init(core): add core

README.md

@@ -0,0 +1,19 @@
+<h1 align="center">Tanabata file manager</h1>
+
+---
+
+## Contents
+
+- [About](#about)
+
+## About
+
+Tanabata (_jp._ 七夕) is a Japanese festival. People generally celebrate this day by writing wishes, sometimes in the form of poetry, on _tanzaku_ (_jp._ 短冊), small pieces of paper, and hanging them on _sasa_ (_jp._ 笹), bamboo. See [this Wikipedia page](https://en.wikipedia.org/wiki/Tanabata) for more information.
+
+Tanabata FM is a file manager for Linux that will let you enjoy the Tanabata festival. It organizes files as _sasa_ bamboos, on which you can hang almost any number of _tanzaku_, just like adding tags on it.
+
+By now, there is only the core of Tanabata FM.
+
+---
+
+<h6 align="center"><i>&copy; Masahiko AMANO aka H1K0, 2022—present</i></h6>

include/core.h

@@ -0,0 +1,172 @@
+// Tanabata file manager core lib
+// By Masahiko AMANO aka H1K0
+
+#ifndef TANABATA_CORE_H
+#define TANABATA_CORE_H
+
+#ifdef __cplusplus
+#include <cstdint>
+#include <cstdio>
+extern "C" {
+#else
+#include <stdint.h>
+#include <stdio.h>
+#endif
+
+// ==================== STRUCTS AND TYPEDEFS ==================== //
+
+// Sasa (笹) - a file record
+typedef struct sasa {
+    uint64_t  id;           // Sasa ID
+    uint64_t  created_ts;   // Sasa creation timestamp
+    char     *path;         // Path to file
+} Sasa;
+
+// Tanzaku (短冊) - a tag record
+typedef struct tanzaku {
+    uint64_t  id;           // Tanzaku ID
+    uint64_t  created_ts;   // Tanzaku creation timestamp
+    uint64_t  modified_ts;  // Tanzaku last modification timestamp
+    char     *name;         // Tanzaku name
+    char     *alias;        // Tanzaku alias
+    char     *description;  // Tanzaku description
+} Tanzaku;
+
+// Kazari (飾り) - a sasa-tanzaku association record
+typedef struct kazari {
+    uint64_t  created_ts;   // Kazari creation timestamp
+    uint64_t  sasa_id;      // Sasa ID
+    uint64_t  tanzaku_id;   // Tanzaku ID
+} Kazari;
+
+// Sasahyou (笹表) - the file database
+typedef struct sasahyou {
+    uint64_t  created_ts;   // Sasahyou creation timestamp
+    uint64_t  modified_ts;  // Sasahyou last modification timestamp
+    uint64_t  size;         // Sasahyou size (including unstaged units)
+    uint64_t  removed_cnt;  // Number of removed sasa
+    Sasa     *contents;     // Array of sasa
+    FILE     *file;         // Storage file for sasahyou
+} Sasahyou;
+
+// Sappyou (冊表) - the tanzaku database
+typedef struct sappyou {
+    uint64_t  created_ts;   // Sappyou creation timestamp
+    uint64_t  modified_ts;  // Sappyou last modification timestamp
+    uint64_t  size;         // Sappyou size
+    uint64_t  removed_cnt;  // Number of removed tanzaku
+    Tanzaku  *contents;     // Array of tanzaku
+    FILE     *file;         // Storage file for sappyou
+} Sappyou;
+
+// Shoppyou (飾表) - the kazari database
+typedef struct shoppyou {
+    uint64_t  created_ts;   // Shoppyou creation timestamp
+    uint64_t  modified_ts;  // Shoppyou last modification timestamp
+    uint64_t  size;         // Shoppyou size
+    uint64_t  removed_cnt;  // Number of removed kazari
+    Kazari   *contents;     // Array of kazari
+    FILE     *file;         // Storage file for shoppyou
+} Shoppyou;
+
+// ==================== FILE SIGNATURES ==================== //
+
+// Sasahyou file signature: 七夕笹表
+static const uint16_t SASAHYOU_SIG[4] = {L'七', L'夕', L'笹', L'表'};
+// Sappyou file signature: 七夕冊表
+static const uint16_t SAPPYOU_SIG[4] = {L'七', L'夕', L'冊', L'表'};
+// Shoppyou file signature: 七夕飾表
+static const uint16_t SHOPPYOU_SIG[4] = {L'七', L'夕', L'飾', L'表'};
+
+// ==================== SASAHYOU SECTION ==================== //
+
+// Initialize empty sasahyou
+int sasahyou_init(Sasahyou *sasahyou);
+
+// Free sasahyou
+int sasahyou_free(Sasahyou *sasahyou);
+
+// Weed sasahyou
+int sasahyou_weed(Sasahyou *sasahyou);
+
+// Load sasahyou
+int sasahyou_load(Sasahyou *sasahyou);
+
+// Save sasahyou
+int sasahyou_save(Sasahyou *sasahyou);
+
+// Open sasahyou
+int sasahyou_open(Sasahyou *sasahyou, const char *path);
+
+// Dump sasahyou
+int sasahyou_dump(Sasahyou *sasahyou, const char *path);
+
+// Add sasa to sasahyou
+int sasa_add(Sasahyou *sasahyou, const char *path);
+
+// Remove sasa from sasahyou
+int sasa_rem(Sasahyou *sasahyou, uint64_t sasa_id);
+
+// ==================== SAPPYOU SECTION ==================== //
+
+// Initialize empty sappyou
+int sappyou_init(Sappyou *sappyou);
+
+// Free sappyou
+int sappyou_free(Sappyou *sappyou);
+
+// Weed sappyou
+int sappyou_weed(Sappyou *sappyou);
+
+// Load sappyou
+int sappyou_load(Sappyou *sappyou);
+
+// Save sappyou
+int sappyou_save(Sappyou *sappyou);
+
+// Open sappyou
+int sappyou_open(Sappyou *sappyou, const char *path);
+
+// Dump sappyou
+int sappyou_dump(Sappyou *sappyou, const char *path);
+
+// Add new tanzaku to sappyou
+int tanzaku_add(Sappyou *sappyou, const char *name, const char *alias, const char *description);
+
+// Remove tanzaku from sappyou
+int tanzaku_rem(Sappyou *sappyou, uint64_t tanzaku_id);
+
+// ==================== SHOPPYOU SECTION ==================== //
+
+// Initialize empty shoppyou
+int shoppyou_init(Shoppyou *shoppyou);
+
+// Free shoppyou
+int shoppyou_free(Shoppyou *shoppyou);
+
+// Weed shoppyou
+int shoppyou_weed(Shoppyou *shoppyou);
+
+// Load shoppyou
+int shoppyou_load(Shoppyou *shoppyou);
+
+// Save shoppyou
+int shoppyou_save(Shoppyou *shoppyou);
+
+// Open shoppyou
+int shoppyou_open(Shoppyou *shoppyou, const char *path);
+
+// Dump shoppyou
+int shoppyou_dump(Shoppyou *shoppyou, const char *path);
+
+// Add kazari to shoppyou
+int kazari_add(Shoppyou *shoppyou, uint64_t sasa_id, uint64_t tanzaku_id);
+
+// Remove kazari from shoppyou
+int kazari_rem(Shoppyou *shoppyou, uint64_t sasa_id, uint64_t tanzaku_id);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif //TANABATA_CORE_H

src/core/sappyou.c

@@ -0,0 +1,177 @@
+#include <malloc.h>
+#include <string.h>
+#include <time.h>
+
+#include "../../include/core.h"
+
+int sappyou_init(Sappyou *sappyou) {
+    uint64_t timestamp = time(NULL);
+    sappyou->created_ts = timestamp;
+    sappyou->modified_ts = timestamp;
+    sappyou->size = 0;
+    sappyou->removed_cnt = 0;
+    sappyou->contents = NULL;
+    sappyou->file = NULL;
+
+    return 0;
+}
+
+int sappyou_free(Sappyou *sappyou) {
+    for (uint64_t i = 0; i < sappyou->size; i++) {
+        free(sappyou->contents[i].name);
+        free(sappyou->contents[i].alias);
+        free(sappyou->contents[i].description);
+    }
+    free(sappyou->contents);
+    if (sappyou->file != NULL) {
+        fclose(sappyou->file);
+    }
+
+    return 0;
+}
+
+int sappyou_weed(Sappyou *sappyou) {
+    if (sappyou->removed_cnt == 0) {
+        return 0;
+    }
+    uint64_t weeded_size = sappyou->size - sappyou->removed_cnt;
+    for (uint64_t i = 0, count = 0; i < sappyou->size; i++) {
+        if (sappyou->contents[i].id != 0) {
+            sappyou->contents[i - count] = sappyou->contents[i];
+        } else {
+            count++;
+        }
+    }
+    sappyou->size = weeded_size;
+    sappyou->removed_cnt = 0;
+    sappyou->contents = realloc(sappyou->contents, sappyou->size * sizeof(Tanzaku));
+
+    return 0;
+}
+
+int sappyou_load(Sappyou *sappyou) {
+    if (sappyou->file == NULL) {
+        fprintf(stderr, "Failed to load sappyou: file not specified\n");
+        return 1;
+    }
+    uint16_t signature[4];
+    rewind(sappyou->file);
+    fread(signature, 2, 4, sappyou->file);
+    if (memcmp(signature, SAPPYOU_SIG, 8) != 0) {
+        fprintf(stderr, "Failed to load sappyou: invalid signature\n");
+        return 1;
+    }
+    fread(&sappyou->created_ts, 8, 1, sappyou->file);
+    fread(&sappyou->modified_ts, 8, 1, sappyou->file);
+    fread(&sappyou->size, 8, 1, sappyou->file);
+    sappyou->removed_cnt = 0;
+    sappyou->contents = malloc(sappyou->size * sizeof(Tanzaku));
+    size_t max_string_len = SIZE_MAX;
+    for (uint64_t i = 0; i < sappyou->size; i++) {
+        fread(&sappyou->contents[i].id, 8, 1, sappyou->file);
+        fread(&sappyou->contents[i].created_ts, 8, 1, sappyou->file);
+        fread(&sappyou->contents[i].modified_ts, 8, 1, sappyou->file);
+        getdelim(&sappyou->contents[i].name, &max_string_len, 0, sappyou->file);
+        getdelim(&sappyou->contents[i].alias, &max_string_len, 0, sappyou->file);
+        getdelim(&sappyou->contents[i].description, &max_string_len, 0, sappyou->file);
+    }
+
+    return 0;
+}
+
+int sappyou_save(Sappyou *sappyou) {
+    if (sappyou->file == NULL) {
+        fprintf(stderr, "Failed to save sappyou: file not specified\n");
+        return 1;
+    }
+    if (sappyou_weed(sappyou) != 0) {
+        fprintf(stderr, "Failed to save sappyou: failed to weed sappyou\n");
+        return 1;
+    }
+    rewind(sappyou->file);
+    fwrite(SAPPYOU_SIG, 2, 4, sappyou->file);
+    fwrite(&sappyou->created_ts, 8, 1, sappyou->file);
+    fwrite(&sappyou->modified_ts, 8, 1, sappyou->file);
+    fwrite(&sappyou->size, 8, 1, sappyou->file);
+    fflush(sappyou->file);
+    for (uint64_t i = 0; i < sappyou->size; i++) {
+        fwrite(&sappyou->contents[i].id, 8, 1, sappyou->file);
+        fwrite(&sappyou->contents[i].created_ts, 8, 1, sappyou->file);
+        fwrite(&sappyou->contents[i].modified_ts, 8, 1, sappyou->file);
+        fwrite(sappyou->contents[i].name, 1, strlen(sappyou->contents[i].name) + 1, sappyou->file);
+        fwrite(sappyou->contents[i].alias, 1, strlen(sappyou->contents[i].alias) + 1, sappyou->file);
+        fwrite(sappyou->contents[i].description, 1, strlen(sappyou->contents[i].description) + 1, sappyou->file);
+    }
+    fflush(sappyou->file);
+
+    return 0;
+}
+
+int sappyou_open(Sappyou *sappyou, const char *path) {
+    sappyou->file = fopen(path, "r+b");
+    if (sappyou->file == NULL) {
+        fprintf(stderr, "Failed to dump sappyou: failed to open file '%s'\n", path);
+        return 1;
+    }
+    return sappyou_load(sappyou);
+}
+
+int sappyou_dump(Sappyou *sappyou, const char *path) {
+    sappyou->file = fopen(path, "w+b");
+    if (sappyou->file == NULL) {
+        fprintf(stderr, "Failed to dump sappyou: failed to open file '%s'\n", path);
+        return 1;
+    }
+    return sappyou_save(sappyou);
+}
+
+int tanzaku_add(Sappyou *sappyou, const char *name, const char *alias, const char *description) {
+    if (sappyou->size == -1) {
+        fprintf(stderr, "Failed to add tanzaku: sappyou is full\n");
+        return 1;
+    }
+    for (uint64_t i = 0; i < sappyou->size; i++) {
+        if (strcmp(name, sappyou->contents[i].name) == 0) {
+            fprintf(stderr, "Failed to add tanzaku: tanzaku with the name '%s' already exists\n", name);
+            return 1;
+        }
+    }
+    Tanzaku newbie;
+    newbie.created_ts = time(NULL);
+    newbie.modified_ts = newbie.created_ts;
+    size_t name_size = strlen(name),
+            alias_size = strlen(alias),
+            description_size = strlen(description);
+    newbie.name = malloc(name_size + 1);
+    strcpy(newbie.name, name);
+    newbie.name[name_size] = 0;
+    newbie.alias = malloc(alias_size + 1);
+    strcpy(newbie.alias, alias);
+    newbie.alias[alias_size] = 0;
+    newbie.description = malloc(description_size + 1);
+    strcpy(newbie.description, description);
+    newbie.description[description_size] = 0;
+    sappyou->size++;
+    newbie.id = sappyou->size;
+    sappyou->contents = realloc(sappyou->contents, sappyou->size * sizeof(Tanzaku));
+    sappyou->contents[sappyou->size - 1] = newbie;
+    sappyou->modified_ts = newbie.created_ts;
+
+    return 0;
+}
+
+int tanzaku_rem(Sappyou *sappyou, uint64_t tanzaku_id) {
+    if (tanzaku_id > sappyou->size) {
+        fprintf(stderr, "Failed to remove tanzaku: target tanzaku does not exist\n");
+        return 1;
+    }
+    if (sappyou->contents[tanzaku_id - 1].id == 0) {
+        fprintf(stderr, "Failed to remove tanzaku: target tanzaku is already removed\n");
+        return 1;
+    }
+    sappyou->modified_ts = time(NULL);
+    sappyou->contents[tanzaku_id - 1].id = 0;
+    sappyou->removed_cnt++;
+
+    return 0;
+}

src/core/sasahyou.c

@@ -0,0 +1,166 @@
+#include <malloc.h>
+#include <string.h>
+#include <time.h>
+#include <sys/stat.h>
+#include <stdio.h>
+
+#include "../../include/core.h"
+
+int sasahyou_init(Sasahyou *sasahyou) {
+    sasahyou->created_ts = time(NULL);;
+    sasahyou->modified_ts = sasahyou->created_ts;
+    sasahyou->size = 0;
+    sasahyou->removed_cnt = 0;
+    sasahyou->contents = NULL;
+    sasahyou->file = NULL;
+
+    return 0;
+}
+
+int sasahyou_free(Sasahyou *sasahyou) {
+    for (uint64_t i = 0; i < sasahyou->size; i++) {
+        free(sasahyou->contents[i].path);
+    }
+    free(sasahyou->contents);
+    if (sasahyou->file != NULL) {
+        fclose(sasahyou->file);
+    }
+
+    return 0;
+}
+
+int sasahyou_weed(Sasahyou *sasahyou) {
+    if (sasahyou->removed_cnt == 0) {
+        return 0;
+    }
+    uint64_t weeded_size = sasahyou->size - sasahyou->removed_cnt;
+    for (uint64_t i = 0, count = 0; i < sasahyou->size; i++) {
+        if (sasahyou->contents[i].id != 0) {
+            sasahyou->contents[i - count] = sasahyou->contents[i];
+        } else {
+            count++;
+        }
+    }
+    sasahyou->size = weeded_size;
+    sasahyou->removed_cnt = 0;
+    sasahyou->contents = realloc(sasahyou->contents, sasahyou->size * sizeof(Sasa));
+
+    return 0;
+}
+
+int sasahyou_load(Sasahyou *sasahyou) {
+    if (sasahyou->file == NULL) {
+        fprintf(stderr, "Failed to load sasahyou: file not specified\n");
+        return 1;
+    }
+    uint16_t signature[4];
+    rewind(sasahyou->file);
+    fread(signature, 2, 4, sasahyou->file);
+    if (memcmp(signature, SASAHYOU_SIG, 8) != 0) {
+        fprintf(stderr, "Failed to load sasahyou: invalid signature\n");
+        return 1;
+    }
+    fread(&sasahyou->created_ts, 8, 1, sasahyou->file);
+    fread(&sasahyou->modified_ts, 8, 1, sasahyou->file);
+    fread(&sasahyou->size, 8, 1, sasahyou->file);
+    sasahyou->removed_cnt = 0;
+    sasahyou->contents = malloc(sasahyou->size * sizeof(Sasa));
+    size_t max_path_len = SIZE_MAX;
+    for (uint64_t i = 0; i < sasahyou->size; i++) {
+        fread(&sasahyou->contents[i].id, 8, 1, sasahyou->file);
+        fread(&sasahyou->contents[i].created_ts, 8, 1, sasahyou->file);
+        getdelim(&sasahyou->contents[i].path, &max_path_len, 0, sasahyou->file);
+    }
+
+    return 0;
+}
+
+int sasahyou_save(Sasahyou *sasahyou) {
+    if (sasahyou->file == NULL) {
+        fprintf(stderr, "Failed to save sasahyou: file not specified\n");
+        return 1;
+    }
+    if (sasahyou_weed(sasahyou) != 0) {
+        fprintf(stderr, "Failed to save sasahyou: failed to weed sasahyou\n");
+        return 1;
+    }
+    rewind(sasahyou->file);
+    fwrite(SASAHYOU_SIG, 2, 4, sasahyou->file);
+    fwrite(&sasahyou->created_ts, 8, 1, sasahyou->file);
+    fwrite(&sasahyou->modified_ts, 8, 1, sasahyou->file);
+    fwrite(&sasahyou->size, 8, 1, sasahyou->file);
+    fflush(sasahyou->file);
+    for (uint64_t i = 0; i < sasahyou->size; i++) {
+        fwrite(&sasahyou->contents[i].id, 8, 1, sasahyou->file);
+        fwrite(&sasahyou->contents[i].created_ts, 8, 1, sasahyou->file);
+        fwrite(sasahyou->contents[i].path, 1, strlen(sasahyou->contents[i].path) + 1, sasahyou->file);
+    }
+    fflush(sasahyou->file);
+
+    return 0;
+}
+
+int sasahyou_open(Sasahyou *sasahyou, const char *path) {
+    sasahyou->file = fopen(path, "r+b");
+    if (sasahyou->file == NULL) {
+        fprintf(stderr, "Failed to dump sasahyou: failed to open file '%s'\n", path);
+        return 1;
+    }
+    return sasahyou_load(sasahyou);
+}
+
+int sasahyou_dump(Sasahyou *sasahyou, const char *path) {
+    sasahyou->file = fopen(path, "w+b");
+    if (sasahyou->file == NULL) {
+        fprintf(stderr, "Failed to dump sasahyou: failed to open file '%s'\n", path);
+        return 1;
+    }
+    return sasahyou_save(sasahyou);
+}
+
+int sasa_add(Sasahyou *sasahyou, const char *path) {
+    if (sasahyou->size == -1) {
+        fprintf(stderr, "Failed to add sasa: sasahyou is full\n");
+        return 1;
+    }
+    for (uint64_t i = 0; i < sasahyou->size; i++) {
+        if (strcmp(path, sasahyou->contents[i].path) == 0) {
+            fprintf(stderr, "Failed to add sasa: file '%s' is already listed\n", path);
+            return 1;
+        }
+    }
+    struct stat st;
+    if (stat(path, &st) != 0) {
+        fprintf(stderr, "Failed to add sasa: invalid path '%s'\n", path);
+        return 1;
+    }
+    Sasa newbie;
+    newbie.created_ts = (uint64_t) time(NULL);
+    size_t path_size = strlen(path);
+    newbie.path = malloc(path_size + 1);
+    strcpy(newbie.path, path);
+    newbie.path[path_size] = 0;
+    sasahyou->size++;
+    newbie.id = sasahyou->size;
+    sasahyou->contents = realloc(sasahyou->contents, sasahyou->size * sizeof(Sasa));
+    sasahyou->contents[sasahyou->size - 1] = newbie;
+    sasahyou->modified_ts = newbie.created_ts;
+
+    return 0;
+}
+
+int sasa_rem(Sasahyou *sasahyou, uint64_t sasa_id) {
+    if (sasa_id > sasahyou->size) {
+        fprintf(stderr, "Failed to remove sasa: target sasa does not exist\n");
+        return 1;
+    }
+    if (sasahyou->contents[sasa_id - 1].id == 0) {
+        fprintf(stderr, "Failed to remove sasa: target sasa is already removed\n");
+        return 1;
+    }
+    sasahyou->contents[sasa_id - 1].id = 0;
+    sasahyou->removed_cnt++;
+    sasahyou->modified_ts = time(NULL);
+
+    return 0;
+}

src/core/shoppyou.c

@@ -0,0 +1,152 @@
+#include <malloc.h>
+#include <string.h>
+#include <time.h>
+
+#include "../../include/core.h"
+
+int shoppyou_init(Shoppyou *shoppyou) {
+    uint64_t timestamp = time(NULL);
+    shoppyou->created_ts = timestamp;
+    shoppyou->modified_ts = timestamp;
+    shoppyou->size = 0;
+    shoppyou->removed_cnt = 0;
+    shoppyou->contents = NULL;
+    shoppyou->file = NULL;
+
+    return 0;
+}
+
+int shoppyou_free(Shoppyou *shoppyou) {
+    free(shoppyou->contents);
+    if (shoppyou->file != NULL) {
+        fclose(shoppyou->file);
+    }
+
+    return 0;
+}
+
+int shoppyou_weed(Shoppyou *shoppyou) {
+    if (shoppyou->removed_cnt == 0) {
+        return 0;
+    }
+    uint64_t weeded_size = shoppyou->size - shoppyou->removed_cnt;
+    for (uint64_t i = 0, count = 0; i < shoppyou->size; i++) {
+        if (shoppyou->contents[i].sasa_id != 0 || shoppyou->contents[i].tanzaku_id != 0) {
+            shoppyou->contents[i - count] = shoppyou->contents[i];
+        } else {
+            count++;
+        }
+    }
+    shoppyou->size = weeded_size;
+    shoppyou->removed_cnt = 0;
+    shoppyou->contents = realloc(shoppyou->contents, shoppyou->size * sizeof(Kazari));
+
+    return 0;
+}
+
+int shoppyou_load(Shoppyou *shoppyou) {
+    if (shoppyou->file == NULL) {
+        fprintf(stderr, "Failed to load shoppyou: file not specified\n");
+        return 1;
+    }
+    uint16_t signature[4];
+    rewind(shoppyou->file);
+    fread(signature, 2, 4, shoppyou->file);
+    if (memcmp(signature, SHOPPYOU_SIG, 8) != 0) {
+        fprintf(stderr, "Failed to load shoppyou: invalid signature\n");
+        return 1;
+    }
+    fread(&shoppyou->created_ts, 8, 1, shoppyou->file);
+    fread(&shoppyou->modified_ts, 8, 1, shoppyou->file);
+    fread(&shoppyou->size, 8, 1, shoppyou->file);
+    shoppyou->removed_cnt = 0;
+    shoppyou->contents = malloc(shoppyou->size * sizeof(Kazari));
+    for (uint64_t i = 0; i < shoppyou->size; i++) {
+        fread(&shoppyou->contents[i].created_ts, 8, 1, shoppyou->file);
+        fread(&shoppyou->contents[i].sasa_id, 8, 1, shoppyou->file);
+        fread(&shoppyou->contents[i].tanzaku_id, 8, 1, shoppyou->file);
+    }
+
+    return 0;
+}
+
+int shoppyou_save(Shoppyou *shoppyou) {
+    if (shoppyou->file == NULL) {
+        fprintf(stderr, "Failed to save shoppyou: file not specified\n");
+        return 1;
+    }
+    if (shoppyou_weed(shoppyou) != 0) {
+        fprintf(stderr, "Failed to save shoppyou: failed to weed sappyou\n");
+        return 1;
+    }
+    rewind(shoppyou->file);
+    fwrite(SHOPPYOU_SIG, 2, 4, shoppyou->file);
+    fwrite(&shoppyou->created_ts, 8, 1, shoppyou->file);
+    fwrite(&shoppyou->modified_ts, 8, 1, shoppyou->file);
+    fwrite(&shoppyou->size, 8, 1, shoppyou->file);
+    fflush(shoppyou->file);
+    for (uint64_t i = 0; i < shoppyou->size; i++) {
+        fwrite(&shoppyou->contents[i].created_ts, 8, 1, shoppyou->file);
+        fwrite(&shoppyou->contents[i].sasa_id, 8, 1, shoppyou->file);
+        fwrite(&shoppyou->contents[i].tanzaku_id, 8, 1, shoppyou->file);
+    }
+    fflush(shoppyou->file);
+
+    return 0;
+}
+
+int shoppyou_open(Shoppyou *shoppyou, const char *path) {
+    shoppyou->file = fopen(path, "r+b");
+    if (shoppyou->file == NULL) {
+        fprintf(stderr, "Failed to dump shoppyou: failed to open file '%s'\n", path);
+        return 1;
+    }
+    return shoppyou_load(shoppyou);
+}
+
+int shoppyou_dump(Shoppyou *shoppyou, const char *path) {
+    shoppyou->file = fopen(path, "w+b");
+    if (shoppyou->file == NULL) {
+        fprintf(stderr, "Failed to dump shoppyou: failed to open file '%s'\n", path);
+        return 1;
+    }
+    return shoppyou_save(shoppyou);
+}
+
+int kazari_add(Shoppyou *shoppyou, uint64_t sasa_id, uint64_t tanzaku_id) {
+    if (shoppyou->size == -1) {
+        fprintf(stderr, "Failed to add kazari: shoppyou is full\n");
+        return 1;
+    }
+    for (uint64_t i = 0; i < shoppyou->size; i++) {
+        if (shoppyou->contents[i].sasa_id == sasa_id && shoppyou->contents[i].tanzaku_id == tanzaku_id) {
+            fprintf(stderr, "Failed to add kazari: kazari with sasa_id=%lu and tanzaku_id=%lu already exists\n",
+                    sasa_id, tanzaku_id);
+            return 1;
+        }
+    }
+    Kazari newbie;
+    newbie.created_ts = time(NULL);
+    newbie.sasa_id = sasa_id;
+    newbie.tanzaku_id = tanzaku_id;
+    shoppyou->size++;
+    shoppyou->contents = realloc(shoppyou->contents, shoppyou->size * sizeof(Kazari));
+    shoppyou->contents[shoppyou->size - 1] = newbie;
+    shoppyou->modified_ts = newbie.created_ts;
+
+    return 0;
+}
+
+int kazari_rem(Shoppyou *shoppyou, uint64_t sasa_id, uint64_t tanzaku_id) {
+    for (uint64_t i = 0; i < shoppyou->size; i++) {
+        if (shoppyou->contents[i].sasa_id == sasa_id && shoppyou->contents[i].tanzaku_id == tanzaku_id) {
+            shoppyou->modified_ts = time(NULL);
+            shoppyou->contents[i].sasa_id = 0;
+            shoppyou->contents[i].tanzaku_id = 0;
+            shoppyou->removed_cnt++;
+            return 0;
+        }
+    }
+    fprintf(stderr, "Failed to remove kazari: target kazari does not exist or is already removed\n");
+    return 1;
+}