_stdin
		Returns an <IOHANDLE> to the standard input.
*/
IOHANDLE io_stdin();

/*
	Function: io_stdout
		Returns an <IOHANDLE> to the standard output.
*/
IOHANDLE io_stdout();

/*
	Function: io_stderr
		Returns an <IOHANDLE> to the standard error.
*/
IOHANDLE io_stderr();


/* Group: Threads */

/*
	Function: thread_sleep
		Suspends the current thread for a given period.
	
	Parameters:
		milliseconds - Number of milliseconds to sleep.
*/
void thread_sleep(int milliseconds);

/*
	Function: thread_create
		Creates a new thread.
	
	Parameters:
		threadfunc - Entry point for the new thread.
		user - Pointer to pass to the thread.
		
*/
void *thread_create(void (*threadfunc)(void *), void *user);

/*
	Function: thread_wait
		Waits for a thread to be done or destroyed.
	
	Parameters:
		thread - Thread to wait for.
*/
void thread_wait(void *thread);

/*
	Function: thread_destroy
		Destroys a thread.
	
	Parameters:
		thread - Thread to destroy.
*/
void thread_destroy(void *thread);

/*
	Function: thread_yeild
		Yeild the current threads execution slice.
*/
void thread_yield();


/* Group: Locks */
typedef void* LOCK;

LOCK lock_create();
void lock_destroy(LOCK lock);

int lock_try(LOCK lock);
void lock_wait(LOCK lock);
void lock_release(LOCK lock);

/* Group: Timer */
#ifdef __GNUC__
/* if compiled with -pedantic-errors it will complain about long
	not being a C90 thing.
*/
__extension__ typedef long long int64;
#else
typedef long long int64;
#endif
/*
	Function: time_get
		Fetches a sample from a high resolution timer.
	
	Returns:
		Current value of the timer.

	Remarks:
		To know how fast the timer is ticking, see <time_freq>.
*/
int64 time_get();

/*
	Function: time_freq
		Returns the frequency of the high resolution timer.
	
	Returns:
		Returns the frequency of the high resolution timer.
*/
int64 time_freq();

/*
	Function: time_timestamp
		Retrives the current time as a UNIX timestamp
	
	Returns:
		The time as a UNIX timestamp
*/
unsigned time_timestamp();

/* Group: Network General */
typedef int NETSOCKET;
enum
{
	NETSOCKET_INVALID = -1,
	
	NETTYPE_INVALID = 0,
	NETTYPE_IPV4 = 1,
	NETTYPE_IPV6 = 2,
	NETTYPE_ALL = ~0
};

typedef struct
{
	unsigned int type;
	unsigned char ip[16];
	unsigned short port;
} NETADDR;

/*
	Function: net_init
		Initiates network functionallity.
	
	Returns:
		Returns 0 on success,
		
	Remarks:
		You must call this function before using any other network
		functions.
*/
int net_init();

/*
	Function: net_host_lookup
		Does a hostname lookup by name and fills out the passed
		NETADDR struct with the recieved details.

	Returns:
		0 on success.
*/
int net_host_lookup(const char *hostname, NETADDR *addr, int types);

/*
	Function: net_addr_comp
		Compares two network addresses.
	
	Parameters:
		a - Address to compare
		b - Address to compare to.
	
	Returns:
		<0 - Address a is lesser then address b
		0 - Address a is equal to address b
		>0 - Address a is greater then address b
*/
int net_addr_comp(const NETADDR *a, const NETADDR *b);

/*
	Function: net_addr_str
		Turns a network address into a representive string.
	
	Parameters:
		addr - Address to turn into a string.
		string - Buffer to fill with the string.
		max_length - Maximum size of the string.
		
	Remarks:
		- The string will always be zero terminated

*/
void net_addr_str(const NETADDR *addr, char *string, int max_length);

/*
	Function: net_addr_from_str
		Turns string into a network address.
	
	Returns:
		0 on success
	
	Parameters:
		addr - Address to fill in.
		string - String to parse.
*/
int net_addr_from_str(NETADDR *addr, const char *string);

/* Group: Network UDP */

/*
	Function: net_udp_create
		Creates a UDP socket and binds it to a port.

	Parameters:
		bindaddr - Address to bind the socket to.
	
	Returns:
		On success it returns an handle to the socket. On failure it
		returns NETSOCKET_INVALID.
*/
NETSOCKET net_udp_create(NETADDR bindaddr);

/*
	Function: net_udp_send
		Sends a packet over an UDP socket.

	Parameters:
		sock - Socket to use.
		addr - Where to send the packet.
		data - Pointer to the packet data to send.
		size - Size of the packet.
	
	Returns:
		On success it returns the number of bytes sent. Returns -1
		on error.
*/
int net_udp_send(NETSOCKET sock, const NETADDR *addr, const void *data, int size);

/*
	Function: net_udp_recv
		Recives a packet over an UDP socket.

	Parameters:
		sock - Socket to use.
		addr - Pointer to an NETADDR that will recive the address.
		data - Pointer to a buffer that will recive the data.
		maxsize - Maximum size to recive.
	
	Returns:
		On success it returns the number of bytes recived. Returns -1
		on error.
*/
int net_udp_recv(NETSOCKET sock, NETADDR *addr, void *data, int maxsize);

/*
	Function: net_udp_close
		Closes an UDP socket.

	Parameters:
		sock - Socket to close.
	
	Returns:
		Returns 0 on success. -1 on error.
*/
int net_udp_close(NETSOCKET sock);


/* Group: Network TCP */

/*
	Function: net_tcp_create
		Creates a TCP socket.
	
	Parameters:
		bindaddr - Address to bind the socket to.

	Returns:
		On success it returns an handle to the socket. On failure it returns NETSOCKET_INVALID.
*/
NETSOCKET net_tcp_create(const NETADDR *a);

/*
	Function: net_tcp_listen
		Makes the socket start listening for new connections.
	
	Parameters:
		sock - Socket to start listen to.
		backlog - Size of the queue of incomming connections to keep.
	
	Returns:
		Returns 0 on success.
*/
int net_tcp_listen(NETSOCKET sock, int backlog);

/*
	Function: net_tcp_accept
		Polls a listning socket for a new connection.
		
	Parameters:
		sock - Listning socket to poll.
		new_sock - Pointer to a socket to fill in with the new socket.
		addr - Pointer to an address that will be filled in the remote address (optional, can be NULL).
	
	Returns:
		Returns a non-negative integer on success. Negative integer on failure.
*/
int net_tcp_accept(NETSOCKET sock, NETSOCKET *new_sock, NETADDR *addr);

/*
	Function: net_tcp_connect
		Connects one socket to another.
		
	Parameters:
		sock - Socket to connect.
		addr - Address to connect to.

	Returns:
		Returns 0 on success.
			
*/
int net_tcp_connect(NETSOCKET sock, const NETADDR *addr);

/*
	Function: net_tcp_send
		Sends data to a TCP stream.
	
	Parameters:
		sock - Socket to send data to.
		data - Pointer to the data to send.
		size - Size of the data to send.
	
	Returns:
		Number of bytes sent. Negative value on failure.
*/
int net_tcp_send(NETSOCKET sock, const void *data, int size);

/*
	Function: net_tcp_recv
		Recvives data from a TCP stream.
		
	Parameters:
		sock - Socket to recvive data from.
		data - Pointer to a buffer to write the data to
		max_size - Maximum of data to write to the buffer.
		
	Returns:
		Number of bytes recvived. Negative value on failure. When in
		non-blocking mode, it returns 0 when there is no more data to
		be fetched.
*/
int net_tcp_recv(NETSOCKET sock, void *data, int maxsize);

/*
	Function: net_tcp_close
		Closes a TCP socket.
	
	Parameters:
		sock - Socket to close.
	
	Returns:
		Returns 0 on success. Negative value on failure.
*/
int net_tcp_close(NETSOCKET sock);

/* Group: Strings */

/*
	Function: str_append
		Appends a string to another.
	
	Parameters:
		dst - Pointer to a buffer that contains a string.
		src - String to append.
		dst_size - Size of the buffer of the dst string.
		
	Remarks:
		- The strings are treated as zero-termineted strings.
		- Garantees that dst string will contain zero-termination.
*/
void str_append(char *dst, const char *src, int dst_size);

/*
	Function: str_copy
		Copies a string to another.
		
	Parameters:
		dst - Pointer to a buffer that shall recive the string.
		src - String to be copied.
		dst_size - Size of the buffer dst.

	Remarks:
		- The strings are treated as zero-termineted strings.
		- Garantees that dst string will contain zero-termination.
*/
void str_copy(char *dst, const char *src, int dst_size);

/*
	Function: str_length
		Returns the length of a zero terminated string.
		
	Parameters:
		str - Pointer to the string.
		
	Returns:
		Length of string in bytes excluding the zero termination.
*/
int str_length(const char *str);

/*
	Function: str_format
		Performs printf formating into a buffer.
		
	Parameters:
		buffer - Pointer to the buffer to recive the formated string.
		buffer_size - Size of the buffer.
		format - printf formating string.
		... - Parameters for the formating.

	Remarks:
		- See the C manual for syntax for the printf formating string.
		- The strings are treated as zero-termineted strings.
		- Garantees that dst string will contain zero-termination.
*/
void str_format(char *buffer, int buffer_size, const char *format, ...);

/*
	Function: str_sanitize_strong
		Replaces all characters below 32 and above 127 with whitespace.
	
	Parameters:
		str - String to sanitize.

	Remarks:
		- The strings are treated as zero-termineted strings.
*/
void str_sanitize_strong(char *str);

/*
	Function: str_sanitize_cc
		Replaces all characters below 32 with whitespace.
	
	Parameters:
		str - String to sanitize.

	Remarks:
		- The strings are treated as zero-termineted strings.
*/
void str_sanitize_cc(char *str);

/*
	Function: str_sanitize
		Replaces all characters below 32 with whitespace with
		exception to \t, \n and \r.
	
	Parameters:
		str - String to sanitize.

	Remarks:
		- The strings are treated as zero-termineted strings.
*/
void str_sanitize(char *str);

/*
	Function: str_skip_to_whitespace
		Skips leading non-whitespace characters(all but ' ', '\t', '\n', '\r').
	
	Parameters:
		str - Pointer to the string.

	Returns:
		Pointer to the first whitespace character found
		within the string.

	Remarks:
		- The strings are treated as zero-termineted strings.
*/
char *str_skip_to_whitespace(char *str);

/*
	Function: str_skip_whitespaces
		Skips leading whitespace characters(' ', '\t', '\n', '\r').
	
	Parameters:
		str - Pointer to the string.

	Returns:
		Pointer to the first non-whitespace character found
		within the string.

	Remarks:
		- The strings are treated as zero-termineted strings.
*/
char *str_skip_whitespaces(char *str);

/*
	Function: str_comp_nocase
		Compares to strings case insensitive.
	
	Parameters:
		a - String to compare.
		b - String to compare.
	
	Returns:	
		<0 - String a is lesser then string b
		0 - String a is equal to string b
		>0 - String a is greater then string b

	Remarks:
		- Only garanted to work with a-z/A-Z.
		- The strings are treated as zero-termineted strings.
*/
int str_comp_nocase(const char *a, const char *b);


/*
	Function: str_comp
		Compares to strings case sensitive.
	
	Parameters:
		a - String to compare.
		b - String to compare.
	
	Returns:	
		<0 - String a is lesser then string b
		0 - String a is equal to string b
		>0 - String a is greater then string b

	Remarks:
		- The strings are treated as zero-termineted strings.
*/
int str_comp(const char *a, const char *b);

/*
	Function: str_comp_num
		Compares up to num characters of two strings case sensitive.
	
	Parameters:
		a - String to compare.
		b - String to compare.
		num - Maximum characters to compare
	
	Returns:	
		<0 - String a is lesser then string b
		0 - String a is equal to string b
		>0 - String a is greater then string b

	Remarks:
		- The strings are treated as zero-termineted strings.
*/
int str_comp_num(const char *a, const char *b, const int num);

/*
	Function: str_comp_filenames
		Compares two strings case sensitive, digit chars will be compared as numbers.
	
	Parameters:
		a - String to compare.
		b - String to compare.
	
	Returns:	
		<0 - String a is lesser then string b
		0 - String a is equal to string b
		>0 - String a is greater then string b

	Remarks:
		- The strings are treated as zero-termineted strings.
*/
int str_comp_filenames(const char *a, const char *b);

/*
	Function: str_find_nocase
		Finds a string inside another string case insensitive.

	Parameters:
		haystack - String to search in
		needle - String to search for
		
	Returns:
		A pointer into haystack where the needle was found.
		Returns NULL of needle could not be found.

	Remarks:
		- Only garanted to work with a-z/A-Z.
		- The strings are treated as zero-termineted strings.
*/
const char *str_find_nocase(const char *haystack, const char *needle);

/*
	Function: str_find
		Finds a string inside another string case sensitive.

	Parameters:
		haystack - String to search in
		needle - String to search for
		
	Returns:
		A pointer into haystack where the needle was found.
		Returns NULL of needle could not be found.

	Remarks:
		- The strings are treated as zero-termineted strings.
*/
const char *str_find(const char *haystack, const char *needle);

/*
	Function: str_hex
		Takes a datablock and generates a hexstring of it.

	Parameters:
		dst - Buffer to fill with hex data
		dst_size - size of the buffer
		data - Data to turn into hex
		data - Size of the data

	Remarks:
		- The desination buffer will be zero-terminated
*/
void str_hex(char *dst, int dst_size, const void *data, int data_size);

/* Group: Filesystem */

/*
	Function: fs_listdir
		Lists the files in a directory
		
	Parameters:
		dir - Directory to list
		cb - Callback function to call for each entry
		type - Type of the directory
		user - Pointer to give to the callback
	
	Returns:
		Always returns 0.
*/
typedef void (*FS_LISTDIR_CALLBACK)(const char *name, int is_dir, int dir_type, void *user);
int fs_listdir(const char *dir, FS_LISTDIR_CALLBACK cb, int type, void *user);

/*
	Function: fs_makedir
		Creates a directory
	
	Parameters:
		path - Directory to create
	
	Returns:
		Returns 0 on success. Negative value on failure.
	
	Remarks:
		Does not create several directories if needed. "a/b/c" will result
		in a failure if b or a does not exist.
*/
int fs_makedir(const char *path);

/*
	Function: fs_storage_path
		Fetches per user configuration directory.
	
	Returns:
		Returns 0 on success. Negative value on failure.
	
	Remarks:
		- Returns ~/.appname on UNIX based systems
		- Returns ~/Library/Applications Support/appname on Mac OS X
		- Returns %APPDATA%/Appname on Windows based systems
*/
int fs_storage_path(const char *appname, char *path, int max);

/*
	Function: fs_is_dir
		Checks if directory exists
	
	Returns:
		Returns 1 on success, 0 on failure.
*/
int fs_is_dir(const char *path);

/*
	Function: fs_chdir
		Changes current working directory
	
	Returns:
		Returns 0 on success, 1 on failure.
*/
int fs_chdir(const char *path);

/*
	Function: fs_parent_dir
		Get the parent directory of a directory
	
	Parameters:
		path - The directory string

	Returns:
		Returns 0 on success, 1 on failure.

	Remarks:
		- The string is treated as zero-termineted string.
*/
int fs_parent_dir(char *path);

/*
	Group: Undocumented
*/


/*
	Function: net_tcp_connect_non_blocking
	
	DOCTODO: serp
*/
int net_tcp_connect_non_blocking(NETSOCKET sock, const NETADDR *a);

/*
	Function: net_tcp_set_non_blocking

	DOCTODO: serp
*/
int net_tcp_set_non_blocking(NETSOCKET sock);

/*
	Function: net_tcp_set_non_blocking

	DOCTODO: serp
*/
int net_tcp_set_blocking(NETSOCKET sock);

/*
	Function: net_errno

	DOCTODO: serp
*/
int net_errno();

/*
	Function: net_would_block

	DOCTODO: serp
*/
int net_would_block();

int net_socket_read_wait(NETSOCKET sock, int time);

void mem_debug_dump();

void swap_endian(void *data, unsigned elem_size, unsigned num);

/* Group: Debug levels */
//by format
enum {
	DBG_FMT_RAW				= 1,	//raw output
	DBG_FMT_TIME			= 2,	//show time
	DBG_FMT_SYS				= 3,	//show sys
	DBG_FMT_FULL			= 4		//show both
};

enum {
	DBG_LEVEL_IMPORTANT			= 0,	//important always showed messages
	DBG_LEVEL_ERROR				= 1,	//error messages
	DBG_LEVEL_WARNING			= 2,	//warning messages
	DBG_LEVEL_MSG				= 3,	//extra debug messages
	DBG_LEVEL_INFO				= 4		//info messages
};

#define DBG_LEVEL_LOW DBG_LEVEL_IMPORTANT
#define DBG_LEVEL_HIGH DBG_LEVEL_INFO

typedef void (*DBG_LOGGER)(const char *line); 
void dbg_logger(DBG_LOGGER logger);

void dbg_logger_stdout();
void dbg_logger_debugger();
void dbg_logger_file(const char *filename);

typedef struct
{
	int allocated;
	int active_allocations;
	int total_allocations;
} MEMSTATS;

const MEMSTATS *mem_stats();

typedef struct
{
	int sent_packets;
	int sent_bytes;
	int recv_packets;
	int recv_bytes;
} NETSTATS;


void net_stats(NETSTATS *stats);

int str_toint(const char *str);
float str_tofloat(const char *str);
int str_isspace(char c);
char str_uppercase(char c);
unsigned str_quickhash(const char *str);

/*
	Function: gui_messagebox
		Display plain OS-dependent message box
	
	Parameters:
		title - title of the message box
		message - text to display
*/
void gui_messagebox(const char *title, const char *message);


/*
	Function: str_utf8_rewind
		Moves a cursor backwards in an utf8 string
	
	Parameters:
		str - utf8 string
		cursor - position in the string

	Returns:
		New cursor position.

	Remarks:
		- Won't move the cursor less then 0
*/
int str_utf8_rewind(const char *str, int cursor);

/*
	Function: str_utf8_forward
		Moves a cursor forwards in an utf8 string
	
	Parameters:
		str - utf8 string
		cursor - position in the string
		
	Returns:
		New cursor position.

	Remarks:
		- Won't move the cursor beyond the zero termination marker
*/
int str_utf8_forward(const char *str, int cursor);

/*
	Function: str_utf8_decode
		Decodes an utf8 character
	
	Parameters:
		ptr - pointer to an utf8 string. this pointer will be moved forward
		
	Returns:
		Unicode value for the character. -1 for invalid characters and 0 for end of string.

	Remarks:
		- This function will also move the pointer forward.
*/
int str_utf8_decode(const char **ptr);

/*
	Function: str_utf8_encode
		Encode an utf8 character
	
	Parameters:
		ptr - Pointer to a buffer that should recive the data. Should be able to hold at least 4 bytes.
		
	Returns:
		Number of bytes put into the buffer.

	Remarks:
		- Does not do zero termination of the string.
*/
int str_utf8_encode(char *ptr, int chr);

/*
	Function: str_utf8_check
		Checks if a strings contains just valid utf8 characters.
	
	Parameters:
		str - Pointer to a possible utf8 string.
		
	Returns:
		0 - invalid characters found.
		1 - only valid characters found.

	Remarks:
		- The string is treated as zero-terminated utf8 string.
*/
int str_utf8_check(const char *str);

#ifdef __cplusplus
}
#endif

#endif