X-Git-Url: https://git.ucc.asn.au/?a=blobdiff_plain;f=Kernel%2Flib.c;h=0dbb9b96afc3e0a1b02e09a0628803c608bd1a0f;hb=4d166a859db826e94382e6222d5aa4d14ef1d3be;hp=ee9f24e0f6bba679a0f977661918cd1f73b17b43;hpb=8bc40333b1401d7616b225945fee53d972c2f418;p=tpg%2Facess2.git

diff --git a/Kernel/lib.c b/Kernel/lib.c
index ee9f24e0..0dbb9b96 100644
--- a/Kernel/lib.c
+++ b/Kernel/lib.c
@@ -5,6 +5,9 @@
 #include <common.h>
 
 // === CONSTANTS ===
+#define	RANDOM_SEED	0xACE55052
+#define	RANDOM_A	0x12231ADE
+#define	RANDOM_C	0x1BADBEEF
 //                          Jan Feb Mar Apr May  Jun  Jul  Aug  Sept Oct  Nov  Dec
 const short DAYS_BEFORE[] = {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334};
 #define UNIX_TO_2K	((30*365*3600*24) + (7*3600*24))	//Normal years + leap years
@@ -168,6 +171,8 @@ int strpos8(char *str, Uint32 Search)
  */
 int ReadUTF8(Uint8 *str, Uint32 *Val)
 {
+	*Val = 0xFFFD;	// Assume invalid character
+	
 	// ASCII
 	if( !(*str & 0x80) ) {
 		*Val = *str;
@@ -176,7 +181,6 @@ int ReadUTF8(Uint8 *str, Uint32 *Val)
 	
 	// Middle of a sequence
 	if( (*str & 0xC0) == 0x80 ) {
-		*Val = -1;
 		return 1;
 	}
 	
@@ -217,10 +221,55 @@ int ReadUTF8(Uint8 *str, Uint32 *Val)
 	}
 	
 	// UTF-8 Doesn't support more than four bytes
-	*Val = -1;
 	return 4;
 }
 
+/**
+ * \fn int WriteUTF8(Uint8 *str, Uint32 Val)
+ * \brief Write a UTF-8 character sequence to a string
+ */
+int WriteUTF8(Uint8 *str, Uint32 Val)
+{
+	// ASCII
+	if( Val < 128 ) {
+		*str = Val;
+		return 1;
+	}
+	
+	// Two Byte
+	if( Val < 0x8000 ) {
+		*str = 0xC0 | (Val >> 6);
+		str ++;
+		*str = 0x80 | (Val & 0x3F);
+		return 2;
+	}
+	
+	// Three Byte
+	if( Val < 0x10000 ) {
+		*str = 0xE0 | (Val >> 12);
+		str ++;
+		*str = 0x80 | ((Val >> 6) & 0x3F);
+		str ++;
+		*str = 0x80 | (Val & 0x3F);
+		return 3;
+	}
+	
+	// Four Byte
+	if( Val < 0x110000 ) {
+		*str = 0xF0 | (Val >> 18);
+		str ++;
+		*str = 0x80 | ((Val >> 12) & 0x3F);
+		str ++;
+		*str = 0x80 | ((Val >> 6) & 0x3F);
+		str ++;
+		*str = 0x80 | (Val & 0x3F);
+		return 4;
+	}
+	
+	// UTF-8 Doesn't support more than four bytes
+	return 0;
+}
+
 /**
  * \fn Uint64 timestamp(int sec, int mins, int hrs, int day, int month, int year)
  * \brief Converts a date into an Acess Timestamp
@@ -247,5 +296,25 @@ Sint64 timestamp(int sec, int mins, int hrs, int day, int month, int year)
 	return stamp * 1000;
 }
 
+/**
+ * \fn Uint rand()
+ * \brief Pseudo random number generator
+ * \note Unknown effectiveness (made up on the spot)
+ */
+Uint rand()
+{
+	#if 0
+	static Uint	randomState = RANDOM_SEED;
+	Uint	ret = randomState;
+	 int	roll = randomState & 31;
+	randomState = (randomState << roll) | (randomState >> (32-roll));
+	randomState ^= 0x9A3C5E78;
+	return ret;
+	#else
+	static Uint	randomState = RANDOM_SEED;
+	return randomState = (RANDOM_A*randomState + RANDOM_C) & 0xFFFFFFFF;
+	#endif
+}
+
 EXPORT(timestamp);
 EXPORT(ReadUTF8);