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decoder.c

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+#include <stdio.h>
+#include <stdlib.h>
+
+#include "strings.h"
+
+const char *base32LUT = "S7LCX3JZE8FG4HBKWN52YPA6RTU9VMDQ";
+
+unsigned char decodeBase32Character(char c)
+{
+    /* Look for the character in the custom base32 table */
+    for (unsigned char i = 0; i < 32; i++)
+    {
+        if (c == base32LUT[i])
+            return i;
+    }
+
+    return -1; // Shouldn't ever happen
+}
+
+void decodeCodeString(const char *inStr, unsigned char *outCode)
+{
+    unsigned char filteredCode[16];
+    unsigned char *fp = filteredCode;
+
+    for (;;)
+    {
+        char ch = *inStr;
+
+        if (!ch || fp - filteredCode > sizeof(filteredCode))
+            break;
+
+        /* Allowed characters */
+        if ((ch >= '2' && ch <= '9') || 
+            (ch >= 'A' && ch <= 'H') ||
+            (ch >= 'J' && ch <= 'N') ||
+            (ch >= 'P' && ch <= 'Z'))
+        {
+            *fp++ = decodeBase32Character(ch);
+        }
+
+        inStr++;
+    }
+
+    /* Extremely crude base32 decoding */
+    outCode[0] = filteredCode[0]  << 3 | filteredCode[1]  >> 2;
+    outCode[1] = filteredCode[1]  << 6 | filteredCode[2]  << 1 | filteredCode[3]  >> 4;
+    outCode[2] = filteredCode[3]  << 4 | filteredCode[4]  >> 1;
+    outCode[3] = filteredCode[4]  << 7 | filteredCode[5]  << 2 | filteredCode[6]  >> 3;
+    outCode[4] = filteredCode[6]  << 5 | filteredCode[7];
+    outCode[5] = filteredCode[8]  << 3 | filteredCode[9]  >> 2;
+    outCode[6] = filteredCode[9]  << 6 | filteredCode[10] << 1 | filteredCode[11] >> 4;
+    outCode[7] = filteredCode[11] << 4 | filteredCode[12] >> 1;
+    outCode[8] = filteredCode[12] << 7 | filteredCode[13] << 2 | filteredCode[14] >> 3;
+    outCode[9] = filteredCode[14] << 5 | filteredCode[15];
+}
+
+void decryptCode(unsigned char *code)
+{
+    /* XOR "crypto" */ 
+    for (int i = 1; i < 10; i++)
+        code[i - 1] ^= code[i];
+
+    code[9] ^= 0xC3;
+}
+
+unsigned short calcChecksum(unsigned char *data, int len)
+{
+    unsigned short sum = 0;
+
+    /* Appears to just be a standard CRC16 algorithm */
+    for (int i = 0; i < len; i++)
+    {
+        unsigned char ch = *data++;
+
+        for (int j = 0; j < 8; j++)
+        {
+            if (sum & 0x8000)
+                sum = (sum << 1) ^ 0x1021;
+            else
+                sum <<= 1;
+
+            if (ch & 0x80)
+                sum ^= 1;
+
+            ch <<= 1;
+        }            
+    }
+
+    return sum;
+}
+
+int main()
+{
+    char buf[32];
+    unsigned char outcode[10];
+    unsigned short checksum, calcsum;
+    unsigned int stats, time, course, kartch;
+
+    printf("Enter code: ");
+    gets(buf);
+    puts("");
+
+    decodeCodeString(buf, outcode);
+    decryptCode(outcode);
+
+    checksum   = outcode[8] << 8 | outcode[9];
+    outcode[8] = outcode[9] = 0;    
+    calcsum    = calcChecksum(outcode, 10);
+    stats      = *(unsigned int *)outcode;
+
+    time   = stats >> 14;
+    course = (stats >> 9) % 32;
+    kartch = stats % 0x200;
+
+    printf("Time:      %d:%02d:%03d\n",
+        time / 60000, (time / 1000) % 60, time % 1000);
+    printf("Course:    %s\n", courseNames[course]);
+    printf("Character: %s\n", characterNames[kartch / 37]);
+    printf("Kart:      %s\n", kartNames[kartch % 37]);
+    wprintf(L"Player:    %c%c\n",
+        *(unsigned short *)&outcode[4], *(unsigned short *)&outcode[6]);
+    printf("Valid?     %s\n", checksum == calcsum ? "Yes" : "No");
+
+    puts("\nPress any key to exit.");
+    getche();
+
+    return 0;
+}

strings.h

@@ -0,0 +1,93 @@
+const char *courseNames[] =
+{
+    "Figure-8 Circuit",
+    "Yoshi Falls",
+    "Cheep Cheep Beach",
+    "Luigi's Mansion",
+    "Desert Hills",
+    "Delfino Square",
+    "Waluigi Pinball",
+    "Shroom Ridge",
+    "DK Pass",
+    "Tick-Tock Clock",
+    "Mario Circuit",
+    "Airship Fortress",
+    "Wario Stadium",
+    "Peach Gardens",
+    "Bowser Castle",
+    "Rainbow Road",
+    "SNES Mario Circuit 1",
+    "N64 Moo Moo Farm",
+    "GBA Peach Circuit",
+    "GCN Luigi Circuit",
+    "SNES Donut Plains 1",
+    "N64 Frappe Snowland",
+    "GBA Bowser Castle 2",
+    "GCN Baby Park",
+    "SNES Koopa Beach 2",
+    "N64 Choco Mountain",
+    "GBA Luigi Circuit",
+    "GCN Mushroom Bridge",
+    "SNES Choco Island 2",
+    "N64 Banshee Boardwalk",
+    "GBA Sky Garden",
+    "GCN Yoshi Circuit"
+};
+
+const char *characterNames[] =
+{
+    "Mario",
+    "Donkey Kong",
+    "Toad",
+    "Bowser",
+    "Peach",
+    "Wario",
+    "Yoshi",
+    "Luigi",
+    "Dry Bones",
+    "Daisy",
+    "Waluigi",
+    "R.O.B.",
+    "Shy Guy"
+};
+
+const char *kartNames[] =
+{
+    "Standard MR",
+    "Shooting Star",
+    "B Dasher",
+    "Standard DK",
+    "Wildlife",
+    "Ranbi Rider",
+    "Standard TD",
+    "Mushmellow",
+    "4-Wheel Cradle",
+    "Standard BW",
+    "Hurricane",
+    "Tyrant",
+    "Standard PC",
+    "Light Tripper",
+    "Royale",
+    "Standard WR",
+    "Brute",
+    "Dragonfly",
+    "Standard YS",
+    "Egg 1",
+    "Cucumber",
+    "Standard LG",
+    "Poltergust 4000",
+    "Streamliner",
+    "Standard DB",
+    "Dry Bomber",
+    "Banisher",
+    "Standard DS",
+    "Light Dancer",
+    "Power Flower",
+    "Standard WL",
+    "Gold Mantis",
+    "Zipper",
+    "Standard RB",
+    "ROB-BLS",
+    "ROB-LGS",
+    "Standard SG"
+};