xref: /third_party/ffmpeg/libavutil/avsscanf.c (revision cabdff1a)
1/*
2 * Copyright (c) 2005-2014 Rich Felker, et al.
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining
5 * a copy of this software and associated documentation files (the
6 * "Software"), to deal in the Software without restriction, including
7 * without limitation the rights to use, copy, modify, merge, publish,
8 * distribute, sublicense, and/or sell copies of the Software, and to
9 * permit persons to whom the Software is furnished to do so, subject to
10 * the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be
13 * included in all copies or substantial portions of the Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
18 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
19 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
20 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
21 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
22 */
23
24#include <errno.h>
25#include <limits.h>
26#include <math.h>
27#include <stdarg.h>
28#include <stddef.h>
29#include <stdint.h>
30#include <stdio.h>
31#include <string.h>
32#include <float.h>
33
34#include "avstring.h"
35#include "libm.h"
36
37typedef struct FFFILE {
38    size_t buf_size;
39    unsigned char *buf;
40    unsigned char *rpos, *rend;
41    unsigned char *shend;
42    ptrdiff_t shlim, shcnt;
43    void *cookie;
44    size_t (*read)(struct FFFILE *, unsigned char *, size_t);
45} FFFILE;
46
47#define SIZE_hh -2
48#define SIZE_h  -1
49#define SIZE_def 0
50#define SIZE_l   1
51#define SIZE_L   2
52#define SIZE_ll  3
53
54#define shcnt(f) ((f)->shcnt + ((f)->rpos - (f)->buf))
55
56static int fftoread(FFFILE *f)
57{
58    f->rpos = f->rend = f->buf + f->buf_size;
59    return 0;
60}
61
62static size_t ffstring_read(FFFILE *f, unsigned char *buf, size_t len)
63{
64    char *src = f->cookie;
65    size_t k = len+256;
66    char *end = memchr(src, 0, k);
67
68    if (end) k = end-src;
69    if (k < len) len = k;
70    memcpy(buf, src, len);
71    f->rpos = (void *)(src+len);
72    f->rend = (void *)(src+k);
73    f->cookie = src+k;
74
75    return len;
76}
77
78static int ffuflow(FFFILE *f)
79{
80    unsigned char c;
81    if (!fftoread(f) && f->read(f, &c, 1)==1) return c;
82    return EOF;
83}
84
85static void ffshlim(FFFILE *f, ptrdiff_t lim)
86{
87    f->shlim = lim;
88    f->shcnt = f->buf - f->rpos;
89    /* If lim is nonzero, rend must be a valid pointer. */
90    if (lim && f->rend - f->rpos > lim)
91        f->shend = f->rpos + lim;
92    else
93        f->shend = f->rend;
94}
95
96static int ffshgetc(FFFILE *f)
97{
98    int c;
99    ptrdiff_t cnt = shcnt(f);
100    if (f->shlim && cnt >= f->shlim || (c=ffuflow(f)) < 0) {
101        f->shcnt = f->buf - f->rpos + cnt;
102        f->shend = 0;
103        return EOF;
104    }
105    cnt++;
106    if (f->shlim && f->rend - f->rpos > f->shlim - cnt)
107        f->shend = f->rpos + (f->shlim - cnt);
108    else
109        f->shend = f->rend;
110    f->shcnt = f->buf - f->rpos + cnt;
111    if (f->rpos[-1] != c) f->rpos[-1] = c;
112    return c;
113}
114
115#define shlim(f, lim) ffshlim((f), (lim))
116#define shgetc(f) (((f)->rpos < (f)->shend) ? *(f)->rpos++ : ffshgetc(f))
117#define shunget(f) ((f)->shend ? (void)(f)->rpos-- : (void)0)
118
119static const unsigned char table[] = { -1,
120    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
121    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
122    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
123    0, 1, 2, 3, 4, 5, 6, 7, 8, 9,-1,-1,-1,-1,-1,-1,
124    -1,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,
125    25,26,27,28,29,30,31,32,33,34,35,-1,-1,-1,-1,-1,
126    -1,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,
127    25,26,27,28,29,30,31,32,33,34,35,-1,-1,-1,-1,-1,
128    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
129    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
130    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
131    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
132    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
133    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
134    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
135    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
136};
137
138static unsigned long long ffintscan(FFFILE *f, unsigned base, int pok, unsigned long long lim)
139{
140    const unsigned char *val = table+1;
141    int c, neg=0;
142    unsigned x;
143    unsigned long long y;
144    if (base > 36 || base == 1) {
145        errno = EINVAL;
146        return 0;
147    }
148    while (av_isspace((c=shgetc(f))));
149    if (c=='+' || c=='-') {
150        neg = -(c=='-');
151        c = shgetc(f);
152    }
153    if ((base == 0 || base == 16) && c=='0') {
154        c = shgetc(f);
155        if ((c|32)=='x') {
156            c = shgetc(f);
157            if (val[c]>=16) {
158                shunget(f);
159                if (pok) shunget(f);
160                else shlim(f, 0);
161                return 0;
162            }
163            base = 16;
164        } else if (base == 0) {
165            base = 8;
166        }
167    } else {
168        if (base == 0) base = 10;
169        if (val[c] >= base) {
170            shunget(f);
171            shlim(f, 0);
172            errno = EINVAL;
173            return 0;
174        }
175    }
176    if (base == 10) {
177        for (x=0; c-'0'<10U && x<=UINT_MAX/10-1; c=shgetc(f))
178            x = x*10 + (c-'0');
179        for (y=x; c-'0'<10U && y<=ULLONG_MAX/10 && 10*y<=ULLONG_MAX-(c-'0'); c=shgetc(f))
180            y = y*10 + (c-'0');
181        if (c-'0'>=10U) goto done;
182    } else if (!(base & base-1)) {
183        int bs = "\0\1\2\4\7\3\6\5"[(0x17*base)>>5&7];
184        for (x=0; val[c]<base && x<=UINT_MAX/32; c=shgetc(f))
185            x = x<<bs | val[c];
186        for (y=x; val[c]<base && y<=ULLONG_MAX>>bs; c=shgetc(f))
187            y = y<<bs | val[c];
188    } else {
189        for (x=0; val[c]<base && x<=UINT_MAX/36-1; c=shgetc(f))
190            x = x*base + val[c];
191        for (y=x; val[c]<base && y<=ULLONG_MAX/base && base*y<=ULLONG_MAX-val[c]; c=shgetc(f))
192            y = y*base + val[c];
193    }
194    if (val[c]<base) {
195        for (; val[c]<base; c=shgetc(f));
196        errno = ERANGE;
197        y = lim;
198        if (lim&1) neg = 0;
199    }
200done:
201    shunget(f);
202    if (y>=lim) {
203        if (!(lim&1) && !neg) {
204            errno = ERANGE;
205            return lim-1;
206        } else if (y>lim) {
207            errno = ERANGE;
208            return lim;
209        }
210    }
211    return (y^neg)-neg;
212}
213
214static long long scanexp(FFFILE *f, int pok)
215{
216    int c;
217    int x;
218    long long y;
219    int neg = 0;
220
221    c = shgetc(f);
222    if (c=='+' || c=='-') {
223        neg = (c=='-');
224        c = shgetc(f);
225        if (c-'0'>=10U && pok) shunget(f);
226    }
227    if (c-'0'>=10U) {
228        shunget(f);
229        return LLONG_MIN;
230    }
231    for (x=0; c-'0'<10U && x<INT_MAX/10; c = shgetc(f))
232        x = 10*x + (c-'0');
233    for (y=x; c-'0'<10U && y<LLONG_MAX/100; c = shgetc(f))
234        y = 10*y + (c-'0');
235    for (; c-'0'<10U; c = shgetc(f));
236    shunget(f);
237    return neg ? -y : y;
238}
239
240#define LD_B1B_DIG 2
241#define LD_B1B_MAX 9007199, 254740991
242#define KMAX 128
243#define MASK (KMAX-1)
244
245static double decfloat(FFFILE *f, int c, int bits, int emin, int sign, int pok)
246{
247    uint32_t x[KMAX];
248    static const uint32_t th[] = { LD_B1B_MAX };
249    int i, j, k, a, z;
250    long long lrp=0, dc=0;
251    long long e10=0;
252    int lnz = 0;
253    int gotdig = 0, gotrad = 0;
254    int rp;
255    int e2;
256    int emax = -emin-bits+3;
257    int denormal = 0;
258    double y;
259    double frac=0;
260    double bias=0;
261    static const int p10s[] = { 10, 100, 1000, 10000,
262        100000, 1000000, 10000000, 100000000 };
263
264    j=0;
265    k=0;
266
267    /* Don't let leading zeros consume buffer space */
268    for (; c=='0'; c = shgetc(f)) gotdig=1;
269    if (c=='.') {
270        gotrad = 1;
271        for (c = shgetc(f); c=='0'; c = shgetc(f)) gotdig=1, lrp--;
272    }
273
274    x[0] = 0;
275    for (; c-'0'<10U || c=='.'; c = shgetc(f)) {
276        if (c == '.') {
277            if (gotrad) break;
278            gotrad = 1;
279            lrp = dc;
280        } else if (k < KMAX-3) {
281            dc++;
282            if (c!='0') lnz = dc;
283            if (j) x[k] = x[k]*10 + c-'0';
284            else x[k] = c-'0';
285            if (++j==9) {
286                k++;
287                j=0;
288            }
289            gotdig=1;
290        } else {
291            dc++;
292            if (c!='0') {
293                lnz = (KMAX-4)*9;
294                x[KMAX-4] |= 1;
295            }
296        }
297    }
298    if (!gotrad) lrp=dc;
299
300    if (gotdig && (c|32)=='e') {
301        e10 = scanexp(f, pok);
302        if (e10 == LLONG_MIN) {
303            if (pok) {
304                shunget(f);
305            } else {
306                shlim(f, 0);
307                return 0;
308            }
309            e10 = 0;
310        }
311        lrp += e10;
312    } else if (c>=0) {
313        shunget(f);
314    }
315    if (!gotdig) {
316        errno = EINVAL;
317        shlim(f, 0);
318        return 0;
319    }
320
321    /* Handle zero specially to avoid nasty special cases later */
322    if (!x[0]) return sign * 0.0;
323
324    /* Optimize small integers (w/no exponent) and over/under-flow */
325    if (lrp==dc && dc<10 && (bits>30 || x[0]>>bits==0))
326        return sign * (double)x[0];
327    if (lrp > -emin/2) {
328        errno = ERANGE;
329        return sign * DBL_MAX * DBL_MAX;
330    }
331    if (lrp < emin-2*DBL_MANT_DIG) {
332        errno = ERANGE;
333        return sign * DBL_MIN * DBL_MIN;
334    }
335
336    /* Align incomplete final B1B digit */
337    if (j) {
338        for (; j<9; j++) x[k]*=10;
339        k++;
340        j=0;
341    }
342
343    a = 0;
344    z = k;
345    e2 = 0;
346    rp = lrp;
347
348    /* Optimize small to mid-size integers (even in exp. notation) */
349    if (lnz<9 && lnz<=rp && rp < 18) {
350        int bitlim;
351        if (rp == 9) return sign * (double)x[0];
352        if (rp < 9) return sign * (double)x[0] / p10s[8-rp];
353        bitlim = bits-3*(int)(rp-9);
354        if (bitlim>30 || x[0]>>bitlim==0)
355            return sign * (double)x[0] * p10s[rp-10];
356    }
357
358    /* Drop trailing zeros */
359    for (; !x[z-1]; z--);
360
361    /* Align radix point to B1B digit boundary */
362    if (rp % 9) {
363        int rpm9 = rp>=0 ? rp%9 : rp%9+9;
364        int p10 = p10s[8-rpm9];
365        uint32_t carry = 0;
366        for (k=a; k!=z; k++) {
367            uint32_t tmp = x[k] % p10;
368            x[k] = x[k]/p10 + carry;
369            carry = 1000000000/p10 * tmp;
370            if (k==a && !x[k]) {
371                a = (a+1 & MASK);
372                rp -= 9;
373            }
374        }
375        if (carry) x[z++] = carry;
376        rp += 9-rpm9;
377    }
378
379    /* Upscale until desired number of bits are left of radix point */
380    while (rp < 9*LD_B1B_DIG || (rp == 9*LD_B1B_DIG && x[a]<th[0])) {
381        uint32_t carry = 0;
382        e2 -= 29;
383        for (k=(z-1 & MASK); ; k=(k-1 & MASK)) {
384            uint64_t tmp = ((uint64_t)x[k] << 29) + carry;
385            if (tmp > 1000000000) {
386                carry = tmp / 1000000000;
387                x[k] = tmp % 1000000000;
388            } else {
389                carry = 0;
390                x[k] = tmp;
391            }
392            if (k==(z-1 & MASK) && k!=a && !x[k]) z = k;
393            if (k==a) break;
394        }
395        if (carry) {
396            rp += 9;
397            a = (a-1 & MASK);
398            if (a == z) {
399                z = (z-1 & MASK);
400                x[z-1 & MASK] |= x[z];
401            }
402            x[a] = carry;
403        }
404    }
405
406    /* Downscale until exactly number of bits are left of radix point */
407    for (;;) {
408        uint32_t carry = 0;
409        int sh = 1;
410        for (i=0; i<LD_B1B_DIG; i++) {
411            k = (a+i & MASK);
412            if (k == z || x[k] < th[i]) {
413                i=LD_B1B_DIG;
414                break;
415            }
416            if (x[a+i & MASK] > th[i]) break;
417        }
418        if (i==LD_B1B_DIG && rp==9*LD_B1B_DIG) break;
419        /* FIXME: find a way to compute optimal sh */
420        if (rp > 9+9*LD_B1B_DIG) sh = 9;
421        e2 += sh;
422        for (k=a; k!=z; k=(k+1 & MASK)) {
423            uint32_t tmp = x[k] & (1<<sh)-1;
424            x[k] = (x[k]>>sh) + carry;
425            carry = (1000000000>>sh) * tmp;
426            if (k==a && !x[k]) {
427                a = (a+1 & MASK);
428                i--;
429                rp -= 9;
430            }
431        }
432        if (carry) {
433            if ((z+1 & MASK) != a) {
434                x[z] = carry;
435                z = (z+1 & MASK);
436            } else x[z-1 & MASK] |= 1;
437        }
438    }
439
440    /* Assemble desired bits into floating point variable */
441    for (y=i=0; i<LD_B1B_DIG; i++) {
442        if ((a+i & MASK)==z) x[(z=(z+1 & MASK))-1] = 0;
443        y = 1000000000.0L * y + x[a+i & MASK];
444    }
445
446    y *= sign;
447
448    /* Limit precision for denormal results */
449    if (bits > DBL_MANT_DIG+e2-emin) {
450        bits = DBL_MANT_DIG+e2-emin;
451        if (bits<0) bits=0;
452        denormal = 1;
453    }
454
455    /* Calculate bias term to force rounding, move out lower bits */
456    if (bits < DBL_MANT_DIG) {
457        bias = copysign(scalbn(1, 2*DBL_MANT_DIG-bits-1), y);
458        frac = fmod(y, scalbn(1, DBL_MANT_DIG-bits));
459        y -= frac;
460        y += bias;
461    }
462
463    /* Process tail of decimal input so it can affect rounding */
464    if ((a+i & MASK) != z) {
465        uint32_t t = x[a+i & MASK];
466        if (t < 500000000 && (t || (a+i+1 & MASK) != z))
467            frac += 0.25*sign;
468        else if (t > 500000000)
469            frac += 0.75*sign;
470        else if (t == 500000000) {
471            if ((a+i+1 & MASK) == z)
472                frac += 0.5*sign;
473            else
474                frac += 0.75*sign;
475        }
476        if (DBL_MANT_DIG-bits >= 2 && !fmod(frac, 1))
477            frac++;
478    }
479
480    y += frac;
481    y -= bias;
482
483    if ((e2+DBL_MANT_DIG & INT_MAX) > emax-5) {
484        if (fabs(y) >= pow(2, DBL_MANT_DIG)) {
485            if (denormal && bits==DBL_MANT_DIG+e2-emin)
486                denormal = 0;
487            y *= 0.5;
488            e2++;
489        }
490        if (e2+DBL_MANT_DIG>emax || (denormal && frac))
491            errno = ERANGE;
492    }
493
494    return scalbn(y, e2);
495}
496
497static double hexfloat(FFFILE *f, int bits, int emin, int sign, int pok)
498{
499    uint32_t x = 0;
500    double y = 0;
501    double scale = 1;
502    double bias = 0;
503    int gottail = 0, gotrad = 0, gotdig = 0;
504    long long rp = 0;
505    long long dc = 0;
506    long long e2 = 0;
507    int d;
508    int c;
509
510    c = shgetc(f);
511
512    /* Skip leading zeros */
513    for (; c=='0'; c = shgetc(f))
514        gotdig = 1;
515
516    if (c=='.') {
517        gotrad = 1;
518        c = shgetc(f);
519        /* Count zeros after the radix point before significand */
520        for (rp=0; c=='0'; c = shgetc(f), rp--) gotdig = 1;
521    }
522
523    for (; c-'0'<10U || (c|32)-'a'<6U || c=='.'; c = shgetc(f)) {
524        if (c=='.') {
525            if (gotrad) break;
526            rp = dc;
527            gotrad = 1;
528        } else {
529            gotdig = 1;
530            if (c > '9') d = (c|32)+10-'a';
531            else d = c-'0';
532            if (dc<8) {
533                x = x*16 + d;
534            } else if (dc < DBL_MANT_DIG/4+1) {
535                y += d*(scale/=16);
536            } else if (d && !gottail) {
537                y += 0.5*scale;
538                gottail = 1;
539            }
540            dc++;
541        }
542    }
543    if (!gotdig) {
544        shunget(f);
545        if (pok) {
546            shunget(f);
547            if (gotrad) shunget(f);
548        } else {
549            shlim(f, 0);
550        }
551        return sign * 0.0;
552    }
553    if (!gotrad) rp = dc;
554    while (dc<8) x *= 16, dc++;
555    if ((c|32)=='p') {
556        e2 = scanexp(f, pok);
557        if (e2 == LLONG_MIN) {
558            if (pok) {
559                shunget(f);
560            } else {
561                shlim(f, 0);
562                return 0;
563            }
564            e2 = 0;
565        }
566    } else {
567        shunget(f);
568    }
569    e2 += 4*rp - 32;
570
571    if (!x) return sign * 0.0;
572    if (e2 > -emin) {
573        errno = ERANGE;
574        return sign * DBL_MAX * DBL_MAX;
575    }
576    if (e2 < emin-2*DBL_MANT_DIG) {
577        errno = ERANGE;
578        return sign * DBL_MIN * DBL_MIN;
579    }
580
581    while (x < 0x80000000) {
582        if (y>=0.5) {
583            x += x + 1;
584            y += y - 1;
585        } else {
586            x += x;
587            y += y;
588        }
589        e2--;
590    }
591
592    if (bits > 32+e2-emin) {
593        bits = 32+e2-emin;
594        if (bits<0) bits=0;
595    }
596
597    if (bits < DBL_MANT_DIG)
598        bias = copysign(scalbn(1, 32+DBL_MANT_DIG-bits-1), sign);
599
600    if (bits<32 && y && !(x&1)) x++, y=0;
601
602    y = bias + sign*(double)x + sign*y;
603    y -= bias;
604
605    if (!y) errno = ERANGE;
606
607    return scalbn(y, e2);
608}
609
610static double fffloatscan(FFFILE *f, int prec, int pok)
611{
612    int sign = 1;
613    size_t i;
614    int bits;
615    int emin;
616    int c;
617
618    switch (prec) {
619    case 0:
620        bits = FLT_MANT_DIG;
621        emin = FLT_MIN_EXP-bits;
622        break;
623    case 1:
624        bits = DBL_MANT_DIG;
625        emin = DBL_MIN_EXP-bits;
626        break;
627    case 2:
628        bits = DBL_MANT_DIG;
629        emin = DBL_MIN_EXP-bits;
630        break;
631    default:
632        return 0;
633    }
634
635    while (av_isspace((c = shgetc(f))));
636
637    if (c=='+' || c=='-') {
638        sign -= 2*(c=='-');
639        c = shgetc(f);
640    }
641
642    for (i=0; i<8 && (c|32)=="infinity"[i]; i++)
643        if (i<7) c = shgetc(f);
644    if (i==3 || i==8 || (i>3 && pok)) {
645        if (i!=8) {
646            shunget(f);
647            if (pok) for (; i>3; i--) shunget(f);
648        }
649        return sign * INFINITY;
650    }
651    if (!i) for (i=0; i<3 && (c|32)=="nan"[i]; i++)
652        if (i<2) c = shgetc(f);
653    if (i==3) {
654        if (shgetc(f) != '(') {
655            shunget(f);
656            return NAN;
657        }
658        for (i=1; ; i++) {
659            c = shgetc(f);
660            if (c-'0'<10U || c-'A'<26U || c-'a'<26U || c=='_')
661                continue;
662            if (c==')') return NAN;
663            shunget(f);
664            if (!pok) {
665                errno = EINVAL;
666                shlim(f, 0);
667                return 0;
668            }
669            while (i--) shunget(f);
670            return NAN;
671        }
672        return NAN;
673    }
674
675    if (i) {
676        shunget(f);
677        errno = EINVAL;
678        shlim(f, 0);
679        return 0;
680    }
681
682    if (c=='0') {
683        c = shgetc(f);
684        if ((c|32) == 'x')
685            return hexfloat(f, bits, emin, sign, pok);
686        shunget(f);
687        c = '0';
688    }
689
690    return decfloat(f, c, bits, emin, sign, pok);
691}
692
693static void *arg_n(va_list ap, unsigned int n)
694{
695    void *p;
696    unsigned int i;
697    va_list ap2;
698    va_copy(ap2, ap);
699    for (i=n; i>1; i--) va_arg(ap2, void *);
700    p = va_arg(ap2, void *);
701    va_end(ap2);
702    return p;
703}
704
705static void store_int(void *dest, int size, unsigned long long i)
706{
707    if (!dest) return;
708    switch (size) {
709    case SIZE_hh:
710        *(char *)dest = i;
711        break;
712    case SIZE_h:
713        *(short *)dest = i;
714        break;
715    case SIZE_def:
716        *(int *)dest = i;
717        break;
718    case SIZE_l:
719        *(long *)dest = i;
720        break;
721    case SIZE_ll:
722        *(long long *)dest = i;
723        break;
724    }
725}
726
727static int ff_vfscanf(FFFILE *f, const char *fmt, va_list ap)
728{
729    int width;
730    int size;
731    int base;
732    const unsigned char *p;
733    int c, t;
734    char *s;
735    void *dest=NULL;
736    int invert;
737    int matches=0;
738    unsigned long long x;
739    double y;
740    ptrdiff_t pos = 0;
741    unsigned char scanset[257];
742    size_t i;
743
744    for (p=(const unsigned char *)fmt; *p; p++) {
745
746        if (av_isspace(*p)) {
747            while (av_isspace(p[1])) p++;
748            shlim(f, 0);
749            while (av_isspace(shgetc(f)));
750            shunget(f);
751            pos += shcnt(f);
752            continue;
753        }
754        if (*p != '%' || p[1] == '%') {
755            shlim(f, 0);
756            if (*p == '%') {
757                p++;
758                while (av_isspace((c=shgetc(f))));
759            } else {
760                c = shgetc(f);
761            }
762            if (c!=*p) {
763                shunget(f);
764                if (c<0) goto input_fail;
765                goto match_fail;
766            }
767            pos += shcnt(f);
768            continue;
769        }
770
771        p++;
772        if (*p=='*') {
773            dest = 0; p++;
774        } else if (av_isdigit(*p) && p[1]=='$') {
775            dest = arg_n(ap, *p-'0'); p+=2;
776        } else {
777            dest = va_arg(ap, void *);
778        }
779
780        for (width=0; av_isdigit(*p); p++) {
781            width = 10*width + *p - '0';
782        }
783
784        if (*p=='m') {
785            s = 0;
786            p++;
787        }
788
789        size = SIZE_def;
790        switch (*p++) {
791        case 'h':
792            if (*p == 'h') p++, size = SIZE_hh;
793            else size = SIZE_h;
794            break;
795        case 'l':
796            if (*p == 'l') p++, size = SIZE_ll;
797            else size = SIZE_l;
798            break;
799        case 'j':
800            size = SIZE_ll;
801            break;
802        case 'z':
803        case 't':
804            size = SIZE_l;
805            break;
806        case 'L':
807            size = SIZE_L;
808            break;
809        case 'd': case 'i': case 'o': case 'u': case 'x':
810        case 'a': case 'e': case 'f': case 'g':
811        case 'A': case 'E': case 'F': case 'G': case 'X':
812        case 's': case 'c': case '[':
813        case 'S': case 'C':
814        case 'p': case 'n':
815            p--;
816            break;
817        default:
818            goto fmt_fail;
819        }
820
821        t = *p;
822
823        /* C or S */
824        if ((t&0x2f) == 3) {
825            t |= 32;
826            size = SIZE_l;
827        }
828
829        switch (t) {
830            case 'c':
831                if (width < 1) width = 1;
832            case '[':
833                break;
834            case 'n':
835                store_int(dest, size, pos);
836                /* do not increment match count, etc! */
837                continue;
838            default:
839                shlim(f, 0);
840                while (av_isspace(shgetc(f)));
841                shunget(f);
842                pos += shcnt(f);
843        }
844
845        shlim(f, width);
846        if (shgetc(f) < 0) goto input_fail;
847        shunget(f);
848
849        switch (t) {
850            case 's':
851            case 'c':
852            case '[':
853                if (t == 'c' || t == 's') {
854                    memset(scanset, -1, sizeof scanset);
855                    scanset[0] = 0;
856                    if (t == 's') {
857                        scanset[1 + '\t'] = 0;
858                        scanset[1 + '\n'] = 0;
859                        scanset[1 + '\v'] = 0;
860                        scanset[1 + '\f'] = 0;
861                        scanset[1 + '\r'] = 0;
862                        scanset[1 + ' ' ] = 0;
863                    }
864                } else {
865                    if (*++p == '^') p++, invert = 1;
866                    else invert = 0;
867                    memset(scanset, invert, sizeof scanset);
868                    scanset[0] = 0;
869                    if (*p == '-') p++, scanset[1+'-'] = 1-invert;
870                    else if (*p == ']') p++, scanset[1+']'] = 1-invert;
871                    for (; *p != ']'; p++) {
872                        if (!*p) goto fmt_fail;
873                        if (*p=='-' && p[1] && p[1] != ']')
874                            for (c=p++[-1]; c<*p; c++)
875                                scanset[1+c] = 1-invert;
876                        scanset[1+*p] = 1-invert;
877                    }
878                }
879                s = 0;
880                i = 0;
881                if ((s = dest)) {
882                    while (scanset[(c=shgetc(f))+1])
883                        s[i++] = c;
884                } else {
885                    while (scanset[(c=shgetc(f))+1]);
886                }
887                shunget(f);
888                if (!shcnt(f)) goto match_fail;
889                if (t == 'c' && shcnt(f) != width) goto match_fail;
890                if (t != 'c') {
891                    if (s) s[i] = 0;
892                }
893                break;
894            case 'p':
895            case 'X':
896            case 'x':
897                base = 16;
898                goto int_common;
899            case 'o':
900                base = 8;
901                goto int_common;
902            case 'd':
903            case 'u':
904                base = 10;
905                goto int_common;
906            case 'i':
907                base = 0;
908int_common:
909                x = ffintscan(f, base, 0, ULLONG_MAX);
910                if (!shcnt(f))
911                    goto match_fail;
912                if (t=='p' && dest)
913                    *(void **)dest = (void *)(uintptr_t)x;
914                else
915                    store_int(dest, size, x);
916                break;
917            case 'a': case 'A':
918            case 'e': case 'E':
919            case 'f': case 'F':
920            case 'g': case 'G':
921                y = fffloatscan(f, size, 0);
922                if (!shcnt(f))
923                    goto match_fail;
924                if (dest) {
925                    switch (size) {
926                    case SIZE_def:
927                        *(float *)dest = y;
928                        break;
929                    case SIZE_l:
930                        *(double *)dest = y;
931                        break;
932                    case SIZE_L:
933                        *(double *)dest = y;
934                        break;
935                    }
936                }
937                break;
938        }
939
940        pos += shcnt(f);
941        if (dest) matches++;
942    }
943    if (0) {
944fmt_fail:
945input_fail:
946        if (!matches) matches--;
947    }
948match_fail:
949    return matches;
950}
951
952static int ff_vsscanf(const char *s, const char *fmt, va_list ap)
953{
954    FFFILE f = {
955        .buf = (void *)s, .cookie = (void *)s,
956        .read = ffstring_read,
957    };
958
959    return ff_vfscanf(&f, fmt, ap);
960}
961
962int av_sscanf(const char *string, const char *format, ...)
963{
964    int ret;
965    va_list ap;
966    va_start(ap, format);
967    ret = ff_vsscanf(string, format, ap);
968    va_end(ap);
969    return ret;
970}
971