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-rw-r--r--source/memory/arena.h78
-rwxr-xr-xsource/memory/memory.c246
-rwxr-xr-xsource/memory/memory.h98
3 files changed, 422 insertions, 0 deletions
diff --git a/source/memory/arena.h b/source/memory/arena.h
new file mode 100644
index 0000000..83ff277
--- /dev/null
+++ b/source/memory/arena.h
@@ -0,0 +1,78 @@
+#pragma once
+
+#ifndef ALIGNMENT
+#define ALIGNMENT (2*sizeof(void*))
+#endif
+
+struct Arena {
+ unsigned char* buffer;
+ size_t prev_offset;
+ size_t curr_offset;
+ size_t capacity;
+};
+
+// definition
+b8 is_power_of_two(uintptr_t x);
+uintptr_t fast_modulo(uintptr_t p, uintptr_t a);
+uintptr_t align_forward(uintptr_t ptr, uintptr_t alignment);
+void arena_init(Arena* a, unsigned char *memory, size_t capacity);
+void* arena_alloc(Arena* a, size_t size);
+void arena_clear(Arena* a);
+
+
+// implementation
+b8 is_power_of_two(uintptr_t x) {
+ return (x & (x-1)) == 0;
+}
+
+uintptr_t fast_modulo(uintptr_t p, uintptr_t a) {
+ return (p & (a - 1));
+}
+
+uintptr_t align_forward(uintptr_t ptr, size_t alignment) {
+ uintptr_t p, a, modulo;
+
+ assert(is_power_of_two(alignment));
+
+ p = ptr;
+ a = (uintptr_t)alignment;
+ modulo = fast_modulo(p, a);
+
+ if (modulo != 0) {
+ p += (a - modulo);
+ }
+
+ return p;
+}
+
+void arena_init(Arena* a, unsigned char *memory, size_t capacity) {
+ a->buffer = memory;
+ a->prev_offset = 0;
+ a->curr_offset = 0;
+ a->capacity = capacity;
+}
+
+void* arena_alloc(Arena* a, size_t size) {
+ void *ptr = NULL;
+
+ assert(is_power_of_two(ALIGNMENT));
+
+ uintptr_t curr_ptr = (uintptr_t)a->buffer + a->curr_offset;
+ uintptr_t offset = align_forward(curr_ptr, ALIGNMENT);
+ offset = offset - (uintptr_t)a->buffer;
+ size_t next_offset = offset + size;
+
+ assert(next_offset <= a->capacity);
+
+ ptr = &a->buffer[offset];
+ a->prev_offset = a->curr_offset;
+ a->curr_offset = next_offset;
+ memset(ptr, 0, size);
+
+ return ptr;
+}
+
+void arena_clear(Arena* a) {
+ a->curr_offset = 0;
+ a->prev_offset = 0;
+}
diff --git a/source/memory/memory.c b/source/memory/memory.c
new file mode 100755
index 0000000..1d521e4
--- /dev/null
+++ b/source/memory/memory.c
@@ -0,0 +1,246 @@
+#include "memory.h"
+
+b8 is_power_of_two(uintptr_t x) { return (x & (x - 1)) == 0; }
+
+uintptr_t fast_modulo(uintptr_t p, uintptr_t a) { return (p & (a - 1)); }
+
+uintptr_t align_forward(uintptr_t ptr, size_t alignment) {
+ uintptr_t p, a, modulo;
+
+ assert(is_power_of_two(alignment));
+
+ p = ptr;
+ a = (uintptr_t)alignment;
+ modulo = fast_modulo(p, a);
+
+ if (modulo != 0) {
+ p += (a - modulo);
+ }
+
+ return p;
+}
+
+//===========================================================================================
+// ---------------------------------- Arena
+// -------------------------------------------------
+//===========================================================================================
+
+/*
+ A cases where arena allocation WILL fail:
+ | size = size_t + ${some_number_that_comes_up_higher_than_offset}
+
+ This is because there is no check being made
+*/
+void arena_init(struct Arena *a, unsigned char *backing_store,
+ size_t capacity) {
+ a->buffer = backing_store;
+ a->curr_offset = 0;
+ a->prev_offset = 0;
+ a->capacity = capacity;
+}
+
+void *arena_alloc_aligned(struct Arena *a, size_t size, size_t alignment) {
+ void *ptr = NULL;
+
+ assert(is_power_of_two(alignment));
+
+ uintptr_t curr_ptr = (uintptr_t)a->buffer + a->curr_offset;
+ uintptr_t offset = align_forward(curr_ptr, alignment);
+ offset = offset - (uintptr_t)a->buffer;
+
+ if (size <= a->capacity - offset) {
+ ptr = &a->buffer[offset];
+ a->prev_offset = a->curr_offset;
+ a->curr_offset = offset + size;
+ memset(ptr, 0, size);
+ }
+
+ return ptr;
+}
+
+void *arena_alloc(struct Arena *a, size_t size) {
+ return arena_alloc_aligned(a, size, DEFAULT_ALIGNMENT);
+}
+
+void *arena_resize_aligned(struct Arena *a, void *old_memory, size_t old_size,
+ size_t new_size, size_t alignment) {
+ unsigned char *old = (unsigned char *)old_memory;
+ void *ptr = NULL;
+
+ assert(is_power_of_two(alignment));
+
+ if (old >= a->buffer && old < a->buffer + a->capacity) {
+ if (a->buffer + a->prev_offset == old) {
+ // extend_last_element
+ if (new_size > old_size) {
+ size_t size_increase = new_size - old_size;
+ if (size_increase > (a->capacity - a->curr_offset)) {
+ new_size = old_size;
+ size_increase = 0;
+ }
+ memset(&a->buffer[a->curr_offset], 0, size_increase);
+ }
+ a->curr_offset = a->prev_offset + new_size;
+ ptr = old_memory;
+ } else {
+ ptr = arena_alloc_aligned(a, new_size, alignment);
+ if (ptr != NULL) {
+ size_t copy_size = old_size < new_size ? old_size : new_size;
+ memmove(ptr, old_memory, copy_size);
+ }
+ }
+ }
+
+ return ptr;
+}
+
+void *arena_resize(struct Arena *a, void *old_mem, size_t old_size,
+ size_t new_size) {
+ return arena_resize_aligned(a, old_mem, old_size, new_size,
+ DEFAULT_ALIGNMENT);
+}
+
+void arena_clear(struct Arena *a) {
+ a->curr_offset = 0;
+ a->prev_offset = 0;
+}
+
+//===========================================================================================
+// ---------------------------------- STACK
+// -------------------------------------------------
+//===========================================================================================
+
+void stack_init(struct stack *s, void *backing_store, size_t capacity) {
+ s->buffer = (unsigned char *)backing_store;
+ s->prev_offset = 0;
+ s->curr_offset = 0;
+ s->capacity = capacity;
+}
+
+size_t calc_padding_with_header(uintptr_t ptr, uintptr_t alignment,
+ size_t hdr_sz) {
+ uintptr_t p, a, modulo, padding, space_needed;
+
+ assert(is_power_of_two(alignment));
+
+ padding = space_needed = 0;
+
+ p = ptr;
+ a = alignment;
+ modulo = fast_modulo(p, a);
+
+ if (modulo != 0) {
+ padding = a - modulo;
+ }
+
+ space_needed = (uintptr_t)hdr_sz;
+ if (padding < space_needed) {
+ space_needed -= padding;
+ if (fast_modulo(space_needed, a) != 0) {
+ padding = padding + space_needed + a;
+ } else {
+ padding = padding + space_needed;
+ }
+ }
+
+ return (size_t)padding;
+}
+
+struct ResVoid stack_alloc_aligned(struct stack *s, size_t size,
+ size_t alignment) {
+ uintptr_t curr_addr, next_addr;
+ size_t padding;
+ struct stack_hdr *header;
+
+ assert(is_power_of_two(alignment));
+ if (alignment > 128) {
+ alignment = 128;
+ }
+
+ struct ResVoid result = {.status = MEM_OK, .bytes_count = 0, .memory = 0};
+
+ curr_addr = (uintptr_t)s->buffer + (uintptr_t)s->curr_offset;
+ padding = calc_padding_with_header(curr_addr, (uintptr_t)alignment,
+ sizeof(struct stack_hdr));
+
+ if (size > s->capacity - (s->curr_offset + padding)) {
+ result.status = MEM_FULL;
+ return result;
+ }
+
+ next_addr = curr_addr + (uintptr_t)padding;
+ header = (struct stack_hdr *)(next_addr - sizeof(struct stack_hdr));
+ header->prev_offset = s->prev_offset;
+ header->padding = padding;
+
+ s->prev_offset = s->curr_offset + padding;
+ s->curr_offset = s->prev_offset + size;
+
+ result.memory = memset((void *)next_addr, 0, size);
+ result.bytes_count = size;
+
+ return result;
+}
+
+struct ResVoid stack_alloc(struct stack *s, size_t size) {
+ return stack_alloc_aligned(s, size, DEFAULT_ALIGNMENT);
+}
+
+enum MemStatus stack_free(struct stack *s) {
+ uintptr_t last_ele = (uintptr_t)s->buffer + (uintptr_t)s->prev_offset;
+ struct stack_hdr *header =
+ (struct stack_hdr *)(last_ele - sizeof(struct stack_hdr));
+
+ uintptr_t prev_ele = (uintptr_t)s->buffer + (uintptr_t)header->prev_offset;
+ s->curr_offset =
+ (size_t)((last_ele - (uintptr_t)header->padding) - (uintptr_t)s->buffer);
+ s->prev_offset = (size_t)(prev_ele - (uintptr_t)s->buffer);
+
+ return MEM_OK;
+}
+
+struct ResVoid stack_resize_aligned(struct stack *s, void *old_memory,
+ size_t old_size, size_t new_size,
+ size_t alignment) {
+ struct ResVoid result = {.status = MEM_OK, .bytes_count = 0, .memory = 0};
+
+ if (old_memory < s->buffer || old_memory > s->buffer + s->capacity) {
+ result.status = MEM_OUT_OF_BOUNDS;
+ return result;
+ }
+
+ // is_last_element()
+ if (s->buffer + s->prev_offset == old_memory) {
+ if (new_size > old_size) {
+ size_t size_difference = new_size - old_size;
+ if (size_difference > s->capacity - s->curr_offset) {
+ result.status = MEM_FULL;
+ return result;
+ }
+
+ memset(&s->buffer[s->curr_offset], 0, size_difference);
+ }
+ s->curr_offset = s->prev_offset + new_size;
+
+ result.memory = old_memory;
+ return result;
+ }
+
+ result = stack_alloc_aligned(s, new_size, alignment);
+ size_t min_size =
+ old_size < result.bytes_count ? old_size : result.bytes_count;
+ memmove(result.memory, old_memory, min_size);
+
+ return result;
+}
+
+struct ResVoid stack_resize(struct stack *s, void *old_memory, size_t old_size,
+ size_t new_size) {
+ return stack_resize_aligned(s, old_memory, old_size, new_size,
+ DEFAULT_ALIGNMENT);
+}
+
+void stack_clear(struct stack *s) {
+ s->prev_offset = 0;
+ s->curr_offset = 0;
+}
diff --git a/source/memory/memory.h b/source/memory/memory.h
new file mode 100755
index 0000000..e402c0b
--- /dev/null
+++ b/source/memory/memory.h
@@ -0,0 +1,98 @@
+#ifndef AMR_MEMORY_H
+#define AMR_MEMORY_H
+
+#include <stddef.h>
+#include <stdint.h>
+#include <assert.h>
+#include <string.h>
+
+#ifndef AMR_TYPES_H
+#define AMR_TYPES_H
+
+typedef int8_t s8;
+typedef int16_t s16;
+typedef int32_t s32;
+typedef int64_t s64;
+
+typedef uint8_t u8;
+typedef uint16_t u16;
+typedef uint32_t u32;
+typedef uint64_t u64;
+
+typedef u8 b8;
+
+#endif // AMR_TYPES_H
+
+
+#ifndef DEFAULT_ALIGNMENT
+#define DEFAULT_ALIGNMENT (2*sizeof(void *))
+#endif
+
+// @todo: build a logging mechanism for handling errors
+// maybe read about that
+
+enum MemStatus { MEM_OK=0, MEM_OUT_OF_BOUNDS, MEM_FULL };
+
+struct ResVoid {
+ enum MemStatus status;
+ size_t bytes_count;
+ void* memory;
+};
+
+b8 is_power_of_two(uintptr_t x);
+uintptr_t fast_modulo(uintptr_t p, uintptr_t a);
+uintptr_t align_forward(uintptr_t ptr, size_t align);
+
+//===========================================================================================
+// ---------------------------------- ARENA -------------------------------------------------
+//===========================================================================================
+
+struct Arena {
+ unsigned char* buffer;
+ size_t prev_offset;
+ size_t curr_offset;
+ size_t capacity;
+};
+
+void arena_init(struct Arena *a, unsigned char *backing_store, size_t capacity);
+void* arena_alloc_aligned(struct Arena* a, size_t size, size_t align);
+void* arena_alloc(struct Arena* a, size_t size);
+void* arena_resize_aligned(struct Arena* a, void* old_memory, size_t old_size,
+ size_t new_size, size_t align);
+void* arena_resize(struct Arena* a, void* old_mem, size_t old_size,
+ size_t new_size);
+void arena_clear(struct Arena *a);
+
+//===========================================================================================
+// ---------------------------------- STACK -------------------------------------------------
+//===========================================================================================
+
+/*
+* @todo: stack needs to be updated, it's really just a work in progress right now.
+* The main thing is minimizing the use of compound types, since that is pretty annoying to deal with.
+* I would rather write code that makes sure to collapse all possible cases and lets me just not worry about code.
+* Would rather stick to worrying about data being data
+*/
+
+struct stack {
+ unsigned char* buffer;
+ size_t prev_offset;
+ size_t curr_offset;
+ size_t capacity;
+};
+
+struct stack_hdr {
+ size_t prev_offset;
+ size_t padding;
+};
+
+void stack_init(struct stack* s, void *backing_store, size_t capacity);
+struct ResVoid stack_alloc_aligned(struct stack* s, size_t size, size_t alignment);
+struct ResVoid stack_alloc(struct stack* s, size_t size);
+enum MemStatus stack_free(struct stack* s);
+struct ResVoid stack_resize_aligned(struct stack* s, void* old_memory, size_t old_size,
+ size_t new_size, size_t alignment);
+struct ResVoid stack_resize(struct stack* s, void* old_memory, size_t old_size, size_t new_size);
+void stack_clear(struct stack* s);
+
+#endif
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