300 lines
10 KiB
C
300 lines
10 KiB
C
/*-*- 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/bits/weaken.h"
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#include "libc/conv/conv.h"
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#include "libc/fmt/fmt.h"
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#include "libc/mem/mem.h"
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#include "libc/runtime/runtime.h"
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#include "libc/str/oldutf16.internal.h"
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#include "libc/str/str.h"
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#include "libc/str/tpdecodecb.internal.h"
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#include "libc/sysv/errfuns.h"
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/**
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* String / file / stream decoder.
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*
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* This scanf implementation is able to tokenize strings containing
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* 8-bit through 128-bit integers (with validation), floating point
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* numbers, etc. It can also be used to convert UTF-8 to UTF-16/32.
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*
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* - `%d` parses integer
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* - `%ms` parses string allocating buffer assigning pointer
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*
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* @param callback supplies UTF-8 characters using -1 sentinel
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* @param fmt is a computer program embedded inside a c string, written
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* in a domain-specific programming language that, by design, lacks
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* Turing-completeness
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* @param va points to the variadic argument state
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* @see libc/fmt/pflink.h (dynamic memory is not a requirement)
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*/
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int vcscanf(int callback(void *), int unget(int, void *), void *arg,
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const char *fmt, va_list va) {
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struct FreeMe {
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struct FreeMe *next;
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void *ptr;
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} *freeme = NULL;
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const unsigned char *p = (const unsigned char *)fmt;
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unsigned i = 0;
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int items = 0;
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int c = callback(arg);
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while (c != -1) {
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switch (p[i++]) {
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case '\0':
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if (c != -1 && unget) {
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unget(c, arg);
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}
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goto Done;
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case ' ':
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case '\t':
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case '\n':
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case '\r':
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case '\v':
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while (isspace(c)) {
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c = callback(arg);
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}
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break;
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case '%': {
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uintmax_t number;
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void *buf;
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size_t bufsize;
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unsigned width = 0;
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unsigned char bits = 32;
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unsigned char charbytes = sizeof(char);
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unsigned char diglet;
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unsigned char base;
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unsigned char prefix;
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bool rawmode = false;
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bool issigned = false;
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bool ismalloc = false;
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bool isneg = false;
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bool thousands = false;
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bool discard = false;
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for (;;) {
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switch (p[i++]) {
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case '%': /* %% → % */
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goto NonDirectiveCharacter;
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case '0':
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case '1':
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case '2':
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case '3':
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case '4':
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case '5':
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case '6':
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case '7':
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case '8':
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case '9':
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width *= 10;
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width += p[i - 1] - '0';
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break;
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case '*':
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discard = true;
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break;
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case 'm':
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ismalloc = true;
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break;
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case 'c':
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rawmode = true;
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if (!width) width = 1;
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/* εpsilon transition */
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case 's':
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goto DecodeString;
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case '\'':
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thousands = true;
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break;
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case 'j': /* 128-bit */
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bits = sizeof(intmax_t) * 8;
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break;
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case 'l': /* long */
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case 'L': /* loooong */
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charbytes = sizeof(wchar_t);
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/* fallthrough */
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case 't': /* ptrdiff_t */
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case 'Z': /* size_t */
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case 'z': /* size_t */
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bits = 64;
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break;
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case 'h': /* short and char */
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charbytes = sizeof(char16_t);
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bits >>= 1;
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break;
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case 'b': /* binary */
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base = 2;
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prefix = 'b';
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goto ConsumeBasePrefix;
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case 'p': /* pointer (NexGen32e) */
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bits = 48;
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/* fallthrough */
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case 'x':
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case 'X': /* hexadecimal */
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base = 16;
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prefix = 'x';
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goto ConsumeBasePrefix;
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case 'o': /* octal */
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base = 8;
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goto DecodeNumber;
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case 'd': /* decimal */
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case 'n': /* TODO(jart): flexidecimal */
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issigned = true;
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if (c == '+' || (isneg = c == '-')) {
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c = callback(arg);
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}
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/* εpsilon transition */
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case 'u':
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base = 10;
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goto DecodeNumber;
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default:
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items = einval();
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goto Done;
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}
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}
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ConsumeBasePrefix:
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if (c == '0') {
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c = callback(arg);
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if (c == prefix || c == prefix + ('a' - 'A')) {
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c = callback(arg);
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}
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}
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DecodeNumber:
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if (c != -1) {
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number = 0;
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do {
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diglet = kBase36[(unsigned char)c];
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if (1 <= diglet && diglet <= base) {
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number *= base;
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number += diglet - 1;
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} else if (thousands && diglet == ',') {
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/* ignore */
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} else {
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break;
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}
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} while ((c = callback(arg)) != -1);
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if (!discard) {
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uintmax_t bane = (uintmax_t)1 << (bits - 1);
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if (!(number & ~((bane - 1) | (issigned ? 0 : bane))) ||
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(issigned && number == bane /* two's complement bane */)) {
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++items;
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} else {
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items = erange();
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goto Done;
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}
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if (issigned && isneg) {
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number = ~number + 1;
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}
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void *out = va_arg(va, void *);
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switch (bits) {
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case sizeof(uintmax_t) * CHAR_BIT:
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*(uintmax_t *)out = number;
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break;
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case 48:
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case 64:
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*(uint64_t *)out = (uint64_t)number;
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break;
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case 32:
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*(uint32_t *)out = (uint32_t)number;
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break;
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case 16:
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*(uint16_t *)out = (uint16_t)number;
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break;
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case 8:
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default:
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*(uint8_t *)out = (uint8_t)number;
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break;
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}
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}
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}
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continue;
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DecodeString:
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bufsize = !width ? 32 : rawmode ? width : width + 1;
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if (discard) {
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buf = NULL;
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} else if (ismalloc) {
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buf = weaken(malloc)(bufsize * charbytes);
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struct FreeMe *entry;
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if (buf && (entry = weaken(calloc)(1, sizeof(struct FreeMe)))) {
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entry->ptr = buf;
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entry->next = freeme;
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freeme = entry;
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}
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} else {
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buf = va_arg(va, void *);
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}
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if (buf) {
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size_t j = 0;
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for (;;) {
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if (ismalloc && !width && j + 2 + 1 >= bufsize &&
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!weaken(__grow)(&buf, &bufsize, charbytes, 0)) {
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width = bufsize - 1;
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}
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if (c != -1 && j + !rawmode < bufsize && (rawmode || !isspace(c))) {
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if (charbytes == 1) {
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((unsigned char *)buf)[j++] = (unsigned char)c;
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c = callback(arg);
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} else if (tpdecodecb((wint_t *)&c, c, (void *)callback, arg) !=
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-1) {
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if (charbytes == sizeof(char16_t)) {
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j += abs(pututf16(&((char16_t *)buf)[j], bufsize - j - 1, c,
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false));
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} else {
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((wchar_t *)buf)[j++] = (wchar_t)c;
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}
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c = callback(arg);
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}
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} else {
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if (!rawmode && j < bufsize) {
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if (charbytes == sizeof(char)) {
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((unsigned char *)buf)[j] = '\0';
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} else if (charbytes == sizeof(char16_t)) {
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((char16_t *)buf)[j] = u'\0';
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} else if (charbytes == sizeof(wchar_t)) {
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((wchar_t *)buf)[j] = L'\0';
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}
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}
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break;
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}
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}
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++items;
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if (ismalloc) {
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*va_arg(va, char **) = buf;
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}
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} else {
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do {
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if (isspace(c)) break;
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} while ((c = callback(arg)) != -1);
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}
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break;
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}
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default:
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NonDirectiveCharacter:
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c = (c == p[i - 1]) ? callback(arg) : -1;
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break;
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}
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}
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Done:
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while (freeme) {
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struct FreeMe *entry = freeme;
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freeme = entry->next;
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if (items == -1) {
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weaken(free_s)((void **)&entry->ptr);
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}
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weaken(free_s)((void **)&entry);
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}
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return items;
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}
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