reader: reimplementation the reader without _skip

include/sqsh_file_private.h

@@ -39,6 +39,7 @@
 #include "sqsh_extract_private.h"
 #include "sqsh_mapper_private.h"
 #include "sqsh_metablock_private.h"
+#include "sqsh_reader_private.h"
 
 #ifdef __cplusplus
 extern "C" {

include/sqsh_mapper_private.h

@@ -37,6 +37,7 @@
 #include "sqsh_mapper.h"
 
 #include "sqsh_primitive_private.h"
+#include "sqsh_reader_private.h"
 #include "sqsh_thread_private.h"
 #include <sys/wait.h>
 

include/sqsh_primitive_private.h

@@ -137,6 +137,19 @@ SQSH_NO_EXPORT SQSH_NO_UNUSED int sqsh__buffer_append(
 SQSH_NO_EXPORT SQSH_NO_UNUSED int
 sqsh__buffer_move(struct SqshBuffer *buffer, struct SqshBuffer *source);
 
+/**
+ * @internal
+ * @memberof SqshBuffer
+ * @brief resets the buffer size to 0.
+ *
+ * This does not free the memory allocated by the buffer so that
+ * the buffer can be reused.
+ *
+ * @param[in,out] buffer The SqshBuffer to drain.
+ */
+
+void sqsh__buffer_drain(struct SqshBuffer *buffer);
+
 /**
  * @internal
  * @memberof SqshBuffer
@@ -509,110 +522,6 @@ sqsh__lru_touch(struct SqshLru *lru, sqsh_index_t id);
  */
 SQSH_NO_EXPORT int sqsh__lru_cleanup(struct SqshLru *lru);
 
-/***************************************
- * primitive/reader.c
- */
-
-/**
- * @internal
- * @brief A buffer that is used to read data from a SqshReader.
- */
-struct SqshIteratorImpl {
-	/**
-	 * @privatesection
-	 */
-	int (*next)(void *iterator, size_t desired_size);
-	int (*skip)(void *iterator, size_t amount, size_t desired_size);
-	size_t (*block_size)(const void *iterator);
-	const uint8_t *(*data)(const void *iterator);
-	size_t (*size)(const void *iterator);
-};
-
-/**
- * @internal
- * @brief A buffer that is used to read data from a SqshReader.
- */
-struct SqshReader {
-	/**
-	 * @privatesection
-	 */
-	const struct SqshIteratorImpl *impl;
-	void *iterator;
-
-	sqsh_index_t iterator_offset;
-	sqsh_index_t buffer_offset;
-	sqsh_index_t data_offset;
-	size_t size;
-	size_t data_size;
-	struct SqshBuffer buffer;
-	const uint8_t *data;
-};
-
-/**
- * @internal
- * @memberof SqshReader
- * @brief Initializes a reader.
- *
- * @param[out] reader    Pointer to the metablock reader to be initialized.
- * @param[in]  impl      Implementation of the iterator.
- * @param[in]  iterator  Iterator to use for the reader.
- *
- * @return 0 on success, less than zero on error.
- */
-SQSH_NO_EXPORT SQSH_NO_UNUSED int sqsh__reader_init(
-		struct SqshReader *reader, const struct SqshIteratorImpl *impl,
-		void *iterator);
-
-/**
- * @internal
- * @memberof SqshReader
- * @brief Advances the reader by the given offset and size.
- *
- * @param[in,out] reader  Pointer to the metablock reader to be advanced.
- * @param[in] offset      Offset to advance the reader by.
- * @param[in] size        Size of the block to advance the reader by.
- *
- * @return 0 on success, less than zero on error.
- */
-SQSH_NO_EXPORT SQSH_NO_UNUSED int sqsh__reader_advance(
-		struct SqshReader *reader, sqsh_index_t offset, size_t size);
-
-/**
- * @internal
- * @memberof SqshReader
- * @brief Returns a pointer to the data at the current position of the metablock
- * reader.
- *
- * @param[in] reader  Pointer to the metablock reader.
- *
- * @return Pointer to the data at the current position of the metablock reader.
- */
-SQSH_NO_EXPORT const uint8_t *
-sqsh__reader_data(const struct SqshReader *reader);
-
-/**
- * @internal
- * @memberof SqshReader
- * @brief Returns the size of the data at the current position of the metablock
- * reader.
- *
- * @param[in] reader Pointer to the metablock reader.
- *
- * @return Size of the data at the current position of the metablock reader.
- */
-SQSH_NO_EXPORT size_t sqsh__reader_size(const struct SqshReader *reader);
-
-/**
- * @internal
- * @memberof SqshReader
- * @brief Cleans up and frees the resources used by the metablock reader.
- *
- * @param[in,out] reader Pointer to the metablock reader to be cleaned up.
- *
- * @return 0 on success, less than zero on error.
- */
-SQSH_NO_EXPORT int sqsh__reader_cleanup(struct SqshReader *reader);
-
 #ifdef __cplusplus
 }
 #endif

include/sqsh_reader_private.h

@@ -0,0 +1,193 @@
+/******************************************************************************
+ *                                                                            *
+ * Copyright (c) 2023, Enno Boland <[email protected]>                                 *
+ *                                                                            *
+ * Redistribution and use in source and binary forms, with or without         *
+ * modification, are permitted provided that the following conditions are     *
+ * met:                                                                       *
+ *                                                                            *
+ * * Redistributions of source code must retain the above copyright notice,   *
+ *   this list of conditions and the following disclaimer.                    *
+ * * Redistributions in binary form must reproduce the above copyright        *
+ *   notice, this list of conditions and the following disclaimer in the      *
+ *   documentation and/or other materials provided with the distribution.     *
+ *                                                                            *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS    *
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,  *
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR     *
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR          *
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,      *
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,        *
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR         *
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF     *
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING       *
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS         *
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.               *
+ *                                                                            *
+ ******************************************************************************/
+
+/**
+ * @author       Enno Boland ([email protected])
+ * @file         sqsh_reader_private.h
+ */
+
+#ifndef SQSH_READER_PRIVATE_H
+#define SQSH_READER_PRIVATE_H
+
+#include "sqsh_common.h"
+#include "sqsh_primitive_private.h"
+#include <sys/wait.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/***************************************
+ * reader/reader.c
+ */
+
+struct SqshReaderIteratorImpl {
+	int (*next)(void *iterator, size_t desired_size);
+	const uint8_t *(*data)(const void *iterator);
+	size_t (*size)(const void *iterator);
+};
+
+/**
+ * @brief An iterator over extended attributes.
+ */
+struct SqshReader {
+	/**
+	 * @privatesection
+	 */
+
+	/**
+	 * @brief The for this reader.
+	 */
+	void *iterator;
+
+	/**
+	 * @brief interface to the iterator.
+	 */
+	const struct SqshReaderIteratorImpl *iterator_impl;
+
+	/**
+	 * @brief The offset of the iterator.
+	 *
+	 * A value of "0" indicates, that the reader currently directly maps data
+	 * from the iterator. That means, that `data` points into memory managed by
+	 * the iterator.
+	 *
+	 * A non-zero value indicates, that the reader has copied data from the
+	 * iterator into the buffer. That means, that `data` points into memory
+	 * managed by the buffer. The actual value of iterator_offset is the offset
+	 * between the buffer and the iterator.
+	 *
+	 * example:
+	 *
+	 * ```
+	 *            0123456789
+	 * buffer:    ##########
+	 * iterator:        ####
+	 * ```
+	 *
+	 * in this case, the iterator_offset is 6.
+	 */
+	sqsh_index_t iterator_offset;
+
+	/**
+	 * @brief The offset of mapped data.
+	 *
+	 * This value is set to zero if the reader uses buffered data.
+	 *
+	 * Otherwise is indicates the offset of the data in the iterator.
+	 */
+	sqsh_index_t offset;
+
+	/**
+	 * @brief The buffer to store data in if they cannot be directly mapped.
+	 */
+	struct SqshBuffer buffer;
+
+	/**
+	 * @brief The data that is presented to the user.
+	 *
+	 * This pointer has the offset already applied if in mapped mode.
+	 *
+	 * Otherwise it points to the beginning of the buffer.
+	 */
+	const uint8_t *data;
+	/**
+	 * @brief The size of the data that is presented to the user.
+	 */
+	size_t size;
+};
+
+/**
+ * @internal
+ * @memberof SqshReader
+ * @brief Initializes a reader.
+ *
+ * @param[out] reader         Pointer to the metablock reader to be initialized.
+ * @param[in]  iterator_impl  Implementation of the iterator.
+ * @param[in]  iterator       Iterator to use for the reader.
+ *
+ * @return 0 on success, less than zero on error.
+ */
+SQSH_NO_EXPORT SQSH_NO_UNUSED int sqsh__reader_init(
+		struct SqshReader *reader,
+		const struct SqshReaderIteratorImpl *iterator_impl, void *iterator);
+
+/**
+ * @internal
+ * @memberof SqshReader
+ * @brief Advances the reader by the given offset and size.
+ *
+ * @param[in,out] reader  Pointer to the metablock reader to be advanced.
+ * @param[in] offset      Offset to advance the reader by.
+ * @param[in] size        Size of the block to advance the reader by.
+ *
+ * @return 0 on success, less than zero on error.
+ */
+SQSH_NO_EXPORT SQSH_NO_UNUSED int sqsh__reader_advance(
+		struct SqshReader *reader, sqsh_index_t offset, size_t size);
+
+/**
+ * @internal
+ * @memberof SqshReader
+ * @brief Returns a pointer to the data at the current position of the metablock
+ * reader.
+ *
+ * @param[in] reader  Pointer to the metablock reader.
+ *
+ * @return Pointer to the data at the current position of the metablock reader.
+ */
+SQSH_NO_EXPORT const uint8_t *
+sqsh__reader_data(const struct SqshReader *reader);
+
+/**
+ * @internal
+ * @memberof SqshReader
+ * @brief Returns the size of the data at the current position of the metablock
+ * reader.
+ *
+ * @param[in] reader Pointer to the metablock reader.
+ *
+ * @return Size of the data at the current position of the metablock reader.
+ */
+SQSH_NO_EXPORT size_t sqsh__reader_size(const struct SqshReader *reader);
+
+/**
+ * @internal
+ * @memberof SqshReader
+ * @brief Cleans up and frees the resources used by the metablock reader.
+ *
+ * @param[in,out] reader Pointer to the metablock reader to be cleaned up.
+ *
+ * @return 0 on success, less than zero on error.
+ */
+SQSH_NO_EXPORT int sqsh__reader_cleanup(struct SqshReader *reader);
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* SQSH_READER_PRIVATE_H */

lib/file/file_reader.c

@@ -35,22 +35,14 @@
 
 #include "../../include/sqsh_archive_private.h"
 #include "../../include/sqsh_error.h"
-#include "../../include/sqsh_primitive_private.h"
+#include "../../include/sqsh_reader_private.h"
 
 #include "../utils/utils.h"
 
 static int
 file_iterator_next(void *iterator, size_t desired_size) {
 	return sqsh_file_iterator_next(iterator, desired_size);
 }
-static int
-file_iterator_skip(void *iterator, size_t amount, size_t desired_size) {
-	return sqsh_file_iterator_skip(iterator, amount, desired_size);
-}
-static size_t
-file_iterator_block_size(const void *iterator) {
-	return sqsh_file_iterator_block_size(iterator);
-}
 static const uint8_t *
 file_iterator_data(const void *iterator) {
 	return sqsh_file_iterator_data(iterator);
@@ -60,10 +52,8 @@ file_iterator_size(const void *iterator) {
 	return sqsh_file_iterator_size(iterator);
 }
 
-static const struct SqshIteratorImpl file_reader_impl = {
+static const struct SqshReaderIteratorImpl file_reader_impl = {
 		.next = file_iterator_next,
-		.skip = file_iterator_skip,
-		.block_size = file_iterator_block_size,
 		.data = file_iterator_data,
 		.size = file_iterator_size,
 };