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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Minios-devel] [UNIKRAFT PATCH 5/5] lib/nolibc: Add vsscanf and sscanf functions
Shamelessly taken from Mini-OS.
Signed-off-by: Costin Lupu <costin.lupu@xxxxxxxxx>
---
lib/nolibc/stdio.c | 592 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 592 insertions(+)
diff --git a/lib/nolibc/stdio.c b/lib/nolibc/stdio.c
index 7e3d368..09676c4 100644
--- a/lib/nolibc/stdio.c
+++ b/lib/nolibc/stdio.c
@@ -475,6 +475,598 @@ int printf(const char *fmt, ...)
return ret;
}
+/*
+ * Fill in the given table from the scanset at the given format
+ * (just after `['). Return a pointer to the character past the
+ * closing `]'. The table has a 1 wherever characters should be
+ * considered part of the scanset.
+ */
+static const unsigned char *
+__sccl(char *tab, const unsigned 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;
+ 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 uint64_t (*ccfntype)(const char *, char **, int);
+
+int
+vsscanf(const char *inp, char const *fmt, va_list ap)
+{
+ int inr;
+ const unsigned char *_fmt = (const unsigned char *) fmt;
+ int c; /* character from format, or conversion */
+ ssize_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, int64_t *) = 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 {
+ p0 = p = va_arg(ap, char *);
+ 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 {
+ p0 = p = va_arg(ap, char *);
+ 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 > (ssize_t) 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 = ((unsigned char *) p)[-1];
+ if (c == 'x' || c == 'X') {
+ --p;
+ inp--;
+ inr++;
+ }
+ if ((flags & SUPPRESS) == 0) {
+ uint64_t 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, int64_t *) = res;
+ else
+ *va_arg(ap, int *) = res;
+ nassigned++;
+ }
+ nread += p - buf;
+ nconversions++;
+ break;
+ }
+ }
+input_failure:
+ return (nconversions != 0 ? nassigned : -1);
+match_failure:
+ return (nassigned);
+}
+
+int sscanf(const char *str, const char *fmt, ...)
+{
+ int ret;
+ va_list ap;
+
+ va_start(ap, fmt);
+ ret = vsscanf(str, fmt, ap);
+ va_end(ap);
+
+ return ret;
+}
+
int fflush(FILE *fp __unused)
{
/* nolibc is not working with buffers */
--
2.11.0
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