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122 lines
4.0 KiB
122 lines
4.0 KiB
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│ |
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│vi: set net 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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│ This program is free software; you can redistribute it and/or modify │ |
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│ it under the terms of the GNU General Public License as published by │ |
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│ the Free Software Foundation; version 2 of the License. │ |
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│ │ |
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│ This program is distributed in the hope that it will be useful, but │ |
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│ WITHOUT ANY WARRANTY; without even the implied warranty of │ |
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│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │ |
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│ General Public License for more details. │ |
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│ │ |
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│ You should have received a copy of the GNU General Public License │ |
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│ along with this program; if not, write to the Free Software │ |
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│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │ |
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│ 02110-1301 USA │ |
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╚─────────────────────────────────────────────────────────────────────────────*/ |
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#include "libc/conv/conv.h" |
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#include "libc/limits.h" |
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#include "libc/nexgen32e/bsr.h" |
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#include "libc/str/str.h" |
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/** |
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* Decodes 128-bit signed integer from ASCII string. |
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* |
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* @param s is a non-NULL NUL-terminated string |
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* @param endptr if non-NULL will always receive a pointer to the char |
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* following the last one this function processed, which is usually |
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* the NUL byte, or in the case of invalid strings, would point to |
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* the first invalid character |
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* @param base can be anywhere between [2,36] or 0 to auto-detect based |
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* on the the prefixes 0 (octal), 0x (hexadecimal), 0b (binary), or |
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* decimal (base 10) by default. |
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* @return the decoded saturated number |
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* @see strtoumax |
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*/ |
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intmax_t strtoimax(const char *s, char **endptr, int base) { |
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uintmax_t x; |
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intmax_t res; |
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unsigned diglet, bits; |
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bool neg, islong, isunsigned; |
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x = 0; |
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bits = 0; |
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neg = false; |
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while (isspace(*s)) { |
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s++; |
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} |
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switch (*s) { |
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case '-': |
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neg = true; |
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/* 𝑠𝑙𝑖𝑑𝑒 */ |
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case '+': |
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s++; |
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break; |
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default: |
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break; |
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} |
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if (!(2 <= base && base <= 36)) { |
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if (*s == '0') { |
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s++; |
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if (*s == 'x' || *s == 'X') { |
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s++; |
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base = 16; |
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} else if (*s == 'b' || *s == 'B') { |
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s++; |
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base = 2; |
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} else { |
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base = 8; |
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} |
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} else { |
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base = 10; |
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} |
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} |
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for (;;) { |
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diglet = kBase36[*s & 0xff]; |
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if (!diglet || diglet > base) break; |
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diglet -= 1; |
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if (!diglet || !x || (bits = bsr(diglet) + bsrmax(x)) < 127) { |
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s++; |
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x *= base; |
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x += diglet; |
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} else if (neg) { |
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if (bits == 127) { |
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x *= base; |
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x += diglet; |
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if (x == INTMAX_MIN) s++; |
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} |
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x = INTMAX_MIN; |
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break; |
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} else { |
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x = INTMAX_MAX; |
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break; |
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} |
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} |
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if ((isunsigned = *s == 'u' || *s == 'U')) s++; |
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if ((islong = *s == 'l' || *s == 'L')) s++; |
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if (endptr) *endptr = s; |
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if (neg) { |
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res = -x; |
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} else { |
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res = x; |
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} |
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if (isunsigned) { |
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if (islong) { |
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res = (uint64_t)res; |
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} else { |
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res = (uint32_t)res; |
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} |
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} |
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return res; |
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}
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