Rich Felker
ecc9c5fcfa
this fixes a number of bugs in integer parsing due to lazy haphazard wrapping, as well as some misinterpretations of the standard. the new parser is able to work character-at-a-time or on whole strings, making it easy to support the wide functions without unbounded space for conversion. it will also be possible to update scanf to use the new parser.
106 lines
2.6 KiB
C
106 lines
2.6 KiB
C
#include <stdint.h>
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#include <limits.h>
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#include <stdlib.h>
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#include <errno.h>
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#include "intparse.h"
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/* Lookup table for digit values. -1==255>=36 -> invalid */
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static const unsigned char digits[] = {
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-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
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-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
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-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9,-1,-1,-1,-1,-1,-1,
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-1,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,
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25,26,27,28,29,30,31,32,33,34,35,-1,-1,-1,-1,-1,
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-1,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,
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25,26,27,28,29,30,31,32,33,34,35,-1,-1,-1,-1,-1,
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-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
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-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
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-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
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-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
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-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
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-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
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-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
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-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
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};
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#define SLIM (UINT_MAX/36-1)
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#define LLIM (UINTMAX_MAX/36-1)
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int __intparse(struct intparse *v, const void *buf, size_t n)
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{
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const unsigned char *s = buf;
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int d, b = v->base;
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v->cnt += n;
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for (; n; n--, s++) switch (v->state) {
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case 0:
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v->state++;
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if (*s=='+' || *s=='-') {
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v->neg = *s=='-';
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continue;
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}
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case 1:
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v->state++;
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if (*s=='0' && (!b || b==16)) continue;
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if (!b) v->base = b = 10;
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v->state++;
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goto firstdigit;
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case 2:
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v->state++;
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if ((!b || b==16) && (*s|32) == 'x') {
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v->base = b = 16;
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continue;
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}
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if (!b) v->base = b = 8;
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goto seconddigit;
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case 3:
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firstdigit:
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if (digits[*s] >= b) {
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v->err = EINVAL;
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return 0;
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}
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seconddigit:
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v->state++;
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case 4:
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if (b==10) {
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for (; n && *s-'0'<10U && v->small<=SLIM; n--, s++)
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v->small = v->small * 10 + (*s-'0');
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} else if ((b&-b) == b) {
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int bs = "\0\1\2\4\7\3\6\5"[(0x17*b)>>5&7];
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for (; n && (d=digits[*s])<b && v->small<=SLIM; n--, s++)
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v->small = (v->small<<bs) + d;
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} else {
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for (; n && (d=digits[*s])<b && v->small<=SLIM; n--, s++)
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v->small = v->small * b + d;
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}
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if (!n) return 1;
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v->state++;
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v->val = v->small;
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case 5:
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for (; n && (d=digits[*s])<b && v->val<=LLIM; n--, s++)
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v->val = v->val * b + d;
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if (!n) return 1;
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if (d >= b) goto finished;
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if (v->val < (UINTMAX_MAX-d)/b)
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v->val = v->val * b + d;
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else
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v->err = ERANGE;
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v->state++;
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n--; s++;
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case 6:
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if (n && digits[*s]<b) {
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v->err = ERANGE;
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v->val = UINTMAX_MAX;
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n--; s++;
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}
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for (; n && digits[*s]<b; n--, s++);
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if (!n) return 1;
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}
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return 1;
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finished:
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v->cnt -= n;
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return 0;
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}
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