X-Git-Url: https://git.ucc.asn.au/?a=blobdiff_plain;f=Kernel%2Flib.c;h=3399d3d85ca7af8fb496117c03f09d7eb4c8e170;hb=ba8c9b788dd5b91dd172d2bbf07ae94e660ffd7d;hp=ee9f24e0f6bba679a0f977661918cd1f73b17b43;hpb=8bc40333b1401d7616b225945fee53d972c2f418;p=tpg%2Facess2.git

diff --git a/Kernel/lib.c b/Kernel/lib.c
index ee9f24e0..3399d3d8 100644
--- a/Kernel/lib.c
+++ b/Kernel/lib.c
@@ -5,6 +5,10 @@
 #include <common.h>
 
 // === CONSTANTS ===
+#define	RANDOM_SEED	0xACE55052
+#define	RANDOM_A	0x00731ADE
+#define	RANDOM_C	12345
+#define	RANDOM_SPRUCE	0xf12b02b
 //                          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
@@ -12,6 +16,9 @@ const short DAYS_BEFORE[] = {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 3
 // === PROTOTYPES ===
  int	ReadUTF8(Uint8 *str, Uint32 *Val);
 
+// === GLOBALS ===
+static Uint	giRandomState = RANDOM_SEED;
+
 // === CODE ===
 static const char cUCDIGITS[] = "0123456789ABCDEF";
 /**
@@ -134,11 +141,24 @@ int strcmp(char *str1, char *str2)
  */
 int strncmp(char *Str1, char *Str2, size_t num)
 {
-	while(num-- && *Str1 && *Str1 == *Str2)
+	if(num == 0)	return 0;	// TODO: Check what should officially happen here
+	while(--num && *Str1 && *Str1 == *Str2)
 		Str1++, Str2++;
 	return *Str1-*Str2;
 }
 
+/**
+ * \fn char *strdup(char *str)
+ * \brief Duplicates a string
+ */
+char *strdup(char *str)
+{
+	char	*ret;
+	ret = malloc(strlen(str)+1);
+	strcpy(ret, str);
+	return ret;
+}
+
 /**
  * \fn int strpos8(char *str, Uint32 search)
  * \brief Search a string for a UTF-8 character
@@ -168,6 +188,8 @@ 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 +198,6 @@ int ReadUTF8(Uint8 *str, Uint32 *Val)
 	
 	// Middle of a sequence
 	if( (*str & 0xC0) == 0x80 ) {
-		*Val = -1;
 		return 1;
 	}
 	
@@ -217,10 +238,55 @@ 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 +313,20 @@ 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()
+{
+	Uint	old = giRandomState;
+	// Get the next state value
+	giRandomState = (RANDOM_A*giRandomState + RANDOM_C) & 0xFFFFFFFF;
+	// Check if it has changed, and if it hasn't, change it
+	if(giRandomState == old)	giRandomState += RANDOM_SPRUCE;
+	return giRandomState;
+}
+
 EXPORT(timestamp);
 EXPORT(ReadUTF8);