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49 lines
2.5 KiB
C
49 lines
2.5 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/ctype.h"
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#include "libc/fmt/conv.h"
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#include "libc/str/str.h"
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/**
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* Turns string into long.
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*
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* Decimal is the only radix supported. Leading whitespace (as specified
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* by the isspace() function) is skipped over. Unlike strtol(), the atoi
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* function has undefined behavior on error and it never changes `errno`
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*
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* @param nptr is a non-null nul-terminated string
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* @return the decoded signed saturated integer
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*/
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long atol(const char *nptr) {
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long x;
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int c, d;
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do
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c = *nptr++;
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while (isspace(c));
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d = c == '-' ? -1 : 1;
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if (c == '-' || c == '+')
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c = *nptr++;
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for (x = 0; isdigit(c); c = *nptr++) {
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x *= 10;
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x += (c - '0') * d;
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}
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return x;
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}
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__weak_reference(atol, atoll);
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