baddc

commit 79ee5e2f5c025da1f2b0c4dad23439514625a519
Author: phoebos <ben@bvnf.space>
Date:   Sun, 30 Jan 2022 21:09:50 +0000

initial: integer operations, little error checking

Diffstat:
A
.gitignore
 | 
1
+
A
Makefile
 | 
13
+++++++++++++
A
baddc.c
 | 
158
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

3 files changed, 172 insertions(+), 0 deletions(-)
diff --git a/.gitignore b/.gitignore
@@ -0,0 +1 @@
+baddc
diff --git a/Makefile b/Makefile
@@ -0,0 +1,13 @@
+.POSIX:
+
+BIN = baddc
+SRCS = baddc.c
+XCFLAGS = -Wall -Wextra -pedantic -g
+
+$(BIN): $(SRCS)
+	$(CC) $(XCFLAGS) -o $(BIN) $(SRCS)
+
+clean:
+	rm -f $(BIN)
+
+.PHONY: clean
diff --git a/baddc.c b/baddc.c
@@ -0,0 +1,158 @@
+#define _XOPEN_SOURCE 700
+#include <ctype.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+#define STACK_LEN 50
+
+int stack[STACK_LEN] = {0};
+int *stackp = stack - 1;
+
+int ibase = 10;
+int obase = 10;
+
+void push(int a) {
+	stackp++;
+	if (stackp - stack >= STACK_LEN) {
+		fprintf(stderr, "stack overflow!\n");
+		stackp--;
+	} else {
+		*stackp = a;
+	}
+}
+
+int pop(void) {
+	if (stackp == stack - 1) {
+		fprintf(stderr, "no value on stack!\n");
+		return 0;
+	}
+	return *stackp--;
+}
+
+int peek(void) {
+	if (stackp == stack - 1) {
+		fprintf(stderr, "no value on stack!\n");
+		return 0;
+	}
+	return *stackp;
+}
+
+void view_stack(void) {
+	for (int *p = stackp; p - stack >= 0; p--)
+		printf("%d\n", *p);
+}
+
+void dup(void) {
+	push(peek());
+}
+
+void clear(void) {
+	stackp = stack - 1;
+}
+
+void add(void) {
+	push(pop() + pop());
+}
+
+void subtract(void) {
+	int a = pop();
+	push(-a + pop());
+}
+
+void multiply(void) {
+	push(pop() * pop());
+}
+
+void divide(void) {
+	int div = pop();
+	push(pop() / div);
+}
+
+void i_base(void) {
+	ibase = pop();
+}
+
+void I_base(void) {
+	printf("%d\n", ibase);
+}
+
+void o_base(void) {
+	obase = pop();
+}
+
+void O_base(void) {
+	printf("%d\n", obase);
+}
+
+
+struct map {
+	char op;
+	void (*f)(void);
+} ops[] = {
+	{ 'f', view_stack },
+	{ 'd', dup },
+	{ 'c', clear },
+	{ '+', add },
+	{ '-', subtract },
+	{ '*', multiply },
+	{ '/', divide },
+	{ 'i', i_base },
+	{ 'I', I_base },
+	{ 'o', o_base },
+	{ 'O', O_base },
+};
+
+#define NUM_OPS ((sizeof(ops)) / (sizeof(*ops)))
+
+int main(void) {
+	char *buf = NULL;
+	size_t buflen = 0;
+	ssize_t n = 0;
+
+	int curnum = 0;
+	int numready = 0;
+	int neg = 1;
+	while ((n = getline(&buf, &buflen, stdin)) != -1) {
+		for (size_t i = 0; i < n - 1; i++) {
+			if (buf[i] == 'q')
+				goto end;
+			if (buf[i] == '_')
+				neg = -1;
+			else if (buf[i] == '.')
+				fprintf(stderr, "no floating point please\n");
+			else if (isdigit(buf[i])) {
+				curnum = (curnum * ibase) + (buf[i] - '0');
+				numready = 1;
+			} else {
+				if (numready) {
+					push(curnum * neg);
+					numready = 0;
+					neg = 1;
+				}
+				curnum = 0;
+				if (isspace(buf[i])) {
+					//fprintf(stderr, "space ");
+					continue;
+				} if (isdigit(buf[i])) {
+					//fprintf(stderr, "push('%d') ", buf[i]);
+					push(buf[i] - '0');
+				} else if (buf[i] == 'p') {
+					//fprintf(stderr, "peek ");
+					printf("%d\n", peek());
+				} else {
+					for (size_t j = 0; j < NUM_OPS; j++) {
+						if (buf[i] == ops[j].op) {
+							//fprintf(stderr, "execute '%c' ", buf[i]);
+							ops[j].f();
+						}
+					}
+				}
+			}
+		}
+	}
+end:
+	free(buf);
+
+	return 0;
+}