pop/push/inspect_stack

3 files changed, 48 insertions, 0 deletions

diff --git a/main.c b/main.c
index ca14497..ffb4516 100644
--- a/main.c
+++ b/main.c
@@ -8,12 +8,19 @@ int main(int argc, char **argv)
 	(void)argc, (void)argv;
 	/* Initialize sloth. */
 	Sloth *const sloth = calloc(1, sizeof(Sloth));
+	SlothError err;
 	if (sloth == NULL)
 		return 1;
 	/* Read stdin line by line until exhaustion. */
 	char *line = NULL;
 	while ((line = getln(stdin)) != NULL) {
 		printf("%s", line);
+		err = sloth_push(sloth, line[0]);
+		if (err != NULL) {
+			fprintf(stderr, "%s\n", err);
+			break;
+		}
+		sloth_inspect_stack(sloth);
 		free(line);
 	}
 	/* Free everything. */
diff --git a/sloth.c b/sloth.c
index 99222a9..7f76017 100644
--- a/sloth.c
+++ b/sloth.c
@@ -1,4 +1,5 @@
 #include "sloth.h"
+#include <stdio.h>
 #include <stdlib.h>
 
 void sloth_deinit(Sloth *ctx)
@@ -8,3 +9,39 @@ void sloth_deinit(Sloth *ctx)
 		ctx->stack = NULL;
 	}
 }
+
+SlothError sloth_pop(Sloth *ctx, SlothByte *v)
+{
+	if (ctx->stack_size == 0)
+		return "sloth_pull: stack is empty";
+	*v = ctx->stack[ctx->stack_size - 1];
+	ctx->stack_size -= 1;
+	return NULL;
+}
+
+SlothError sloth_push(Sloth *ctx, SlothByte v)
+{
+	if (ctx->stack == NULL) {
+		ctx->stack = malloc(sizeof(SlothByte) * 16);
+		if (ctx->stack == NULL)
+			return "sloth_push: calloc failed";
+		ctx->stack_capacity = 16;
+	} else if (ctx->stack_size == ctx->stack_capacity) {
+		SlothByte *const new_stack =
+			realloc(ctx->stack, ctx->stack_capacity * 2);
+		if (new_stack == NULL)
+			return "sloth_push: realloc failed";
+		ctx->stack_capacity *= 2;
+	}
+	ctx->stack[ctx->stack_size] = v;
+	ctx->stack_size += 1;
+	return NULL;
+}
+
+void sloth_inspect_stack(const Sloth *ctx)
+{
+	printf("size:     %lu\n", ctx->stack_size);
+	printf("capacity: %lu\n", ctx->stack_capacity);
+	for (size_t i = 0; i < ctx->stack_size; i++)
+		printf("%08lx: %d\n", i, ctx->stack[i]);
+}
diff --git a/sloth.h b/sloth.h
index 9b30e93..af6a7c1 100644
--- a/sloth.h
+++ b/sloth.h
@@ -6,6 +6,7 @@
 #define SLOTH_BITS 16
 typedef uint16_t SlothByte;
 
+typedef const char* SlothError;
 typedef struct Sloth {
 	SlothByte *stack;
 	size_t stack_size;
@@ -14,3 +15,6 @@ typedef struct Sloth {
 } Sloth;
 
 void sloth_deinit(Sloth *ctx);
+SlothError sloth_pop(Sloth *ctx, SlothByte *v);
+SlothError sloth_push(Sloth *ctx, SlothByte v);
+void sloth_inspect_stack(const Sloth *ctx);