7.3: initial commit, no printf was abused in the process

fractional number support is not complete, but most things
should work.

4 files changed, 187 insertions, 0 deletions

diff --git a/7.3/Makefile b/7.3/Makefile
new file mode 100644
index 0000000..434eecd
--- /dev/null
+++ b/7.3/Makefile
@@ -0,0 +1,12 @@
+objects = main.o mprintf.o
+CC = gcc
+CFLAGS = -Wvla -Wall -Wextra -Wstrict-prototypes -Wmissing-prototypes -fsanitize=address
+
+print : $(objects)
+	$(CC) $(CFLAGS) -o print $(objects) -lm
+
+main.o : mprintf.h
+
+.PHONY : clean
+clean :
+	rm print $(objects)
diff --git a/7.3/main.c b/7.3/main.c
new file mode 100644
index 0000000..3b58a5c
--- /dev/null
+++ b/7.3/main.c
@@ -0,0 +1,9 @@
+#include "mprintf.h"
+
+int main(void)
+{
+	char p = 'c';
+	mprintf("%-10s-%3d-%.1f-%x-%p-%o\n", "sneed", 44, 2.4, 0xa7, &p, 023);
+
+	return 0;
+}
diff --git a/7.3/mprintf.c b/7.3/mprintf.c
new file mode 100644
index 0000000..740f395
--- /dev/null
+++ b/7.3/mprintf.c
@@ -0,0 +1,165 @@
+#include <stdio.h>
+#include <string.h>
+#include <math.h>
+#include <stdarg.h>
+#include <ctype.h>
+#include "mprintf.h"
+
+#define DEFPRES 6
+enum base { OCT = 8, DEC = 10, HEX = 16 };
+
+struct flags {
+	unsigned int fw;
+	unsigned int pres;
+	unsigned int fwc;
+	unsigned int laligne : 1;
+} flags;
+
+void printnum(long long num, struct flags flags, int base);
+void printflt(double num, struct flags flags);
+void printstr(char *s, struct flags flags);
+int reverse(long long *num, int base);
+
+void mprintf(char *fmt, ...)
+{
+	va_list ap;
+	char *p;
+	int dlim;
+
+	va_start(ap, fmt);
+	for (p = fmt; *p; ++p) {
+		if (*p != '%') {
+			putchar(*p);
+			continue;
+		}
+
+		flags.fwc = ' ';
+		flags.fw = dlim = flags.pres = 0;
+		while (!isalpha(*++p) && *p != '\0') {
+			if (isalnum(*p) && !dlim)
+				flags.fw = flags.fw * 10 + *p - '0';
+			else if (isalnum(*p) && dlim)
+				flags.pres = flags.pres * 10 + *p - '0';
+			else if (*p == '.')
+				dlim = 1;
+			else if (*p == '-')
+				flags.laligne = 1;
+		}
+		if (!dlim)
+			flags.pres = DEFPRES;
+
+		switch (*p) {
+		case 'd':
+		case 'i':
+			printnum(va_arg(ap, int), flags, DEC);
+			break;
+		case 'o':
+			printnum(va_arg(ap, int), flags, DEC);
+			break;
+		case 'u':
+			printnum(va_arg(ap, unsigned), flags, DEC);
+			break;
+		case 'x':
+			printnum(va_arg(ap, unsigned), flags, HEX);
+			break;
+		case 'c':
+			putchar(va_arg(ap, unsigned));
+			break;
+		case 'p':
+			mprintf("0x");
+			printnum(va_arg(ap, long long), flags, HEX);
+			break;
+		case 'f':
+			printflt(va_arg(ap, double), flags);
+			break;
+		case 's':
+			printstr(va_arg(ap, char *), flags);
+			break;
+		default:
+			putchar(*p);
+			break;
+		}
+	}
+	va_end(ap);
+
+	return;
+}
+
+void printstr(char *s, struct flags flags)
+{
+	int blank; 
+
+	blank = flags.fw - strlen(s);
+	for (; blank > 0 && !flags.laligne; --blank)
+		putchar(flags.fwc);
+
+	for (; *s; ++s)
+		putchar(*s);
+
+	for (; blank > 0 && flags.laligne; --blank)
+		putchar(flags.fwc);
+}
+void printnum(long long num, struct flags flags, int base)
+{
+	int temp, blank;
+
+	if (num < 0) {
+		putchar('-');
+		num *= -1;
+	}
+
+	blank = flags.fw - reverse(&num, base);
+	for (; blank > 0 && !flags.laligne; --blank)
+		putchar(flags.fwc);
+
+	for (; num; num /= base) {
+		switch (temp = num % base) {
+		case 10:
+			putchar('a');
+			break;
+		case 11:
+			putchar('b');
+			break;
+		case 12:
+			putchar('c');
+			break;
+		case 13:
+			putchar('d');
+			break;
+		case 14:
+			putchar('e');
+			break;
+		case 15:
+			putchar('f');
+			break;
+		default:
+			putchar(temp + '0');
+			break;
+		}
+	}
+
+	for (; blank > 0 && flags.laligne; --blank)
+		putchar(flags.fwc);
+}
+
+void printflt(double num, struct flags flags)
+{
+	printnum((int) num, flags, DEC);
+	if (flags.pres) {
+		flags.fwc = '0';
+		putchar('.');
+		printnum((long long) ((num - (int) num) *
+	                 powl(10, flags.pres)), flags, DEC);
+	}
+}
+
+int reverse(long long *num, int base)
+{
+	long long temp = *num;
+	int len;
+
+	for (*num = len = 0; temp; temp /= base, ++len)
+		*num = *num * base + temp % base;
+
+	return len;
+}
diff --git a/7.3/mprintf.h b/7.3/mprintf.h
new file mode 100644
index 0000000..a53d2b9
--- /dev/null
+++ b/7.3/mprintf.h
@@ -0,0 +1 @@
+void mprintf(char *fmt, ...);