ravi/ravicomp/src/allocate.h

#ifndef ravicomp_ALLOCATOR_H
#define ravicomp_ALLOCATOR_H

/*
 * allocate.c - simple space-efficient blob allocator.
 *
 * Copyright (C) 2003 Transmeta Corp.
 *               2003-2004 Linus Torvalds
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * Simple allocator for data that doesn't get partially free'd.
 * The tokenizer and parser allocate a _lot_ of small data structures
 * (often just two-three bytes for things like small integers),
 * and since they all depend on each other you can't free them
 * individually _anyway_. So do something that is very space-
 * efficient: allocate larger "blobs", and give out individual
 * small bits and pieces of it with no maintenance overhead.
 */
/*
 * Portions Copyright (C) 2017-2021 Dibyendu Majumdar
 */
#ifndef ravicomp_ALLOCATE_H
#define ravicomp_ALLOCATE_H

#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifdef __cplusplus
extern "C" {
#endif

typedef struct AllocationBlob AllocationBlob;
struct AllocationBlob {
	AllocationBlob *next;
	size_t left, offset;
	unsigned char data[];
};

/*
 * Our "blob" allocator works on chunks that are multiples
 * of this size (the underlying allocator may be a mmap that
 * cannot handle smaller chunks, for example, so trying to
 * allocate blobs that aren't aligned is not going to work).
 */
#define CHUNK 32768

typedef struct Allocator {
	const char *name_;
	AllocationBlob *blobs_;
	size_t size_;
	unsigned int alignment_;
	unsigned int chunking_;
	void *freelist_;
	size_t allocations, total_bytes, useful_bytes;
} Allocator;

extern void raviX_allocator_init(Allocator *A, const char *name, size_t size, unsigned int alignment,
				 unsigned int chunking);

extern void *raviX_allocator_allocate(Allocator *A, size_t extra);

extern void raviX_allocator_free(Allocator *A, void *entry);

extern void raviX_allocator_show_allocations(Allocator *A);

extern void raviX_allocator_drop_all_allocations(Allocator *A);

extern void raviX_allocator_destroy(Allocator *A);

extern void raviX_allocator_transfer(Allocator *A, Allocator *transfer_to);

/*
Reallocate array from old_n to new_n. If new_n is 0 then array memory is freed.
If new_n is greater than old_n then old data is copied across and the
additional allocated space is zeroed out so caller can rely on the extra space being
initialized to zeros.
*/
extern void *raviX_realloc_array(void *oldp, size_t element_size, size_t old_n, size_t new_n);
/*
Delete n elements starting at i from array a of size array_size, where sizeof(each element) is element_size.
The freed up space will be zero initialized. Returns the new array_size.
*/
extern size_t raviX_del_array_element(void *p, size_t element_size, size_t array_size, size_t i, size_t n);

/* structure of a node */
#define DECLARE_ARRAY(array_type, TYPE)                                                                                \
	typedef struct array_type {                                                                                    \
		unsigned allocated;                                                                                    \
		unsigned count;                                                                                        \
		TYPE *data;                                                                                            \
	} array_type
#define array_push(A, value)                                                                                           \
	{                                                                                                              \
		if ((A)->count == (A)->allocated) {                                                                    \
			unsigned newsize = (A)->allocated += 10;                                                       \
			(A)->data = raviX_realloc_array((A)->data, sizeof((A)->data[0]), (A)->allocated, newsize);     \
			(A)->allocated = newsize;                                                                      \
		}                                                                                                      \
		(A)->data[(A)->count++] = value;                                                                       \
	}
#define array_clearmem(A)                                                                                              \
	{                                                                                                              \
		raviX_realloc_array((A)->data, sizeof((A)->data[0]), (A)->allocated, 0);                               \
		(A)->data = NULL;                                                                                      \
		(A)->allocated = 0;                                                                                    \
		(A)->count = 0;                                                                                        \
	}

#ifdef __cplusplus
}
#endif

#endif

#endif