cosmopolitan/libc/stdio/appendr.c
Justine Tunney 39bf41f4eb Make numerous improvements
- Python static hello world now 1.8mb
- Python static fully loaded now 10mb
- Python HTTPS client now uses MbedTLS
- Python REPL now completes import stmts
- Increase stack size for Python for now
- Begin synthesizing posixpath and ntpath
- Restore Python \N{UNICODE NAME} support
- Restore Python NFKD symbol normalization
- Add optimized code path for Intel SHA-NI
- Get more Python unit tests passing faster
- Get Python help() pagination working on NT
- Python hashlib now supports MbedTLS PBKDF2
- Make memcpy/memmove/memcmp/bcmp/etc. faster
- Add Mersenne Twister and Vigna to LIBC_RAND
- Provide privileged __printf() for error code
- Fix zipos opendir() so that it reports ENOTDIR
- Add basic chmod() implementation for Windows NT
- Add Cosmo's best functions to Python cosmo module
- Pin function trace indent depth to that of caller
- Show memory diagram on invalid access in MODE=dbg
- Differentiate stack overflow on crash in MODE=dbg
- Add stb_truetype and tools for analyzing font files
- Upgrade to UNICODE 13 and reduce its binary footprint
- COMPILE.COM now logs resource usage of build commands
- Start implementing basic poll() support on bare metal
- Set getauxval(AT_EXECFN) to GetModuleFileName() on NT
- Add descriptions to strerror() in non-TINY build modes
- Add COUNTBRANCH() macro to help with micro-optimizations
- Make error / backtrace / asan / memory code more unbreakable
- Add fast perfect C implementation of μ-Law and a-Law audio codecs
- Make strtol() functions consistent with other libc implementations
- Improve Linenoise implementation (see also github.com/jart/bestline)
- COMPILE.COM now suppresses stdout/stderr of successful build commands
2021-09-28 01:52:34 -07:00

76 lines
3.2 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 2021 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/assert.h"
#include "libc/dce.h"
#include "libc/macros.internal.h"
#include "libc/mem/mem.h"
#include "libc/nexgen32e/bsr.h"
#include "libc/stdio/append.internal.h"
#include "libc/str/str.h"
#define W sizeof(size_t)
/**
* Resets length of append buffer, e.g.
*
* char *b = 0;
* appends(&b, "hello");
* appendr(&b, 1);
* assert(!strcmp(b, "h"));
* appendr(&b, 0);
* assert(!strcmp(b, ""));
* free(b);
*
* If `i` is greater than the current length then the extra bytes are
* filled with NUL characters. If `i` is less than the current length
* then memory is released to the system.
*
* The resulting buffer is guarranteed to be NUL-terminated, i.e.
* `!b[appendz(b).i]` will be the case even if both params are 0.
*
* @return `i` or -1 if `ENOMEM`
* @see appendz(b).i to get buffer length
*/
ssize_t appendr(char **b, size_t i) {
char *p;
size_t n;
struct appendz z;
assert(b);
z = appendz((p = *b));
if (i != z.i || !p) {
n = ROUNDUP(i + 1, 8) + W;
if (n > z.n || bsrl(n) < bsrl(z.n)) {
if ((p = realloc(p, n))) {
n = malloc_usable_size(p);
assert(!(n & (W - 1)));
*b = p;
} else {
return -1;
}
}
if (i > z.i) {
bzero(p + z.i, i - z.i + 1);
} else {
p[i] = 0;
}
*(size_t *)(p + n - W) =
i | (!IsTiny() && W == 8 ? (size_t)APPEND_COOKIE << 48 : 0);
}
return i;
}