LuatOS/luat/vfs/luat_fs_mem.c

#include "luat_base.h"
#include "luat_fs.h"
#include "luat_mem.h"

#define LUAT_LOG_TAG "fs"
#include "luat_log.h"

#if 1

#define BLOCK_SIZE 4096
#define MEMFS_MAX_FILE_NAME 63

typedef struct ram_file_block
{
    uint8_t data[BLOCK_SIZE];
    struct ram_file_block* next;
} ram_file_block_t;

typedef struct ram_file
{
    size_t size;     // 当前文件大小
    char name[MEMFS_MAX_FILE_NAME + 1];   // 文件名称
    ram_file_block_t* head; // 链表头指针
} ram_file_t;

typedef struct luat_ram_fd
{
    int fid;
    uint32_t offset;
    uint8_t readonly;
} luat_raw_fd_t;

#define RAM_FILE_MAX (64)
static ram_file_t* files[RAM_FILE_MAX];

size_t luat_vfs_ram_fread(void* userdata, void *ptr, size_t size, size_t nmemb, FILE *stream);

FILE* luat_vfs_ram_fopen(void* userdata, const char *filename, const char *mode) {
    (void)userdata;
    // LLOGD("ram fs open %s %s", filename, mode);
    if (filename == NULL || mode == NULL || strlen(filename) > MEMFS_MAX_FILE_NAME) {
        return NULL;
    }
    // 读文件
    if (!strcmp("r", mode) || !strcmp("rb", mode)) {
        for (size_t i = 0; i < RAM_FILE_MAX; i++)
        {
            if (files[i] == NULL)
                continue;
            if (!strcmp(files[i]->name, filename)) {
                luat_raw_fd_t* fd = luat_heap_malloc(sizeof(luat_raw_fd_t));
                if (fd == NULL) {
                    LLOGE("out of memory when malloc luat_raw_fd_t");
                    return NULL;
                }
                fd->fid = i;
                fd->offset = 0;
                fd->readonly = 1;
                return (FILE*)fd;
            }
        }
        return NULL;
    }
    // 写文件
    else if (!strcmp("w", mode) || !strcmp("wb", mode) || !strcmp("w+", mode) || !strcmp("wb+", mode) || !strcmp("w+b", mode) || !strcmp("r+", mode) || !strcmp("rb+", mode) || !strcmp("r+b", mode)) {
        // 先看看是否存在, 如果存在就重用老的
        for (size_t i = 0; i < RAM_FILE_MAX; i++)
        {
            if (files[i] == NULL)
                continue;
            if (!strcmp(files[i]->name, filename)) {
                luat_raw_fd_t* fd = luat_heap_malloc(sizeof(luat_raw_fd_t));
                if (fd == NULL) {
                    LLOGE("out of memory when malloc luat_raw_fd_t");
                    return NULL;
                }
                fd->fid = i;
                fd->readonly = 0;
                fd->offset = 0;
                if (!strcmp("w+", mode) || !strcmp("wb+", mode) || !strcmp("w+b", mode)) {
                    // 截断模式
                    files[i]->size = 0;
                    ram_file_block_t* block = files[i]->head;
                    while (block) {
                        ram_file_block_t* next = block->next;
                        luat_heap_free(block);
                        block = next;
                    }
                    files[i]->head = NULL;
                }
                return (FILE*)fd;
            }
        }
        for (size_t i = 0; i < RAM_FILE_MAX; i++)
        {
            if (files[i] != NULL)
                continue;
            ram_file_t *file = luat_heap_malloc(sizeof(ram_file_t));
            if (file == NULL) {
                LLOGE("out of memory when malloc ram_file_t");
                return NULL;
            }
            memset(file, 0, sizeof(ram_file_t));
            strcpy(file->name, filename);
            files[i] = file;
            luat_raw_fd_t* fd = luat_heap_malloc(sizeof(luat_raw_fd_t));
            if (fd == NULL) {
                LLOGE("out of memory when malloc luat_raw_fd_t");
                return NULL;
            }
            fd->fid = i;
            fd->offset = 0;
            fd->readonly = 0;
            return (FILE*)fd;
        }
    }
    // 追加模式
    else if (!strcmp("a", mode) || !strcmp("ab", mode) || !strcmp("a+", mode) || !strcmp("ab+", mode) || !strcmp("a+b", mode) ) {
        // 先看看是否存在, 如果存在就重用老的
        for (size_t i = 0; i < RAM_FILE_MAX; i++)
        {
            if (files[i] == NULL)
                continue;
            if (!strcmp(files[i]->name, filename)) {
                luat_raw_fd_t* fd = luat_heap_malloc(sizeof(luat_raw_fd_t));
                if (fd == NULL) {
                    LLOGE("out of memory when malloc luat_raw_fd_t");
                    return NULL;
                }
                fd->fid = i;
                fd->offset = files[i]->size;
                fd->readonly = 0;
                return (FILE*)fd;
            }
        }
        LLOGW("file %s not found, can't open with mode %s", filename, mode);
        return NULL;
    }
    else {
        LLOGE("unkown open mode %s", mode);
        return NULL;
    }
    LLOGE("too many ram files >= %d", RAM_FILE_MAX);
    return NULL;
}

int luat_vfs_ram_getc(void* userdata, FILE* stream) {
    uint8_t c = 0;
    size_t len = luat_vfs_ram_fread(userdata, &c, 1, 1, stream);
    if (len == 1) {
            return c;
    }
    return -1;
}

int luat_vfs_ram_fseek(void* userdata, FILE* stream, long int offset, int origin) {
    (void)userdata;
    luat_raw_fd_t* fd = (luat_raw_fd_t*)stream;
    // LLOGE("luat_vfs_ram_fseek seek %p %p %d %d", userdata, stream, offset, origin);
    if (origin == SEEK_CUR) {
        fd->offset += offset;
    }
    else if (origin == SEEK_SET) {
        fd->offset = offset;
    }
    else {
        fd->offset = files[fd->fid]->size - offset;
    }
    if (fd->offset > files[fd->fid]->size) {
        // 如果偏移量超过了文件大小，设置为文件大小
        fd->offset = files[fd->fid]->size;
    }
    return 0;
}

int luat_vfs_ram_ftell(void* userdata, FILE* stream) {
    (void)userdata;
    luat_raw_fd_t* fd = (luat_raw_fd_t*)stream;
    // LLOGD("tell %p %p offset %d", userdata, stream, fd->offset);
    return fd->offset;
}

int luat_vfs_ram_fclose(void* userdata, FILE* stream) {
    (void)userdata;
    luat_raw_fd_t* fd = (luat_raw_fd_t*)stream;
    //LLOGD("fclose %p %p %d %d", userdata, stream, fd->size, fd->offset);
    luat_heap_free(fd);
    return 0;
}

int luat_vfs_ram_feof(void* userdata, FILE* stream) {
    (void)userdata;
    luat_raw_fd_t* fd = (luat_raw_fd_t*)stream;
    //LLOGD("feof %p %p %d %d", userdata, stream, fd->size, fd->offset);
    return fd->offset >= files[fd->fid]->size ? 1 : 0;
}

int luat_vfs_ram_ferror(void* userdata, FILE *stream) {
    (void)userdata;
    (void)stream;
    return 0;
}

size_t luat_vfs_ram_fread(void* userdata, void *ptr, size_t size, size_t nmemb, FILE *stream) {
    (void)userdata;
    luat_raw_fd_t* fd = (luat_raw_fd_t*)stream;
    size_t read_size = size * nmemb;

    // 如果偏移量已经超出文件大小
    if (fd->offset >= files[fd->fid]->size) {
        return 0;
    }

    // 如果读取的大小超出文件剩余大小，调整读取大小
    if (fd->offset + read_size > files[fd->fid]->size) {
        read_size = files[fd->fid]->size - fd->offset;
    }

    // 找到offset对应的起始block
    ram_file_block_t* block = files[fd->fid]->head;
    size_t offset = fd->offset;
    while (block != NULL && offset >= BLOCK_SIZE) {
        offset -= BLOCK_SIZE;
        block = block->next;
    }

    // 如果没有找到对应的block
    if (block == NULL) {
        LLOGW("no block for offset %d", fd->offset);
        return 0;
    }

    // 开始读取
    uint8_t* dst = (uint8_t*)ptr;
    size_t bytes_read = 0; // 用于记录实际读取的字节数
    while (block != NULL && read_size > 0) {
        size_t copy_size = BLOCK_SIZE - (offset % BLOCK_SIZE);
        if (copy_size > read_size) {
            copy_size = read_size;
        }
        memcpy(dst, block->data + (offset % BLOCK_SIZE), copy_size);
        dst += copy_size;
        read_size -= copy_size;
        offset += copy_size;
        bytes_read += copy_size; // 累加读取的字节数
        if (offset % BLOCK_SIZE == 0) {
            block = block->next;
        }
    }

    fd->offset += bytes_read; // 更新文件偏移量
    return bytes_read; // 返回实际读取的字节数
}

size_t luat_vfs_ram_fwrite(void* userdata, const void *ptr, size_t size, size_t nmemb, FILE *stream) {
    (void)userdata;
    luat_raw_fd_t* fd = (luat_raw_fd_t*)stream;
    size_t write_size = size * nmemb;
    if (fd->readonly) {
        LLOGW("readonly fd %d!! path %s", fd->fid, files[fd->fid]->name);
        return 0;
    }
    // 原文件大小与本次写入后所需的大小
    size_t old_size = files[fd->fid]->size;
    size_t needed_size = fd->offset + write_size; // 仅覆盖时可能小于 old_size

    // 只在需要扩展时才分配新块, 避免覆盖写导致截断
    if (needed_size > old_size) {
        size_t old_blocks = (old_size + BLOCK_SIZE - 1) / BLOCK_SIZE;
        size_t needed_blocks = (needed_size + BLOCK_SIZE - 1) / BLOCK_SIZE;
        // 找到最后一个块
        ram_file_block_t* last = files[fd->fid]->head;
        if (last == NULL) {
            // 还没有任何块, 分配第一个
            last = luat_heap_malloc(sizeof(ram_file_block_t));
            if (last == NULL) {
                LLOGW("out of memory when malloc ram_file_block_t");
                return 0;
            }
            memset(last, 0, sizeof(ram_file_block_t));
            last->next = NULL;
            files[fd->fid]->head = last;
            old_blocks = 1; // 更新块数量
        } else {
            // 跳到最后一个现有块
            size_t idx = 1;
            while (last->next) {
                last = last->next;
                idx ++;
            }
            // idx 应等于 old_blocks, 不匹配也不影响后续逻辑
        }
        // 追加缺少的块
        for (size_t b = old_blocks; b < needed_blocks; b++) {
            ram_file_block_t* nb = luat_heap_malloc(sizeof(ram_file_block_t));
            if (nb == NULL) {
                LLOGW("out of memory when malloc ram_file_block_t");
                return 0;
            }
            memset(nb, 0, sizeof(ram_file_block_t));
            nb->next = NULL;
            last->next = nb;
            last = nb;
        }
    }

    // 现在偏移到offset对应的block
    ram_file_block_t* block = files[fd->fid]->head;
    size_t offset = fd->offset;
    while (block != NULL && offset >= BLOCK_SIZE) {
        offset -= BLOCK_SIZE;
        block = block->next;
    }

    // 开始写
    const uint8_t* src = (const uint8_t*)ptr;
    while (write_size > 0) {
        size_t copy_size = BLOCK_SIZE - (offset % BLOCK_SIZE);
        if (copy_size > write_size) {
            copy_size = write_size;
        }
        memcpy(block->data + (offset % BLOCK_SIZE), src, copy_size);
        src += copy_size;
        write_size -= copy_size;
        offset += copy_size;
        if (offset % BLOCK_SIZE == 0) {
            block = block->next;
        }
    }

    fd->offset += (size_t)(src - (const uint8_t*)ptr);
    // 仅当写入越过原末尾时更新大小, 避免覆盖写截断
    if (needed_size > old_size) {
        files[fd->fid]->size = needed_size;
    }
    // 打印一下写入的数据
    // LLOGD("write data %s", (char*)ptr);
    return (size_t)(src - (const uint8_t*)ptr);
}

int luat_vfs_ram_remove(void* userdata, const char *filename) {
    (void)userdata;
    for (size_t i = 0; i < RAM_FILE_MAX; i++)
    {
        if (files[i] == NULL)
            continue;
        if (!strcmp(filename, files[i]->name)) {
            ram_file_block_t* block = files[i]->head;
            while (block) {
                ram_file_block_t* next = block->next;
                luat_heap_free(block);
                block = next;
            }
            luat_heap_free(files[i]);
            files[i] = NULL;
            return 0;
        }
    }
    return 0;
}

int luat_vfs_ram_rename(void* userdata, const char *old_filename, const char *new_filename) {
    (void)userdata;
    if (old_filename == NULL || new_filename == NULL)
        return -1;
    if (strlen(old_filename) > MEMFS_MAX_FILE_NAME || strlen(new_filename) > MEMFS_MAX_FILE_NAME)
        return -2;
    for (size_t i = 0; i < RAM_FILE_MAX; i++)
    {
        if (files[i] == NULL)
            continue;
        if (!strcmp(old_filename, files[i]->name)) {
            strcpy(files[i]->name, new_filename);
            return 0;
        }
    }
    return 0;
}

int luat_vfs_ram_fexist(void* userdata, const char *filename) {
    (void)userdata;
    for (size_t i = 0; i < RAM_FILE_MAX; i++)
    {
        if (files[i] == NULL)
            continue;
        if (!strcmp(filename, files[i]->name)) {
            return 1;
        }
    }
    return 0;
}

size_t luat_vfs_ram_fsize(void* userdata, const char *filename) {
    (void)userdata;
    for (size_t i = 0; i < RAM_FILE_MAX; i++)
    {
        if (files[i] == NULL)
            continue;
        if (!strcmp(filename, files[i]->name)) {
            return files[i]->size;
        }
    }
    return 0;
}

void* luat_vfs_ram_mmap(void* userdata, FILE *stream) {
    (void)userdata;
    luat_raw_fd_t *fd = (luat_raw_fd_t*)(stream);
    //LLOGD("fsize %p %p %d %d", userdata, fd);
    return files[fd->fid]->head->data;
}

int luat_vfs_ram_mkfs(void* userdata, luat_fs_conf_t *conf) {
    (void)userdata;
    (void)conf;
    return -1;
}

int luat_vfs_ram_mount(void** userdata, luat_fs_conf_t *conf) {
    (void)userdata;
    (void)conf;
    return 0;
}

int luat_vfs_ram_umount(void* userdata, luat_fs_conf_t *conf) {
    (void)userdata;
    (void)conf;
    return 0;
}

int luat_vfs_ram_mkdir(void* userdata, char const* _DirName) {
    (void)userdata;
    (void)_DirName;
    return -1;
}

int luat_vfs_ram_rmdir(void* userdata, char const* _DirName) {
    (void)userdata;
    (void)_DirName;
    return -1;
}

int luat_vfs_ram_lsdir(void* userdata, char const* _DirName, luat_fs_dirent_t* ents, size_t offset, size_t len) {
    (void)userdata;
    (void)_DirName;
    size_t count = 0;
    for (size_t i = 0; i < RAM_FILE_MAX; i++)
    {
        if (count >= len)
            break;
        if (files[i] == NULL)
            continue;
        if (offset > 0) {
            offset --;
            continue;
        }
        ents[count].d_type = 0;
        strcpy(ents[count].d_name, files[i]->name);
        count ++;
    }
    return count;
}

int luat_vfs_ram_info(void* userdata, const char* path, luat_fs_info_t *conf) {
    (void)userdata;
    (void)path;
    memcpy(conf->filesystem, "ram", strlen("ram")+1);
    size_t ftotal = 0;
    for (size_t i = 0; i < RAM_FILE_MAX; i++)
    {
        if (files[i] == NULL)
            continue;
        ftotal += files[i]->size;
    }
    size_t total; size_t used; size_t max_used;
    luat_meminfo_sys(&total, &used, &max_used);
    
    conf->type = 0;
    conf->total_block = 64;
    conf->block_used = (ftotal + BLOCK_SIZE - 1) / BLOCK_SIZE;
    conf->block_size = BLOCK_SIZE;
    return 0;
}

int luat_vfs_ram_truncate(void* fsdata, char const* path, size_t nsize) {
    for (size_t i = 0; i < RAM_FILE_MAX; i++)
    {
        if (files[i] == NULL)
            continue;
        if (!strcmp(files[i]->name, path)) {
            // 计算需要保留的块数量
            size_t needed_blocks = (nsize + BLOCK_SIZE - 1) / BLOCK_SIZE;
            size_t idx = 0;
            ram_file_block_t* block = files[i]->head;
            ram_file_block_t* prev = NULL;
            while (block) {
                idx++;
                if (idx == needed_blocks) {
                    // 清零最后一个块多余部分
                    if (nsize % BLOCK_SIZE) {
                        memset(block->data + (nsize % BLOCK_SIZE), 0, BLOCK_SIZE - (nsize % BLOCK_SIZE));
                    }
                    // 释放后续块
                    ram_file_block_t* next = block->next;
                    block->next = NULL;
                    while (next) {
                        ram_file_block_t* nn = next->next;
                        luat_heap_free(next);
                        next = nn;
                    }
                    break;
                }
                prev = block;
                block = block->next;
            }
            // 如果需要块为0, 释放所有
            if (needed_blocks == 0) {
                block = files[i]->head;
                while (block) {
                    ram_file_block_t* nn = block->next;
                    luat_heap_free(block);
                    block = nn;
                }
                files[i]->head = NULL;
            }
            files[i]->size = nsize;
            return 0;
        }
    }
    return 0;
}

#else

typedef struct ram_file
{
    size_t size;     // 当前文件大小, 也是指针对应内存块的大小
    // size_t ptr_size; // 数值指针的大小
    char name[32];   // 文件名称
    char ptr[4];
}ram_file_t;

typedef struct luat_ram_fd
{
    int fid;
    uint32_t  offset;
    uint8_t readonly;
}luat_raw_fd_t;

#define RAM_FILE_MAX (64)
static ram_file_t* files[RAM_FILE_MAX];


FILE* luat_vfs_ram_fopen(void* userdata, const char *filename, const char *mode) {
    (void)userdata;
    // LLOGD("ram fs open %s %s", filename, mode);
    if (filename == NULL || mode == NULL || strlen(filename) > 31)
        return NULL;
    // 读文件
    if (!strcmp("r", mode) || !strcmp("rb", mode)) {
        for (size_t i = 0; i < RAM_FILE_MAX; i++)
        {
            if (files[i]== NULL)
                continue;
            if (!strcmp(files[i]->name, filename)) {
                luat_raw_fd_t* fd = luat_heap_malloc(sizeof(luat_raw_fd_t));
                if (fd == NULL) {
                    LLOGE("out of memory when malloc luat_raw_fd_t");
                    return NULL;
                }
                fd->fid = i;
                fd->offset = 0;
                fd->readonly = 1;
                return (FILE*)fd;
            }
        }
        return NULL;
    }
    // 写文件
    else if (!strcmp("w", mode) || !strcmp("wb", mode) || !strcmp("w+", mode) || !strcmp("wb+", mode) || !strcmp("w+b", mode) || !strcmp("r+", mode) || !strcmp("rb+", mode) || !strcmp("r+b", mode)) {
        // 先看看是否存在, 如果存在就重用老的
        for (size_t i = 0; i < RAM_FILE_MAX; i++)
        {
            if (files[i]== NULL)
                continue;
            if (!strcmp(files[i]->name, filename)) {
                luat_raw_fd_t* fd = luat_heap_malloc(sizeof(luat_raw_fd_t));
                if (fd == NULL) {
                    LLOGE("out of memory when malloc luat_raw_fd_t");
                    return NULL;
                }
                fd->fid = i;
                fd->readonly = 0;
                fd->offset = 0;
                if (!strcmp("w+", mode) || !strcmp("wb+", mode) || !strcmp("w+b", mode)) {
                    // 截断模式
                    char* tmp = luat_heap_realloc(files[i], sizeof(ram_file_t));
                    if (tmp) {
                        files[i] = (ram_file_t*)tmp;
                    }
                    else {
                        LLOGE("realloc ram_file_t failed");
                        luat_heap_free(fd);
                        return NULL;
                    }
                    files[i]->size = 0;
                }
                return (FILE*)fd;
            }
        }
        for (size_t i = 0; i < RAM_FILE_MAX; i++)
        {
            if (files[i] != NULL)
                continue;
            ram_file_t *file = luat_heap_malloc(sizeof(ram_file_t));
            if (file == NULL) {
                LLOGE("out of memory when malloc ram_file_t");
                return NULL;
            }
            memset(file, 0, sizeof(ram_file_t));
            strcpy(file->name, filename);
            files[i] = file;
            luat_raw_fd_t* fd = luat_heap_malloc(sizeof(luat_raw_fd_t));
            if (fd == NULL) {
                LLOGE("out of memory when malloc luat_raw_fd_t");
                return NULL;
            }
            fd->fid = i;
            fd->offset = 0;
            fd->readonly = 0;
            return (FILE*)fd;
        }
    }
    // 追加模式
    else if (!strcmp("a", mode) || !strcmp("ab", mode) || !strcmp("a+", mode) || !strcmp("ab+", mode) || !strcmp("a+b", mode) ) {
        // 先看看是否存在, 如果存在就重用老的
        for (size_t i = 0; i < RAM_FILE_MAX; i++)
        {
            if (files[i] == NULL)
                continue;
            if (!strcmp(files[i]->name, filename)) {
                luat_raw_fd_t* fd = luat_heap_malloc(sizeof(luat_raw_fd_t));
                if (fd == NULL) {
                    LLOGE("out of memory when malloc luat_raw_fd_t");
                    return NULL;
                }
                fd->fid = i;
                fd->offset = files[i]->size;
                fd->readonly = 0;
                return (FILE*)fd;
            }
        }
    }
    else {
        LLOGE("unkown open mode %s", mode);
        return NULL;
    }
    LLOGE("too many ram files >= %d", RAM_FILE_MAX);
    return NULL;
}

int luat_vfs_ram_getc(void* userdata, FILE* stream) {
    (void)userdata;
    //LLOGD("getc %p %p", userdata, stream);
    luat_raw_fd_t* fd = (luat_raw_fd_t*)stream;
    //LLOGD("getc %p %p %d %d", userdata, stream, fd->offset, fd->size);
    if (fd->fid < 0 || fd->fid >= RAM_FILE_MAX) {
        return -1;
    }
    if (files[fd->fid] == NULL) {
        return -1;
    }
    if (fd->offset < files[fd->fid]->size) {
        uint8_t c = (uint8_t)files[fd->fid]->ptr[fd->offset];
        fd->offset ++;
        //LLOGD("getc %02X", c);
        return c;
    }
    return -1;
}

int luat_vfs_ram_fseek(void* userdata, FILE* stream, long int offset, int origin) {
    (void)userdata;
    luat_raw_fd_t* fd = (luat_raw_fd_t*)stream;
    if (origin == SEEK_CUR) {
        fd->offset += offset;
        return 0;
    }
    else if (origin == SEEK_SET) {
        fd->offset = offset;
        return 0;
    }
    else {
        fd->offset = files[fd->fid]->size - offset;
        return 0;
    }
}

int luat_vfs_ram_ftell(void* userdata, FILE* stream) {
    (void)userdata;
    luat_raw_fd_t* fd = (luat_raw_fd_t*)stream;
    // LLOGD("tell %p %p offset %d", userdata, stream, fd->offset);
    return fd->offset;
}

int luat_vfs_ram_fclose(void* userdata, FILE* stream) {
    (void)userdata;
    luat_raw_fd_t* fd = (luat_raw_fd_t*)stream;
    //LLOGD("fclose %p %p %d %d", userdata, stream, fd->size, fd->offset);
    luat_heap_free(fd);
    return 0;
}
int luat_vfs_ram_feof(void* userdata, FILE* stream) {
    (void)userdata;
    luat_raw_fd_t* fd = (luat_raw_fd_t*)stream;
    //LLOGD("feof %p %p %d %d", userdata, stream, fd->size, fd->offset);
    return fd->offset >= files[fd->fid]->size ? 1 : 0;
}
int luat_vfs_ram_ferror(void* userdata, FILE *stream) {
    (void)userdata;
    (void)stream;
    return 0;
}
size_t luat_vfs_ram_fread(void* userdata, void *ptr, size_t size, size_t nmemb, FILE *stream) {
    (void)userdata;
    luat_raw_fd_t* fd = (luat_raw_fd_t*)stream;
    //LLOGD("fread %p %p %d %d", userdata, stream, fd->size, fd->offset);
    //LLOGD("fread2 %p %p %d %d", userdata, stream, size * nmemb, fd->offset);
    size_t read_size = size*nmemb;
    if (fd->offset >= files[fd->fid]->size) {
        return 0;
    }
    if (fd->offset + read_size >= files[fd->fid]->size) {
        read_size = files[fd->fid]->size - fd->offset;
    }
    memcpy(ptr, files[fd->fid]->ptr + fd->offset, read_size);
    fd->offset += read_size;
    return read_size;
}
size_t luat_vfs_ram_fwrite(void* userdata, const void *ptr, size_t size, size_t nmemb, FILE *stream) {
    (void)userdata;
    luat_raw_fd_t* fd = (luat_raw_fd_t*)stream;
    size_t write_size = size*nmemb;
    if (write_size > 128 * 1024) {
        LLOGW("ramfs large write !! %ld", write_size);
    }
    if (fd->readonly) {
        LLOGW("readonly fd %d!! path %s", fd->fid, files[fd->fid]->name);
        return 0;
    }
    
    if (fd->offset + write_size > files[fd->fid]->size) {
        char* ptr = luat_heap_realloc(files[fd->fid], fd->offset + write_size + sizeof(ram_file_t));
        if (ptr == NULL) {
            LLOGW("/ram out of sys memory!! %ld", write_size);
            return 0;
        }
        files[fd->fid] = (ram_file_t*)ptr;
        files[fd->fid]->size = fd->offset + write_size;
    }
    memcpy(files[fd->fid]->ptr + fd->offset, ptr, write_size);
    fd->offset += write_size;
    return write_size;
}
int luat_vfs_ram_remove(void* userdata, const char *filename) {
    (void)userdata;
    for (size_t i = 0; i < RAM_FILE_MAX; i++)
    {
        if (files[i] == NULL)
            continue;
        if (!strcmp(filename, files[i]->name)) {
            luat_heap_free(files[i]);
            files[i] = NULL;
        }
    }
    return 0;
}
int luat_vfs_ram_rename(void* userdata, const char *old_filename, const char *new_filename) {
    (void)userdata;
    if (old_filename == NULL || new_filename == NULL)
        return -1;
    if (strlen(old_filename) > 31 || strlen(new_filename) > 31)
        return -2;
    for (size_t i = 0; i < RAM_FILE_MAX; i++)
    {
        if (files[i] == NULL)
            continue;
        if (!strcmp(old_filename, files[i]->name)) {
            strcpy(files[i]->name, new_filename);
            return 0;
        }
    }
    return 0;
}
int luat_vfs_ram_fexist(void* userdata, const char *filename) {
    (void)userdata;
    for (size_t i = 0; i < RAM_FILE_MAX; i++)
    {
        if (files[i] == NULL)
            continue;
        if (!strcmp(filename, files[i]->name)) {
            return 1;
        }
    }
    return 0;
}

size_t luat_vfs_ram_fsize(void* userdata, const char *filename) {
    (void)userdata;
    for (size_t i = 0; i < RAM_FILE_MAX; i++)
    {
        if (files[i] == NULL)
            continue;
        if (!strcmp(filename, files[i]->name)) {
            return files[i]->size;
        }
    }
    return 0;
}

void* luat_vfs_ram_mmap(void* userdata, FILE *stream) {
    (void)userdata;
    luat_raw_fd_t *fd = (luat_raw_fd_t*)(stream);
    //LLOGD("fsize %p %p %d %d", userdata, fd);
    return files[fd->fid]->ptr;
}

int luat_vfs_ram_mkfs(void* userdata, luat_fs_conf_t *conf) {
    (void)userdata;
    (void)conf;
    return -1;
}

int luat_vfs_ram_mount(void** userdata, luat_fs_conf_t *conf) {
    (void)userdata;
    (void)conf;
    return 0;
}

int luat_vfs_ram_umount(void* userdata, luat_fs_conf_t *conf) {
    (void)userdata;
    (void)conf;
    return 0;
}

int luat_vfs_ram_mkdir(void* userdata, char const* _DirName) {
    (void)userdata;
    (void)_DirName;
    return -1;
}

int luat_vfs_ram_rmdir(void* userdata, char const* _DirName) {
    (void)userdata;
    (void)_DirName;
    return -1;
}

int luat_vfs_ram_lsdir(void* userdata, char const* _DirName, luat_fs_dirent_t* ents, size_t offset, size_t len) {
    (void)userdata;
    (void)_DirName;
    size_t count = 0;
    for (size_t i = 0; i < RAM_FILE_MAX; i++)
    {
        if (count >= len)
            break;
        if (files[i] == NULL)
            continue;
        if (offset > 0) {
            offset --;
            continue;
        }
        ents[count].d_type = 0;
        strcpy(ents[count].d_name, files[i]->name);
        count ++;
    }
    return count;
}

int luat_vfs_ram_info(void* userdata, const char* path, luat_fs_info_t *conf) {
    (void)userdata;
    (void)path;
    memcpy(conf->filesystem, "ram", strlen("ram")+1);
    size_t ftotal = 0;
    for (size_t i = 0; i < RAM_FILE_MAX; i++)
    {
        if (files[i] == NULL)
            continue;
        ftotal += files[i]->size;
    }
    size_t total; size_t used; size_t max_used;
    luat_meminfo_sys(&total, &used, &max_used);
    
    conf->type = 0;
    conf->total_block = 64;
    conf->block_used = (ftotal + 1023) / 1024;
    conf->block_size = 1024;
    return 0;
}

int luat_vfs_ram_truncate(void* fsdata, char const* path, size_t nsize) {
    for (size_t i = 0; i < RAM_FILE_MAX; i++)
    {
        if (files[i] == NULL)
            continue;
        if (!strcmp(files[i]->name, path)) {
            if (files[i]->size > nsize) {
                files[i]->size = nsize;
                char* ptr = luat_heap_realloc(files[i], nsize + sizeof(ram_file_t));
                if (ptr) {
                    files[i] = (ram_file_t*)ptr;
                }
            }
            return 0;
        }
    }
    return 0;
}

#endif


#define T(name) .name = luat_vfs_ram_##name
const struct luat_vfs_filesystem vfs_fs_ram = {
    .name = "ram",
    .opts = {
        .mkfs = NULL,
        T(mount),
        T(umount),
        .mkdir = NULL,
        .rmdir = NULL,
        T(lsdir),
        T(remove),
        T(rename),
        T(fsize),
        T(fexist),
        T(info),
        T(truncate)
    },
    .fopts = {
        T(fopen),
        T(getc),
        T(fseek),
        T(ftell),
        T(fclose),
        T(feof),
        T(ferror),
        T(fread),
        T(fwrite)
    }
};