add implementation

1 files changed, 140 insertions, 0 deletions

diff --git a/include/cmmm/arena.h b/include/cmmm/arena.h
new file mode 100644
index 0000000..07c9bef
--- /dev/null
+++ b/include/cmmm/arena.h
@@ -0,0 +1,140 @@
+#ifndef INCLUDED__CMMM__ARENA__H
+#define INCLUDED__CMMM__ARENA__H
+
+// NOTE(cmmm): this implementation assumes that allocations are made
+// at the end, so that we can take advantage of checkpoints.  The
+// downside is that we can't allocate from previous chunks even if
+// there is space left in them...
+
+// NOTE(cmmm): coalescing is nice, but while you're building an
+// "object", it may be split across multiple chunks
+
+#include <stddef.h>
+
+// #define CMMM__ARENA__NO_STDIO
+// #define CMMM__ARENA__STRIP_VENDOR
+
+#ifndef CMMM__ARENA__FIRST_CHUNK_SIZE
+#define CMMM__ARENA__FIRST_CHUNK_SIZE (4 << 10)
+#endif
+
+#ifndef CMMM__ARENA__CHUNK_GROWTH_FACTOR
+#define CMMM__ARENA__CHUNK_GROWTH_FACTOR 2
+#endif
+
+struct cmmm__arena__chunk {
+  struct cmmm__arena__chunk *next;
+  char *free;
+  char *end;
+  char data[];
+};
+
+#define CMMM__ARENA struct cmmm__arena *
+struct cmmm__arena {
+  struct cmmm__arena__chunk *head;
+  struct cmmm__arena__chunk *tail;
+};
+
+struct cmmm__arena__checkpoint {
+  struct cmmm__arena__chunk *tail;
+  char                      *free;
+};
+
+#ifndef ALIGNOF
+#if __STDC_VERSION__ >= 202311L
+#define ALIGNOF alignof
+#elif __STDC_VERSION__ >= 201112L
+#define ALIGNOF _Alignof
+#else
+#define ALIGNOF(O) offsetof (struct { char _; typeof (O) x; }, x)
+#endif
+#endif
+
+#define CMMM__ARENA__RESERVE(            A,    T) cmmm__arena__reserve       ((A),     sizeof (T), ALIGNOF (T))
+#define CMMM__ARENA__RESERVE_ARRAY(      A, N, T) cmmm__arena__reserve       ((A), (N)*sizeof (T), ALIGNOF (T))
+#define CMMM__ARENA__ALLOCATE(           A,    T) cmmm__arena__allocate      ((A),     sizeof (T), ALIGNOF (T))
+#define CMMM__ARENA__ALLOCATE_ARRAY(     A, N, T) cmmm__arena__allocate      ((A), (N)*sizeof (T), ALIGNOF (T))
+#define CMMM__ARENA__ALLOCATE_FAST(      A,    T) cmmm__arena__allocate_fast ((A),     sizeof (T), ALIGNOF (T))
+#define CMMM__ARENA__ALLOCATE_ARRAY_FAST(A, N, T) cmmm__arena__allocate_fast ((A), (N)*sizeof (T), ALIGNOF (T))
+#define CMMM__ARENA__ZERO(               A,    T) cmmm__arena__zero          ((A),     sizeof (T), ALIGNOF (T))
+#define CMMM__ARENA__ZERO_ARRAY(         A, N, T) cmmm__arena__zero          ((A), (N)*sizeof (T), ALIGNOF (T))
+void *cmmm__arena__reserve       (struct cmmm__arena *, size_t size, size_t alignment);
+void *cmmm__arena__allocate      (struct cmmm__arena *, size_t size, size_t alignment);
+void *cmmm__arena__allocate_fast (struct cmmm__arena *, size_t size, size_t alignment);
+void *cmmm__arena__zero          (struct cmmm__arena *, size_t size, size_t alignment);
+
+size_t cmmm__arena__room      (const struct cmmm__arena *, size_t alignment);
+void  *cmmm__arena__next_free (const struct cmmm__arena *, size_t alignment);
+
+#define CMMM__ARENA__COPY(      A, F,    T) cmmm__arena__copy ((A), (F),     sizeof (T), ALIGNOF (T))
+#define CMMM__ARENA__COPY_ARRAY(A, F, N, T) cmmm__arena__copy ((A), (F), (N)*sizeof (T), ALIGNOF (T))
+void *cmmm__arena__copy      (struct cmmm__arena *, const void *, size_t size, size_t alignment);
+char *cmmm__arena__copy_cstr (struct cmmm__arena *, const char *);
+
+void cmmm__arena__reset (struct cmmm__arena *);
+
+struct cmmm__arena__checkpoint cmmm__arena__checkpoint (struct cmmm__arena *);
+size_t cmmm__arena__checkpoint__size_from (struct cmmm__arena__checkpoint);
+void   cmmm__arena__rollback_to        (struct cmmm__arena *, struct cmmm__arena__checkpoint);
+void  *cmmm__arena__coalesce_from      (struct cmmm__arena *, struct cmmm__arena__checkpoint);
+void  *cmmm__arena__coalesce_from_fast (struct cmmm__arena *, struct cmmm__arena__checkpoint, size_t size);
+
+void cmmm__arena__trim (struct cmmm__arena *);
+void cmmm__arena__free (struct cmmm__arena *);
+
+#ifndef CMMM__ARENA__NO_STDIO
+#include <stdarg.h>
+char *cmmm__arena__printf  (struct cmmm__arena *, const char *format, ...);
+char *cmmm__arena__vprintf (struct cmmm__arena *, const char *format, va_list ap);
+#endif
+
+#ifdef CMMM__ARENA__STRIP_VENDOR
+#define ARENA__NO_STDIO     CMMM__ARENA__NO_STDIO
+#define ARENA__STRIP_VENDOR CMMM__ARENA__STRIP_VENDOR
+
+#define ARENA__FIRST_CHUNK_SIZE    CMMM__ARENA__FIRST_CHUNK_SIZE
+#define ARENA__CHUNK_GROWTH_FACTOR CMMM__ARENA__CHUNK_GROWTH_FACTOR
+
+#define arena__chunk      cmmm__arena__chunk
+#define ARENA             CMMM__ARENA
+#define arena__checkpoint cmmm__arena__checkpoint
+
+#define ARENA__RESERVE             CMMM__ARENA__RESERVE
+#define ARENA__RESERVE_ARRAY       CMMM__ARENA__RESERVE_ARRAY
+#define ARENA__ALLOCATE            CMMM__ARENA__ALLOCATE
+#define ARENA__ALLOCATE_ARRAY      CMMM__ARENA__ALLOCATE_ARRAY
+#define ARENA__ALLOCATE_FAST       CMMM__ARENA__ALLOCATE_FAST
+#define ARENA__ALLOCATE_ARRAY_FAST CMMM__ARENA__ALLOCATE_ARRAY_FAST
+#define ARENA__ZERO                CMMM__ARENA__ZERO
+#define ARENA__ZERO_ARRAY          CMMM__ARENA__ZERO_ARRAY
+#define arena__reserve       cmmm__arena__reserve
+#define arena__allocate      cmmm__arena__allocate
+#define arena__allocate_fast cmmm__arena__allocate_fast
+#define arena__zero          cmmm__arena__zero
+
+#define arena__room      cmmm__arena__room
+#define arena__next_free cmmm__arena__next_free
+
+#define ARENA__COPY       CMMM__ARENA__COPY
+#define ARENA__COPY_ARRAY CMMM__ARENA__COPY_ARRAY
+#define arena__copy      cmmm__arena__copy
+#define arena__copy_cstr cmmm__arena__copy_cstr
+
+#define arena__reset cmmm__arena__reset
+
+#define arena__checkpoint         cmmm__arena__checkpoint
+#define arena__rollback_to        cmmm__arena__rollback_to
+#define arena__size_from          cmmm__arena__size_from
+#define arena__coalesce_from      cmmm__arena__coalesce_from
+#define arena__coalesce_from_fast cmmm__arena__coalesce_from_fast
+
+#define arena__trim cmmm__arena__trim
+#define arena__free cmmm__arena__free
+
+#ifndef CMMM__ARENA__NO_STDIO
+#define arena__printf  cmmm__arena__printf
+#define arena__vprintf cmmm__arena__vprintf
+#endif
+#endif
+
+#endif // INCLUDED__CMMM__ARENA__H