Add arena allocator library

Makefile

@@ -10,3 +10,4 @@ include make/libprocess.mk
 include make/libstring.mk
 include make/libkb.mk
 include make/libaux.mk
+include make/libarena.mk

aux/compiledb.sh

@@ -10,3 +10,4 @@ make -B all_compiledb_libterminal
 make -B all_compiledb_libstring
 make -B all_compiledb_libkb
 make -B all_compiledb_libaux
+make -B all_compiledb_libarena

aux/devel.sh

@@ -15,6 +15,7 @@ make -B all_libterminal
 make -B all_libstring
 make -B all_libkb
 make -B all_libaux
+make -B all_libarena
 make -B all_apps
 make -B all_dist
 ./aux/limine_iso_amd64.sh

aux/docs.sh

@@ -11,5 +11,6 @@ make -B docs_libstring
 make -B docs_libterminal
 make -B docs_libkb
 make -B docs_libaux
+make -B docs_libarena
 
 mkdocs build

aux/format.sh

@@ -10,4 +10,5 @@ make -B format_liballoc
 make -B format_libstring
 make -B format_libkb
 make -B format_libaux
+make -B format_libarena
 make -B format_apps

libarena/.gitignore

@@ -0,0 +1,4 @@
+*.o
+*.json
+docs/
+.cache/

libarena/Makefile

@@ -0,0 +1,7 @@
+include ../make/ufuncs.mk
+
+$(eval $(call add_include,liballoc))
+
+libname := libarena
+
+include ../make/lib.mk

libarena/arena.c

@@ -0,0 +1,78 @@
+#include <arena.h>
+#include <liballoc.h>
+#include <stddef.h>
+
+static struct arena_chunk* arena_create_chunk (size_t capacity) {
+  size_t size = sizeof (struct arena_chunk) + sizeof (uintptr_t) * capacity;
+  struct arena_chunk* chunk = malloc (size);
+
+  if (chunk == NULL)
+    return NULL;
+
+  chunk->next = NULL;
+  chunk->size = 0;
+  chunk->capacity = capacity;
+  return chunk;
+}
+
+static void arena_destroy_chunk (struct arena_chunk* chunk) { free (chunk); }
+
+void arena_reset (struct arena* arena) {
+  for (struct arena_chunk* chunk = arena->begin; chunk != NULL; chunk = chunk->next) {
+    chunk->size = 0;
+  }
+
+  arena->end = arena->begin;
+}
+
+void arena_destroy (struct arena* arena) {
+  struct arena_chunk* chunk = arena->begin;
+
+  while (chunk) {
+    struct arena_chunk* chunk1 = chunk;
+    chunk = chunk->next;
+    arena_destroy_chunk (chunk1);
+  }
+
+  arena->begin = NULL;
+  arena->end = NULL;
+}
+
+void* arena_malloc (struct arena* arena, size_t size) {
+  size_t size1 = (size + sizeof (uintptr_t) - 1) / sizeof (uintptr_t);
+
+  if (arena->end == NULL) {
+    size_t capacity = ARENA_CHUNK_CAPACITY;
+
+    if (capacity < size1) {
+      capacity = size1;
+    }
+
+    arena->end = arena_create_chunk (capacity);
+
+    if (arena->end == NULL) {
+      return NULL;
+    }
+
+    arena->begin = arena->end;
+  }
+
+  while (arena->end->size + size1 > arena->end->capacity && arena->end->next != NULL) {
+    arena->end = arena->end->next;
+  }
+
+  if (arena->end->size + size1 > arena->end->capacity) {
+    size_t capacity = ARENA_CHUNK_CAPACITY;
+
+    if (capacity < size1) {
+      capacity = size1;
+    }
+
+    arena->end = arena_create_chunk (capacity);
+    arena->end = arena->end->next;
+  }
+
+  void* result = &arena->end->memory[arena->end->size];
+  arena->end->size += size1;
+  return result;
+}

libarena/arena.h

@@ -0,0 +1,25 @@
+#ifndef _LIBARENA_ARENA_H
+#define _LIBARENA_ARENA_H
+
+#include <stddef.h>
+
+#define ARENA_CHUNK_CAPACITY (8 * 1024)
+
+struct arena_chunk {
+  struct arena_chunk* next;
+  size_t capacity;
+  size_t size;
+  uintptr_t memory[];
+};
+
+struct arena {
+  struct arena_chunk *begin, *end;
+};
+
+void arena_reset (struct arena* arena);
+
+void arena_destroy (struct arena* arena);
+
+void* arena_malloc (struct arena* arena, size_t size);
+
+#endif // _LIBARENA_ARENA_H

libarena/src.mk

@@ -0,0 +1,3 @@
+c += arena.c
+
+o += arena.o

make/libarena.mk

@@ -0,0 +1,16 @@
+all_libarena:
+	make -C libarena platform=$(platform) all
+
+all_compiledb_libarena:
+	bear --output libarena/compile_commands.json -- make -C libarena platform=$(platform) all
+
+clean_libarena:
+	make -C libarena platform=$(platform) clean
+
+format_libarena:
+	make -C libarena platform=$(platform) format
+
+docs_libarena:
+	make -C libarena platform=$(platform) docs
+
+.PHONY: all_libarena clean_libarena format_libarena docs_libarena all_compiledb_libarena