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u-boot/lib/sscanf.c

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// SPDX-License-Identifier: BSD-3-Clause
/*
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Chris Torek.
*
* Copyright (c) 2011 The FreeBSD Foundation
* All rights reserved.
* Portions of this software were developed by David Chisnall
* under sponsorship from the FreeBSD Foundation.
*
* Author: Juergen Gross <jgross@suse.com>
* Date: Jun 2016
*/
#if !defined HAVE_LIBC
#include <os.h>
#include <linux/kernel.h>
#include <linux/ctype.h>
#include <vsprintf.h>
#include <linux/string.h>
#include <malloc.h>
#define __DECONST(type, var) ((type)(uintptr_t)(const void *)(var))
/**
* struct str_info - Input string parameters
* @neg: negative number or not
* 0 - not negative
* 1 - negative
* @any: set any if any `digits' consumed; make it negative to indicate
* overflow
* @acc: accumulated value
*/
struct str_info {
int neg, any;
u64 acc;
};
/**
* str_to_int_convert() - Write string data to structure
* @nptr: pointer to string
* @base: number's base
* @unsign: describes what integer is expected
* 0 - not unsigned
* 1 - unsigned
*
* Ignores `locale' stuff. Assumes that the upper and lower case
* alphabets and digits are each contiguous.
*
* Return: struct str_info *, which contains string data to future process
*/
static struct str_info *
str_to_int_convert(const char **nptr, int base, unsigned int unsign)
{
const char *s = *nptr;
u64 acc;
unsigned char c;
u64 cutoff;
int neg, any, cutlim;
u64 qbase;
struct str_info *info;
/*
* Skip white space and pick up leading +/- sign if any.
* If base is 0, allow 0x for hex and 0 for octal, else
* assume decimal; if base is already 16, allow 0x.
*/
info = (struct str_info *)malloc(sizeof(struct str_info));
if (!info)
return NULL;
do {
c = *s++;
} while (isspace(c));
if (c == '-') {
neg = 1;
c = *s++;
} else {
neg = 0;
if (c == '+')
c = *s++;
}
if ((base == 0 || base == 16) &&
c == '0' && (*s == 'x' || *s == 'X')) {
c = s[1];
s += 2;
base = 16;
}
if (base == 0)
base = c == '0' ? 8 : 10;
/*
* Compute the cutoff value between legal numbers and illegal
* numbers. That is the largest legal value, divided by the
* base. An input number that is greater than this value, if
* followed by a legal input character, is too big. One that
* is equal to this value may be valid or not; the limit
* between valid and invalid numbers is then based on the last
* digit. For instance, if the range for quads is
* [-9223372036854775808..9223372036854775807] and the input base
* is 10, cutoff will be set to 922337203685477580 and cutlim to
* either 7 (neg==0) or 8 (neg==1), meaning that if we have
* accumulated a value > 922337203685477580, or equal but the
* next digit is > 7 (or 8), the number is too big, and we will
* return a range error.
*
* Set any if any `digits' consumed; make it negative to indicate
* overflow.
*/
qbase = (unsigned int)base;
if (!unsign) {
cutoff = neg ? (u64)-(LLONG_MIN + LLONG_MAX) + LLONG_MAX : LLONG_MAX;
cutlim = cutoff % qbase;
cutoff /= qbase;
} else {
cutoff = (u64)ULLONG_MAX / qbase;
cutlim = (u64)ULLONG_MAX % qbase;
}
for (acc = 0, any = 0;; c = *s++) {
if (!isascii(c))
break;
if (isdigit(c))
c -= '0';
else if (isalpha(c))
c -= isupper(c) ? 'A' - 10 : 'a' - 10;
else
break;
if (c >= base)
break;
if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim)) {
any = -1;
} else {
any = 1;
acc *= qbase;
acc += c;
}
}
info->any = any;
info->neg = neg;
info->acc = acc;
*nptr = s;
return info;
}
/**
* strtoq() - Convert a string to a quad integer
* @nptr: pointer to string
* @endptr: pointer to number's end in the string
* @base: number's base
*
* Return: s64 quad integer number converted from input string
*/
static s64
strtoq(const char *nptr, char **endptr, int base)
{
const char *s = nptr;
u64 acc;
int unsign = 0;
struct str_info *info;
info = str_to_int_convert(&s, base, unsign);
if (!info)
return -1;
acc = info->acc;
if (info->any < 0)
acc = info->neg ? LLONG_MIN : LLONG_MAX;
else if (info->neg)
acc = -acc;
if (endptr != 0)
*endptr = __DECONST(char *, info->any ? s - 1 : nptr);
free(info);
return acc;
}
/**
* strtouq() - Convert a string to an unsigned quad integer
* @nptr: pointer to string
* @endptr: pointer to number's end in the string
* @base: number's base
*
* Return: s64 unsigned quad integer number converted from
* input string
*/
u64
strtouq(const char *nptr, char **endptr, int base)
{
const char *s = nptr;
u64 acc;
int unsign = 1;
struct str_info *info;
info = str_to_int_convert(&s, base, unsign);
if (!info)
return -1;
acc = info->acc;
if (info->any < 0)
acc = ULLONG_MAX;
else if (info->neg)
acc = -acc;
if (endptr != 0)
*endptr = __DECONST(char *, info->any ? s - 1 : nptr);
free(info);
return acc;
}
/**
* __sccl() - Fill in the given table from the scanset at the given format
* (just after `[')
* @tab: table to fill in
* @fmt: format of buffer
*
* The table has a 1 wherever characters should be considered part of the
* scanset.
*
* Return: pointer to the character past the closing `]'
*/
static const u_char *
__sccl(char *tab, const u_char *fmt)
{
int c, n, v;
/* first `clear' the whole table */
c = *fmt++; /* first char hat => negated scanset */
if (c == '^') {
v = 1; /* default => accept */
c = *fmt++; /* get new first char */
} else {
v = 0; /* default => reject */
}
/* XXX: Will not work if sizeof(tab*) > sizeof(char) */
for (n = 0; n < 256; n++)
tab[n] = v; /* memset(tab, v, 256) */
if (c == 0)
return (fmt - 1);/* format ended before closing ] */
/*
* Now set the entries corresponding to the actual scanset
* to the opposite of the above.
*
* The first character may be ']' (or '-') without being special;
* the last character may be '-'.
*/
v = 1 - v;
for (;;) {
tab[c] = v; /* take character c */
doswitch:
n = *fmt++; /* and examine the next */
switch (n) {
case 0: /* format ended too soon */
return (fmt - 1);
case '-':
/*
* A scanset of the form
* [01+-]
* is defined as `the digit 0, the digit 1,
* the character +, the character -', but
* the effect of a scanset such as
* [a-zA-Z0-9]
* is implementation defined. The V7 Unix
* scanf treats `a-z' as `the letters a through
* z', but treats `a-a' as `the letter a, the
* character -, and the letter a'.
*
* For compatibility, the `-' is not considerd
* to define a range if the character following
* it is either a close bracket (required by ANSI)
* or is not numerically greater than the character
* we just stored in the table (c).
*/
n = *fmt;
if (n == ']' || n < c) {
c = '-';
break; /* resume the for(;;) */
}
fmt++;
/* fill in the range */
do {
tab[++c] = v;
} while (c < n);
c = n;
/*
* Alas, the V7 Unix scanf also treats formats
* such as [a-c-e] as `the letters a through e'.
* This too is permitted by the standard....
*/
goto doswitch;
break;
case ']': /* end of scanset */
return (fmt);
default: /* just another character */
c = n;
break;
}
}
/* NOTREACHED */
}
/**
* vsscanf - Unformat a buffer into a list of arguments
* @buf: input buffer
* @fmt: format of buffer
* @args: arguments
*/
#define BUF 32 /* Maximum length of numeric string. */
/*
* Flags used during conversion.
*/
#define LONG 0x01 /* l: long or double */
#define SHORT 0x04 /* h: short */
#define SUPPRESS 0x08 /* suppress assignment */
#define POINTER 0x10 /* weird %p pointer (`fake hex') */
#define NOSKIP 0x20 /* do not skip blanks */
#define QUAD 0x400
#define SHORTSHORT 0x4000 /** hh: char */
/*
* The following are used in numeric conversions only:
* SIGNOK, NDIGITS, DPTOK, and EXPOK are for floating point;
* SIGNOK, NDIGITS, PFXOK, and NZDIGITS are for integral.
*/
#define SIGNOK 0x40 /* +/- is (still) legal */
#define NDIGITS 0x80 /* no digits detected */
#define DPTOK 0x100 /* (float) decimal point is still legal */
#define EXPOK 0x200 /* (float) exponent (e+3, etc) still legal */
#define PFXOK 0x100 /* 0x prefix is (still) legal */
#define NZDIGITS 0x200 /* no zero digits detected */
/*
* Conversion types.
*/
#define CT_CHAR 0 /* %c conversion */
#define CT_CCL 1 /* %[...] conversion */
#define CT_STRING 2 /* %s conversion */
#define CT_INT 3 /* integer, i.e., strtoq or strtouq */
typedef u64 (*ccfntype)(const char *, char **, int);
int
vsscanf(const char *inp, char const *fmt0, va_list ap)
{
int inr;
const u_char *fmt = (const u_char *)fmt0;
int c; /* character from format, or conversion */
size_t width; /* field width, or 0 */
char *p; /* points into all kinds of strings */
int n; /* handy integer */
int flags; /* flags as defined above */
char *p0; /* saves original value of p when necessary */
int nassigned; /* number of fields assigned */
int nconversions; /* number of conversions */
int nread; /* number of characters consumed from fp */
int base; /* base argument to strtoq/strtouq */
ccfntype ccfn; /* conversion function (strtoq/strtouq) */
char ccltab[256]; /* character class table for %[...] */
char buf[BUF]; /* buffer for numeric conversions */
/* `basefix' is used to avoid `if' tests in the integer scanner */
static short basefix[17] = { 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,
12, 13, 14, 15, 16 };
inr = strlen(inp);
nassigned = 0;
nconversions = 0;
nread = 0;
base = 0; /* XXX just to keep gcc happy */
ccfn = NULL; /* XXX just to keep gcc happy */
for (;;) {
c = *fmt++;
if (c == 0)
return (nassigned);
if (isspace(c)) {
while (inr > 0 && isspace(*inp))
nread++, inr--, inp++;
continue;
}
if (c != '%')
goto literal;
width = 0;
flags = 0;
/*
* switch on the format. continue if done;
* break once format type is derived.
*/
again: c = *fmt++;
switch (c) {
case '%':
literal:
if (inr <= 0)
goto input_failure;
if (*inp != c)
goto match_failure;
inr--, inp++;
nread++;
continue;
case '*':
flags |= SUPPRESS;
goto again;
case 'l':
if (flags & LONG) {
flags &= ~LONG;
flags |= QUAD;
} else {
flags |= LONG;
}
goto again;
case 'q':
flags |= QUAD;
goto again;
case 'h':
if (flags & SHORT) {
flags &= ~SHORT;
flags |= SHORTSHORT;
} else {
flags |= SHORT;
}
goto again;
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
width = width * 10 + c - '0';
goto again;
/*
* Conversions.
*
*/
case 'd':
c = CT_INT;
ccfn = (ccfntype)strtoq;
base = 10;
break;
case 'i':
c = CT_INT;
ccfn = (ccfntype)strtoq;
base = 0;
break;
case 'o':
c = CT_INT;
ccfn = strtouq;
base = 8;
break;
case 'u':
c = CT_INT;
ccfn = strtouq;
base = 10;
break;
case 'x':
flags |= PFXOK; /* enable 0x prefixing */
c = CT_INT;
ccfn = strtouq;
base = 16;
break;
case 's':
c = CT_STRING;
break;
case '[':
fmt = __sccl(ccltab, fmt);
flags |= NOSKIP;
c = CT_CCL;
break;
case 'c':
flags |= NOSKIP;
c = CT_CHAR;
break;
case 'p': /* pointer format is like hex */
flags |= POINTER | PFXOK;
c = CT_INT;
ccfn = strtouq;
base = 16;
break;
case 'n':
nconversions++;
if (flags & SUPPRESS) /* ??? */
continue;
if (flags & SHORTSHORT)
*va_arg(ap, char *) = nread;
else if (flags & SHORT)
*va_arg(ap, short *) = nread;
else if (flags & LONG)
*va_arg(ap, long *) = nread;
else if (flags & QUAD)
*va_arg(ap, s64 *) = nread;
else
*va_arg(ap, int *) = nread;
continue;
}
/*
* We have a conversion that requires input.
*/
if (inr <= 0)
goto input_failure;
/*
* Consume leading white space, except for formats
* that suppress this.
*/
if ((flags & NOSKIP) == 0) {
while (isspace(*inp)) {
nread++;
if (--inr > 0)
inp++;
else
goto input_failure;
}
/*
* Note that there is at least one character in
* the buffer, so conversions that do not set NOSKIP
* can no longer result in an input failure.
*/
}
/*
* Do the conversion.
*/
switch (c) {
case CT_CHAR:
/* scan arbitrary characters (sets NOSKIP) */
if (width == 0)
width = 1;
if (flags & SUPPRESS) {
size_t sum = 0;
if ((n = inr) < width) {
sum += n;
width -= n;
inp += n;
if (sum == 0)
goto input_failure;
} else {
sum += width;
inr -= width;
inp += width;
}
nread += sum;
} else {
memcpy(va_arg(ap, char *), inp, width);
inr -= width;
inp += width;
nread += width;
nassigned++;
}
nconversions++;
break;
case CT_CCL:
/* scan a (nonempty) character class (sets NOSKIP) */
if (width == 0)
width = (size_t)~0; /* `infinity' */
/* take only those things in the class */
if (flags & SUPPRESS) {
n = 0;
while (ccltab[(unsigned char)*inp]) {
n++, inr--, inp++;
if (--width == 0)
break;
if (inr <= 0) {
if (n == 0)
goto input_failure;
break;
}
}
if (n == 0)
goto match_failure;
} else {
p = va_arg(ap, char *);
p0 = p;
while (ccltab[(unsigned char)*inp]) {
inr--;
*p++ = *inp++;
if (--width == 0)
break;
if (inr <= 0) {
if (p == p0)
goto input_failure;
break;
}
}
n = p - p0;
if (n == 0)
goto match_failure;
*p = 0;
nassigned++;
}
nread += n;
nconversions++;
break;
case CT_STRING:
/* like CCL, but zero-length string OK, & no NOSKIP */
if (width == 0)
width = (size_t)~0;
if (flags & SUPPRESS) {
n = 0;
while (!isspace(*inp)) {
n++, inr--, inp++;
if (--width == 0)
break;
if (inr <= 0)
break;
}
nread += n;
} else {
p = va_arg(ap, char *);
p0 = p;
while (!isspace(*inp)) {
inr--;
*p++ = *inp++;
if (--width == 0)
break;
if (inr <= 0)
break;
}
*p = 0;
nread += p - p0;
nassigned++;
}
nconversions++;
continue;
case CT_INT:
/* scan an integer as if by strtoq/strtouq */
#ifdef hardway
if (width == 0 || width > sizeof(buf) - 1)
width = sizeof(buf) - 1;
#else
/* size_t is unsigned, hence this optimisation */
if (--width > sizeof(buf) - 2)
width = sizeof(buf) - 2;
width++;
#endif
flags |= SIGNOK | NDIGITS | NZDIGITS;
for (p = buf; width; width--) {
c = *inp;
/*
* Switch on the character; `goto ok'
* if we accept it as a part of number.
*/
switch (c) {
/*
* The digit 0 is always legal, but is
* special. For %i conversions, if no
* digits (zero or nonzero) have been
* scanned (only signs), we will have
* base==0. In that case, we should set
* it to 8 and enable 0x prefixing.
* Also, if we have not scanned zero digits
* before this, do not turn off prefixing
* (someone else will turn it off if we
* have scanned any nonzero digits).
*/
case '0':
if (base == 0) {
base = 8;
flags |= PFXOK;
}
if (flags & NZDIGITS)
flags &= ~(SIGNOK | NZDIGITS | NDIGITS);
else
flags &= ~(SIGNOK | PFXOK | NDIGITS);
goto ok;
/* 1 through 7 always legal */
case '1': case '2': case '3':
case '4': case '5': case '6': case '7':
base = basefix[base];
flags &= ~(SIGNOK | PFXOK | NDIGITS);
goto ok;
/* digits 8 and 9 ok iff decimal or hex */
case '8': case '9':
base = basefix[base];
if (base <= 8)
break; /* not legal here */
flags &= ~(SIGNOK | PFXOK | NDIGITS);
goto ok;
/* letters ok iff hex */
case 'A': case 'B': case 'C':
case 'D': case 'E': case 'F':
case 'a': case 'b': case 'c':
case 'd': case 'e': case 'f':
/* no need to fix base here */
if (base <= 10)
break; /* not legal here */
flags &= ~(SIGNOK | PFXOK | NDIGITS);
goto ok;
/* sign ok only as first character */
case '+': case '-':
if (flags & SIGNOK) {
flags &= ~SIGNOK;
goto ok;
}
break;
/* x ok iff flag still set & 2nd char */
case 'x': case 'X':
if (flags & PFXOK && p == buf + 1) {
base = 16; /* if %i */
flags &= ~PFXOK;
goto ok;
}
break;
}
/*
* If we got here, c is not a legal character
* for a number. Stop accumulating digits.
*/
break;
ok:
/*
* c is legal: store it and look at the next.
*/
*p++ = c;
if (--inr > 0)
inp++;
else
break; /* end of input */
}
/*
* If we had only a sign, it is no good; push
* back the sign. If the number ends in `x',
* it was [sign] '' 'x', so push back the x
* and treat it as [sign] ''.
*/
if (flags & NDIGITS) {
if (p > buf) {
inp--;
inr++;
}
goto match_failure;
}
c = ((u_char *)p)[-1];
if (c == 'x' || c == 'X') {
--p;
inp--;
inr++;
}
if ((flags & SUPPRESS) == 0) {
u64 res;
*p = 0;
res = (*ccfn)(buf, (char **)NULL, base);
if (flags & POINTER)
*va_arg(ap, void **) =
(void *)(uintptr_t)res;
else if (flags & SHORTSHORT)
*va_arg(ap, char *) = res;
else if (flags & SHORT)
*va_arg(ap, short *) = res;
else if (flags & LONG)
*va_arg(ap, long *) = res;
else if (flags & QUAD)
*va_arg(ap, s64 *) = res;
else
*va_arg(ap, int *) = res;
nassigned++;
}
nread += p - buf;
nconversions++;
break;
}
}
input_failure:
return (nconversions != 0 ? nassigned : -1);
match_failure:
return (nassigned);
}
/**
* sscanf - Unformat a buffer into a list of arguments
* @buf: input buffer
* @fmt: formatting of buffer
* @...: resulting arguments
*/
int sscanf(const char *buf, const char *fmt, ...)
{
va_list args;
int i;
va_start(args, fmt);
i = vsscanf(buf, fmt, args);
va_end(args);
return i;
}
#endif
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