btcs

commit 51a91bdc10099bfcafe00b6e581ef73e6d6f0fe1
parent 82655221e65fd26595486186bbbb6ae459fb6009
Author: William Casarin <jb55@jb55.com>
Date:   Wed, 25 Oct 2017 11:43:00 -0700

stack: forgot this file

Diffstat:
A
stack.c
 | 
55
+++++++++++++++++++++++++++++++++++++++++++++++++++++++
A
stack.h
 | 
39
+++++++++++++++++++++++++++++++++++++++

2 files changed, 94 insertions(+), 0 deletions(-)
diff --git a/stack.c b/stack.c
@@ -0,0 +1,55 @@
+
+#include "stack.h"
+#include <stdlib.h>
+#include <string.h>
+
+void
+stack_clear(struct stack *stack) {
+  memset(stack->bottom, 0, stack->capacity);
+}
+
+int
+stack_init_size(struct stack *stack, int capacity) {
+  if (capacity > DEFAULT_STACK_SIZE) {
+    u8 *bottom = (u8*)malloc(capacity);
+    if (!bottom) return 0;
+    stack->bottom   = bottom;
+    stack->top      = bottom;
+    stack->capacity = capacity;
+  }
+  else {
+    stack->bottom   = stack->_data;
+    stack->top      = stack->bottom;
+    stack->capacity = DEFAULT_STACK_SIZE;
+  }
+  stack_clear(stack);
+  return 1;
+}
+
+int
+stack_init(struct stack *stack) {
+  return stack_init_size(stack, DEFAULT_STACK_SIZE);
+}
+
+void
+stack_free(struct stack *stack) {
+  if (stack->capacity > DEFAULT_STACK_SIZE)
+    free(stack->bottom);
+  stack->bottom = stack->_data;
+}
+
+
+void
+stack_expand(struct stack *stack) {
+  assert(!"Implement expand");
+}
+
+void
+stack_push(struct stack *stack, u8 byte) {
+  if ((stack_size(stack) + 1) > stack->capacity) {
+    stack_expand(stack);
+  }
+
+  *stack->top++ = byte;
+}
+
diff --git a/stack.h b/stack.h
@@ -0,0 +1,39 @@
+
+#ifndef BTCS_STACK_H
+#define BTCS_STACK_H
+
+#include <assert.h>
+#include "misc.h"
+
+// Maximum number of values on script interpreter stack
+static const int MAX_STACK_SIZE = 1000;
+
+// Maximum number of values on script interpreter stack
+static const int DEFAULT_STACK_SIZE = 64;
+
+struct stack {
+  u8 _data[DEFAULT_STACK_SIZE];
+  u8 * bottom;
+  u8 * top;
+  int capacity;
+};
+
+int  stack_init(struct stack *);
+int  stack_init_size(struct stack *, int size);
+void stack_free(struct stack *);
+void stack_clear(struct stack *);
+void stack_push(struct stack *, u8 val);
+
+static inline u8
+stack_top(struct stack *stack, int ind) {
+  u8 *p = stack->top + ind;
+  assert(p >= stack->bottom);
+  return *p;
+}
+
+static inline int
+stack_size(struct stack *stack) {
+  return stack->top - stack->bottom;
+}
+
+#endif /* BTCS_STACK_H */