Update JoeyLib Utility Functions

JoeyLib-Utility-Functions.md

@@ -1,3 +1,9 @@
+#### jlUtilByteSwap
+```c
+juint16 jlUtilByteSwap(juint16 twoBytes);
+```
+Swaps the two bytes stored in `twoBytes` and returns them.
+
 #### jlUtilDie
 ```c
 void jlUtilDie(const char *why);
@@ -16,18 +22,54 @@ bool jlUtilIsOdd(int x);
 ```
 Fast even/odd macro.  If `x` is odd, it returns `true`.  If `x` is even, it returns `false`.
 
+#### jlUtilMakePathname
+```c
+char *jlUtilMakePathname(char *filename, char *extension);
+```
+Returns a temporary character array that consists of the game data directory name, target specific path specifier, the provided `filename`, and the `extension` concatenated into one string.  DO NOT free the returned string!  If you need to preserve the value returned, `strdup` it to another string.
+
 #### jlUtilMustExit
 ```c
 bool jlUtilMustExit(void);
 ```
 You MUST call `jlUtilMustExit` in any game loop that prevents your application from exiting.  If `jlUtilMustExit` returns `true` your application MUST exit safely.  This is used on platforms where operating system events may need to terminate your application.
 
+#### jlUtilNibbleSwap
+```c
+void jlUtilNibbleSwap(byte *mem, jint16 count, byte old, byte new);
+```
+Swaps all occurrences of the nibble `old` in the block of memory `mem` to `new` for `count` bytes.  Useful for swapping colors on display surfaces.
+
+#### jlUtilRandom
+```c
+juint16 jlUtilRandom(void);
+```
+Returns a random unsigned 16 bit value that is consistent across target platforms.
+
+#### jlUtilRandomSeedGet
+```c
+juint32 jlUtilRandomSeedGet(void);
+```
+Returns the internal "seed" of the random number generator in its current state.  Useful for saving the state of the random number generator.
+
+#### jlUtilRandomSeedSet
+```c
+void jlUtilRandomSeedSet(juint32 seed);
+```
+Specifies the internal "seed" to use for the next random number.
+
 #### jlUtilShutdown
 ```c
 void jlUtilShutdown(void);
 ```
 Cleanly shuts down JoeyLib.  You should free any resources you have allocated before shutting down.  If `JOEY_DEBUG` is defined, various memory statistics will be recorded in a file named `JLSTATS`.  This function does not return.
 
+#### jlUtilSleep
+```c
+void jlUtilSleep(juint16 tenths);
+```
+Pauses program execution for `tenths` one-tenth seconds.
+
 #### jlUtilStackPop
 ```c
 void *jlUtilStackPop(jlStackT stack);
@@ -48,6 +90,12 @@ Starts up JoeyLib and initializes the library.  `appName` is the name of your ap
 
 #### jlUtilTimer
 ```c
-unsigned int jlUtilTimer(void);
+juint16 jlUtilTimer(void);
 ```
-Provides a "wall clock" timer that is consistent across platforms.  The value returned increments (roughly) every 1/10th of a second.  When it reaches `MAX_INT`, it will roll over to zero.
+Provides a "wall clock" timer that is consistent across platforms.  The value returned increments (roughly) every 1/10th of a second.  When it reaches `JUINT16_MAX`, it will roll over to zero.
+
+#### jlUtilTimeSpan
+```c
+juint16 jlUtilTimeSpan(juint16 past, juint16 current);
+```
+Returns the difference, in tenths of a second, between `past` and `current` (which are assumed to be values returned by `jlUtilTimer`).  Handles zero rollover.