From a5f604469d5cde8cb654e209f1ec30bf8e44b51e Mon Sep 17 00:00:00 2001
From: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
Date: Sun, 5 May 2019 21:45:04 +0200
Subject: Comment on all the things

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
---
 include/meta_writer.h | 80 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)

(limited to 'include/meta_writer.h')

diff --git a/include/meta_writer.h b/include/meta_writer.h
index 7f1be9a..9dcc22d 100644
--- a/include/meta_writer.h
+++ b/include/meta_writer.h
@@ -5,21 +5,101 @@
 #include "compress.h"
 #include "squashfs.h"
 
+/**
+ * @struct meta_writer_t
+ *
+ * @brief Abstracts away I/O on SquashFS meta data
+ */
 typedef struct {
+	/**
+	 * @brief A byte offset into the uncompressed data of the current block
+	 */
 	size_t offset;
+
+	/**
+	 * @brief The location of the current block in the file
+	 */
 	size_t block_offset;
+
+	/**
+	 * @brief The underlying file descriptor to write to
+	 */
 	int outfd;
+
+	/**
+	 * @brief A pointer to the compressor to use for compressing the data
+	 */
 	compressor_t *cmp;
+
+	/**
+	 * @brief The raw data chunk that data is appended to
+	 */
 	uint8_t data[SQFS_META_BLOCK_SIZE + 2];
+
+	/**
+	 * @brief Scratch buffer for compressing data
+	 */
 	uint8_t scratch[SQFS_META_BLOCK_SIZE + 2];
 } meta_writer_t;
 
+/**
+ * @brief Create a meta data writer
+ *
+ * @memberof meta_writer_t
+ *
+ * @note This function internally prints error message to stderr on failure
+ *
+ * @param fd  The underlying file descriptor to write from
+ * @param cmp A pointer to a compressor to use for compressing the data
+ *
+ * @return A pointer to a meta data writer, NULL on failure
+ */
 meta_writer_t *meta_writer_create(int fd, compressor_t *cmp);
 
+/**
+ * @brief Destroy a meta data writer and free all memory used by it
+ *
+ * @memberof meta_writer_t
+ *
+ * @param m A pointer to a meta data reader
+ */
 void meta_writer_destroy(meta_writer_t *m);
 
+/**
+ * @brief Flush the currently unfinished meta data block to disk
+ *
+ * @memberof meta_writer_t
+ *
+ * @note This function internally prints error message to stderr on failure
+ *
+ * If data has been collected in the block buffer but it is not complete yet,
+ * this function tries to compress it and write it out anyway and reset the
+ * internal counters.
+ *
+ * @param m A pointer to a meta data reader
+ *
+ * @return Zero on success, -1 on failure
+ */
 int meta_writer_flush(meta_writer_t *m);
 
+/**
+ * @brief Append data to the current meta data block
+ *
+ * @memberof meta_writer_t
+ *
+ * @note This function internally prints error message to stderr on failure
+ *
+ * This function appends the input data to an internal meta data buffer. If
+ * the internal buffer is full, it is compressed and written to disk using
+ * @ref meta_writer flush, i.e. the function allows for transparent writing
+ * across meta data blocks.
+ *
+ * @param m    A pointer to a meta data reader
+ * @param data A pointer to the data block to append
+ * @param size The number of bytes to read from the data blob
+ *
+ * @return Zero on success, -1 on failure
+ */
 int meta_writer_append(meta_writer_t *m, const void *data, size_t size);
 
 #endif /* META_WRITER_H */
-- 
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