From 3483cc605f6b952d30191fd2f79bdb0e658e0b0f Mon Sep 17 00:00:00 2001
From: kdx <kdx@42l.fr>
Date: Sun, 22 Jan 2023 05:11:18 +0100
Subject: blind scope write

---
 Makefile |  2 +-
 Scope.c  | 36 ++++++++++++++++++++++++++++++++++++
 Scope.h  | 17 +++++++++++++++++
 3 files changed, 54 insertions(+), 1 deletion(-)
 create mode 100644 Scope.c
 create mode 100644 Scope.h

diff --git a/Makefile b/Makefile
index 9c3b944..c4a46ec 100644
--- a/Makefile
+++ b/Makefile
@@ -4,7 +4,7 @@ SRC     := $(wildcard *.c)
 OBJ     := $(patsubst %.c,%.o,$(patsubst %.cpp,%.o,$(SRC)))
 NAME    := golem
 CFLAGS  := -g -O0 -Wall -Wextra -std=c99 -pedantic
-LDFLAGS :=
+LDFLAGS := -lxxhash
 
 all: $(NAME)
 
diff --git a/Scope.c b/Scope.c
new file mode 100644
index 0000000..3df00b9
--- /dev/null
+++ b/Scope.c
@@ -0,0 +1,36 @@
+#include "Scope.h"
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <xxhash.h>
+
+Scope *scope_create(const Scope *parent)
+{
+	Scope *const scope = malloc(sizeof(Scope));
+	if (scope == NULL) {
+		perror("scope_create");
+		return NULL;
+	}
+	scope->used = 0;
+	scope->parent = parent;
+	return scope;
+}
+
+int scope_insert(Scope *scope, const char *word, int value)
+{
+	if (scope->used >= SCOPE_WORD_MAX) {
+		fprintf(stderr, "scope full\n");
+		return 1;
+	}
+	const XXH32_hash_t hash = XXH32(word, strlen(word), 0);
+	for (int i = 0; i < scope->used; i++)
+		if (scope->words_hash[i] == hash) {
+			fprintf(stderr, "shadowed word\n");
+			return 1;
+		}
+	scope->words[scope->used] = word;
+	scope->values[scope->used] = value;
+	scope->words_hash[scope->used] = hash;
+	scope->used += 1;
+	return 0;
+}
diff --git a/Scope.h b/Scope.h
new file mode 100644
index 0000000..e5adacd
--- /dev/null
+++ b/Scope.h
@@ -0,0 +1,17 @@
+#pragma once
+#include <xxhash.h>
+
+#define SCOPE_WORD_MAX 256
+
+/* member strings are borrowed and shouldn't be freed by the node */
+typedef struct Scope Scope;
+struct Scope {
+	int used;
+	const char *words[SCOPE_WORD_MAX];
+	int values[SCOPE_WORD_MAX];
+	XXH32_hash_t words_hash[SCOPE_WORD_MAX];
+	const Scope *parent;
+};
+
+Scope *scope_create(const Scope *parent);
+int scope_insert(Scope *scope, const char *word, int value);
-- 
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