Patchwork D9845: bitmanipulation: add utils to read/write bigendian 64bit integers

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Submitter phabricator
Date Jan. 20, 2021, 8:45 p.m.
Message ID <differential-rev-PHID-DREV-aaftnwrbxpdys2n2743g-req@mercurial-scm.org>
Download mbox | patch
Permalink /patch/48154/
State New
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Comments

phabricator - Jan. 20, 2021, 8:45 p.m.
Alphare created this revision.
Herald added a reviewer: hg-reviewers.
Herald added a subscriber: mercurial-patches.

REPOSITORY
  rHG Mercurial

BRANCH
  default

REVISION DETAIL
  https://phab.mercurial-scm.org/D9845

AFFECTED FILES
  mercurial/bitmanipulation.h

CHANGE DETAILS




To: Alphare, #hg-reviewers
Cc: mercurial-patches, mercurial-devel

Patch

diff --git a/mercurial/bitmanipulation.h b/mercurial/bitmanipulation.h
--- a/mercurial/bitmanipulation.h
+++ b/mercurial/bitmanipulation.h
@@ -5,6 +5,29 @@ 
 
 #include "compat.h"
 
+/* Reads a 64 bit integer from big-endian bytes. Assumes that the data is long
+ enough */
+static inline uint64_t getbe64(const char *c)
+{
+	const unsigned char *d = (const unsigned char *)c;
+
+	return ((((uint64_t)d[0]) << 56)
+          |
+          (((uint64_t)d[1]) << 48)
+          |
+          (((uint64_t)d[2]) << 40)
+          |
+          (((uint64_t)d[3]) << 32)
+          |
+          (((uint64_t)d[4]) << 24)
+          |
+          (((uint64_t)d[5]) << 16)
+          |
+          (((uint64_t)d[6]) << 8)
+          |
+          (d[7]));
+}
+
 static inline uint32_t getbe32(const char *c)
 {
 	const unsigned char *d = (const unsigned char *)c;
@@ -27,6 +50,20 @@ 
 	return ((d[0] << 8) | (d[1]));
 }
 
+/* Writes a 64 bit integer to bytes in a big-endian format.
+ Assumes that the buffer is long enough */
+static inline void putbe64(uint64_t x, char *c)
+{
+	c[0] = (x >> 56) & 0xff;
+	c[1] = (x >> 48) & 0xff;
+	c[2] = (x >> 40) & 0xff;
+	c[3] = (x >> 32) & 0xff;
+	c[4] = (x >> 24) & 0xff;
+	c[5] = (x >> 16) & 0xff;
+	c[6] = (x >> 8) & 0xff;
+	c[7] = (x) & 0xff;
+}
+
 static inline void putbe32(uint32_t x, char *c)
 {
 	c[0] = (x >> 24) & 0xff;