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authorRich Felker <dalias@aerifal.cx>2012-04-16 16:03:45 -0400
committerRich Felker <dalias@aerifal.cx>2012-04-16 16:03:45 -0400
commit18efeb320b763e541a7dbf61a7da1cbe13ab2be9 (patch)
treef8eb42a87b9c07ad8d9de0380356af3541b425aa /src/internal/intscan.c
parentcc762434d91a2f441a1d2f44962ab1d4854b607b (diff)
downloadmusl-18efeb320b763e541a7dbf61a7da1cbe13ab2be9.tar.gz
new scanf implementation and corresponding integer parser/converter
advantages over the old code: - correct results for floating point (old code was bogus) - wide/regular scanf separated so scanf does not pull in wide code - well-defined behavior on integers that overflow dest type - support for %[a-b] ranges with %[ (impl-defined by widely used) - no intermediate conversion of fmt string to wide string - cleaner, easier to share code with strto* functions - better standards conformance for corner cases the old code remains in the source tree, as the wide versions of the scanf-family functions are still using it. it will be removed when no longer needed.
Diffstat (limited to 'src/internal/intscan.c')
-rw-r--r--src/internal/intscan.c97
1 files changed, 97 insertions, 0 deletions
diff --git a/src/internal/intscan.c b/src/internal/intscan.c
new file mode 100644
index 00000000..a00f2ccc
--- /dev/null
+++ b/src/internal/intscan.c
@@ -0,0 +1,97 @@
+#include <limits.h>
+#include <errno.h>
+#include "shgetc.h"
+
+/* Lookup table for digit values. -1==255>=36 -> invalid */
+static const unsigned char table[] = { -1,
+-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,-1,-1,-1,-1,-1,-1,
+-1,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,
+25,26,27,28,29,30,31,32,33,34,35,-1,-1,-1,-1,-1,
+-1,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,
+25,26,27,28,29,30,31,32,33,34,35,-1,-1,-1,-1,-1,
+-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+};
+
+unsigned long long __intscan(FILE *f, unsigned base, int pok, unsigned long long lim)
+{
+ const unsigned char *val = table+1;
+ int c, neg=0;
+ unsigned x;
+ unsigned long long y;
+ if (base > 36) {
+ errno = EINVAL;
+ return 0;
+ }
+ c = shgetc(f);
+ if (c=='+' || c=='-') {
+ neg = -(c=='-');
+ c = shgetc(f);
+ }
+ if ((base == 0 || base == 16) && c=='0') {
+ c = shgetc(f);
+ if ((c|32)=='x') {
+ c = shgetc(f);
+ if (val[c]>=16) {
+ shunget(f);
+ if (pok) shunget(f);
+ else shlim(f, 0);
+ return 0;
+ }
+ base = 16;
+ } else if (base == 0) {
+ base = 8;
+ }
+ } else {
+ if (base == 0) base = 10;
+ if (val[c] >= base) {
+ shlim(f, 0);
+ errno = EINVAL;
+ return 0;
+ }
+ }
+ if (base == 10) {
+ for (x=0; c-'0'<10U && x<=UINT_MAX/10-1; c=shgetc(f))
+ x = x*10 + (c-'0');
+ for (y=x; c-'0'<10U && y<=ULLONG_MAX/10 && 10*y<=ULLONG_MAX-(c-'0'); c=shgetc(f))
+ y = y*10 + (c-'0');
+ if (c-'0'>=10U) goto done;
+ } else if (!(base & base-1)) {
+ int bs = "\0\1\2\4\7\3\6\5"[(0x17*base)>>5&7];
+ for (x=0; val[c]<base && x<=UINT_MAX/32; c=shgetc(f))
+ x = x<<bs | val[c];
+ for (y=x; val[c]<base && y<=ULLONG_MAX>>bs; c=shgetc(f))
+ y = y<<bs | val[c];
+ } else {
+ for (x=0; val[c]<base && x<=UINT_MAX/36-1; c=shgetc(f))
+ x = x*base + val[c];
+ for (y=x; val[c]<base && y<=ULLONG_MAX/base && base*y<=ULLONG_MAX-val[c]; c=shgetc(f))
+ y = y*base + val[c];
+ }
+ if (val[c]<base) {
+ for (; val[c]<base; c=shgetc(f));
+ errno = ERANGE;
+ y = lim;
+ }
+done:
+ shunget(f);
+ if (y>=lim) {
+ if (!(lim&1) && !neg) {
+ errno = ERANGE;
+ return lim-1;
+ } else if (y>lim) {
+ errno = ERANGE;
+ return lim;
+ }
+ }
+ return (y^neg)-neg;
+}