/*
 * Copyright (c) 2016-2020,2022,2024 Josef 'Jeff' Sipek <jeffpc@josefsipek.net>
 *
 * 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.
 */

#ifndef __JEFFPC_INT_H
#define __JEFFPC_INT_H

#include <sys/types.h>
#include <inttypes.h>
#include <limits.h>
#include <stdint.h>
#include <stddef.h>
#include <stdlib.h>
#include <stdbool.h>
#include <errno.h>

#include <jeffpc/config.h>

/*
 * string to integer conversion
 */
#define STR_TO_INT(size, imax)						\
static inline int str2u##size##_full(const char *restrict s,		\
				     uint##size##_t *i,			\
				     int base,				\
				     char terminator)			\
{									\
	char *endptr;							\
	uint64_t tmp;							\
									\
	*i = 0;								\
									\
	/*								\
	 * negative numbers aren't representable by uintXX_t; this may	\
	 * mask a -EINVAL if the input is of the form:			\
	 * "-<some non-number>"						\
	 */								\
	if (*s == '-')							\
		return -ERANGE;						\
									\
	errno = 0;							\
	tmp = strtoull(s, &endptr, base);				\
									\
	if (errno)							\
		return -errno;						\
									\
	/* parsed nothing or input is empty */				\
	if (endptr == s)						\
		return -EINVAL;						\
									\
	/* first unparsed char must be the expected terminator */	\
	if (*endptr != (terminator))					\
		return -EINVAL;						\
									\
	if (tmp > imax)							\
		return -ERANGE;						\
									\
	*i = tmp;							\
	return 0;							\
}

STR_TO_INT(64, 0xffffffffffffffffull)
STR_TO_INT(32, 0x00000000fffffffful)
STR_TO_INT(16, 0x000000000000fffful)
STR_TO_INT(8,  0x00000000000000fful)

#undef STR_TO_INT

/*
 * string to float conversion
 */

#define STR_TO_FLOAT(type, cvtfxn)					\
static inline int str2##type##_full(const char *restrict s,		\
				    type *n,				\
				    char terminator)			\
{									\
	char *endptr;							\
	type tmp;							\
									\
	*n = 0;								\
									\
	errno = 0;							\
	tmp = cvtfxn(s, &endptr);					\
									\
	if (errno)							\
		return -errno;						\
									\
	/* parsed nothing or input is empty */				\
	if (endptr == s)						\
		return -EINVAL;						\
									\
	/* first unparsed char must be the expected terminator */	\
	if (*endptr != (terminator))					\
		return -EINVAL;						\
									\
	*n = tmp;							\
	return 0;							\
}

STR_TO_FLOAT(float, strtof)
STR_TO_FLOAT(double, strtod)

#undef STR_TO_FLOAT

/*
 * These prototypes exist to catch bugs in the code generating macros above.
 */
static inline int str2u64_full(const char *restrict s, uint64_t *i,
			       int base, char terminator);
static inline int str2u32_full(const char *restrict s, uint32_t *i,
			       int base, char terminator);
static inline int str2u16_full(const char *restrict s, uint16_t *i,
			       int base, char terminator);
static inline int str2u8_full(const char *restrict s, uint8_t *i,
			      int base, char terminator);

static inline int str2float_full(const char *restrict s, float *n,
				 char terminator);
static inline int str2double_full(const char *restrict s, double *n,
				  char terminator);

/* base [2, 36], nul-terminated */
#define str2u64_base(s, i, b)	str2u64_full((s), (i), (b), '\0')
#define str2u32_base(s, i, b)	str2u32_full((s), (i), (b), '\0')
#define str2u16_base(s, i, b)	str2u16_full((s), (i), (b), '\0')
#define str2u8_base(s, i, b)	str2u8_full((s), (i), (b), '\0')

/* base 10, nul-terminated */
#define str2u64(s, i)	str2u64_full((s), (i), 10, '\0')
#define str2u32(s, i)	str2u32_full((s), (i), 10, '\0')
#define str2u16(s, i)	str2u16_full((s), (i), 10, '\0')
#define str2u8(s, i)	str2u8_full((s), (i), 10, '\0')

/* floats (base 2 and 10), nul-terminated */
#define str2float(s, n)		str2float_full((s), (n), '\0')
#define str2double(s, n)	str2double_full((s), (n), '\0')

/*
 * Powers of 2 mangling
 */
/* is the value a power of two? */
static inline bool is_p2(uint64_t val)
{
	return !(val & (val - 1));
}

/* round val to the next multiple of align (a power of 2) */
static inline uint64_t p2roundup(uint64_t val, uint64_t align)
{
	if (align <= 1)
		return val;

	/*
	 * alignment must be a power of two - if it isn't, panic
	 *
	 * Note: We cannot include error.h since we don't want everyone that
	 * includes in types.h (and therefore int.h) to automatically pull
	 * in error.h.  We work around it by making a local prototype and
	 * then calling it.  This is still type safe, since many places
	 * include both error.h (and therefore get the real panic prototype)
	 * and this header.  In those compilation units, the compiler makes
	 * sure that the two signatures match.  No warnings/errors there,
	 * imply that the below prototype is 100% correct.
	 */
	if (!is_p2(align)) {
		extern void panic(const char *, ...);

		panic("roundup - non-power of 2 align: %#"PRIx64, align);
	}

	return (val + (align - 1)) & ~(align - 1);
}

/*
 * These prototypes exist to catch bugs in the code generating macros below.
 */
/* return byte swapped input */
static inline uint64_t bswap_64(uint64_t in);
static inline uint32_t bswap_32(uint32_t in);
static inline uint16_t bswap_16(uint16_t in);
static inline uint8_t bswap_8(uint8_t in);

/* load an unaligned cpu native endian number from memory */
static inline uint64_t cpu64_to_cpu_unaligned(const void *in);
static inline uint32_t cpu32_to_cpu_unaligned(const void *in);
static inline uint16_t cpu16_to_cpu_unaligned(const void *in);
static inline uint8_t cpu8_to_cpu_unaligned(const void *in);

/* load an unaligned big endian number from memory */
static inline uint64_t be64_to_cpu_unaligned(const void *in);
static inline uint32_t be32_to_cpu_unaligned(const void *in);
static inline uint16_t be16_to_cpu_unaligned(const void *in);
static inline uint8_t be8_to_cpu_unaligned(const void *in);

/* load an unaligned little endian number from memory */
static inline uint64_t le64_to_cpu_unaligned(const void *in);
static inline uint32_t le32_to_cpu_unaligned(const void *in);
static inline uint16_t le16_to_cpu_unaligned(const void *in);
static inline uint8_t le8_to_cpu_unaligned(const void *in);

/* store into memory a cpu native endian number as a big endian number */
static inline void cpu64_to_be_unaligned(uint64_t in, void *out);
static inline void cpu32_to_be_unaligned(uint32_t in, void *out);
static inline void cpu16_to_be_unaligned(uint16_t in, void *out);
static inline void cpu8_to_be_unaligned(uint8_t in, void *out);

/* store into memory a cpu native endian number as a little endian number */
static inline void cpu64_to_le_unaligned(uint64_t in, void *out);
static inline void cpu32_to_le_unaligned(uint32_t in, void *out);
static inline void cpu16_to_le_unaligned(uint16_t in, void *out);
static inline void cpu8_to_le_unaligned(uint8_t in, void *out);

/* convert a big endian input into cpu native endian */
static inline uint64_t be64_to_cpu(uint64_t in);
static inline uint32_t be32_to_cpu(uint32_t in);
static inline uint16_t be16_to_cpu(uint16_t in);
static inline uint8_t be8_to_cpu(uint8_t in);

/* convert a cpu native endian input into big endian */
static inline uint64_t cpu64_to_be(uint64_t in);
static inline uint32_t cpu32_to_be(uint32_t in);
static inline uint16_t cpu16_to_be(uint16_t in);
static inline uint8_t cpu8_to_be(uint8_t in);

/* convert a little endian input into cpu native endian */
static inline uint64_t le64_to_cpu(uint64_t in);
static inline uint32_t le32_to_cpu(uint32_t in);
static inline uint16_t le16_to_cpu(uint16_t in);
static inline uint8_t le8_to_cpu(uint8_t in);

/* convert a cpu native endian input into little endian */
static inline uint64_t cpu64_to_le(uint64_t in);
static inline uint32_t cpu32_to_le(uint32_t in);
static inline uint16_t cpu16_to_le(uint16_t in);
static inline uint8_t cpu8_to_le(uint8_t in);

/*
 * byte swapping
 */
static inline uint64_t bswap_64(uint64_t in)
{
	return ((in & 0xff00000000000000ull) >> 56) |
	       ((in & 0x00ff000000000000ull) >> 40) |
	       ((in & 0x0000ff0000000000ull) >> 24) |
	       ((in & 0x000000ff00000000ull) >> 8) |
	       ((in & 0x00000000ff000000ull) << 8) |
	       ((in & 0x0000000000ff0000ull) << 24) |
	       ((in & 0x000000000000ff00ull) << 40) |
	       ((in & 0x00000000000000ffull) << 56);
}

static inline uint32_t bswap_32(uint32_t in)
{
	return ((in & 0xff000000) >> 24) |
	       ((in & 0x00ff0000) >> 8) |
	       ((in & 0x0000ff00) << 8) |
	       ((in & 0x000000ff) << 24);
}

static inline uint16_t bswap_16(uint16_t in)
{
	return ((in & 0xff00) >> 8) |
	       ((in & 0x00ff) << 8);
}

static inline uint8_t bswap_8(uint8_t in)
{
	return (in & 0xff);
}

/*
 * unaligned big-endian integer
 */
static inline uint64_t be64_to_cpu_unaligned(const void *in)
{
	const uint8_t *p = in;

	return (((uint64_t) p[0] << 56) |
		((uint64_t) p[1] << 48) |
		((uint64_t) p[2] << 40) |
		((uint64_t) p[3] << 32) |
		((uint64_t) p[4] << 24) |
		((uint64_t) p[5] << 16) |
		((uint64_t) p[6] << 8) |
		((uint64_t) p[7]));
}

static inline void cpu64_to_be_unaligned(uint64_t in, void *out)
{
	uint8_t *p = out;

	p[0] = (in >> 56) & 0xff;
	p[1] = (in >> 48) & 0xff;
	p[2] = (in >> 40) & 0xff;
	p[3] = (in >> 32) & 0xff;
	p[4] = (in >> 24) & 0xff;
	p[5] = (in >> 16) & 0xff;
	p[6] = (in >> 8) & 0xff;
	p[7] = in & 0xff;
}

static inline uint32_t be32_to_cpu_unaligned(const void *in)
{
	const uint8_t *p = in;

	return (((uint32_t) p[0] << 24) |
		((uint32_t) p[1] << 16) |
		((uint32_t) p[2] << 8) |
		((uint32_t) p[3]));
}

static inline void cpu32_to_be_unaligned(uint32_t in, void *out)
{
	uint8_t *p = out;

	p[0] = (in >> 24) & 0xff;
	p[1] = (in >> 16) & 0xff;
	p[2] = (in >> 8) & 0xff;
	p[3] = in & 0xff;
}

static inline uint16_t be16_to_cpu_unaligned(const void *in)
{
	const uint8_t *p = in;

	return (((uint16_t) p[0] << 8) |
		((uint16_t) p[1]));
}

static inline void cpu16_to_be_unaligned(uint16_t in, void *out)
{
	uint8_t *p = out;

	p[0] = (in >> 8) & 0xff;
	p[1] = in & 0xff;
}

static inline uint8_t be8_to_cpu_unaligned(const void *in)
{
	return *((const uint8_t *) in);
}

static inline void cpu8_to_be_unaligned(uint8_t in, void *out)
{
	uint8_t *p = out;

	*p = in;
}

/*
 * unaligned little-endian & cpu-endian integers
 */
#define __GEN(size, bswap)						\
static inline uint##size##_t le##size##_to_cpu_unaligned(const void *in)\
{									\
	uint##size##_t x = be##size##_to_cpu_unaligned(in);		\
	/* we read a LE int as BE, so we always have to byte swap */	\
	return bswap_##size(x);						\
}									\
static inline void cpu##size##_to_le_unaligned(uint##size##_t in,	\
					       void *out)		\
{									\
	/* we'll be writing in BE, so we always have to byte swap */	\
	cpu##size##_to_be_unaligned(bswap_##size(in), out);		\
}									\
static inline uint##size##_t cpu##size##_to_cpu_unaligned(const void *in)\
{									\
	uint##size##_t x = be##size##_to_cpu_unaligned(in);		\
	return bswap;							\
}

#ifdef JEFFPC_CPU_BIG_ENDIAN
#define GEN(size)	__GEN(size, x)
#else
#define GEN(size)	__GEN(size, bswap_##size(x))
#endif

GEN(64)
GEN(32)
GEN(16)
GEN(8)

#undef __GEN
#undef GEN

/*
 * byte ordering
 */
#define ___GEN(from, size, to, bswap)					\
static inline uint##size##_t from##size##_to_##to(uint##size##_t x)	\
{									\
	return bswap;							\
}

#ifdef JEFFPC_CPU_BIG_ENDIAN
#define __GEN(from, size, to, be, le) ___GEN(from, size, to, be)
#else
#define __GEN(from, size, to, be, le) ___GEN(from, size, to, le)
#endif

#define GEN(size)							\
	__GEN(be,  size, cpu, x, bswap_##size(x))			\
	__GEN(cpu, size, be,  x, bswap_##size(x))			\
	__GEN(le,  size, cpu, bswap_##size(x), x)			\
	__GEN(cpu, size, le,  bswap_##size(x), x)

GEN(64)
GEN(32)
GEN(16)
GEN(8)

#undef ___GEN
#undef __GEN
#undef GEN

#endif