Refactor headers

[wimlib] / include / wimlib / buffer_io.h

diff --git a/include/wimlib/buffer_io.h b/include/wimlib/buffer_io.h
new file mode 100644 (file)
index 0000000..43e497b
--- /dev/null
+++ b/include/wimlib/buffer_io.h
@@ -0,0 +1,133 @@
+/*
+ * buffer_io.h
+ *
+ * A few endianness-aware macros for reading and writing data from in-memory
+ * buffers.
+ */
+
+#ifndef _WIMLIB_BUFFER_IO_H
+#define _WIMLIB_BUFFER_IO_H
+
+#include "wimlib/types.h"
+#include "endianness.h"
+#include <string.h>
+
+/* Note that in the WIM format, integers are always in little-endian format. */
+
+/* The get_u8, get_u16, get_u32, get_u56, and get_u64 functions take in a
+ * pointer to an input location as the first argument and a pointer to an output
+ * location as the second argument.  The data in the input location is copied to
+ * the output location, with the size indicated in the function name, in little
+ * endian format.  A pointer to the input location directly following the bytes
+ * read is returned. */
+static inline const void *
+get_u8(const void *p, u8 *res)
+{
+       *res = *(const u8*)p;
+       return p + 1;
+}
+
+static inline const void *
+get_u16(const void *p, u16 *res)
+{
+       *res = le16_to_cpu(*(const u16*)p);
+       return p + 2;
+}
+
+
+
+static inline const void *
+get_u32(const void *p, u32 *res)
+{
+       *res = le32_to_cpu(*(const u32*)p);
+       return p + 4;
+}
+
+
+static inline const void *
+get_u56(const void *p, u64 *res)
+{
+       *res = le64_to_cpu(*(const u64*)p) & 0x00ffffffffffffff;
+       return p + 7;
+}
+
+
+static inline const void *
+get_u64(const void *p, u64 *res)
+{
+       *res = le64_to_cpu(*(const u64*)p);
+       return p + 8;
+}
+
+/* The put_u8, put_u16, put_u32, put_u56, and put_u64 functions take in a
+ * pointer to an output location as the first argument and a value for the
+ * second argument.  The value of the second argument is written to the output
+ * location in little-endian format as the data type indicated in the function
+ * name, and a pointer to the output location directory following the bytes
+ * written is returned. */
+static inline void *
+put_u8(void *res, u8 val)
+{
+       *(u8*)res = val;
+       return res + 1;
+}
+
+static inline void *
+put_u16(void *res, u16 val)
+{
+       *(uint16_t*)res = cpu_to_le16(val);
+       return res + 2;
+}
+
+static inline void *
+put_u32(void *res, u32 val)
+{
+       *(uint32_t*)res = cpu_to_le32(val);
+       return res + 4;
+}
+
+static inline void *
+put_u56(void *res, u64 val)
+{
+       const u8 *__p = (const u8*)&val;
+#ifdef WORDS_BIGENDIAN
+       res[0] = __p[6];
+       res[1] = __p[5];
+       res[2] = __p[4];
+       res[3] = __p[3];
+       res[4] = __p[2];
+       res[5] = __p[1];
+       res[6] = __p[0];
+#else
+       memcpy(res, __p, 7);
+#endif
+       return res + 7;
+}
+
+static inline void *
+put_u64(void *res, u64 val)
+{
+       *(u64*)res = cpu_to_le64(val);
+       return res + 8;
+}
+
+static inline const void *
+get_bytes(const void *p, size_t num_bytes, void *res)
+{
+       memcpy(res, p, num_bytes);
+       return p + num_bytes;
+}
+
+static inline void *
+put_zeroes(void *p, size_t num_bytes)
+{
+       return memset(p, 0, num_bytes) + num_bytes;
+}
+
+static inline void *
+put_bytes(void *p, size_t num_bytes, const void *input)
+{
+       return memcpy(p, input, num_bytes) + num_bytes;
+}
+
+#endif /* _WIMLIB_BUFFER_IO_H */