Initial Commit

Original Git Repo "went bad" so I had to restart.

1 files changed, 221 insertions, 0 deletions

diff --git a/src/common.cpp b/src/common.cpp
new file mode 100644
index 000000000..7b8f7cf02
--- /dev/null
+++ b/src/common.cpp
@@ -0,0 +1,221 @@
+#define GB_NO_WINDOWS_H
+#define GB_IMPLEMENTATION
+#include "gb/gb.h"
+
+// NOTE(bill): Used for UTF-8 strings
+typedef struct String {
+	u8 *text;
+	isize len;
+} String;
+// NOTE(bill): used for printf style arguments
+#define LIT(x) (x).len, (x).text
+
+
+gb_inline String make_string(u8 *text, isize len) {
+	String s;
+	s.text = text;
+	if (len < 0)
+		len = gb_strlen(cast(char *)text);
+	s.len = len;
+	return s;
+}
+
+gb_inline String make_string(char *text) {
+	return make_string(cast(u8 *)cast(void *)text, gb_strlen(text));
+}
+
+gb_inline b32 are_strings_equal(String a, String b) {
+	if (a.len == b.len) {
+		return gb_memcompare(a.text, b.text, a.len) == 0;
+	}
+	return false;
+}
+
+// Hasing
+
+gb_inline u64 hashing_proc(void const *data, isize len) {
+	return gb_murmur64(data, len);
+}
+
+gb_inline u64 hash_string(String s) {
+	return hashing_proc(s.text, s.len);
+}
+
+gb_inline u64 hash_pointer(void *ptr) {
+	u64 p = cast(u64)cast(uintptr)ptr;
+	return p;
+}
+
+////////////////////////////////////////////////////////////////
+//
+// Generic Data Structures
+//
+////////////////////////////////////////////////////////////////
+
+
+typedef struct MapFindResult {
+	isize hash_index;
+	isize entry_prev;
+	isize entry_index;
+} MapFindResult;
+
+template <typename T>
+struct MapEntry {
+	u64 key;
+	isize next;
+	T value;
+};
+
+template <typename T>
+struct Map {
+	gbArray(isize) hashes;
+	gbArray(MapEntry<T>) entries;
+};
+
+template <typename T> void map_init   (Map<T> *h, gbAllocator a);
+template <typename T> void map_destroy(Map<T> *h);
+template <typename T> T *  map_get    (Map<T> *h, u64 key);
+template <typename T> void map_set    (Map<T> *h, u64 key, T value);
+template <typename T> void map_remove (Map<T> *h, u64 key);
+template <typename T> void map_clear  (Map<T> *h);
+template <typename T> void map_grow   (Map<T> *h);
+template <typename T> void map_rehash (Map<T> *h, isize new_count);
+
+
+
+template <typename T>
+gb_inline void map_init(Map<T> *h, gbAllocator a) {
+	gb_array_init(h->hashes,  a);
+	gb_array_init(h->entries, a);
+}
+
+template <typename T>
+gb_inline void map_destroy(Map<T> *h) {
+	if (h->entries) gb_array_free(h->entries);
+	if (h->hashes)  gb_array_free(h->hashes);
+}
+
+template <typename T>
+gb_internal isize map__add_entry(Map<T> *h, u64 key) {
+	MapEntry<T> e = {0};
+	e.key = key;
+	e.next = -1;
+	gb_array_append(h->entries, e);
+	return gb_array_count(h->entries)-1;
+}
+
+template <typename T>
+gb_internal MapFindResult map__find(Map<T> *h, u64 key) {
+	MapFindResult fr = {-1, -1, -1};
+	if (gb_array_count(h->hashes) > 0) {
+		fr.hash_index  = key % gb_array_count(h->hashes);
+		fr.entry_index = h->hashes[fr.hash_index];
+		while (fr.entry_index >= 0) {
+			if (h->entries[fr.entry_index].key == key)
+				return fr;
+			fr.entry_prev = fr.entry_index;
+			fr.entry_index = h->entries[fr.entry_index].next;
+		}
+	}
+	return fr;
+}
+
+template <typename T>
+gb_internal b32 map__full(Map<T> *h) {
+	return 0.75f * gb_array_count(h->hashes) <= gb_array_count(h->entries);
+}
+
+template <typename T>
+gb_inline void map_grow(Map<T> *h) {
+	isize new_count = GB_ARRAY_GROW_FORMULA(gb_array_count(h->entries));
+	map_rehash(h, new_count);
+}
+
+template <typename T>
+void map_rehash(Map<T> *h, isize new_count) {
+	isize i, j;
+	Map<T> nh = {0};
+	map_init(&nh, gb_array_allocator(h->hashes));
+	gb_array_resize(nh.hashes, new_count);
+	gb_array_reserve(nh.entries, gb_array_count(h->entries));
+	for (i = 0; i < new_count; i++)
+		nh.hashes[i] = -1;
+	for (i = 0; i < gb_array_count(h->entries); i++) {
+		MapEntry<T> *e = &h->entries[i];
+		MapFindResult fr;
+		if (gb_array_count(nh.hashes) == 0)
+			map_grow(&nh);
+		fr = map__find(&nh, e->key);
+		j = map__add_entry(&nh, e->key);
+		if (fr.entry_prev < 0)
+			nh.hashes[fr.hash_index] = j;
+		else
+			nh.entries[fr.entry_prev].next = j;
+		nh.entries[j].next = fr.entry_index;
+		nh.entries[j].value = e->value;
+		if (map__full(&nh))
+			map_grow(&nh);
+	}
+	map_destroy(h);
+	*h = nh;
+}
+
+template <typename T>
+gb_inline T *map_get(Map<T> *h, u64 key) {
+	isize index = map__find(h, key).entry_index;
+	if (index >= 0)
+		return &h->entries[index].value;
+	return NULL;
+}
+
+template <typename T>
+void map_set(Map<T> *h, u64 key, T value) {
+	isize index;
+	MapFindResult fr;
+	if (gb_array_count(h->hashes) == 0)
+		map_grow(h);
+	fr = map__find(h, key);
+	if (fr.entry_index >= 0) {
+		index = fr.entry_index;
+	} else {
+		index = map__add_entry(h, key);
+		if (fr.entry_prev >= 0) {
+			h->entries[fr.entry_prev].next = index;
+		} else {
+			h->hashes[fr.hash_index] = index;
+		}
+	}
+	h->entries[index].value = value;
+
+	if (map__full(h))
+		map_grow(h);
+}
+
+template <typename T>
+void map_remove(Map<T> *h, u64 key) {
+	MapFindResult fr = map__find(h, key);
+	if (fr.entry_index >= 0) {
+		if (fr.entry_prev < 0) {
+			h->hashes[fr.hash_index] = h->entries[fr.entry_index].next;
+		} else {
+			h->entries[fr.entry_prev].next = h->entries[fr.entry_index].next;
+		}
+		if (fr.entry_index == gb_array_count(h->entries)-1) {
+			gb_array_pop(h->entries);
+			return;
+		}
+		h->entries[fr.entry_index] = h->entries[gb_array_count(h->entries)-1];
+		MapFindResult last = map__find(h, h->entries[fr.entry_index].key);
+		if (last.entry_prev >= 0) {
+			h->entries[last.entry_prev].next = fr.entry_index;
+		} else {
+			h->hashes[last.hash_index] = fr.entry_index;
+		}
+	}
+}
+
+template <typename T>
+gb_inline void map_clear(Map<T> *h) {
+	gb_array_clear(h->hashes);
+	gb_array_clear(h->entries);
+}