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f4f8d8bb1a
Add format string handling operator to the setexpr command. It allows to use C or Bash like format string expressions to be evaluated with the result being stored inside the environment variable name. setexpr <name> fmt <format> [value]... The following example setexpr foo fmt "%d, 0x%x" 0x100 ff will result in $foo being set to "256, 0xff". Signed-off-by: Roland Gaudig <roland.gaudig@weidmueller.com> Reviewed-by: Simon Glass <sjg@chromium.org>
647 lines
16 KiB
C
647 lines
16 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Copyright (C) 2021 Weidmüller Interface GmbH & Co. KG
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* Roland Gaudig <roland.gaudig@weidmueller.com>
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*
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* Copyright 1999 Dave Cinege
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* Portions copyright (C) 1990-1996 Free Software Foundation, Inc.
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*
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* Licensed under GPLv2 or later, see file LICENSE in this source tree.
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*/
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/*
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* This file provides a shell printf like format string expansion as required
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* for the setexpr <name> fmt <format> <value> command.
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* This source file was mostly taken from the BusyBox project (www.busybox.net)
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* In contrast to the original sources the output is not written to stdout
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* anymore but into a char array, which can be used as input for the env_set()
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* function.
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*/
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/* Usage: printf format [argument...]
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*
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* A front end to the printf function that lets it be used from the shell.
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*
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* Backslash escapes:
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*
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* \" = double quote
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* \\ = backslash
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* \a = alert (bell)
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* \b = backspace
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* \c = produce no further output
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* \f = form feed
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* \n = new line
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* \r = carriage return
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* \t = horizontal tab
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* \v = vertical tab
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* \0ooo = octal number (ooo is 0 to 3 digits)
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* \xhhh = hexadecimal number (hhh is 1 to 3 digits)
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*
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* Additional directive:
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*
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* %b = print an argument string, interpreting backslash escapes
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*
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* The 'format' argument is re-used as many times as necessary
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* to convert all of the given arguments.
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*
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* David MacKenzie <djm@gnu.ai.mit.edu>
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*/
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/* 19990508 Busy Boxed! Dave Cinege */
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//config:config PRINTF
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//config: bool "printf (3.8 kb)"
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//config: default y
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//config: help
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//config: printf is used to format and print specified strings.
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//config: It's similar to 'echo' except it has more options.
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//applet:IF_PRINTF(APPLET_NOFORK(printf, printf, BB_DIR_USR_BIN, BB_SUID_DROP, printf))
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//kbuild:lib-$(CONFIG_PRINTF) += printf.o
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//kbuild:lib-$(CONFIG_ASH_PRINTF) += printf.o
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//kbuild:lib-$(CONFIG_HUSH_PRINTF) += printf.o
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//usage:#define printf_trivial_usage
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//usage: "FORMAT [ARG]..."
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//usage:#define printf_full_usage "\n\n"
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//usage: "Format and print ARG(s) according to FORMAT (a-la C printf)"
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//usage:
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//usage:#define printf_example_usage
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//usage: "$ printf \"Val=%d\\n\" 5\n"
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//usage: "Val=5\n"
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/* A note on bad input: neither bash 3.2 nor coreutils 6.10 stop on it.
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* They report it:
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* bash: printf: XXX: invalid number
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* printf: XXX: expected a numeric value
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* bash: printf: 123XXX: invalid number
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* printf: 123XXX: value not completely converted
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* but then they use 0 (or partially converted numeric prefix) as a value
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* and continue. They exit with 1 in this case.
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* Both accept insane field width/precision (e.g. %9999999999.9999999999d).
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* Both print error message and assume 0 if %*.*f width/precision is "bad"
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* (but negative numbers are not "bad").
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* Both accept negative numbers for %u specifier.
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*
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* We try to be compatible.
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*/
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#include <common.h>
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#include <ctype.h>
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#include <errno.h>
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#include <stddef.h>
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#include <stdio.h>
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#include <stdlib.h>
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#define WANT_HEX_ESCAPES 0
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#define PRINT_CONVERSION_ERROR 1
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#define PRINT_TRUNCATED_ERROR 2
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#define PRINT_SIZE_ERROR 4
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struct print_inf {
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char *str;
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size_t size;
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size_t offset;
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unsigned int error;
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};
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typedef void (*converter)(const char *arg, void *result);
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/**
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* printf_str() - print formatted into char array with length checks
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*
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* This function povides a printf like function for printing into a char array
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* with checking the boundaries.
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* Unlike snprintf, all checks are performed inside this function and status
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* reports are stored inside the print_inf struct. That way, this function can
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* be used almost as drop-in replacement without needing much code changes.
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* Unlike snprintf errors are not reported by return value, but inside the
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* error member of struct print_inf. The output stored inside the struct
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* print_inf str member shall only be used when the error member is 0.
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*
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* @inf: Info structure for print operation
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* @char: format string with optional arguments
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*/
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static void printf_str(struct print_inf *inf, char *format, ...)
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{
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va_list args;
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int i;
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if (!inf)
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return;
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/* Do not write anything if previous error is pending */
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if (inf->error)
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return;
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/* Check if end of receiving buffer is already reached */
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if (inf->offset >= inf->size) {
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inf->error |= PRINT_SIZE_ERROR;
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return;
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}
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size_t remaining = inf->size - inf->offset;
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va_start(args, format);
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i = vsnprintf(inf->str + inf->offset, remaining, format, args);
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va_end(args);
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if (i >= remaining)
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inf->error |= PRINT_TRUNCATED_ERROR;
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else if (i < 0)
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inf->error |= PRINT_CONVERSION_ERROR;
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else
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inf->offset += i;
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}
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/**
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* putchar_str() - Print single character into char array with length checks
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*
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* This function provices a putchar like function, which stores the output
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* into a char array with checking boundaries.
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*
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* @inf: Info structure for print operation
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* @char: Single character to be printed
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*/
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static void putchar_str(struct print_inf *inf, char c)
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{
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printf_str(inf, "%c", c);
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}
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static char process_escape_sequence(const char **ptr)
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{
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const char *q;
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unsigned int num_digits;
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unsigned int n;
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unsigned int base;
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num_digits = 0;
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n = 0;
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base = 8;
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q = *ptr;
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if (WANT_HEX_ESCAPES && *q == 'x') {
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++q;
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base = 16;
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++num_digits;
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}
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/* bash requires leading 0 in octal escapes:
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* \02 works, \2 does not (prints \ and 2).
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* We treat \2 as a valid octal escape sequence.
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*/
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do {
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unsigned int r;
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unsigned int d = (unsigned char)(*q) - '0';
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#if WANT_HEX_ESCAPES
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if (d >= 10) {
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d = (unsigned char)tolower(*q) - 'a';
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//d += 10;
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/* The above would map 'A'-'F' and 'a'-'f' to 10-15,
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* however, some chars like '@' would map to 9 < base.
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* Do not allow that, map invalid chars to N > base:
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*/
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if ((int)d >= 0)
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d += 10;
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}
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#endif
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if (d >= base) {
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if (WANT_HEX_ESCAPES && base == 16) {
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--num_digits;
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if (num_digits == 0) {
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/* \x<bad_char>: return '\',
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* leave ptr pointing to x
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*/
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return '\\';
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}
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}
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break;
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}
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r = n * base + d;
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if (r > 255)
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break;
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n = r;
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++q;
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} while (++num_digits < 3);
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if (num_digits == 0) {
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/* Not octal or hex escape sequence.
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* Is it one-letter one?
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*/
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/* bash builtin "echo -e '\ec'" interprets \e as ESC,
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* but coreutils "/bin/echo -e '\ec'" does not.
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* Manpages tend to support coreutils way.
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* Update: coreutils added support for \e on 28 Oct 2009.
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*/
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static const char charmap[] = {
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'a', 'b', 'e', 'f', 'n', 'r', 't', 'v', '\\', '\0',
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'\a', '\b', 27, '\f', '\n', '\r', '\t', '\v', '\\', '\\',
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};
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const char *p = charmap;
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do {
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if (*p == *q) {
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q++;
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break;
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}
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} while (*++p != '\0');
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/* p points to found escape char or NUL,
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* advance it and find what it translates to.
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* Note that \NUL and unrecognized sequence \z return '\'
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* and leave ptr pointing to NUL or z.
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*/
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n = p[sizeof(charmap) / 2];
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}
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*ptr = q;
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return (char)n;
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}
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static char *skip_whitespace(const char *s)
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{
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/* In POSIX/C locale (the only locale we care about: do we REALLY want
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* to allow Unicode whitespace in, say, .conf files? nuts!)
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* isspace is only these chars: "\t\n\v\f\r" and space.
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* "\t\n\v\f\r" happen to have ASCII codes 9,10,11,12,13.
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* Use that.
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*/
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while (*s == ' ' || (unsigned char)(*s - 9) <= (13 - 9))
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s++;
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return (char *)s;
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}
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/* Like strcpy but can copy overlapping strings. */
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static void overlapping_strcpy(char *dst, const char *src)
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{
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/* Cheap optimization for dst == src case -
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* better to have it here than in many callers.
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*/
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if (dst != src) {
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while ((*dst = *src) != '\0') {
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dst++;
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src++;
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}
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}
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}
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static int multiconvert(const char *arg, void *result, converter convert)
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{
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if (*arg == '"' || *arg == '\'')
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sprintf((char *)arg + strlen(arg), "%u", (unsigned char)arg[1]);
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//errno = 0;
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convert(arg, result);
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/* Unlike their Posix counterparts, simple_strtoll and
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* simple_strtoull do not set errno
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*
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* if (errno) {
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* printf("error invalid number '%s'", arg);
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* return 1;
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* }
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*/
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return 0;
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}
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static void conv_strtoull(const char *arg, void *result)
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{
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/* both coreutils 6.10 and bash 3.2:
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* $ printf '%x\n' -2
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* fffffffffffffffe
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* Mimic that:
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*/
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if (arg[0] == '-') {
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*(unsigned long long *)result = simple_strtoll(arg, NULL, 16);
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return;
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}
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/* Allow leading '+' - simple_strtoull() by itself does not allow it,
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* and probably shouldn't (other callers might require purely numeric
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* inputs to be allowed.
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*/
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if (arg[0] == '+')
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arg++;
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*(unsigned long long *)result = simple_strtoull(arg, NULL, 16);
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}
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static void conv_strtoll(const char *arg, void *result)
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{
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if (arg[0] == '+')
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arg++;
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*(long long *)result = simple_strtoll(arg, NULL, 16);
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}
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/* Callers should check errno to detect errors */
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static unsigned long long my_xstrtoull(const char *arg)
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{
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unsigned long long result;
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if (multiconvert(arg, &result, conv_strtoull))
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result = 0;
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return result;
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}
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static long long my_xstrtoll(const char *arg)
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{
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long long result;
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if (multiconvert(arg, &result, conv_strtoll))
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result = 0;
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return result;
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}
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/* Handles %b; return 1 if output is to be short-circuited by \c */
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static int print_esc_string(struct print_inf *inf, const char *str)
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{
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char c;
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while ((c = *str) != '\0') {
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str++;
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if (c == '\\') {
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/* %b also accepts 4-digit octals of the form \0### */
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if (*str == '0') {
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if ((unsigned char)(str[1] - '0') < 8) {
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/* 2nd char is 0..7: skip leading '0' */
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str++;
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}
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} else if (*str == 'c') {
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return 1;
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}
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{
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/* optimization: don't force arg to be on-stack,
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* use another variable for that.
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*/
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const char *z = str;
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c = process_escape_sequence(&z);
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str = z;
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}
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}
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putchar_str(inf, c);
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}
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return 0;
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}
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static void print_direc(struct print_inf *inf, char *format, unsigned int fmt_length,
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int field_width, int precision,
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const char *argument)
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{
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long long llv;
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char saved;
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char *have_prec, *have_width;
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saved = format[fmt_length];
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format[fmt_length] = '\0';
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have_prec = strstr(format, ".*");
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have_width = strchr(format, '*');
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if (have_width - 1 == have_prec)
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have_width = NULL;
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/* multiconvert sets errno = 0, but %s needs it cleared */
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errno = 0;
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switch (format[fmt_length - 1]) {
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case 'c':
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printf_str(inf, format, *argument);
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break;
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case 'd':
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case 'i':
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llv = my_xstrtoll(skip_whitespace(argument));
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print_long:
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if (!have_width) {
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if (!have_prec)
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printf_str(inf, format, llv);
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else
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printf_str(inf, format, precision, llv);
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} else {
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if (!have_prec)
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printf_str(inf, format, field_width, llv);
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else
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printf_str(inf, format, field_width, precision, llv);
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}
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break;
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case 'o':
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case 'u':
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case 'x':
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case 'X':
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llv = my_xstrtoull(skip_whitespace(argument));
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/* cheat: unsigned long and long have same width, so... */
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goto print_long;
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case 's':
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/* Are char* and long long the same? */
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if (sizeof(argument) == sizeof(llv)) {
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llv = (long long)(ptrdiff_t)argument;
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goto print_long;
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} else {
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/* Hope compiler will optimize it out by moving call
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* instruction after the ifs...
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*/
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if (!have_width) {
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if (!have_prec)
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printf_str(inf, format, argument,
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/*unused:*/ argument, argument);
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else
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printf_str(inf, format, precision,
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argument, /*unused:*/ argument);
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} else {
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if (!have_prec)
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printf_str(inf, format, field_width,
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argument, /*unused:*/ argument);
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else
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printf_str(inf, format, field_width,
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precision, argument);
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}
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break;
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}
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break;
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} /* switch */
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format[fmt_length] = saved;
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}
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/* Handle params for "%*.*f". Negative numbers are ok (compat). */
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static int get_width_prec(const char *str)
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{
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long v = simple_strtol(str, NULL, 10);
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/* Unlike its Posix counterpart, simple_strtol does not set errno
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*
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* if (errno) {
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* printf("error invalid number '%s'", str);
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* v = 0;
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* }
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*/
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return (int)v;
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}
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/* Print the text in FORMAT, using ARGV for arguments to any '%' directives.
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* Return advanced ARGV.
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*/
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static char **print_formatted(struct print_inf *inf, char *f, char **argv, int *conv_err)
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{
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char *direc_start; /* Start of % directive. */
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unsigned int direc_length; /* Length of % directive. */
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int field_width; /* Arg to first '*' */
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int precision; /* Arg to second '*' */
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char **saved_argv = argv;
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for (; *f; ++f) {
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switch (*f) {
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case '%':
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direc_start = f++;
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direc_length = 1;
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field_width = 0;
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precision = 0;
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if (*f == '%') {
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putchar_str(inf, '%');
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break;
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}
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if (*f == 'b') {
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if (*argv) {
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if (print_esc_string(inf, *argv))
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return saved_argv; /* causes main() to exit */
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++argv;
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}
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break;
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}
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if (*f && strchr("-+ #", *f)) {
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++f;
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++direc_length;
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}
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if (*f == '*') {
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++f;
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++direc_length;
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if (*argv)
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field_width = get_width_prec(*argv++);
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} else {
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while (isdigit(*f)) {
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++f;
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++direc_length;
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}
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}
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if (*f == '.') {
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++f;
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++direc_length;
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if (*f == '*') {
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++f;
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++direc_length;
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if (*argv)
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precision = get_width_prec(*argv++);
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} else {
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while (isdigit(*f)) {
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++f;
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++direc_length;
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}
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}
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}
|
|
|
|
/* Remove "lLhz" size modifiers, repeatedly.
|
|
* bash does not like "%lld", but coreutils
|
|
* happily takes even "%Llllhhzhhzd"!
|
|
* We are permissive like coreutils
|
|
*/
|
|
while ((*f | 0x20) == 'l' || *f == 'h' || *f == 'z')
|
|
overlapping_strcpy(f, f + 1);
|
|
/* Add "ll" if integer modifier, then print */
|
|
{
|
|
static const char format_chars[] = "diouxXcs";
|
|
char *p = strchr(format_chars, *f);
|
|
/* needed - try "printf %" without it */
|
|
if (!p || *f == '\0') {
|
|
printf("`%s': invalid format\n", direc_start);
|
|
/* causes main() to exit with error */
|
|
return saved_argv - 1;
|
|
}
|
|
++direc_length;
|
|
if (p - format_chars <= 5) {
|
|
/* it is one of "diouxX" */
|
|
p = malloc(direc_length + 3);
|
|
if (!p) {
|
|
/* exit with error */
|
|
return saved_argv - 1;
|
|
}
|
|
memcpy(p, direc_start, direc_length);
|
|
p[direc_length + 1] = p[direc_length - 1];
|
|
p[direc_length - 1] = 'l';
|
|
p[direc_length] = 'l';
|
|
//bb_error_msg("<%s>", p);
|
|
direc_length += 2;
|
|
direc_start = p;
|
|
} else {
|
|
p = NULL;
|
|
}
|
|
if (*argv) {
|
|
print_direc(inf, direc_start, direc_length,
|
|
field_width, precision, *argv++);
|
|
} else {
|
|
print_direc(inf, direc_start, direc_length,
|
|
field_width, precision, "");
|
|
}
|
|
*conv_err |= errno;
|
|
free(p);
|
|
}
|
|
break;
|
|
case '\\':
|
|
if (*++f == 'c')
|
|
return saved_argv; /* causes main() to exit */
|
|
putchar_str(inf, process_escape_sequence((const char **)&f));
|
|
f--;
|
|
break;
|
|
default:
|
|
putchar_str(inf, *f);
|
|
}
|
|
}
|
|
|
|
return argv;
|
|
}
|
|
|
|
/**
|
|
* printf_setexpr() - Implements the setexpr <name> fmt <format> command
|
|
*
|
|
* This function implements the format string evaluation for the
|
|
* setexpr <name> fmt <format> <value> command.
|
|
*
|
|
* @str: Output string of the evaluated expression
|
|
* @size: Length of @str buffer
|
|
* @argc: Number of arguments
|
|
* @argv: Argument list
|
|
* @return: 0 if OK, 1 on error
|
|
*/
|
|
int printf_setexpr(char *str, size_t size, int argc, char *const *argv)
|
|
{
|
|
int conv_err;
|
|
char *format;
|
|
char **argv2;
|
|
struct print_inf inf = {
|
|
.str = str,
|
|
.size = size,
|
|
.offset = 0,
|
|
.error = 0,
|
|
};
|
|
|
|
if (!str || !size)
|
|
return 1;
|
|
|
|
inf.str[0] = '\0';
|
|
|
|
format = argv[0];
|
|
argv2 = (char **)argv + 1;
|
|
|
|
conv_err = 0;
|
|
argv = argv2;
|
|
/* In case any print_str call raises an error inf.error will be
|
|
* set after print_formatted returns.
|
|
*/
|
|
argv2 = print_formatted(&inf, format, (char **)argv, &conv_err);
|
|
|
|
/* coreutils compat (bash doesn't do this):
|
|
*if (*argv)
|
|
* fprintf(stderr, "excess args ignored");
|
|
*/
|
|
|
|
return (argv2 < argv) || /* if true, print_formatted errored out */
|
|
conv_err || /* print_formatted saw invalid number */
|
|
inf.error; /* print_str reported error */
|
|
}
|