/* SPDX-License-Identifier: LGPL-2.1-only */

/* Copyright (C) 2020-2021 Gediminas Jakutis */

#ifndef ALGOS_DEFS_H_INCLUDED
#define ALGOS_DEFS_H_INCLUDED

#include <stddef.h>
#include <stdint.h>
#include <sys/types.h>
#include <rin/diagnostic.h>
#include <rin/definitions.h>

#define try_s(a,l) do {\
	if(unlikely(a)) {\
		goto l;\
	}} while (0);

#define try(a,l,e,m,...) do {\
	if(unlikely(a)) {\
		ret = e;\
		rin_err(m __VA_OPT__(,) __VA_ARGS__);\
		goto l;\
	}} while (0);

/* 8 to 64 bits fit into basic types */

#if entry_field_size == 8
#	ifdef entry_field_signed
		typedef int8_t field;
#	else
		typedef uint8_t field;
#	endif
#elif entry_field_size == 16
#	ifdef entry_field_signed
		typedef int16_t field;
#	else
		typedef uint16_t field;
#	endif
#elif entry_field_size == 32
#	ifdef entry_field_signed
		typedef int32_t field;
#	else
		typedef uint32_t field;
#	endif
#elif entry_field_size == 64
#	ifdef entry_field_signed
		typedef int64_t field;
#	else
		typedef uint64_t field;
#	endif

/* 128 bit and up do not fit in basic types; building composites */

#elif entry_field_size == 128
#	ifdef entry_field_signed
		typedef struct field {
			uint64_t low;
			int64_t high;
		} field;
#	else
		typedef struct field {
			uint64_t low;
			uint64_t high;
		} field;
#	endif
#elif entry_field_size == 256
#	ifdef entry_field_signed
		typedef struct field {
			uint64_t low;
			uint64_t midlow;
			uint64_t midhigh;
			int64_t high;
		} field;
#	else
		typedef struct field {
			uint64_t low;
			uint64_t midlow;
			uint64_t midhigh;
			uint64_t high;
		} field;
#	endif
#endif

union nextoff {
	struct entry_l *next;
	void *nextaddr;
	ptrdiff_t offset;
	int64_t spacer; /* make sure it is 8-byte-alligned on 32 bit pointer systems */
};

union cachewrap {
	char *cache;
	struct entry *cache_a;
	struct entry_l *cache_l;
};

/* for array implementation */
struct entry {
	field val;
};

/* for linked list implementation */
struct entry_l {
	struct entry;
	union nextoff;
};

enum opmode {
	mode_normal,
	mode_fetch,
	mode_generate
};

enum accessmode {
	cached,
	direct
};

enum dataformat {
	array,
	list
};

enum streamtype {
	stream_invalid,
	stream_in,
	stream_out,
	stream_lite,
	stream_cache,
	stream_randread
};

struct stream {
	size_t n;
	int fd;
	enum streamtype type;
	char *name;
	size_t index;
	struct entry_l *cnode; /* "current" node */
	union cachewrap;
	struct settings *settings;
	struct entry_l *(*get)(struct stream * const);
	int (*put)(struct stream * const, struct entry_l const * const);
	int (*split)(struct stream * const, struct stream * const, struct stream * const);
	int (*rewind)(struct stream * restrict const);
	int (*copy)(struct stream * restrict const, struct stream * restrict const);
};

struct settings {
	size_t ss;
	size_t to;
	size_t stride;
	char *filein;
	char *fileout;
	enum opmode opmode;
	enum dataformat format;
	enum accessmode access;
};

#endif /* ALGOS_DEFS_H_INCLUDED */