cosmopolitan/libc/fmt/zleb128.c
Justine Tunney 47a53e143b Productionize new APE loader and more
The APE_NO_MODIFY_SELF loader payload has been moved out of the examples
folder and improved so that it works on BSD systems, and permits general
elf program headers. This brings its quality up enough that it should be
acceptable to use by default for many programs, e.g. Python, Lua, SQLite
and Python. It's the responsibility of the user to define an appropriate
TMPDIR if /tmp is considered an adversarial environment. Mac OS shall be
supported by APE_NO_MODIFY_SELF soon.

Fixes and improvements have been made to program_executable_name as it's
now the one true way to get the absolute path of the executing image.

This change fixes a memory leak in linenoise history loading, introduced
by performance optimizations in 51904e2687
This change fixes a longstanding regression with Mach system calls, that
23ae9dfceb back in February which impacted
our sched_yield() implementation, which is why no one noticed until now.

The Blinkenlights PC emulator has been improved. We now fix rendering on
XNU and BSD by not making the assumption that the kernel terminal driver
understands UTF8 since that seems to break its internal modeling of \r\n
which is now being addressed by using \e[𝑦H instead. The paneling is now
more compact in real mode so you won't need to make your font as tiny if
you're only emulating an 8086 program. The CLMUL ISA is now emulated too

This change also makes improvement to time. CLOCK_MONOTONIC now does the
right thing on Windows NT. The nanosecond time module functions added in
Python 3.7 have been backported.

This change doubles the performance of Argon2 password stretching simply
by not using its copy_block and xor_block helper functions, as they were
trivial to inline thus resulting in us needing to iterate over each 1024
byte block four fewer times.

This change makes code size improvements. _PyUnicode_ToNumeric() was 64k
in size and now it's 10k. The CJK codec lookup tables now use lazy delta
zigzag deflate (δzd) encoding which reduces their size from 600k to 200k
plus the code bloat caused by macro abuse in _decimal.c is now addressed
so our fully-loaded statically-linked hermetically-sealed Python virtual
interpreter container is now 9.4 megs in the default build mode and 5.5m
in MODE=tiny which leaves plenty of room for chibicc.

The pydoc web server now accommodates the use case of people who work by
SSH'ing into a different machine w/ python.com -m pydoc -p8080 -h0.0.0.0

Finally Python Capsulae delenda est and won't be supported in the future
2021-10-02 08:27:03 -07:00

40 lines
2.1 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/fmt/leb128.h"
/**
* Encodes signed integer to array.
*/
char *zleb128(char *p, int128_t x) {
int c;
uint128_t u;
u = x;
u <<= 1;
u ^= x >> 127;
for (;;) {
c = u & 127;
if (!(u >>= 7)) {
*p++ = c;
return p;
} else {
*p++ = c | 128;
}
}
}