From 3abf5e3f7f8263ccbc096a65cc148f81bbeb63aa Mon Sep 17 00:00:00 2001
From: flysand7 <thebumboni@gmail.com>
Date: Fri, 28 Jul 2023 21:49:56 +1100
Subject: [PATCH] Memory API

---
 include/cia-mem.h            | 32 +++++++++++++++++++++++++++++++
 include/tinyrt.h             |  7 +++++++
 src/impl/cia-mem/allocator.c | 37 ++++++++++++++++++++++++++++++++++++
 src/impl/cia-mem/arena.c     | 35 ++++++++++++++++++++++++++++++++++
 src/impl/cia-mem/util.c      | 12 ++++++++++++
 src/library.json             | 13 +++++++++++++
 src/linux/tinyrt.json        |  1 +
 src/windows/tinyrt.c         | 17 +++++++++++++++++
 src/windows/tinyrt.json      |  1 +
 9 files changed, 155 insertions(+)
 create mode 100644 include/cia-mem.h
 create mode 100644 src/impl/cia-mem/allocator.c
 create mode 100644 src/impl/cia-mem/arena.c
 create mode 100644 src/impl/cia-mem/util.c

diff --git a/include/cia-mem.h b/include/cia-mem.h
new file mode 100644
index 0000000..9700267
--- /dev/null
+++ b/include/cia-mem.h
@@ -0,0 +1,32 @@
+
+#pragma once
+
+void *cia_ptr_alignf(void *ptr, u64 alignment);
+void *cia_ptr_alignb(void *ptr, u64 alignment);
+
+struct Cia_Allocator typedef Cia_Allocator;
+struct Cia_Allocator {
+    void *ctx;
+    void *(*alloc)(void *ctx, u64 size);
+    void *(*alloc_a)(void *ctx, u64 size, u64 alignment);
+    void (*free)(void *ctx, void *ptr);
+    void (*free_all)(void *ctx, void *ptr);
+    void *(*realloc)(void *ctx, void *ptr, u64 new_size);
+};
+
+Cia_Allocator cia_allocator_null();
+Cia_Allocator cia_allocator_pages();
+
+struct Cia_Arena typedef Cia_Arena;
+struct Cia_Arena {
+    Cia_Allocator allocator;
+    u64 buffer_size;
+    u64 used;
+    u8* buffer;
+};
+
+void cia_arena_create(Cia_Arena *arena, Cia_Allocator backing_allocator, u64 max_size);
+void *cia_arena_alloc(Cia_Arena *arena, u64 size);
+void *cia_arena_alloc_aligned(Cia_Arena *arena, u64 size, u64 align);
+void cia_arena_free_all(Cia_Arena *arena);
+void cia_arena_destroy(Cia_Arena *arena);
diff --git a/include/tinyrt.h b/include/tinyrt.h
index a8fa692..2da36d6 100644
--- a/include/tinyrt.h
+++ b/include/tinyrt.h
@@ -5,6 +5,7 @@
 #define _RT_STATUS_OK                     0  // No errors
 #define _RT_ERROR_NOT_IMPLEMENTED        -1  // Function not implemented
 #define _RT_ERROR_BAD_PARAM              -2  // One of the function parameters was wrong
+#define _RT_ERROR_GENERIC                -3  // Just any random error
 
 // File API errors
 #define _RT_STATUS_FILE_ACCESS            1  // No access to the file
@@ -69,3 +70,9 @@ struct _RT_File {
     static _RT_Status _rt_file_write(_RT_File *to, u64 size, void *buffer, u64 *out_bytes_written);
     static _RT_Status _rt_file_close(_RT_File *file);
 #endif
+
+// Memory API
+#if _RT_API_MEMORY == 1
+    static _RT_Status _rt_mem_alloc(void *optional_desired_addr, u64 min_size, void **out_addr);
+    static _RT_Status _rt_mem_free(void *ptr);
+#endif
diff --git a/src/impl/cia-mem/allocator.c b/src/impl/cia-mem/allocator.c
new file mode 100644
index 0000000..12ad51e
--- /dev/null
+++ b/src/impl/cia-mem/allocator.c
@@ -0,0 +1,37 @@
+
+Cia_Allocator cia_allocator_null() {
+    Cia_Allocator allocator = {
+        .ctx = NULL,
+        .alloc = NULL,
+        .alloc_a = NULL,
+        .free = NULL,
+        .free_all = NULL,
+        .realloc = NULL
+    };
+    return allocator;
+}
+
+static void *page_alloc(void *ctx, u64 size) {
+    void *addr;
+    _RT_Status status = _rt_mem_alloc(NULL, size, &addr);
+    if(status != _RT_STATUS_OK) {
+        return NULL;
+    }
+    return addr;
+}
+
+static void page_free(void *ptr) {
+    _rt_mem_free(ptr);
+}
+
+Cia_Allocator cia_allocator_pages() {
+    Cia_Allocator allocator = {
+        .ctx = NULL,
+        .alloc = page_alloc,
+        .alloc_a = NULL,
+        .free = page_free,
+        .free_all = NULL,
+        .realloc = NULL,
+    };
+    return allocator;
+}
diff --git a/src/impl/cia-mem/arena.c b/src/impl/cia-mem/arena.c
new file mode 100644
index 0000000..45d2e24
--- /dev/null
+++ b/src/impl/cia-mem/arena.c
@@ -0,0 +1,35 @@
+
+void cia_arena_create(Cia_Arena *arena, Cia_Allocator backing_allocator, u64 buffer_size) {
+    arena->allocator = backing_allocator;
+    arena->buffer_size = buffer_size;
+    arena->used = 0;
+    arena->buffer = arena->allocator.alloc(arena->allocator.ctx, buffer_size);
+}
+
+void *cia_arena_alloc(Cia_Arena *arena, u64 size) {
+    if(arena->used + size > arena->buffer_size) {
+        return NULL;
+    }
+    void *ptr = &arena->buffer[arena->used];
+    arena->used += arena->buffer_size;
+    return ptr;
+}
+
+void *cia_arena_alloc_aligned(Cia_Arena *arena, u64 size, u64 align) {
+    void *buffer_end = &arena->buffer[arena->buffer_size];
+    void *region_ptr = cia_ptr_alignf(&arena->buffer[arena->used], align);
+    void *region_end = (void *)((u64)region_ptr + size);
+    if(region_end > buffer_end) {
+        return NULL;
+    }
+    arena->used = (u64)region_ptr - (u64)arena->buffer;
+    return region_ptr;
+}
+
+void cia_arena_free_all(Cia_Arena *arena) {
+    arena->used = 0;
+}
+
+void cia_arena_destroy(Cia_Arena *arena) {
+    arena->allocator.free(arena->allocator.ctx, arena->buffer);
+}
diff --git a/src/impl/cia-mem/util.c b/src/impl/cia-mem/util.c
new file mode 100644
index 0000000..d33ed99
--- /dev/null
+++ b/src/impl/cia-mem/util.c
@@ -0,0 +1,12 @@
+
+void *cia_ptr_alignf(void *ptr, u64 alignment) {
+    u64 addr = (u64)ptr;
+    u64 aligned = (addr + alignment - 1) & ~(alignment - 1);
+    return (void *)aligned;
+}
+
+void *cia_ptr_alignb(void *ptr, u64 alignment) {
+    u64 addr = (u64)ptr;
+    u64 aligned = addr & ~(alignment - 1);
+    return (void *)aligned;
+}
\ No newline at end of file
diff --git a/src/library.json b/src/library.json
index 616554a..df0b7fc 100644
--- a/src/library.json
+++ b/src/library.json
@@ -24,6 +24,7 @@
 includes: [
     "stdlib.h",
     "stdio.h",
+    "cia-mem.h",
 ],
 
 platforms: [
@@ -53,6 +54,18 @@ platforms: [
 ],
 
 apis: [
+    {
+        name: "cia_memory",
+        path: "impl/cia-mem",
+        includes: [
+            "util.c",
+            "allocator.c",
+            "arena.c",
+        ],
+        reqs: [
+            "rt_api_memory"
+        ]
+    },
     {
         name: "stdlib_program",
         path: "impl/stdlib-program",
diff --git a/src/linux/tinyrt.json b/src/linux/tinyrt.json
index 85639ae..32d09dd 100644
--- a/src/linux/tinyrt.json
+++ b/src/linux/tinyrt.json
@@ -7,3 +7,4 @@
 rt_api_file: true,
 rt_api_program: true,
 rt_api_shell: false,
+rt_api_memory: false,
diff --git a/src/windows/tinyrt.c b/src/windows/tinyrt.c
index adc7680..af72ab2 100644
--- a/src/windows/tinyrt.c
+++ b/src/windows/tinyrt.c
@@ -74,3 +74,20 @@ static _RT_Status _rt_file_close(_RT_File *file) {
     __builtin_unreachable();
 }
 
+static _RT_Status _rt_mem_alloc(void *optional_desired_addr, u64 min_size, void **out_addr) {
+    void *addr = VirtualAlloc(optional_desired_addr, min_size, MEM_COMMIT|MEM_RESERVE, PAGE_READWRITE);
+    *out_addr = addr;
+    if(addr == NULL) {
+        return _RT_ERROR_GENERIC;
+    }
+    return _RT_STATUS_OK;
+}
+
+static _RT_Status _rt_mem_free(void *addr) {
+    BOOL ok = VirtualFree(addr, 0, MEM_RELEASE);
+    if(!ok) {
+        return _RT_ERROR_GENERIC;
+    }
+    return _RT_STATUS_OK;
+}
+
diff --git a/src/windows/tinyrt.json b/src/windows/tinyrt.json
index acea106..7278cd6 100644
--- a/src/windows/tinyrt.json
+++ b/src/windows/tinyrt.json
@@ -6,3 +6,4 @@
 rt_api_file: true,
 rt_api_program: true,
 rt_api_shell: false,
+rt_api_memory: true,
\ No newline at end of file