build system refresh

rlibc/src/stdio.c

@@ -0,0 +1,122 @@
+#include <stdio.h>
+#include <unistd.h>
+
+static void utoa(unsigned int value, char *buf, int base) {
+    char temp[32];
+    int i = 0;
+
+    // Handle zero explicitly
+    if (value == 0) {
+        buf[0] = '0';
+        buf[1] = '\0';
+        return;
+    }
+
+    // Convert digits in reverse order
+    while (value > 0) {
+        int remainder = value % base;
+        if (remainder < 10) {
+            temp[i++] = '0' + remainder;
+        } else {
+            temp[i++] = 'a' + (remainder - 10);
+        }
+        value /= base;
+    }
+
+    // Reverse the string into the output destination buffer
+    int j = 0;
+    while (i > 0) {
+        buf[j++] = temp[--i];
+    }
+    buf[j] = '\0';
+}
+
+/* Helper function to convert a signed integer to a string */
+static void itoa(int value, char *buf, int base) {
+    if (value < 0 && base == 10) {
+        *buf++ = '-';
+        value = -value;
+    }
+    utoa((unsigned int)value, buf, base);
+}
+
+int printf(const char *format, ...) {
+    va_list args;
+    va_start(args, format);
+
+    int written_total = 0;
+    char num_buf[32]; // Stack-allocated scratchpad for string conversions
+
+    while (*format != '\0') {
+        if (*format == '%') {
+            format++; // Move past '%'
+            
+            switch (*format) {
+                case 'c': {
+                    char c = (char)va_arg(args, int);
+                    write(1, &c, 1);
+                    written_total++;
+                    break;
+                }
+                case 's': {
+                    char *s = va_arg(args, char *);
+                    if (!s) s = "(null)";
+                    // Find length manually without dragging headers
+                    int len = 0;
+                    while (s[len] != '\0') len++;
+                    write(1, s, len);
+                    written_total += len;
+                    break;
+                }
+                case 'd':
+                case 'i': {
+                    int n = va_arg(args, int);
+                    itoa(n, num_buf, 10);
+                    int len = 0;
+                    while (num_buf[len] != '\0') len++;
+                    write(1, num_buf, len);
+                    written_total += len;
+                    break;
+                }
+                case 'x': {
+                    unsigned int x = va_arg(args, unsigned int);
+                    utoa(x, num_buf, 16);
+                    int len = 0;
+                    while (num_buf[len] != '\0') len++;
+                    write(1, num_buf, len);
+                    written_total += len;
+                    break;
+                }
+                case '%': {
+                    write(1, "%", 1);
+                    written_total++;
+                    break;
+                }
+                default:
+                    // Unknown conversion, print verbatim
+                    write(1, format - 1, 2);
+                    written_total += 2;
+                    break;
+            }
+        } else {
+            // Standard text character
+            write(1, format, 1);
+            written_total++;
+        }
+        format++;
+    }
+
+    va_end(args);
+    return written_total;
+}
+
+char getchar(void) {
+    char c;
+    int res = read(0, &c, 1);
+    
+    if (res <= 0) {
+        return -1;
+    }
+
+    return (char)c;
+}