update CMakeLists to correctly compile sources - update readme to reflect that

factor out reused functions to shared.cpp/shared.h

shared.cpp

@@ -0,0 +1,103 @@
+//
+// Created by neo on 5/26/2023.
+//
+
+#include "shared.h"
+
+uint8_t cset[] = "BCDFGHJKMPQRTVWXY2346789";
+
+// Reverse data
+void endian(uint8_t *data, int len)
+{
+    int i;
+    for (i = 0; i < len/2; i++) {
+        uint8_t temp;
+        temp = data[i];
+        data[i] = data[len-i-1];
+        data[len-i-1] = temp;
+    }
+}
+
+void unbase24(uint32_t *x, uint8_t *c)
+{
+
+    memset(x, 0, 16);
+    int i, n;
+
+    BIGNUM *y = BN_new();
+    BN_zero(y);
+
+    for (i = 0; i < 25; i++)
+    {
+        BN_mul_word(y, 24);
+        BN_add_word(y, c[i]);
+    }
+    n = BN_num_bytes(y);
+    BN_bn2bin(y, (uint8_t *)x);
+    BN_free(y);
+
+    endian((uint8_t *)x, n);
+}
+
+void base24(uint8_t *c, uint32_t *x)
+{
+    uint8_t y[16];
+    int i;
+    BIGNUM *z;
+
+    // Convert x to BigNum z
+    memcpy(y, x, sizeof(y));				// Copy X to Y; Y=X
+    for (i = 15; y[i] == 0; i--) {} i++;	// skip following nulls
+    endian(y, i);							// Reverse y
+    z = BN_bin2bn(y, i, NULL);				// Convert y to BigNum z
+
+
+    // Divide z by 24 and convert remainder with cset to Base24-CDKEY Char
+    c[25] = 0;
+    for (i = 24; i >= 0; i--) {
+        uint8_t t = BN_div_word(z, 24);
+        c[i] = cset[t];
+    }
+
+    BN_free(z);
+}
+
+void print_product_id(uint32_t *pid)
+{
+    char raw[12];
+    char b[6], c[8];
+    int i, digit = 0;
+
+    //	Cut a away last bit of pid and convert it to an accii-number (=raw)
+    sprintf(raw, "%d", pid[0] >> 1);
+
+    // Make b-part {640-....}
+    strncpy(b, raw, 3);
+    b[3] = 0;
+
+    // Make c-part {...-123456X...}
+    strcpy(c, raw + 3);
+
+    printf("> %s\n", c);
+    // Make checksum digit-part {...56X-}
+    assert(strlen(c) == 6);
+    for (i = 0; i < 6; i++)
+        digit -= c[i] - '0';	// Sum digits
+
+    while (digit < 0)
+        digit += 7;
+    c[6] = digit + '0';
+    c[7] = 0;
+
+    printf("Product ID: 55274-%s-%s-23xxx\n", b, c);
+}
+
+void print_product_key(uint8_t *pk)
+{
+    int i;
+    assert(strlen((const char *)pk) == 25);
+    for (i = 0; i < 25; i++) {
+        putchar(pk[i]);
+        if (i != 24 && i % 5 == 4) putchar('-');
+    }
+}