Finish Chapter 14

Implements code chunks, a couple of basic opcodes, constants, and
basic execution of those opcodes.

Signed-off-by: Daniel Henry <iamdanhenry@gmail.com>

src/chunk.c

@@ -0,0 +1,37 @@
+#include "chunk.h"
+#include "memory.h"
+#include <stdlib.h>
+
+void initChunk(Chunk *chunk) {
+  chunk->count = 0;
+  chunk->capacity = 0;
+  chunk->code = NULL;
+  chunk->lines = NULL;
+  initValueArray(&chunk->constants);
+}
+
+void freeChunk(Chunk *chunk) {
+  FREE_ARRAY(uint8_t, chunk->code, chunk->capacity);
+  FREE_ARRAY(int, chunk->lines, chunk->capacity);
+  freeValueArray(&chunk->constants);
+  initChunk(chunk);
+}
+
+void writeChunk(Chunk *chunk, uint8_t byte, int line) {
+  if (chunk->capacity < chunk->count + 1) {
+    int oldCapacity = chunk->capacity;
+    chunk->capacity = GROW_CAPACITY(oldCapacity);
+    chunk->code =
+        GROW_ARRAY(uint8_t, chunk->code, oldCapacity, chunk->capacity);
+    chunk->lines = GROW_ARRAY(int, chunk->lines, oldCapacity, chunk->capacity);
+  }
+
+  chunk->code[chunk->count] = byte;
+  chunk->lines[chunk->count] = line;
+  chunk->count++;
+}
+
+int addConstant(Chunk *chunk, Value value) {
+  writeValueArray(&chunk->constants, value);
+  return chunk->constants.count - 1;
+}