From b72c271d8731e1f67fdef29cd64726dfce893fe7 Mon Sep 17 00:00:00 2001
From: dan <me@danrh.co.uk>
Date: Mon, 29 May 2023 13:53:46 -0400
Subject: feat: add .s,roll,pick,and depth commands to c forth

---
 stack.c | 44 ++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 40 insertions(+), 4 deletions(-)

(limited to 'stack.c')

diff --git a/stack.c b/stack.c
index 80b8ed2..617e621 100644
--- a/stack.c
+++ b/stack.c
@@ -1,6 +1,6 @@
 #include "stack.h"
 
-stack* newstack() {
+stack* stack_new() {
     stack* s = (stack*)malloc(sizeof(stack));
     s->size = 0;
     s->maxsize = 1024;
@@ -8,7 +8,7 @@ stack* newstack() {
     return s;
 }
 
-stackitem pop(stack* s) {
+stackitem stack_pop(stack* s) {
     if (s->size > 0) {
         s->size = s->size - 1;
         stackitem si = s->start[s->size];
@@ -19,7 +19,7 @@ stackitem pop(stack* s) {
     }
 }
 
-stackitem peek(stack* s) {
+stackitem stack_peek(stack* s) {
     if (s->size > 0) {
         return s->start[s->size - 1];
     } else {
@@ -28,7 +28,7 @@ stackitem peek(stack* s) {
     }
 }
 
-void push(stack *s, stackitem si) {
+void stack_push(stack *s, stackitem si) {
 //        fprintf(stderr, "pushing %d", si);
     if (s->size >= s->maxsize) {
         fprintf(stderr, "Error Stack Overflow");
@@ -38,3 +38,39 @@ void push(stack *s, stackitem si) {
         s->size = s->size + 1;
     }
 }
+
+int stack_depth(stack *s) {
+    return s->size;
+}
+
+void stack_printall(stack *s) {
+    printf("<%d>", s->size);
+    for (int i = 0; i < s->size; i++) {
+        printf(" %d", s->start[i]);
+    }
+    printf("\n");
+}
+
+void stack_roll(stack *s) {
+    int posfromtop = stack_pop(s); // top is 0, bottom is s->size - 1
+    const int maxindex = s->size - 1;
+    int i = maxindex - posfromtop;
+    if (i >= 0) {
+        int newtop = s->start[i];
+        for (; i + 1 < s->size; i++) {
+            s->start[i] = s->start[i+1];
+        }
+        s->start[i] = newtop;
+    }
+}
+
+void stack_pick(stack *s) {
+    int posfromtop = stack_pop(s); // top is 0, bottom is s->size - 1
+    const int maxindex = s->size - 1;
+    if (s->size > posfromtop) {
+        stack_push(s, s->start[maxindex - posfromtop]);
+    } else {
+        // no item found
+        stack_push(s, 0);
+    }
+}
-- 
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