first commit for chrg

rt-thread/components/dfs/dfs_v2/include/dfs_seq_file.h

@@ -0,0 +1,78 @@
+/*
+ * Copyright (c) 2006-2025 RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ */
+
+#ifndef __DFS_SEQ_FILE_H__
+#define __DFS_SEQ_FILE_H__
+
+#include <dfs.h>
+#include <dfs_fs.h>
+
+struct dfs_seq_ops;
+
+/**
+ * Sequence file control structure
+ */
+struct dfs_seq_file
+{
+    char *buf;          /* Data buffer pointer */
+    size_t size;        /* Total buffer size in bytes */
+    size_t from;        /* Start offset of valid data in buffer */
+    size_t count;       /* Length of valid data in buffer */
+    size_t pad_until;   /* Padding target position for alignment */
+
+    off_t index;        /* Current item index in sequence */
+    off_t read_pos;     /* Current read position in file */
+
+    struct rt_mutex lock; /* Mutex for thread safety */
+
+    const struct dfs_seq_ops *ops; /* Operation function table */
+    const struct dfs_file *file;  /* Associated file object */
+    void *data;         /* Private data pointer */
+};
+
+/**
+ * Sequence file operations structure
+ */
+struct dfs_seq_ops
+{
+    void *(*start)(struct dfs_seq_file *seq, off_t *index);  /* Start sequence traversal */
+    void (*stop)(struct dfs_seq_file *seq, void *data);      /* Stop sequence traversal */
+    void *(*next)(struct dfs_seq_file *seq, void *data, off_t *index); /* Get next item in sequence */
+    int (*show)(struct dfs_seq_file *seq, void *data);  /* Show current item */
+};
+
+/**
+ * check if the buffer is full
+ */
+static inline rt_bool_t dfs_seq_is_full(struct dfs_seq_file *seq)
+{
+    return seq->count == seq->size;
+}
+
+/**
+ * set padding width size
+ */
+static inline void dfs_seq_setwidth(struct dfs_seq_file *seq, size_t size)
+{
+    seq->pad_until = seq->count + size;
+}
+
+int dfs_seq_open(struct dfs_file *file, const struct dfs_seq_ops *ops);
+ssize_t dfs_seq_read(struct dfs_file *file, void *buf, size_t size, off_t *pos);
+off_t dfs_seq_lseek(struct dfs_file *file, off_t offset, int whence);
+int dfs_seq_release(struct dfs_file *file);
+int dfs_seq_write(struct dfs_seq_file *seq, const void *data, size_t len);
+
+void dfs_seq_vprintf(struct dfs_seq_file *seq, const char *fmt, va_list args);
+void dfs_seq_printf(struct dfs_seq_file *seq, const char *fmt, ...);
+void dfs_seq_putc(struct dfs_seq_file *seq, char c);
+void dfs_seq_puts(struct dfs_seq_file *seq, const char *s);
+void dfs_seq_pad(struct dfs_seq_file *seq, char c);
+
+#endif