Started from buttom go to the sky

stdme/src/hash/sip/sip_utils.c

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+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   sip_utils.c                                        :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: maix <marvin@42.fr>                        +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2023/12/10 20:02:12 by maix              #+#    #+#             */
+/*   Updated: 2023/12/11 19:09:32 by maiboyer         ###   ########.fr       */
+/*                                                                            */
+/* ************************************************************************** */
+
+#include "me/hash/sip.h"
+#include "me/hash/sip/sip_utils.h"
+#include "me/num/u64.h"
+#include "me/num/usize.h"
+#include <stdio.h>
+#include <stdlib.h>
+
+static t_usize	me_min(t_usize lhs, t_usize rhs)
+{
+	if (lhs < rhs)
+		return (lhs);
+	return (rhs);
+}
+
+static t_usize	handle_remaining(t_sip13 *self, t_u8 *msg, t_usize count,
+		bool *exit_early)
+{
+	t_usize	needed;
+
+	needed = 0;
+	*exit_early = false;
+	if (self->ntail != 0)
+	{
+		needed = 8 - self->ntail;
+		self->tail |= u64_from_bytes(msg, me_min(count, needed)) << (8 \
+			* self->ntail);
+		if (count < needed)
+		{
+			self->ntail += count;
+			*exit_early = true;
+			return (needed);
+		}
+		else
+		{
+			self->state.v3 ^= self->tail;
+			compress(&self->state);
+			self->state.v0 ^= self->tail;
+			self->ntail = 0;
+		}
+	}
+	return (needed);
+}
+
+t_usize	read_u8_to_u64(t_u8 p[])
+{
+	return (((t_u64)((p)[0])) | ((t_u64)((p)[1]) << 8) | \
+	((t_u64)((p)[2]) << 16) | ((t_u64)((p)[3]) << 24) | \
+	((t_u64)((p)[4]) << 32) | ((t_u64)((p)[5]) << 40) | \
+	((t_u64)((p)[6]) << 48) | ((t_u64)((p)[7]) << 56));
+}
+
+void	sip13_write_bytes(t_sip13 *self, t_u8 *msg, t_usize count)
+{
+	bool	exit_early;
+	t_usize	needed;
+	t_usize	left;
+	t_usize	i;
+	t_u64	mi;
+
+	self->length += count;
+	needed = handle_remaining(self, msg, count, &exit_early);
+	if (exit_early)
+		return ;
+	count = count - needed;
+	left = count & 0x7;
+	i = needed;
+	while (i < count - left)
+	{
+		mi = read_u8_to_u64(msg + i);
+		self->state.v3 ^= mi;
+		compress(&self->state);
+		self->state.v0 ^= mi;
+		i += 8;
+	}
+	self->tail = u64_from_7bytes(msg, i, left);
+	self->ntail = left;
+}
+
+t_u64	sip13_finish(t_sip13 *self)
+{
+	t_sip_state	state;
+	t_u64		b;
+
+	state = self->state;
+	b = (((t_u64)self->length & 0xff) << 56) | self->tail;
+	state.v3 ^= b;
+	compress(&state);
+	state.v0 ^= b;
+	state.v2 ^= 0xff;
+	compress(&state);
+	compress(&state);
+	free(self);
+	return (state.v0 ^ state.v1 ^ state.v2 ^ state.v3);
+}