summaryrefslogtreecommitdiffstats
path: root/sg_unaligned.h
diff options
context:
space:
mode:
Diffstat (limited to 'sg_unaligned.h')
-rw-r--r--sg_unaligned.h489
1 files changed, 489 insertions, 0 deletions
diff --git a/sg_unaligned.h b/sg_unaligned.h
new file mode 100644
index 0000000..ca702e8
--- /dev/null
+++ b/sg_unaligned.h
@@ -0,0 +1,489 @@
+#ifndef SG_UNALIGNED_H
+#define SG_UNALIGNED_H
+
+/*
+ * Copyright (c) 2014-2018 Douglas Gilbert.
+ * All rights reserved.
+ * Use of this source code is governed by a BSD-style
+ * license that can be found in the BSD_LICENSE file.
+ */
+
+#include <stdbool.h>
+#include <stdint.h> /* for uint8_t and friends */
+#include <string.h> /* for memcpy */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* These inline functions convert integers (always unsigned) to byte streams
+ * and vice versa. They have two goals:
+ * - change the byte ordering of integers between host order and big
+ * endian ("_be") or little endian ("_le")
+ * - copy the big or little endian byte stream so it complies with any
+ * alignment that host integers require
+ *
+ * Host integer to given endian byte stream is a "_put_" function taking
+ * two arguments (integer and pointer to byte stream) returning void.
+ * Given endian byte stream to host integer is a "_get_" function that takes
+ * one argument and returns an integer of appropriate size (uint32_t for 24
+ * bit operations, uint64_t for 48 bit operations).
+ *
+ * Big endian byte format "on the wire" is the default used by SCSI
+ * standards (www.t10.org). Big endian is also the network byte order.
+ * Little endian is used by ATA, PCI and NVMe.
+ */
+
+/* The generic form of these routines was borrowed from the Linux kernel,
+ * via mhvtl. There is a specialised version of the main functions for
+ * little endian or big endian provided that not-quite-standard defines for
+ * endianness are available from the compiler and the <byteswap.h> header
+ * (a GNU extension) has been detected by ./configure . To force the
+ * generic version, use './configure --disable-fast-lebe ' . */
+
+/* Note: Assumes that the source and destination locations do not overlap.
+ * An example of overlapping source and destination:
+ * sg_put_unaligned_le64(j, ((uint8_t *)&j) + 1);
+ * Best not to do things like that.
+ */
+
+
+#ifdef HAVE_CONFIG_H
+#include "config.h" /* need this to see if HAVE_BYTESWAP_H */
+#endif
+
+#undef GOT_UNALIGNED_SPECIALS /* just in case */
+
+#if defined(__BYTE_ORDER__) && defined(HAVE_BYTESWAP_H) && \
+ ! defined(IGNORE_FAST_LEBE)
+
+#if defined(__LITTLE_ENDIAN__) || (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__)
+
+#define GOT_UNALIGNED_SPECIALS 1
+
+#include <byteswap.h> /* for bswap_16(), bswap_32() and bswap_64() */
+
+// #warning ">>>>>> Doing Little endian special unaligneds"
+
+static inline uint16_t sg_get_unaligned_be16(const void *p)
+{
+ uint16_t u;
+
+ memcpy(&u, p, 2);
+ return bswap_16(u);
+}
+
+static inline uint32_t sg_get_unaligned_be32(const void *p)
+{
+ uint32_t u;
+
+ memcpy(&u, p, 4);
+ return bswap_32(u);
+}
+
+static inline uint64_t sg_get_unaligned_be64(const void *p)
+{
+ uint64_t u;
+
+ memcpy(&u, p, 8);
+ return bswap_64(u);
+}
+
+static inline void sg_put_unaligned_be16(uint16_t val, void *p)
+{
+ uint16_t u = bswap_16(val);
+
+ memcpy(p, &u, 2);
+}
+
+static inline void sg_put_unaligned_be32(uint32_t val, void *p)
+{
+ uint32_t u = bswap_32(val);
+
+ memcpy(p, &u, 4);
+}
+
+static inline void sg_put_unaligned_be64(uint64_t val, void *p)
+{
+ uint64_t u = bswap_64(val);
+
+ memcpy(p, &u, 8);
+}
+
+static inline uint16_t sg_get_unaligned_le16(const void *p)
+{
+ uint16_t u;
+
+ memcpy(&u, p, 2);
+ return u;
+}
+
+static inline uint32_t sg_get_unaligned_le32(const void *p)
+{
+ uint32_t u;
+
+ memcpy(&u, p, 4);
+ return u;
+}
+
+static inline uint64_t sg_get_unaligned_le64(const void *p)
+{
+ uint64_t u;
+
+ memcpy(&u, p, 8);
+ return u;
+}
+
+static inline void sg_put_unaligned_le16(uint16_t val, void *p)
+{
+ memcpy(p, &val, 2);
+}
+
+static inline void sg_put_unaligned_le32(uint32_t val, void *p)
+{
+ memcpy(p, &val, 4);
+}
+
+static inline void sg_put_unaligned_le64(uint64_t val, void *p)
+{
+ memcpy(p, &val, 8);
+}
+
+#elif defined(__BIG_ENDIAN__) || (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
+
+#define GOT_UNALIGNED_SPECIALS 1
+
+#include <byteswap.h>
+
+// #warning ">>>>>> Doing BIG endian special unaligneds"
+
+static inline uint16_t sg_get_unaligned_le16(const void *p)
+{
+ uint16_t u;
+
+ memcpy(&u, p, 2);
+ return bswap_16(u);
+}
+
+static inline uint32_t sg_get_unaligned_le32(const void *p)
+{
+ uint32_t u;
+
+ memcpy(&u, p, 4);
+ return bswap_32(u);
+}
+
+static inline uint64_t sg_get_unaligned_le64(const void *p)
+{
+ uint64_t u;
+
+ memcpy(&u, p, 8);
+ return bswap_64(u);
+}
+
+static inline void sg_put_unaligned_le16(uint16_t val, void *p)
+{
+ uint16_t u = bswap_16(val);
+
+ memcpy(p, &u, 2);
+}
+
+static inline void sg_put_unaligned_le32(uint32_t val, void *p)
+{
+ uint32_t u = bswap_32(val);
+
+ memcpy(p, &u, 4);
+}
+
+static inline void sg_put_unaligned_le64(uint64_t val, void *p)
+{
+ uint64_t u = bswap_64(val);
+
+ memcpy(p, &u, 8);
+}
+
+static inline uint16_t sg_get_unaligned_be16(const void *p)
+{
+ uint16_t u;
+
+ memcpy(&u, p, 2);
+ return u;
+}
+
+static inline uint32_t sg_get_unaligned_be32(const void *p)
+{
+ uint32_t u;
+
+ memcpy(&u, p, 4);
+ return u;
+}
+
+static inline uint64_t sg_get_unaligned_be64(const void *p)
+{
+ uint64_t u;
+
+ memcpy(&u, p, 8);
+ return u;
+}
+
+static inline void sg_put_unaligned_be16(uint16_t val, void *p)
+{
+ memcpy(p, &val, 2);
+}
+
+static inline void sg_put_unaligned_be32(uint32_t val, void *p)
+{
+ memcpy(p, &val, 4);
+}
+
+static inline void sg_put_unaligned_be64(uint64_t val, void *p)
+{
+ memcpy(p, &val, 8);
+}
+
+#endif /* __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ */
+#endif /* #if defined __BYTE_ORDER__ && defined <byteswap.h> &&
+ * ! defined IGNORE_FAST_LEBE */
+
+
+#ifndef GOT_UNALIGNED_SPECIALS
+
+/* Now we have no tricks left, so use the only way this can be done
+ * correctly in C safely: lots of shifts. */
+
+// #warning ">>>>>> Doing GENERIC unaligneds"
+
+static inline uint16_t sg_get_unaligned_be16(const void *p)
+{
+ return ((const uint8_t *)p)[0] << 8 | ((const uint8_t *)p)[1];
+}
+
+static inline uint32_t sg_get_unaligned_be32(const void *p)
+{
+ return ((const uint8_t *)p)[0] << 24 | ((const uint8_t *)p)[1] << 16 |
+ ((const uint8_t *)p)[2] << 8 | ((const uint8_t *)p)[3];
+}
+
+static inline uint64_t sg_get_unaligned_be64(const void *p)
+{
+ return (uint64_t)sg_get_unaligned_be32(p) << 32 |
+ sg_get_unaligned_be32((const uint8_t *)p + 4);
+}
+
+static inline void sg_put_unaligned_be16(uint16_t val, void *p)
+{
+ ((uint8_t *)p)[0] = (uint8_t)(val >> 8);
+ ((uint8_t *)p)[1] = (uint8_t)val;
+}
+
+static inline void sg_put_unaligned_be32(uint32_t val, void *p)
+{
+ sg_put_unaligned_be16(val >> 16, p);
+ sg_put_unaligned_be16(val, (uint8_t *)p + 2);
+}
+
+static inline void sg_put_unaligned_be64(uint64_t val, void *p)
+{
+ sg_put_unaligned_be32(val >> 32, p);
+ sg_put_unaligned_be32(val, (uint8_t *)p + 4);
+}
+
+
+static inline uint16_t sg_get_unaligned_le16(const void *p)
+{
+ return ((const uint8_t *)p)[1] << 8 | ((const uint8_t *)p)[0];
+}
+
+static inline uint32_t sg_get_unaligned_le32(const void *p)
+{
+ return ((const uint8_t *)p)[3] << 24 | ((const uint8_t *)p)[2] << 16 |
+ ((const uint8_t *)p)[1] << 8 | ((const uint8_t *)p)[0];
+}
+
+static inline uint64_t sg_get_unaligned_le64(const void *p)
+{
+ return (uint64_t)sg_get_unaligned_le32((const uint8_t *)p + 4) << 32 |
+ sg_get_unaligned_le32(p);
+}
+
+static inline void sg_put_unaligned_le16(uint16_t val, void *p)
+{
+ ((uint8_t *)p)[0] = val & 0xff;
+ ((uint8_t *)p)[1] = val >> 8;
+}
+
+static inline void sg_put_unaligned_le32(uint32_t val, void *p)
+{
+ sg_put_unaligned_le16(val >> 16, (uint8_t *)p + 2);
+ sg_put_unaligned_le16(val, p);
+}
+
+static inline void sg_put_unaligned_le64(uint64_t val, void *p)
+{
+ sg_put_unaligned_le32(val >> 32, (uint8_t *)p + 4);
+ sg_put_unaligned_le32(val, p);
+}
+
+#endif /* #ifndef GOT_UNALIGNED_SPECIALS */
+
+/* Following are lesser used conversions that don't have specializations
+ * for endianness; big endian first. In summary these are the 24, 48 bit and
+ * given-length conversions plus the "nz" conditional put conversions. */
+
+/* Now big endian, get 24+48 then put 24+48 */
+static inline uint32_t sg_get_unaligned_be24(const void *p)
+{
+ return ((const uint8_t *)p)[0] << 16 | ((const uint8_t *)p)[1] << 8 |
+ ((const uint8_t *)p)[2];
+}
+
+/* Assume 48 bit value placed in uint64_t */
+static inline uint64_t sg_get_unaligned_be48(const void *p)
+{
+ return (uint64_t)sg_get_unaligned_be16(p) << 32 |
+ sg_get_unaligned_be32((const uint8_t *)p + 2);
+}
+
+/* Returns 0 if 'num_bytes' is less than or equal to 0 or greater than
+ * 8 (i.e. sizeof(uint64_t)). Else returns result in uint64_t which is
+ * an 8 byte unsigned integer. */
+static inline uint64_t sg_get_unaligned_be(int num_bytes, const void *p)
+{
+ if ((num_bytes <= 0) || (num_bytes > (int)sizeof(uint64_t)))
+ return 0;
+ else {
+ const uint8_t * xp = (const uint8_t *)p;
+ uint64_t res = *xp;
+
+ for (++xp; num_bytes > 1; ++xp, --num_bytes)
+ res = (res << 8) | *xp;
+ return res;
+ }
+}
+
+static inline void sg_put_unaligned_be24(uint32_t val, void *p)
+{
+ ((uint8_t *)p)[0] = (val >> 16) & 0xff;
+ ((uint8_t *)p)[1] = (val >> 8) & 0xff;
+ ((uint8_t *)p)[2] = val & 0xff;
+}
+
+/* Assume 48 bit value placed in uint64_t */
+static inline void sg_put_unaligned_be48(uint64_t val, void *p)
+{
+ sg_put_unaligned_be16(val >> 32, p);
+ sg_put_unaligned_be32(val, (uint8_t *)p + 2);
+}
+
+/* Now little endian, get 24+48 then put 24+48 */
+static inline uint32_t sg_get_unaligned_le24(const void *p)
+{
+ return (uint32_t)sg_get_unaligned_le16(p) |
+ ((const uint8_t *)p)[2] << 16;
+}
+
+/* Assume 48 bit value placed in uint64_t */
+static inline uint64_t sg_get_unaligned_le48(const void *p)
+{
+ return (uint64_t)sg_get_unaligned_le16((const uint8_t *)p + 4) << 32 |
+ sg_get_unaligned_le32(p);
+}
+
+static inline void sg_put_unaligned_le24(uint32_t val, void *p)
+{
+ ((uint8_t *)p)[2] = (val >> 16) & 0xff;
+ ((uint8_t *)p)[1] = (val >> 8) & 0xff;
+ ((uint8_t *)p)[0] = val & 0xff;
+}
+
+/* Assume 48 bit value placed in uint64_t */
+static inline void sg_put_unaligned_le48(uint64_t val, void *p)
+{
+ ((uint8_t *)p)[5] = (val >> 40) & 0xff;
+ ((uint8_t *)p)[4] = (val >> 32) & 0xff;
+ ((uint8_t *)p)[3] = (val >> 24) & 0xff;
+ ((uint8_t *)p)[2] = (val >> 16) & 0xff;
+ ((uint8_t *)p)[1] = (val >> 8) & 0xff;
+ ((uint8_t *)p)[0] = val & 0xff;
+}
+
+/* Returns 0 if 'num_bytes' is less than or equal to 0 or greater than
+ * 8 (i.e. sizeof(uint64_t)). Else returns result in uint64_t which is
+ * an 8 byte unsigned integer. */
+static inline uint64_t sg_get_unaligned_le(int num_bytes, const void *p)
+{
+ if ((num_bytes <= 0) || (num_bytes > (int)sizeof(uint64_t)))
+ return 0;
+ else {
+ const uint8_t * xp = (const uint8_t *)p + (num_bytes - 1);
+ uint64_t res = *xp;
+
+ for (--xp; num_bytes > 1; --xp, --num_bytes)
+ res = (res << 8) | *xp;
+ return res;
+ }
+}
+
+/* Since cdb and parameter blocks are often memset to zero before these
+ * unaligned function partially fill them, then check for a val of zero
+ * and ignore if it is with these variants. First big endian, then little */
+static inline void sg_nz_put_unaligned_be16(uint16_t val, void *p)
+{
+ if (val)
+ sg_put_unaligned_be16(val, p);
+}
+
+static inline void sg_nz_put_unaligned_be24(uint32_t val, void *p)
+{
+ if (val) {
+ ((uint8_t *)p)[0] = (val >> 16) & 0xff;
+ ((uint8_t *)p)[1] = (val >> 8) & 0xff;
+ ((uint8_t *)p)[2] = val & 0xff;
+ }
+}
+
+static inline void sg_nz_put_unaligned_be32(uint32_t val, void *p)
+{
+ if (val)
+ sg_put_unaligned_be32(val, p);
+}
+
+static inline void sg_nz_put_unaligned_be64(uint64_t val, void *p)
+{
+ if (val)
+ sg_put_unaligned_be64(val, p);
+}
+
+static inline void sg_nz_put_unaligned_le16(uint16_t val, void *p)
+{
+ if (val)
+ sg_put_unaligned_le16(val, p);
+}
+
+static inline void sg_nz_put_unaligned_le24(uint32_t val, void *p)
+{
+ if (val) {
+ ((uint8_t *)p)[2] = (val >> 16) & 0xff;
+ ((uint8_t *)p)[1] = (val >> 8) & 0xff;
+ ((uint8_t *)p)[0] = val & 0xff;
+ }
+}
+
+static inline void sg_nz_put_unaligned_le32(uint32_t val, void *p)
+{
+ if (val)
+ sg_put_unaligned_le32(val, p);
+}
+
+static inline void sg_nz_put_unaligned_le64(uint64_t val, void *p)
+{
+ if (val)
+ sg_put_unaligned_le64(val, p);
+}
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* SG_UNALIGNED_H */
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-21 13:22:11 +0000