2105064b10
In put_be32(), we right-shift a uint32_t value various amounts and then assign the low 8-bits to individual "unsigned char" bytes, throwing away the high bits. For shifts smaller than 24 bits, those thrown away bits will be arbitrary bits from the original uint32_t. This works exactly as we want, but if you feed a constant, then sparse complains. For example if we write this (which we plan to do in a future patch): put_be32(hdr, PACK_SIGNATURE); then "make sparse" produces: compat/bswap.h:175:22: error: cast truncates bits from constant value (5041 becomes 41) compat/bswap.h:176:22: error: cast truncates bits from constant value (504143 becomes 43) compat/bswap.h:177:22: error: cast truncates bits from constant value (5041434b becomes 4b) And the same issue exists in the other put_be*() functions, when used with a constant. We can silence this warning by explicitly masking off the truncated bits. The compiler is smart enough to know the result is the same, and the asm generated by gcc (with both -O0 and -O2) is identical. Curiously this line already exists: put_be32(&hdr_version, INDEX_EXTENSION_VERSION2); in the fsmonitor.c file, but it does not get flagged because the CPP macro expands to a small integer (2). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Git - fast, scalable, distributed revision control system
Git is a fast, scalable, distributed revision control system with an unusually rich command set that provides both high-level operations and full access to internals.
Git is an Open Source project covered by the GNU General Public License version 2 (some parts of it are under different licenses, compatible with the GPLv2). It was originally written by Linus Torvalds with help of a group of hackers around the net.
Please read the file INSTALL for installation instructions.
Many Git online resources are accessible from https://git-scm.com/ including full documentation and Git related tools.
See Documentation/gittutorial.txt to get started, then see
Documentation/giteveryday.txt for a useful minimum set of commands, and
Documentation/git-<commandname>.txt for documentation of each command.
If git has been correctly installed, then the tutorial can also be
read with man gittutorial or git help tutorial, and the
documentation of each command with man git-<commandname> or git help <commandname>.
CVS users may also want to read Documentation/gitcvs-migration.txt
(man gitcvs-migration or git help cvs-migration if git is
installed).
The user discussion and development of Git take place on the Git mailing list -- everyone is welcome to post bug reports, feature requests, comments and patches to git@vger.kernel.org (read Documentation/SubmittingPatches for instructions on patch submission and Documentation/CodingGuidelines).
Those wishing to help with error message, usage and informational message
string translations (localization l10) should see po/README.md
(a po file is a Portable Object file that holds the translations).
To subscribe to the list, send an email to git+subscribe@vger.kernel.org (see https://subspace.kernel.org/subscribing.html for details). The mailing list archives are available at https://lore.kernel.org/git/, https://marc.info/?l=git and other archival sites.
Issues which are security relevant should be disclosed privately to the Git Security mailing list git-security@googlegroups.com.
The maintainer frequently sends the "What's cooking" reports that list the current status of various development topics to the mailing list. The discussion following them give a good reference for project status, development direction and remaining tasks.
The name "git" was given by Linus Torvalds when he wrote the very first version. He described the tool as "the stupid content tracker" and the name as (depending on your mood):
- random three-letter combination that is pronounceable, and not actually used by any common UNIX command. The fact that it is a mispronunciation of "get" may or may not be relevant.
- stupid. contemptible and despicable. simple. Take your pick from the dictionary of slang.
- "global information tracker": you're in a good mood, and it actually works for you. Angels sing, and a light suddenly fills the room.
- "goddamn idiotic truckload of sh*t": when it breaks