Added rand.h implementation

Supported types for now:
- Numbers: Int, Long, Long Long, Double
- Chars: Char, Lower, Upper, Alpha, Digit
- String

templates/resolver.go

@@ -3,8 +3,9 @@ package templates
 import (
 	"errors"
 	"fmt"
-	"github.com/chermehdi/egor/config"
 	"io/ioutil"
+
+	"github.com/chermehdi/egor/config"
 )
 
 const BruteH = `
@@ -22,10 +23,135 @@ int main() {
 // We could consider using some new Go feature to embed it as a static resource.
 // At the time of creation of this, this is not a priority.
 const RandH = `
+#pragma once
+#include <ctime>
+#include <string>
+
+const std::string LOWERCASE_ALPHABET = "abcdefghijklmnopqrstuvwyxz";
+const std::string UPPERCASE_ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWYXZ";
+const std::string DIGITS_SET = "0123456789";
+
+// Used to determine the set of allowed characters
+// for the String method of the Rand class
+const int LOWER = 1;
+const int UPPER = 1 << 1;
+const int DIGITS = 1 << 2;
+
+// Returns a random value of the following types
+// int, long long, double, char, string
+// given main arguments 
+// Example:
+// Rand rand(argc, argv);
+// int randomInt = rand.Int();
+// string randomString = rand.String(10, DIGITS);
 class Rand {
+  unsigned int seed;
+
+  unsigned int ReadSeedFromArgs(int argc, char * argv[]) {
+    if (argc > 0) {
+      return std::stoi(argv[1]);
+    }
+    return 0;
+  }
+
 public:
-	Rand(int argc, char** argv) {
-	}
+
+  Rand(unsigned int _seed = 0) : seed(_seed) {
+    srand(seed);
+  }
+
+  Rand(int argc, char * argv[]) {
+    unsigned int seed = ReadSeedFromArgs(argc, argv);
+    Rand{ seed };
+  }
+
+  // Returns an random int value in the range [from, to] inclusive
+  int Int(int from, int to) {
+    return rand() % (to - from) + from;
+  }
+
+  // Returns an random long long value in the range [from, to] inclusive
+  long long Long(long long from, long long to) {
+    return rand() % (to - from) + from;
+  }
+
+  // Returns an random double value in the range [from, to] inclusive
+  double Double(double from, double to) {
+    double tmp = (double)rand() / RAND_MAX;
+    return from + tmp * (to - from);
+  }
+
+  // Returns an random char value in the range [from, to] inclusive
+  // Parameters are optional
+  char Char(char from = CHAR_MIN, char to = CHAR_MAX) {
+    return static_cast <char> (Int(from, to));
+  }
+
+  // Returns an random char value in the range [from, to] inclusive
+  // Parameters are optional, by default returns a random lowercase letter
+  char Lower(char from = 'a', char to = 'z') {
+    return Char(from, to);
+  }
+
+  // Returns an random char value in the range [from, to] inclusive
+  // Parameters are optional, by default returns a random uppercase letter
+  char Upper(char from = 'A', char to = 'Z') {
+    return Char(from, to);
+  }
+
+  // Returns an random letter either in lowercase or uppercase
+  char Alpha() {
+    int k = rand() % 52;
+    if (k < 26) return Lower('a', 'a' + k);
+    return Upper('a', 'a' + k % 26);
+  }
+
+  // Returns an random digit character
+  // Parameters are optional, by default returns a random digit character in the range ['0', '9'] inclusive
+  char Digit(char from = '0', char to = '9') {
+    return Char(from, to);
+  }
+
+  // Returns a random alphanumerical character
+  char AlphaNum() {
+    if (rand() & 1) return Alpha();
+    return Digit();
+  }
+
+
+  // Returns an std::string of length size consisting only of characters allowed in the given mask
+  // using the constants LOWER, UPPER, DIGITS
+  // Example:
+  // Rand rand(argc, argv);
+  // std::string str = rand.String(10, LOWER | DIGITS); 
+  // str is an std::string of size 10 consisting only of lowercase letters and digits
+  std::string String(size_t size, const int mask = LOWER | UPPER) {
+    std::string charset;
+
+    // Building the set of allowed charset from the mask
+    if (mask & LOWER) {
+      charset += LOWERCASE_ALPHABET;
+    }
+    if (mask & UPPER) {
+      charset += UPPERCASE_ALPHABET;
+    }
+    if (mask & DIGITS) {
+      charset += DIGITS_SET;
+    }
+
+    std::random_shuffle(charset.begin(), charset.end());
+
+    std::string res(size, ' ');
+
+    int len = charset.size();
+    
+    for (char& c : res) {
+      size_t randomIndex = Int(0, len - 1);
+      c = charset[randomIndex];
+    }
+
+    return res;
+  }
 };
 `