Fully implemented stdio.h!

libc/stdio/char.c

@@ -7,7 +7,7 @@ int putchar(int c) { return putc(c, stdout); }
 int getc(FILE* stream) {
     if (!stream) { return EOF; }
 
-    unsigned char ch;
+    unsigned char ch = '\0';
     ssize_t res = read(stream->_file, &ch, 1);
     if (res <= 0) { return EOF; }
 

libc/stdio/file.c

@@ -4,6 +4,10 @@
 #include <string.h>
 #include <fcntl.h>
 
+FILE* stdin;
+FILE* stdout;
+FILE* stderr;
+
 FILE* fopen(const char* path, const char* mode) {
     FILE* fp = (FILE*)malloc(sizeof(FILE));
     if (!fp) { return NULL; }

libc/stdio/printf.c

@@ -2,6 +2,7 @@
 #include <stdarg.h>
 #include <stdlib.h>
 #include <string.h>
+#include <ctype.h>
 
 /* Internal definitions */
 typedef struct {
@@ -11,6 +12,57 @@ typedef struct {
 } printfEnv_t;
 
 /* Helpers */
+// Digit to character
+static char _dtoc(int digit) { return digit < 10 ? '0' + digit : 'a' + (digit - 10); }
+static double _fabs(double x) { return (x < 0.0) ? -x : x; }
+static void _fmtInt(void (*outfn)(char c, void* arg), void* arg, int n, int base, int width, char padc) {
+    char buf[32];
+    int negative = 0;
+    int i = 0;
+
+    if (n < 0 && base == 10) {
+        negative = 1;
+        n = -n;
+    }
+
+    // Convert number, this will be done in reverse
+    do {
+        buf[i++] = _dtoc(n % base);
+        n /= base;
+    } while (n > 0);
+
+    // Padding
+    while (i < width) { buf[i++] = padc; }
+    // Add negative sign
+    if (negative) { buf[i++] = '-'; }
+
+    // Funny arrow
+    while (i --> 0) { outfn(buf[i], arg); }
+}
+
+static void _fmtFloat(void (*outfn)(char c, void* arg), void* arg, double f) {
+    int whole = (int)f;
+    double frac = _fabs(f - whole);
+    int decPlaces = 6;
+
+    // Add negative sign
+    if (f < 0) { outfn('-', arg); }
+
+    // Print whole part
+    _fmtInt(outfn, arg, whole, 10, 0, ' ');
+
+    // Print decimal point
+    outfn('.', arg);
+
+    // Format fractional part
+    for (int i = 0; i < decPlaces; i++) {
+        frac *= 10;
+        int digit = (int)frac;
+        outfn('0' + digit, arg);
+        frac -= digit;
+    }
+}
+
 static void _dynamicPutc(char c, void* arg) {
     printfEnv_t* env = (printfEnv_t*)arg;
     if (!env->buf) { return; }
@@ -40,8 +92,67 @@ static void _staticPutc(char c, void* arg) {
 
 /* Impementation */
 int vpprintf(void (*outfn)(char c, void* arg), void* arg, const char* fmt, va_list va) {
-    // TODO
-    return -1;
+    int i = 0;
+
+    while (fmt[i] != '\0') {
+        if (fmt[i] != '%') { // Just print the character
+            outfn(fmt[i++], arg);
+            continue;
+        }
+
+        i++;    // Consume the %
+        if (fmt[i] == '\0') { // End of string
+            outfn('%', arg);
+            break;
+        }
+
+        
+        // Parse fmt string
+        int width = 0;
+        char pad = ' ';
+
+        // Check for zero pad and parse width
+        if (isdigit(fmt[i])) {
+            if (fmt[i] == '0') { pad = '0'; i++; }
+
+            while (isdigit(fmt[i])) { // Parse width
+                width *= 10;
+                width += fmt[i++] - '0';
+            }
+        }
+
+        // Parse specifier
+        switch (fmt[i]) {
+              case 'c': { // Character
+                char c = va_arg(va, char);
+                outfn(c, arg);
+                break;
+            } case 's': { // String
+                char* s = va_arg(va, char*);
+                while (*s) { outfn(*s++, arg); }
+                break;
+            } case 'd': { // Decimal number
+                int d = va_arg(va, int);
+                _fmtInt(outfn, arg, d, 10, width, pad);
+                break;
+            } case 'x': { // Hex number
+                int x = va_arg(va, int);
+                _fmtInt(outfn, arg, x, 16, width, pad);
+                break;
+            } case 'f': { // Float
+                double f = va_arg(va, double);
+                _fmtFloat(outfn, arg, f);
+                break;
+            } default: {
+                outfn(fmt[i], arg);
+                break;
+            }
+        }
+
+        i++;
+    }
+
+    return i;
 }
 
 int vsnprintf(char* str, size_t size, const char* fmt, va_list va) {