From e22e022cd8e70ebc7f6b37fa685fcd5c79d78665 Mon Sep 17 00:00:00 2001
From: Sage Vaillancourt <sagev9000@tutanota.com>
Date: Mon, 28 Mar 2022 09:56:24 -0400
Subject: [PATCH] Reference count strings.

---
 src/Makefile   |  2 +-
 src/env.c      |  2 ++
 src/object.c   | 26 ++++++++++++++++++--------
 src/object.h   |  2 ++
 src/pebblisp.c |  4 ++--
 src/plfunc.c   | 17 +++++++----------
 6 files changed, 32 insertions(+), 21 deletions(-)

diff --git a/src/Makefile b/src/Makefile
index 37c64a3..72a2b82 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -32,7 +32,7 @@ run:
 install:
 	cp -pf ./$(exe) $(BINPREFIX)
 	mkdir -p $(SCRIPTDIR)
-	cp ./examples/* $(SCRIPTDIR)
+	cp -r ./examples/* $(SCRIPTDIR)
 
 uninstall:
 	rm $(BINPREFIX)/$(exe)
diff --git a/src/env.c b/src/env.c
index 56366cf..cdb1c45 100644
--- a/src/env.c
+++ b/src/env.c
@@ -363,6 +363,8 @@ int runTests(int detailed)
         printf("");
     }
     printf("%d tests failed!\n", failureCount);
+    // fprintf(stderr, "TOTAL ALLOCATIONS: %d\n", getAllocations());
+    // fprintf(stderr, "TOTAL BYTES: %zu\n", getBytes());
     return failureCount;
 }
 
diff --git a/src/object.c b/src/object.c
index 41ce58a..3a03e4d 100644
--- a/src/object.c
+++ b/src/object.c
@@ -207,7 +207,7 @@ int stringList(char* dest, const Object* obj)
     dest += sprintf(dest, "(");
 
     FOR_POINTER_IN_LIST(obj) {
-        char tok[90] = "";
+        char tok[256] = "";
         stringObj(tok, POINTER);
         dest += sprintf(dest, " %s", tok);
     }
@@ -439,7 +439,9 @@ void cleanObject(Object* target)
     switch (target->type) {
         case TYPE_STRING:
         case TYPE_SYMBOL:
-            free(target->string);
+            if (!(target->string[-1] -= 1)) {
+                free(target->string - 1);
+            }
             break;
         case TYPE_LIST:
         case TYPE_SLIST:
@@ -642,9 +644,7 @@ inline Object cloneLambda(const Object old)
 
 Object cloneString(Object obj)
 {
-    const char* string = obj.string;
-    obj.string = malloc(sizeof(char) * (strlen(string) + 1));
-    strcpy(obj.string, string);
+    obj.string[-1] += 1;
     return obj;
 }
 
@@ -721,9 +721,19 @@ inline Object stringFromSlice(const char* string, int len)
 
 inline Object symFromSlice(const char* string, int len)
 {
-    Object o = newObject(TYPE_SYMBOL);
-    o.string = calloc(sizeof(char), len + 1);
-    strncpy(o.string, string, len);
+    Object o = withLen(len, TYPE_SYMBOL);
+    snprintf(o.string, len + 1, "%s", string);
+    return o;
+}
+
+/// Creates a stringy object with room for a reference-count prefix and trailing null byte.
+/// Thus, withLen(3, TYPE_STRING) will actually allocate a 5-byte "string".
+inline Object withLen(int len, enum Type type)
+{
+    Object o = newObject(type);
+    o.string = malloc(sizeof(char) * (len + 2));
+    o.string[0] = 1;
+    o.string += 1;
     return o;
 }
 
diff --git a/src/object.h b/src/object.h
index 7acfa9c..0d80522 100644
--- a/src/object.h
+++ b/src/object.h
@@ -201,6 +201,8 @@ Object stringFromSlice(const char* string, int len);
 
 Object symFromSlice(const char* string, int len);
 
+Object withLen(int len, enum Type type);
+
 Object boolObject(int b);
 
 Object numberObject(int num);
diff --git a/src/pebblisp.c b/src/pebblisp.c
index 8a4a232..8a7dedc 100644
--- a/src/pebblisp.c
+++ b/src/pebblisp.c
@@ -714,8 +714,8 @@ int main(int argc, const char* argv[])
     }
     deleteEnv(&env);
     shredDictionary();
-    // printf("TOTAL ALLOCATIONS: %d\n", getAllocations());
-    // printf("TOTAL BYTES: %d\n", getBytes());
+    // fprintf(stderr, "TOTAL ALLOCATIONS: %d\n", getAllocations());
+    // fprintf(stderr, "TOTAL BYTES: %zu\n", getBytes());
 }
 
 #endif
diff --git a/src/plfunc.c b/src/plfunc.c
index 68dcceb..4724047 100644
--- a/src/plfunc.c
+++ b/src/plfunc.c
@@ -25,20 +25,18 @@ Object charAt(Object* params, int length, struct Environment* env)
     Object string = params[0];
     Object at = params[1];
 
-    char* c = malloc(sizeof(char) * 2);
-    c[1] = '\0';
+    Object c = withLen(1, string.type);
+    c.string[1] = '\0';
 
     for (int i = 0; i < at.number; i++) {
         if (string.string[i] == '\0') {
-            c[0] = '\0';
-            string.string = c;
-            return string;
+            c.string[0] = '\0';
+            return c;
         }
     }
 
-    c[0] = string.string[at.number];
-    string.string = c;
-    return string;
+    c.string[0] = string.string[at.number];
+    return c;
 }
 
 Object filter(Object* params, int length, struct Environment* env)
@@ -216,8 +214,7 @@ Object _catObjects(Object obj1, Object obj2, struct Environment* env)
     cleanObject(&evalObj1);
     cleanObject(&evalObj2);
 
-    Object o = newObject(TYPE_STRING);
-    o.string = malloc(sizeof(char) * length + 1);
+    Object o = withLen(length, TYPE_STRING);
     sprintf(o.string, "%s%s", str1, str2);
 
     return o;