Begin adding some C code

[fur] / c / rope.c

diff --git a/c/rope.c b/c/rope.c
new file mode 100644 (file)
index 0000000..716a5af
--- /dev/null
+++ b/c/rope.c
@@ -0,0 +1,90 @@
+#ifndef ROPE_C
+#define ROPE_C
+
+#include <assert.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+enum RopeType;
+typedef enum RopeType RopeType;
+enum RopeType {
+  ROPETYPE_CONCATENATION,
+  ROPETYPE_STRING
+};
+
+struct Concatenation;
+typedef struct Concatenation Concatenation;
+struct Concatenation {
+  Rope* r0;
+  Rope* r1;
+};
+
+struct String;
+typedef struct String String;
+struct String {
+  size_t length;
+  uint32_t* characters;
+};
+
+union RopeInstance;
+typedef union RopeInstance RopeInstance;
+union RopeInstance {
+  Concatenation concatenation;
+  String string;
+};
+
+struct Rope {
+  volatile size_t referenceCount;
+  RopeType type;
+  RopeInstance instance;
+};
+
+Rope* Rope_rereference(Rope* self) {
+  __sync_add_and_fetch(&(self->referenceCount), 1);
+  return self;
+}
+
+void Rope_destruct(Rope* self) {
+  size_t referenceCount = __sync_sub_and_fetch(&(self->referenceCount), 1);
+
+  if(referenceCount == 0) {
+    switch(self->type) {
+      case ROPETYPE_CONCATENATION:
+        Rope_destruct(self->instance.concatenation.r0);
+        Rope_destruct(self->instance.concatenation.r1);
+        break;
+
+      case ROPETYPE_STRING:
+        free(self->instance.string.characters);
+        break;
+
+      default:
+        assert(false);
+    }
+
+    free(self);
+  }
+}
+
+void Rope_write(Rope*, Encoding, FILE) {
+  // TODO Implement
+  printf("Not implemented");
+}
+
+Rope* Rope_read(Encoding, FILE) {
+  // TODO Implement
+  printf("Not implemented");
+  return NULL;
+}
+
+Rope* Rope_concatenate(Rope* r0, Rope* r1) {
+  Rope* result = malloc(sizeof(Rope));
+  result->referenceCount = 0;
+  result->type = ROPETYPE_CONCATENATION;
+  result->instance.concatenation.r0 = Rope_rereference(r0);
+  result->instance.concatenation.r1 = Rope_rereference(r1);
+  return result;
+}
+
+#endif