Day 2 Complete

* Added puzzle_input.c to help handle common input parsing
* Accepts a parser callback function to do the day specific parsing
* Updated day_1 to use new parsing system

CMakeLists.txt

@@ -3,4 +3,4 @@ project(aoc_2021 C)
 
 set(CMAKE_C_STANDARD 99)
 
-add_executable(aoc_2021 src/main.c src/day_1.c src/day.h)
+add_executable(aoc_2021 src/main.c src/day_1.c src/day.h src/day_2.c src/puzzle_input.c src/puzzle_input.h)

src/day.h

@@ -2,5 +2,6 @@
 #define AOC_2021_DAY_H
 
 int day_1();
+int day_2();
 
 #endif //AOC_2021_DAY_H

src/day_1.c

@@ -4,77 +4,11 @@
 #include <limits.h>
 
 #include "day.h"
+#include "puzzle_input.h"
 
 #define DATA_MAX_LEN 2048
 
-int parse_long_from_buff(char * buffer, int64_t * val) {
-    *val = strtol(buffer, NULL, 16);
-
-    if (*val == LONG_MIN || *val == LONG_MAX) {
-        return -2;
-    }
-
-    return 0;
-}
-
-int read_input(const char * file_path, int64_t *data, uint16_t max_len) {
-    char buffer[64];
-    int c;
-    int ret = 0;
-    FILE * file = fopen(file_path, "r");
-    int data_ndx = 0;
-
-    if (file != NULL) {
-        int buffer_ndx = 0;
-        while ((c = fgetc(file)) != EOF) {
-            if (c == '\n') {
-                buffer[buffer_ndx] = 0;
-
-                ret = parse_long_from_buff(buffer, &data[data_ndx]);
-
-                if (ret < 0) {
-                    break;
-                }
-
-                data_ndx++;
-
-                if (data_ndx >= max_len) {
-                    ret = -3;
-                    break;
-                }
-
-                buffer_ndx = 0;
-            }
-            else {
-                buffer[buffer_ndx] = (char)c;
-                buffer_ndx++;
-            }
-        }
-
-        if (buffer_ndx > 0) {
-            ret = parse_long_from_buff(buffer, &data[data_ndx]);
-
-            if (ret == 0) {
-                data_ndx++;
-            }
-        }
-    }
-    else {
-        ret = -1;
-    }
-
-    if (ret == 0) {
-        ret = data_ndx;
-    }
-
-    if (file != NULL) {
-        fclose(file);
-    }
-
-    return ret;
-}
-
-void part_1(const int64_t * data, uint16_t data_len) {
+static void part_1(const int64_t * data, uint16_t data_len) {
     int64_t last_value;
     int16_t inc_count = 0;
 
@@ -89,7 +23,7 @@ void part_1(const int64_t * data, uint16_t data_len) {
     printf("PART 1: %d values increased!\n", inc_count);
 }
 
-void part_2(const int64_t * data, uint16_t data_len) {
+static void part_2(const int64_t * data, uint16_t data_len) {
     int64_t old_window_sum;
     int64_t window_sum;
     int16_t inc_count = 0;
@@ -111,19 +45,19 @@ void part_2(const int64_t * data, uint16_t data_len) {
 
 int day_1() {
     char * path = "../inputs/day_1.txt";
-    int data_len;
+    uint16_t data_len;
     int64_t data[DATA_MAX_LEN];
 
-    data_len = read_input(path, data, DATA_MAX_LEN);
-
-    if (data_len < 0) {
-        printf("read_input returned an error: %d\n", data_len);
-        return data_len;
-    }
+    parse_ret_t res = read_input(path, (void *)data, DATA_MAX_LEN, parse_long_from_buff, &data_len);
 
+    if (res == PARSER_OK) {
         part_1(data, data_len);
-
         part_2(data, data_len);
+    }
+    else {
+        printf("Failed to parse data: %d\n", res);
+        return res;
+    }
 
     return 0;
 }

src/day_2.c

@@ -0,0 +1,120 @@
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <limits.h>
+#include <string.h>
+
+#include "puzzle_input.h"
+#include "day.h"
+
+#define MAX_COURSE_SIZE 1024
+
+typedef enum {
+    FORWARD,
+    DOWN ,
+    UP,
+} course_dir_t;
+
+typedef struct {
+    course_dir_t dir;
+    int64_t units;
+} course_entry_t;
+
+int parse_course_entry(char * buffer, void * data, uint16_t data_index) {
+    char * save_ptr;
+    char * dir_str = strtok_r(buffer, " ", &save_ptr);
+    char * unit_str = strtok_r(NULL, " ", &save_ptr);
+    parse_ret_t ret;
+    int64_t units;
+
+    ret = parse_long(unit_str, &units);
+
+    if (ret == PARSER_OK) {
+        course_dir_t dir;
+
+        switch (dir_str[0]) {
+            case 'f':
+                dir = FORWARD;
+                break;
+            case 'd':
+                dir = DOWN;
+                break;
+            case 'u':
+                dir = UP;
+                break;
+            default:
+                ret = PARSER_INVALID;
+        }
+
+        if (ret == PARSER_OK) {
+            course_entry_t entry = {
+                    .dir = dir,
+                    .units = units
+            };
+
+            course_entry_t *course = (course_entry_t *)data;
+            course[data_index] = entry;
+        }
+    }
+
+    return ret;
+}
+
+static void part_1(course_entry_t * course, uint16_t course_len) {
+    int64_t horizontal_pos = 0;
+    int64_t depth = 0;
+
+    for (int course_ndx = 0; course_ndx < course_len; course_ndx++) {
+        int dir_sign = 1;
+        switch (course[course_ndx].dir) {
+            case FORWARD:
+                horizontal_pos += course[course_ndx].units;
+                break;
+            case UP:
+                dir_sign = -1;
+            case DOWN:
+                depth += dir_sign*course[course_ndx].units;
+        }
+    }
+
+    printf("PART 1: Final Horizontal * Final Depth = %ld\n", horizontal_pos*depth);
+}
+
+static void part_2(course_entry_t * course, uint16_t course_len) {
+    int64_t horizontal_pos = 0;
+    int64_t depth = 0;
+    int64_t aim = 0;
+
+    for (int course_ndx = 0; course_ndx < course_len; course_ndx++) {
+        int dir_sign = 1;
+        int64_t units = course[course_ndx].units;
+        switch (course[course_ndx].dir) {
+            case FORWARD:
+                horizontal_pos += units;
+                depth += units * aim;
+                break;
+            case UP:
+                dir_sign = -1;
+            case DOWN:
+                aim += dir_sign*units;
+        }
+    }
+
+    printf("PART 2: Final Horizontal * Final Depth = %ld\n", horizontal_pos*depth);
+}
+
+int day_2() {
+    course_entry_t course[MAX_COURSE_SIZE];
+    uint16_t data_len;
+    parse_ret_t res = read_input("../inputs/day_2.txt", (void *)course, MAX_COURSE_SIZE, parse_course_entry, &data_len);
+
+    if (res == PARSER_OK) {
+        part_1(course, data_len);
+        part_2(course, data_len);
+    }
+    else {
+        printf("Failed to parse data: %d", res);
+    }
+}
+
+

src/main.c

@@ -19,6 +19,9 @@ int main(int argc, char * argv[]) {
         case 1:
             day_1();
             break;
+        case 2:
+            day_2();
+            break;
         default:
             printf("Invalid day ding dong!\n");
             return -2;

src/puzzle_input.c

@@ -0,0 +1,87 @@
+#include <limits.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdio.h>
+#include "puzzle_input.h"
+
+parse_ret_t parse_long(char * buffer, int64_t *val) {
+    *val = strtol(buffer, NULL, 10);
+
+    if (*val == LONG_MIN || *val == LONG_MAX) {
+        return PARSER_INVALID;
+    }
+
+    return PARSER_OK;
+
+}
+
+parse_ret_t parse_long_from_buff(char * buffer, void * data, uint16_t index) {
+    uint64_t * int_data = (uint64_t *)data;
+    uint64_t val;
+    int ret;
+
+    ret = parse_long(buffer, (int64_t *)&val);
+
+    if (ret != PARSER_OK) {
+        return ret;
+    }
+
+    int_data[index] = val;
+
+    return PARSER_OK;
+}
+
+parse_ret_t read_input(const char * file_path, void * data, uint16_t max_len, input_parser_t parser, uint16_t * len) {
+    char buffer[64];
+    int c;
+    int ret = 0;
+    FILE * file = fopen(file_path, "r");
+    uint16_t data_ndx = 0;
+
+    if (file != NULL) {
+        int buffer_ndx = 0;
+        while ((c = fgetc(file)) != EOF) {
+            if (c == '\n') {
+                buffer[buffer_ndx] = 0;
+
+                ret = parser(buffer, data, data_ndx);
+
+                if (ret != PARSER_OK) {
+                    break;
+                }
+
+                data_ndx++;
+
+                if (data_ndx >= max_len) {
+                    ret = PARSER_RANGE_OVERFLOW;
+                    break;
+                }
+
+                buffer_ndx = 0;
+            }
+            else {
+                buffer[buffer_ndx] = (char)c;
+                buffer_ndx++;
+            }
+        }
+
+        if (buffer_ndx > 0) {
+            ret = parser(buffer, data, data_ndx);
+
+            if (ret == PARSER_OK) {
+                data_ndx++;
+            }
+        }
+    }
+    else {
+        ret = PARSE_FILE_ERR;
+    }
+
+    if (file != NULL) {
+        fclose(file);
+    }
+
+    *len = data_ndx;
+
+    return ret;
+}

src/puzzle_input.h

@@ -0,0 +1,23 @@
+#ifndef AOC_2021_PUZZLE_INPUT_H
+#define AOC_2021_PUZZLE_INPUT_H
+
+#include <stdint.h>
+
+typedef enum {
+    PARSER_OK = 0,
+    PARSER_INVALID = -1,
+    PARSER_RANGE_OVERFLOW = -2,
+    PARSE_FILE_ERR = -3,
+} parse_ret_t;
+
+typedef parse_ret_t (*input_parser_t)(char * buffer, void * data, uint16_t index);
+
+parse_ret_t read_input(const char * file_path, void * data, uint16_t max_len, input_parser_t parser, uint16_t * len);
+
+// Parsers
+parse_ret_t parse_long_from_buff(char * buffer, void * data, uint16_t index);
+
+//Helpers
+parse_ret_t parse_long(char * buffer, int64_t * val);
+
+#endif //AOC_2021_PUZZLE_INPUT_H