1 files changed, 126 insertions, 0 deletions
diff --git a/shlab-handout/util.h b/shlab-handout/util.h
new file mode 100644
index 0000000..26dab12
--- /dev/null
+++ b/shlab-handout/util.h
@@ -0,0 +1,126 @@
+#pragma once
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <ctype.h>
+#include <signal.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <errno.h>
+#include <iostream>
+#include <vector>
+#include <string>
+
+#define LOG !(ov4::GLOBAL_DEBUG && ov4::DEBUG) ? (void)0 : ov4::LogVoidify() & std::clog
+
+namespace ov4 {
+
+void atomic_print(char*, bool);
+void atomic_print(int x);
+void atomic_debug(char*, bool);
+void atomic_debug(int);
+bool isnum(char*);
+void reverse(char[], int);
+char *itoa(int, char*, int);
+
+constexpr bool GLOBAL_DEBUG = true;
+bool DEBUG = false; // verbose mode, can be enabled on demand using something like -v
+struct LogVoidify { void operator&(std::ostream&) const {} };
+
+const int DECIMAL = 10;
+const int LENGTH = 25;
+
+void atomic_print(char *s, bool ignore_wrap = false)
+{
+    if (ignore_wrap)
+        for (int i = 0; s[i] != 0; i++)
+            if (s[i] == '\n')
+            {
+                write(STDOUT_FILENO, s, i);
+                return;
+            }
+    write(STDOUT_FILENO, s, strlen(s));
+}
+
+void atomic_print(int x)
+{
+    char msg[LENGTH];
+    itoa(x, msg, DECIMAL);
+    atomic_print(msg);
+}
+
+void reverse(char str[], int length)
+{
+    int start = 0;
+    int end = length - 1;
+    while (start < end) {
+        char temp = str[start];
+        str[start] = str[end];
+        str[end] = temp;
+        end--;
+        start++;
+    }
+}
+
+void atomic_debug(char *s, bool ignore_wrap = false)
+{
+    if (DEBUG && GLOBAL_DEBUG) atomic_print(s, ignore_wrap);
+}
+
+void atomic_debug(int x)
+{
+    if (DEBUG && GLOBAL_DEBUG) atomic_print(x);
+}
+
+bool isnum(char *s)
+{
+    for (int i = 0; s[i] != 0; i++)
+        if (!isdigit(s[i]))
+            return false;
+    return true;
+}
+
+
+char *itoa(int num, char* str, int base)
+{
+    int i = 0;
+    bool isNegative = false;
+
+    /* Handle 0 explicitly, otherwise empty string is
+     * printed for 0 */
+    if (num == 0) {
+        str[i++] = '0';
+        str[i] = '\0';
+        return str;
+    }
+
+    // In standard itoa(), negative numbers are handled
+    // only with base 10. Otherwise numbers are
+    // considered unsigned.
+    if (num < 0 && base == 10) {
+        isNegative = true;
+        num = -num;
+    }
+
+    // Process individual digits
+    while (num != 0) {
+        int rem = num % base;
+        str[i++] = (rem > 9) ? (rem - 10) + 'a' : rem + '0';
+        num = num / base;
+    }
+
+    // If number is negative, append '-'
+    if (isNegative)
+        str[i++] = '-';
+
+    str[i] = '\0'; // Append string terminator
+
+    // Reverse the string
+    reverse(str, i);
+
+    return str;
+}
+
+}