From fbb340d465bc3cc3729deb7c98e0bed2e2f4c90c Mon Sep 17 00:00:00 2001
From: Ivar Fatland <fatland99@hotmail.com>
Date: Tue, 24 Feb 2026 22:42:48 +0100
Subject: [PATCH] WIP hashmap

---
 .clangd   |  2 ++
 cig.h     | 54 +++++++++++++++++++++++++++++++++++++-----------------
 hashmap.c | 28 ++++++++++++++++++++++++++++
 3 files changed, 67 insertions(+), 17 deletions(-)
 create mode 100644 .clangd
 create mode 100644 hashmap.c

diff --git a/.clangd b/.clangd
new file mode 100644
index 0000000..024b5a7
--- /dev/null
+++ b/.clangd
@@ -0,0 +1,2 @@
+CompileFlags:
+  Add: [-xc, -std=c99]
diff --git a/cig.h b/cig.h
index 8972e64..40fb13f 100644
--- a/cig.h
+++ b/cig.h
@@ -162,6 +162,15 @@ void *dyn_array_create_func(dyn_array_create_func_args_t args);
 	.allocator = __VA_ARGS__, \
 }))
 
+#define init_arr(PTR, ...) do { \
+	PTR = dyn_array_create_func((dyn_array_create_func_args_t){ \
+		.itemsize = sizeof(*PTR), \
+		.file = __FILE__, \
+		.line = __LINE__, \
+		.allocator = __VA_ARGS__, \
+	}); \
+} while(0);
+
 // Always reassign the array. if multiple variables reference the same growing
 // array, then you should be using pointer pointers.
 void *dyn_array_grow_func(void *this, size_t n_new_items, const char *file, int line);
@@ -228,39 +237,50 @@ void arr_qsort(void *this, dyn_array_cmp_fn cmp_fn);
 typedef int (*hash_func_t)(void *key);
 typedef int (*equals_func_t)(void *key1, void *key2);
 
+// TODO: after this comes the actual hash map. it maps keys to indexes into the
+// key-value pair array. (which does not actually need values, only a key
+// field.)
+// TODO: This means that when allocating memory for the array of key-value
+// pairs, we actually need to allocate it in terms of the max_align type, and
+// increase in size by using that size as the smallest increment. Which will
+// keep the hash array aligned properly in memory.
+
 typedef struct hashmap_header {
-	size_t n_items, capacity, itemsize, keysize;
+	int n_items, capacity, itemsize, keysize;
 	allocator_t allocator;
-	hash_func_t hash_func;
-	equals_func_t equals_func;
+	hash_func_t hash;
+	equals_func_t equals;
 	union {
 		uint8_t bytes[1];
 		any_align_t _[1];
 	};
-	// TODO: after this comes the actual hash map. it maps keys to indexes into
-	// the key-value pair array. (which does not actually need values, only a
-	// key field.)
+	// The above union is actually a different size. Then comes an array of
+	// integers which is double the size of n_items * sizeof(int). int
+	// indexes[...];
 } hashmap_header_t;
 
 typedef struct hashmap_create_func_args {
 	allocator_t allocator;
-	size_t itemsize;
-	size_t initial_capacity;
 	const char *file;
-	hash_func_t hash_func;
-	equals_func_t equals_func;
+	hash_func_t hash; // OPTIONAL
+	equals_func_t equals; // OPTIONAL
+	int initial_capacity; // OPTIONAL
+	int itemsize;
 	int keysize;
 	int line;
 } hashmap_create_func_args_t;
+
 void *hashmap_create_func(hashmap_create_func_args_t args);
 
-// TODO: use sizeof on a declared variable in this and arrays. e.g.
-// char *charlist;
-// init_arr(charlist, allocator, .initial_capacity=10);
-// so I can do:
-// struct {int key; int val;} *my_map;
-// init_map(my_map, allocator, .initial_capacity=10);
-#define make_map()
+#define init_map(PTR, ...) do { \
+	PTR = hashmap_create_func((hashmap_create_func_args_t) { \
+		.itemsize=sizeof(*PTR), \
+		.keysize=sizeof(PTR->key), \
+		.file=__FILE__, \
+		.line=__LINE__, \
+		.allocator=__VA_ARGS__ \
+	}); \
+} while(0);
 
 // TODO this shite
 
diff --git a/hashmap.c b/hashmap.c
new file mode 100644
index 0000000..57dcc42
--- /dev/null
+++ b/hashmap.c
@@ -0,0 +1,28 @@
+#include "cig.h"
+
+void *hashmap_create_func(
+	hashmap_create_func_args_t args
+) {
+	size_t size_of_index_arr = sizeof(int) * args.initial_capacity * 2;
+	size_t INC = sizeof(any_align_t);
+	size_t SIZE = args.itemsize * args.initial_capacity;
+	size_t size_of_items_arr = (SIZE + INC - 1) / INC;
+	size_t bytes = sizeof(hashmap_header_t) + size_of_items_arr + size_of_index_arr;
+
+	hashmap_header_t *header = allocator_alloc_func(
+		args.allocator,
+		bytes,
+		args.file,
+		args.line
+	);
+
+	header->n_items = 0;
+	header->capacity = args.initial_capacity;
+	header->itemsize = args.itemsize;
+	header->keysize = args.keysize;
+	header->allocator = args.allocator;
+	header->hash = args.hash;
+	header->equals = args.equals;
+
+	return header->bytes;
+}