/***************************************************************************
 *   Copyright (C) 2004, 2005 by Dominic Rath                              *
 *   Dominic.Rath@gmx.de                                                   *
 *                                                                         *
 *   Copyright (C) 2007,2008 Øyvind Harboe                                 *
 *   oyvind.harboe@zylin.com                                               *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>. *
 ***************************************************************************/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "log.h"
#include "binarybuffer.h"

static const unsigned char bit_reverse_table256[] = {
	0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0, 0x10, 0x90, 0x50, 0xD0, 0x30, 0xB0, 0x70, 0xF0,
	0x08, 0x88, 0x48, 0xC8, 0x28, 0xA8, 0x68, 0xE8, 0x18, 0x98, 0x58, 0xD8, 0x38, 0xB8, 0x78, 0xF8,
	0x04, 0x84, 0x44, 0xC4, 0x24, 0xA4, 0x64, 0xE4, 0x14, 0x94, 0x54, 0xD4, 0x34, 0xB4, 0x74, 0xF4,
	0x0C, 0x8C, 0x4C, 0xCC, 0x2C, 0xAC, 0x6C, 0xEC, 0x1C, 0x9C, 0x5C, 0xDC, 0x3C, 0xBC, 0x7C, 0xFC,
	0x02, 0x82, 0x42, 0xC2, 0x22, 0xA2, 0x62, 0xE2, 0x12, 0x92, 0x52, 0xD2, 0x32, 0xB2, 0x72, 0xF2,
	0x0A, 0x8A, 0x4A, 0xCA, 0x2A, 0xAA, 0x6A, 0xEA, 0x1A, 0x9A, 0x5A, 0xDA, 0x3A, 0xBA, 0x7A, 0xFA,
	0x06, 0x86, 0x46, 0xC6, 0x26, 0xA6, 0x66, 0xE6, 0x16, 0x96, 0x56, 0xD6, 0x36, 0xB6, 0x76, 0xF6,
	0x0E, 0x8E, 0x4E, 0xCE, 0x2E, 0xAE, 0x6E, 0xEE, 0x1E, 0x9E, 0x5E, 0xDE, 0x3E, 0xBE, 0x7E, 0xFE,
	0x01, 0x81, 0x41, 0xC1, 0x21, 0xA1, 0x61, 0xE1, 0x11, 0x91, 0x51, 0xD1, 0x31, 0xB1, 0x71, 0xF1,
	0x09, 0x89, 0x49, 0xC9, 0x29, 0xA9, 0x69, 0xE9, 0x19, 0x99, 0x59, 0xD9, 0x39, 0xB9, 0x79, 0xF9,
	0x05, 0x85, 0x45, 0xC5, 0x25, 0xA5, 0x65, 0xE5, 0x15, 0x95, 0x55, 0xD5, 0x35, 0xB5, 0x75, 0xF5,
	0x0D, 0x8D, 0x4D, 0xCD, 0x2D, 0xAD, 0x6D, 0xED, 0x1D, 0x9D, 0x5D, 0xDD, 0x3D, 0xBD, 0x7D, 0xFD,
	0x03, 0x83, 0x43, 0xC3, 0x23, 0xA3, 0x63, 0xE3, 0x13, 0x93, 0x53, 0xD3, 0x33, 0xB3, 0x73, 0xF3,
	0x0B, 0x8B, 0x4B, 0xCB, 0x2B, 0xAB, 0x6B, 0xEB, 0x1B, 0x9B, 0x5B, 0xDB, 0x3B, 0xBB, 0x7B, 0xFB,
	0x07, 0x87, 0x47, 0xC7, 0x27, 0xA7, 0x67, 0xE7, 0x17, 0x97, 0x57, 0xD7, 0x37, 0xB7, 0x77, 0xF7,
	0x0F, 0x8F, 0x4F, 0xCF, 0x2F, 0xAF, 0x6F, 0xEF, 0x1F, 0x9F, 0x5F, 0xDF, 0x3F, 0xBF, 0x7F, 0xFF
};

static const char hex_digits[] = {
	'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
	'a', 'b', 'c', 'd', 'e', 'f'
};

void *buf_cpy(const void *from, void *_to, unsigned size)
{
	if (NULL == from || NULL == _to)
		return NULL;

	/* copy entire buffer */
	memcpy(_to, from, DIV_ROUND_UP(size, 8));

	/* mask out bits that don't belong to the buffer */
	unsigned trailing_bits = size % 8;
	if (trailing_bits) {
		uint8_t *to = _to;
		to[size / 8] &= (1 << trailing_bits) - 1;
	}
	return _to;
}

static bool buf_cmp_masked(uint8_t a, uint8_t b, uint8_t m)
{
	return (a & m) != (b & m);
}
static bool buf_cmp_trailing(uint8_t a, uint8_t b, uint8_t m, unsigned trailing)
{
	uint8_t mask = (1 << trailing) - 1;
	return buf_cmp_masked(a, b, mask & m);
}

bool buf_cmp(const void *_buf1, const void *_buf2, unsigned size)
{
	if (!_buf1 || !_buf2)
		return _buf1 != _buf2;

	unsigned last = size / 8;
	if (memcmp(_buf1, _buf2, last) != 0)
		return false;

	unsigned trailing = size % 8;
	if (!trailing)
		return false;

	const uint8_t *buf1 = _buf1, *buf2 = _buf2;
	return buf_cmp_trailing(buf1[last], buf2[last], 0xff, trailing);
}

bool buf_cmp_mask(const void *_buf1, const void *_buf2,
	const void *_mask, unsigned size)
{
	if (!_buf1 || !_buf2)
		return _buf1 != _buf2 || _buf1 != _mask;

	const uint8_t *buf1 = _buf1, *buf2 = _buf2, *mask = _mask;
	unsigned last = size / 8;
	for (unsigned i = 0; i < last; i++) {
		if (buf_cmp_masked(buf1[i], buf2[i], mask[i]))
			return true;
	}
	unsigned trailing = size % 8;
	if (!trailing)
		return false;
	return buf_cmp_trailing(buf1[last], buf2[last], mask[last], trailing);
}


void *buf_set_ones(void *_buf, unsigned size)
{
	uint8_t *buf = _buf;
	if (!buf)
		return NULL;

	memset(buf, 0xff, size / 8);

	unsigned trailing_bits = size % 8;
	if (trailing_bits)
		buf[size / 8] = (1 << trailing_bits) - 1;

	return buf;
}

void *buf_set_buf(const void *_src, unsigned src_start,
	void *_dst, unsigned dst_start, unsigned len)
{
	const uint8_t *src = _src;
	uint8_t *dst = _dst;
	unsigned i, sb, db, sq, dq, lb, lq;

	sb = src_start / 8;
	db = dst_start / 8;
	sq = src_start % 8;
	dq = dst_start % 8;
	lb = len / 8;
	lq = len % 8;

	src += sb;
	dst += db;

	/* check if both buffers are on byte boundary and
	 * len is a multiple of 8bit so we can simple copy
	 * the buffer */
	if ((sq == 0) && (dq == 0) &&  (lq == 0)) {
		for (i = 0; i < lb; i++)
			*dst++ = *src++;
		return _dst;
	}

	/* fallback to slow bit copy */
	for (i = 0; i < len; i++) {
		if (((*src >> (sq&7)) & 1) == 1)
			*dst |= 1 << (dq&7);
		else
			*dst &= ~(1 << (dq&7));
		if (sq++ == 7) {
			sq = 0;
			src++;
		}
		if (dq++ == 7) {
			dq = 0;
			dst++;
		}
	}

	return _dst;
}

uint32_t flip_u32(uint32_t value, unsigned int num)
{
	uint32_t c = (bit_reverse_table256[value & 0xff] << 24) |
		(bit_reverse_table256[(value >> 8) & 0xff] << 16) |
		(bit_reverse_table256[(value >> 16) & 0xff] << 8) |
		(bit_reverse_table256[(value >> 24) & 0xff]);

	if (num < 32)
		c = c >> (32 - num);

	return c;
}

static int ceil_f_to_u32(float x)
{
	if (x < 0)	/* return zero for negative numbers */
		return 0;

	uint32_t y = x;	/* cut off fraction */

	if ((x - y) > 0.0)	/* if there was a fractional part, increase by one */
		y++;

	return y;
}

char *buf_to_str(const void *_buf, unsigned buf_len, unsigned radix)
{
	float factor;
	switch (radix) {
		case 16:
			factor = 2.0;	/* log(256) / log(16) = 2.0 */
			break;
		case 10:
			factor = 2.40824;	/* log(256) / log(10) = 2.40824 */
			break;
		case 8:
			factor = 2.66667;	/* log(256) / log(8) = 2.66667 */
			break;
		default:
			return NULL;
	}

	unsigned str_len = ceil_f_to_u32(DIV_ROUND_UP(buf_len, 8) * factor);
	char *str = calloc(str_len + 1, 1);

	const uint8_t *buf = _buf;
	int b256_len = DIV_ROUND_UP(buf_len, 8);
	for (int i = b256_len - 1; i >= 0; i--) {
		uint32_t tmp = buf[i];
		if (((unsigned)i == (buf_len / 8)) && (buf_len % 8))
			tmp &= (0xff >> (8 - (buf_len % 8)));

		/* base-256 digits */
		for (unsigned j = str_len; j > 0; j--) {
			tmp += (uint32_t)str[j-1] * 256;
			str[j-1] = (uint8_t)(tmp % radix);
			tmp /= radix;
		}
	}

	const char * const DIGITS = "0123456789ABCDEF";
	for (unsigned j = 0; j < str_len; j++)
		str[j] = DIGITS[(int)str[j]];

	return str;
}

/** identify radix, and skip radix-prefix (0, 0x or 0X) */
static void str_radix_guess(const char **_str, unsigned *_str_len,
	unsigned *_radix)
{
	unsigned radix = *_radix;
	if (0 != radix)
		return;
	const char *str = *_str;
	unsigned str_len = *_str_len;
	if (str[0] == '0' && (str[1] == 'x' || str[1] == 'X')) {
		radix = 16;
		str += 2;
		str_len -= 2;
	} else if ((str[0] == '0') && (str_len != 1)) {
		radix = 8;
		str += 1;
		str_len -= 1;
	} else
		radix = 10;
	*_str = str;
	*_str_len = str_len;
	*_radix = radix;
}

int str_to_buf(const char *str, unsigned str_len,
	void *_buf, unsigned buf_len, unsigned radix)
{
	str_radix_guess(&str, &str_len, &radix);

	float factor;
	if (radix == 16)
		factor = 0.5;	/* log(16) / log(256) = 0.5 */
	else if (radix == 10)
		factor = 0.41524;	/* log(10) / log(256) = 0.41524 */
	else if (radix == 8)
		factor = 0.375;	/* log(8) / log(256) = 0.375 */
	else
		return 0;

	/* copy to zero-terminated buffer */
	char *charbuf = strndup(str, str_len);

	/* number of digits in base-256 notation */
	unsigned b256_len = ceil_f_to_u32(str_len * factor);
	uint8_t *b256_buf = calloc(b256_len, 1);

	/* go through zero terminated buffer
	 * input digits (ASCII) */
	unsigned i;
	for (i = 0; charbuf[i]; i++) {
		uint32_t tmp = charbuf[i];
		if ((tmp >= '0') && (tmp <= '9'))
			tmp = (tmp - '0');
		else if ((tmp >= 'a') && (tmp <= 'f'))
			tmp = (tmp - 'a' + 10);
		else if ((tmp >= 'A') && (tmp <= 'F'))
			tmp = (tmp - 'A' + 10);
		else
			continue;	/* skip characters other than [0-9,a-f,A-F] */

		if (tmp >= radix)
			continue;	/* skip digits invalid for the current radix */

		/* base-256 digits */
		for (unsigned j = 0; j < b256_len; j++) {
			tmp += (uint32_t)b256_buf[j] * radix;
			b256_buf[j] = (uint8_t)(tmp & 0xFF);
			tmp >>= 8;
		}

	}

	uint8_t *buf = _buf;
	for (unsigned j = 0; j < DIV_ROUND_UP(buf_len, 8); j++) {
		if (j < b256_len)
			buf[j] = b256_buf[j];
		else
			buf[j] = 0;
	}

	/* mask out bits that don't belong to the buffer */
	if (buf_len % 8)
		buf[(buf_len / 8)] &= 0xff >> (8 - (buf_len % 8));

	free(b256_buf);
	free(charbuf);

	return i;
}

void bit_copy_queue_init(struct bit_copy_queue *q)
{
	INIT_LIST_HEAD(&q->list);
}

int bit_copy_queued(struct bit_copy_queue *q, uint8_t *dst, unsigned dst_offset, const uint8_t *src,
	unsigned src_offset, unsigned bit_count)
{
	struct bit_copy_queue_entry *qe = malloc(sizeof(*qe));
	if (!qe)
		return ERROR_FAIL;

	qe->dst = dst;
	qe->dst_offset = dst_offset;
	qe->src = src;
	qe->src_offset = src_offset;
	qe->bit_count = bit_count;
	list_add_tail(&qe->list, &q->list);

	return ERROR_OK;
}

void bit_copy_execute(struct bit_copy_queue *q)
{
	struct bit_copy_queue_entry *qe;
	struct bit_copy_queue_entry *tmp;
	list_for_each_entry_safe(qe, tmp, &q->list, list) {
		bit_copy(qe->dst, qe->dst_offset, qe->src, qe->src_offset, qe->bit_count);
		list_del(&qe->list);
		free(qe);
	}
}

void bit_copy_discard(struct bit_copy_queue *q)
{
	struct bit_copy_queue_entry *qe;
	struct bit_copy_queue_entry *tmp;
	list_for_each_entry_safe(qe, tmp, &q->list, list) {
		list_del(&qe->list);
		free(qe);
	}
}

/**
 * Convert a string of hexadecimal pairs into its binary
 * representation.
 *
 * @param[out] bin Buffer to store binary representation. The buffer size must
 *                 be at least @p count.
 * @param[in] hex String with hexadecimal pairs to convert into its binary
 *                representation.
 * @param[in] count Number of hexadecimal pairs to convert.
 *
 * @return The number of converted hexadecimal pairs.
 */
size_t unhexify(uint8_t *bin, const char *hex, size_t count)
{
	size_t i;
	char tmp;

	if (!bin || !hex)
		return 0;

	memset(bin, 0, count);

	for (i = 0; i < 2 * count; i++) {
		if (hex[i] >= 'a' && hex[i] <= 'f')
			tmp = hex[i] - 'a' + 10;
		else if (hex[i] >= 'A' && hex[i] <= 'F')
			tmp = hex[i] - 'A' + 10;
		else if (hex[i] >= '0' && hex[i] <= '9')
			tmp = hex[i] - '0';
		else
			return i / 2;

		bin[i / 2] |= tmp << (4 * ((i + 1) % 2));
	}

	return i / 2;
}

/**
 * Convert binary data into a string of hexadecimal pairs.
 *
 * @param[out] hex Buffer to store string of hexadecimal pairs. The buffer size
 *                 must be at least @p length.
 * @param[in] bin Buffer with binary data to convert into hexadecimal pairs.
 * @param[in] count Number of bytes to convert.
 * @param[in] length Maximum number of characters, including null-terminator,
 *                   to store into @p hex.
 *
 * @returns The length of the converted string excluding null-terminator.
 */
size_t hexify(char *hex, const uint8_t *bin, size_t count, size_t length)
{
	size_t i;
	uint8_t tmp;

	if (!length)
		return 0;

	for (i = 0; i < length - 1 && i < 2 * count; i++) {
		tmp = (bin[i / 2] >> (4 * ((i + 1) % 2))) & 0x0f;
		hex[i] = hex_digits[tmp];
	}

	hex[i] = 0;

	return i;
}

void buffer_shr(void *_buf, unsigned buf_len, unsigned count)
{
	unsigned i;
	unsigned char *buf = _buf;
	unsigned bytes_to_remove;
	unsigned shift;

	bytes_to_remove = count / 8;
	shift = count - (bytes_to_remove * 8);

	for (i = 0; i < (buf_len - 1); i++)
		buf[i] = (buf[i] >> shift) | ((buf[i+1] << (8 - shift)) & 0xff);

	buf[(buf_len - 1)] = buf[(buf_len - 1)] >> shift;

	if (bytes_to_remove) {
		memmove(buf, &buf[bytes_to_remove], buf_len - bytes_to_remove);
		memset(&buf[buf_len - bytes_to_remove], 0, bytes_to_remove);
	}
}
