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Add scansets to the scanf function. Enabled CONFIG_LIBC_SCANSET option.

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Author: Aleksandr Vyhovanec 2016-12-17 14:39:19 -06:00 committed by Gregory Nutt
parent 93e6d16f75
commit 7be1b86a81
2 changed files with 226 additions and 0 deletions
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6
libc/Kconfig
View File

@ -61,6 +61,12 @@ config LIBC_LONG_LONG
libraries that will be drawn into the build if long long support
is enabled.
config LIBC_SCANSET
default "Scanset support"
default n
---help---
Add scanset support to sscanf().
config LIBC_IOCTL_VARIADIC
bool "Enable variadic ioctl()"
default n

220
libc/stdio/lib_sscanf.c
View File

@ -134,6 +134,153 @@ static int findwidth(FAR const char *buf, FAR const char *fmt)
return strcspn(buf, spaces);
}
/****************************************************************************
* Function: findscanset
*
* Description:
* Fill in the given table from the scanset at the given format.
* Return a pointer to the character the closing ']'.
* The table has a 1 wherever characters should be considered part of the
* scanset.
****************************************************************************/
#ifdef CONFIG_LIBC_SCANSET
static FAR const char *findscanset(FAR const char *fmt,
FAR unsigned char set[32])
{
int c;
int n;
int v;
fmt++; /* Skip '[' */
/* 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 */
}
memset(set, 0, 32);
if (c == 0)
{
goto doexit;
}
/* 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 '-'.
*/
for (;;)
{
set[c / 8] |= (1 << (c % 8)); /* take character c */
doswitch:
n = *fmt++; /* and examine the next */
switch (n)
{
case 0: /* format ended too soon */
case ']': /* end of scanset */
goto doexit;
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++;
do
{
/* Fill in the range */
c++;
set[c / 8] |= (1 << (c % 8)); /* Take character c */
}
while (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;
default: /* just another character */
c = n;
break;
}
}
doexit:
if (v) /* default => accept */
{
for (int i = 0; i < 32; i++) /* invert all */
{
set[i] ^= 0xFF;
}
}
return (fmt - 1);
}
#endif
/****************************************************************************
* Function: scansetwidth
****************************************************************************/
#ifdef CONFIG_LIBC_SCANSET
static int scansetwidth(FAR const char *buf,
FAR const unsigned char set[32])
{
FAR const char *next = buf;
int c;
while (*next)
{
c = *next;
if ((set[c / 8] & (1 << (c % 8))) == 0)
{
break;
}
next++;
}
return (next - buf);
}
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
@ -177,6 +324,9 @@ int vsscanf(FAR const char *buf, FAR const char *fmt, va_list ap)
int fwidth;
int base = 10;
char tmp[MAXLN];
#ifdef CONFIG_LIBC_SCANSET
unsigned char set[32]; /* Bit field (256 / 8) */
#endif
linfo("vsscanf: buf=\"%s\" fmt=\"%s\"\n", buf, fmt);
@ -220,7 +370,11 @@ int vsscanf(FAR const char *buf, FAR const char *fmt, va_list ap)
{
linfo("vsscanf: Processing %c\n", *fmt);
#ifdef CONFIG_LIBC_SCANSET
if (strchr("dibouxcsefgn[%", *fmt))
#else
if (strchr("dibouxcsefgn%", *fmt))
#endif
{
break;
}
@ -307,6 +461,72 @@ int vsscanf(FAR const char *buf, FAR const char *fmt, va_list ap)
}
}
#ifdef CONFIG_LIBC_SCANSET
/* Process %[: Scanset conversion */
if (*fmt == '[')
{
linfo("vsscanf: Performing scanset conversion\n");
fmt = findscanset(fmt, set); /* find scanset */
/* Get a pointer to the char * value. We need to do this even
* if we have reached the end of the input data in order to
* update the 'ap' variable.
*/
tv = NULL; /* To avoid warnings about begin uninitialized */
if (!noassign)
{
tv = va_arg(ap, FAR char *);
tv[0] = '\0';
}
/* But we only perform the data conversion is we still have
* bytes remaining in the input data stream.
*/
if (*buf)
{
/* Skip over white space */
while (isspace(*buf))
{
buf++;
}
/* Guess a field width using some heuristics */
fwidth = scansetwidth(buf, set);
/* Use the actual field's width if 1) no fieldwidth
* specified or 2) the actual field's width is smaller
* than fieldwidth specified
*/
if (!width || fwidth < width)
{
width = fwidth;
}
width = MIN(sizeof(tmp) - 1, width);
/* Copy the string (if we are making an assignment) */
if (!noassign)
{
strncpy(tv, buf, width);
tv[width] = '\0';
count++;
}
/* Update the buffer pointer past the string in the input */
buf += width;
}
}
#endif
/* Process %c: Character conversion */
else if (*fmt == 'c')