aboutsummaryrefslogtreecommitdiff
path: root/include/frag_reader.h
diff options
context:
space:
mode:
Diffstat (limited to 'include/frag_reader.h')
-rw-r--r--include/frag_reader.h45
1 files changed, 45 insertions, 0 deletions
diff --git a/include/frag_reader.h b/include/frag_reader.h
index 6495f5b..8a3d4cc 100644
--- a/include/frag_reader.h
+++ b/include/frag_reader.h
@@ -8,6 +8,11 @@
#include <stdint.h>
#include <stddef.h>
+/**
+ * @struct frag_reader_t
+ *
+ * @brief A simple interface for accessing fragments in a SquashFS image
+ */
typedef struct {
sqfs_fragment_t *tbl;
size_t num_fragments;
@@ -20,11 +25,51 @@ typedef struct {
uint8_t buffer[];
} frag_reader_t;
+/**
+ * @brief Create a fragment reader
+ *
+ * @memberof frag_reader_t
+ *
+ * This function internally reads and decodes the fragment table from the
+ * image and prints error messages to stderr on the way if it fails.
+ *
+ * @param super A pointer to the SquashFS super block read from the image
+ * @param fd A file descriptor of opened the SquashFS image
+ * @param cmp A pointer to a compressor object to be used for reading meta
+ * data blocks from the image.
+ *
+ * @return A pointer to a new fragment reader or NULL on failure
+ */
frag_reader_t *frag_reader_create(sqfs_super_t *super, int fd,
compressor_t *cmp);
+/**
+ * @brief Destroy a fragment reader and free all memory it uses
+ *
+ * @memberof frag_reader_t
+ *
+ * @param f A pointer to a fragment reader object
+ */
void frag_reader_destroy(frag_reader_t *f);
+/**
+ * @brief Read tail-end packed data from a fragment
+ *
+ * @memberof frag_reader_t
+ *
+ * This function internally takes care of loading and uncompressing the
+ * fragment block (which is skipped if it has already been loaded earlier).
+ * It prints error messages to stderr on the way if it fails, including such
+ * errors as trying to index beyond the fragment table.
+ *
+ * @param f A pointer to a fragment reader object
+ * @param index A fragment index such as stored in an inode
+ * @param offset A byte offset into the fragment block addressed by the index
+ * @param buffer A pointer to a destination buffer to copy decoded data to
+ * @param size The number of bytes to copy into the destination buffer
+ *
+ * @return Zero on success, -1 on failure
+ */
int frag_reader_read(frag_reader_t *f, size_t index, size_t offset,
void *buffer, size_t size);