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-rw-r--r--src/xz/file_io.h34
1 files changed, 28 insertions, 6 deletions
diff --git a/src/xz/file_io.h b/src/xz/file_io.h
index b0bbe11a..58bf7b5e 100644
--- a/src/xz/file_io.h
+++ b/src/xz/file_io.h
@@ -11,13 +11,22 @@
///////////////////////////////////////////////////////////////////////////////
// Some systems have suboptimal BUFSIZ. Use a bit bigger value on them.
+// We also need that IO_BUFFER_SIZE is a multiple of 8 (sizeof(uint64_t))
#if BUFSIZ <= 1024
# define IO_BUFFER_SIZE 8192
#else
-# define IO_BUFFER_SIZE BUFSIZ
+# define IO_BUFFER_SIZE (BUFSIZ & ~7U)
#endif
+/// is_sparse() accesses the buffer as uint64_t for maximum speed.
+/// Use an union to make sure that the buffer is properly aligned.
+typedef union {
+ uint8_t u8[IO_BUFFER_SIZE];
+ uint64_t u64[IO_BUFFER_SIZE / sizeof(uint64_t)];
+} io_buf;
+
+
typedef struct {
/// Name of the source filename (as given on the command line) or
/// pointer to static "(stdin)" when reading from standard input.
@@ -33,15 +42,24 @@ typedef struct {
/// File descriptor of the target file
int dest_fd;
+ /// True once end of the source file has been detected.
+ bool src_eof;
+
+ /// If true, we look for long chunks of zeros and try to create
+ /// a sparse file.
+ bool dest_try_sparse;
+
+ /// This is used only if dest_try_sparse is true. This holds the
+ /// number of zero bytes we haven't written out, because we plan
+ /// to make that byte range a sparse chunk.
+ off_t dest_pending_sparse;
+
/// Stat of the source file.
struct stat src_st;
/// Stat of the destination file.
struct stat dest_st;
- /// True once end of the source file has been detected.
- bool src_eof;
-
} file_pair;
@@ -49,6 +67,10 @@ typedef struct {
extern void io_init(void);
+/// \brief Disable creation of sparse files when decompressing
+extern void io_no_sparse(void);
+
+
/// \brief Opens a file pair
extern file_pair *io_open(const char *src_name);
@@ -72,7 +94,7 @@ extern void io_close(file_pair *pair, bool success);
/// \return On success, number of bytes read is returned. On end of
/// file zero is returned and pair->src_eof set to true.
/// On error, SIZE_MAX is returned and error message printed.
-extern size_t io_read(file_pair *pair, uint8_t *buf, size_t size);
+extern size_t io_read(file_pair *pair, io_buf *buf, size_t size);
/// \brief Writes a buffer to the destination file
@@ -83,4 +105,4 @@ extern size_t io_read(file_pair *pair, uint8_t *buf, size_t size);
///
/// \return On success, zero is returned. On error, -1 is returned
/// and error message printed.
-extern bool io_write(const file_pair *pair, const uint8_t *buf, size_t size);
+extern bool io_write(file_pair *pair, const io_buf *buf, size_t size);