Various Changes

[tpg/acess2.git] / Kernel / lib.c

diff --git a/Kernel/lib.c b/Kernel/lib.c
index ee9f24e..d3fff54 100644 (file)
--- 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";
 /**
@@ -63,7 +70,7 @@ int tolower(int c)
  * \fn int strucmp(char *Str1, char *Str2)
  * \brief Compare \a Str1 and \a Str2 case-insensitively
  */
-int strucmp(char *Str1, char *Str2)
+int strucmp(const char *Str1, const char *Str2)
 {
        while(*Str1 && tolower(*Str1) == tolower(*Str2))
                Str1++, Str2++;
@@ -74,7 +81,7 @@ int strucmp(char *Str1, char *Str2)
  * \fn int strpos(char *Str, char Ch)
  * \brief Search a string for an ascii character
  */
-int strpos(char *Str, char Ch)
+int strpos(const char *Str, char Ch)
 {
         int    pos;
        for(pos=0;Str[pos];pos++)
@@ -97,7 +104,7 @@ int ByteSum(void *Ptr, int Size)
  * \fn Uint strlen(char *__str)
  * \brief Get the length of string
  */
-Uint strlen(char *__str)
+Uint strlen(const char *__str)
 {
        Uint    ret = 0;
        while(*__str++) ret++;
@@ -108,7 +115,7 @@ Uint strlen(char *__str)
  * \fn char *strcpy(char *__str1, char *__str2)
  * \brief Copy a string to a new location
  */
-char *strcpy(char *__str1, char *__str2)
+char *strcpy(char *__str1, const char *__str2)
 {
        while(*__str2)
                *__str1++ = *__str2++;
@@ -121,7 +128,7 @@ char *strcpy(char *__str1, char *__str2)
  * \brief Compare two strings return the difference between
  *        the first non-matching characters.
  */
-int strcmp(char *str1, char *str2)
+int strcmp(const char *str1, const char *str2)
 {
        while(*str1 && *str1 == *str2)
                str1++, str2++;
@@ -132,18 +139,42 @@ int strcmp(char *str1, char *str2)
  * \fn int strncmp(char *Str1, char *Str2, size_t num)
  * \brief Compare strings \a Str1 and \a Str2 to a maximum of \a num characters
  */
-int strncmp(char *Str1, char *Str2, size_t num)
+int strncmp(const char *Str1, const 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(const char *str)
+{
+       char    *ret;
+       ret = malloc(strlen(str)+1);
+       strcpy(ret, str);
+       return ret;
+}
+
+/**
+ * \fn int DivUp(int num, int dem)
+ * \brief Divide two numbers, rounding up
+ * \param num  Numerator
+ * \param dem  Denominator
+ */
+int DivUp(int num, int dem)
+{
+       return (num+dem-1)/dem;
+}
+
 /**
  * \fn int strpos8(char *str, Uint32 search)
  * \brief Search a string for a UTF-8 character
  */
-int strpos8(char *str, Uint32 Search)
+int strpos8(const char *str, Uint32 Search)
 {
         int    pos;
        Uint32  val = 0;
@@ -168,6 +199,8 @@ 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 +209,6 @@ int ReadUTF8(Uint8 *str, Uint32 *Val)
        
        // Middle of a sequence
        if( (*str & 0xC0) == 0x80 ) {
-               *Val = -1;
                return 1;
        }
        
@@ -217,10 +249,55 @@ 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 +324,20 @@ 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);