commit 196660ccb172f5c7244fabef1ab1313b0c6c5bd9
Author: Felix Suchert <dev@felixsuchert.de>
Date:   Sun Dec 25 21:15:50 2022 +0100

    Add day 1, task 1

diff --git a/day_1/Makefile b/day_1/Makefile
new file mode 100644
index 0000000..545eddb
--- /dev/null
+++ b/day_1/Makefile
@@ -0,0 +1,54 @@
+CC := clang
+YACC := bison
+LEX := flex
+CFLAGS := -std=c17 -Wpedantic -Wall -Wextra
+BUILD := ./build
+INCLUDE	:= -I./
+OBJ_DIR := $(BUILD)/objects
+APP_DIR := $(BUILD)/bin
+TARGET := day_1
+
+SRC := $(wildcard ./*.cpp) lexer.c parser.c
+
+OBJECTS	:= $(SRC:%.c=$(OBJ_DIR)/%.o)
+
+# targets
+all: build $(APP_DIR)/$(TARGET)
+
+run: all
+	$(APP_DIR)/$(TARGET)
+
+flex:
+	$(LEX) --outfile=lexer.c --header-file=lexer.h lexer.l
+
+bison:
+	$(YACC) --output=parser.c parser.y
+
+generate: flex bison
+
+$(OBJ_DIR)/%.o: %.c
+	@mkdir -p $(@D)
+	$(CC) $(CFLAGS) $(INCLUDE) -o $@ -c $<
+
+$(APP_DIR)/$(TARGET): flex bison $(OBJECTS)
+	@mkdir -p $(@D)
+	$(CC) $(CFLAGS) $(INCLUDE) $(LDFLAGS) -o $(APP_DIR)/$(TARGET) $(OBJECTS)
+
+.PHONY: all build clean debug release
+
+build:
+	@mkdir -p $(APP_DIR)
+	@mkdir -p $(OBJ_DIR)
+
+debug: CFLAGS += -DDEBUG -g
+debug: all
+
+sanitize: CFLAGS += -DDEBUG -g -fsanitize=address
+sanitize: all
+
+release: CFLAGS += -O2
+release: all
+
+clean:
+	-@rm -rvf $(BUILD)
+	-@rm -rvf {lexer.c,parser.c} {lexer.h,parser.h}
diff --git a/day_1/lexer.l b/day_1/lexer.l
new file mode 100644
index 0000000..6e92a74
--- /dev/null
+++ b/day_1/lexer.l
@@ -0,0 +1,53 @@
+%{ /* -*- C -*- */
+#include <stdio.h>
+#include <stdlib.h>
+#include "parser.h"
+%}
+
+%option warn nodefault
+
+/* makes the scanner terminate after reaching <<EOF>> instead of assuming a new input was provided */
+%option noyywrap
+/* disable some unused functionality, add scanner tracking */
+%option nounput noinput batch debug
+
+/* gimme a reentrant parser (overkill but more pure) */
+%option reentrant
+
+%option bison-bridge
+
+
+NL      [\n]
+NUM     [0-9]
+
+
+%%
+
+{NL}        {
+                return NEWLINE;
+            }
+{NUM}+      {
+                unsigned num = strtoul(yytext, NULL, 10);
+                printf("number: %d\n", num);
+                yylval->num = num;
+                return NUMBER;
+            }
+<<EOF>>     {
+                return END_OF_FILE;
+            }
+.           {
+                printf("[error] Encountered unexpected token %s\n", yytext);
+                return 0;
+            }
+
+%%
+
+/*int main() {*/
+    /*std::cout << "hello" << std::endl;*/
+
+    /*yyFlexLexer scanner;*/
+    /*scanner.yylex();*/
+
+    /*std::cout << "done" << std::endl;*/
+    /*return 0;*/
+/*}*/
diff --git a/day_1/parser.y b/day_1/parser.y
new file mode 100644
index 0000000..7818687
--- /dev/null
+++ b/day_1/parser.y
@@ -0,0 +1,111 @@
+/* Require bison minimal version */
+%require "3.2"
+
+/* write out a header file containing the token defines */
+%header
+
+// Code for the c file
+%{
+    #include <stdio.h>
+    #include <stdlib.h>
+    #include "parser.h"
+    #include "lexer.h"
+
+    void push_value(struct parser_state* state) {
+        // TODO(feliix42): error handling here?
+        state->calorie_list = realloc(state->calorie_list, state->size+1);
+        state->calorie_list[state->size] = state->tmp_val;
+        state->tmp_val = 0;
+        state->size++;
+    }
+
+    void yyerror(struct parser_state* state, yyscan_t scanner, const char* msg) {
+        (void)state;
+        (void)scanner;
+        fprintf(stderr, "\033[93mSyntax Error: %s\033[0m\n", msg);
+    }
+%}
+
+// Code for the header file generated by bison
+%code requires {
+    typedef void* yyscan_t;
+
+    struct parser_state {
+        unsigned tmp_val;
+        unsigned* calorie_list;
+        size_t size;
+    };
+}
+
+// define a reentrant parser
+%define api.pure
+
+// enable parser tracing and detailed error messages (plus Lookahead Correction)
+%define parse.trace
+%define parse.error detailed
+%define parse.lac full
+
+%lex-param   { yyscan_t scanner }
+%parse-param { struct parser_state* state }
+%parse-param { yyscan_t scanner }
+
+%union {
+    unsigned long num;
+}
+
+
+%start input
+%token NEWLINE END_OF_FILE
+%token <unsigned> NUMBER
+
+%%
+
+input
+    : line input
+    | END_OF_FILE       { /* done. */ }
+    ;
+
+line
+    : NUMBER NEWLINE    { state->tmp_val += yylval.num; }
+    | NEWLINE           { push_value(state); }
+    ;
+
+%%
+
+int main(int argc, char** argv) {
+    struct parser_state* parser_state = calloc(1, sizeof(struct parser_state));
+    if (!parser_state) {
+        fprintf(stderr, "[error] failed to allocate parser state\n");
+        return EXIT_FAILURE;
+    }
+    
+    yyscan_t scanner;
+    /*YY_BUFFER_STATE state;*/
+
+    printf("Hello World\n");
+    if (yylex_init(&scanner)) {
+        fprintf(stderr, "\033[91m[error] Could not initialize lexer\n");
+        return EXIT_FAILURE;
+    }
+
+    if (yyparse(parser_state, scanner)) {
+		// TODO: Error handling https://www.gnu.org/software/bison/manual/html_node/Parser-Function.html
+		// error during parse occured
+		return EXIT_FAILURE;
+	}
+
+    yylex_destroy(scanner);
+    
+    // task 1.1
+    unsigned max_val = 0;
+    for (int i = 0; i < parser_state->size; i++) {
+        if (parser_state->calorie_list[i] > max_val) {
+            max_val = parser_state->calorie_list[i];
+        }
+    }
+
+    printf("Largest individual calorie load: %d\n", max_val);
+
+
+    return 0;
+}
diff --git a/day_1/state.c b/day_1/state.c
new file mode 100644
index 0000000..3323891
--- /dev/null
+++ b/day_1/state.c
@@ -0,0 +1,15 @@
+#include <stdlib.h>
+
+struct parser_state {
+    unsigned tmp_val;
+    unsigned* calorie_list;
+    size_t size;
+};
+
+void push_value(struct parser_state* state) {
+    // TODO(feliix42): error handling here?
+    state->calorie_list = realloc(state->calorie_list, state->size+1);
+    state->calorie_list[state->size] = state->tmp_val;
+    state->tmp_val = 0;
+    state->size++;
+}