91 lines
2.7 KiB
C
91 lines
2.7 KiB
C
/* Custom string builder, should be slightly faster than using Sv* macros directly. */
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typedef struct {
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SV *sv;
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SV *mortal;
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char *cur;
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char *end;
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size_t maxlen;
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int setutf8;
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char sbuf[4096];
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} fustr;
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static void fustr_init_(pTHX_ fustr *s, SV *mortal, size_t maxlen) {
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s->sv = NULL;
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s->cur = s->sbuf;
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s->end = s->sbuf + (maxlen > sizeof s->sbuf ? sizeof s->sbuf : maxlen);
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s->maxlen = maxlen;
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s->mortal = mortal;
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s->setutf8 = 0;
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}
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#define fustr_start(s) (((s)->sv ? SvPVX((s)->sv) : (s)->sbuf))
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static void fustr_grow(pTHX_ fustr *s, size_t add) {
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size_t off = s->cur - (s->sv ? SvPVX(s->sv) : s->sbuf);
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size_t newlen = sizeof s->sbuf;
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char *buf;
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add += off;
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if (add > s->maxlen) croak("maximum string length exceeded");
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/* Increment to next power of two; SvGROW's default strategy is slow */
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while (newlen < add) newlen <<= 1;
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if (newlen > s->maxlen) newlen = s->maxlen;
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if (s->sv) {
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buf = SvGROW(s->sv, newlen);
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} else {
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if (s->mortal) {
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s->sv = s->mortal;
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sv_setpv_bufsize(s->sv, off, newlen);
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} else {
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s->sv = newSV(newlen);
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}
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SvPOK_only(s->sv);
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buf = SvPVX(s->sv);
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memcpy(buf, s->sbuf, off);
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}
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s->cur = buf + off;
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s->end = buf + (SvLEN(s->sv) > s->maxlen ? s->maxlen : SvLEN(s->sv));
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}
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static inline void fustr_reserve_(pTHX_ fustr *s, size_t add) {
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if (UNLIKELY(s->end < s->cur + add)) fustr_grow(aTHX_ s, add);
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}
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static inline void fustr_write_(pTHX_ fustr *s, const char *str, size_t n) {
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fustr_reserve_(aTHX_ s, n);
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memcpy(s->cur, str, n);
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s->cur += n;
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}
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static inline void fustr_write_ch_(pTHX_ fustr *s, char x) {
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fustr_reserve_(aTHX_ s, 1);
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*(s->cur++) = x;
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}
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/* Adds n uninitialized bytes to the string and returns a buffer to write the data to */
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static inline char *fustr_write_buf_(pTHX_ fustr *s, size_t n) {
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fustr_reserve_(aTHX_ s, n);
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char *buf = s->cur;
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s->cur += n;
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return buf;
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}
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static SV *fustr_done_(pTHX_ fustr *s) {
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fustr_reserve_(aTHX_ s, 1);
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*s->cur = 0;
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if (s->sv) {
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SvCUR_set(s->sv, s->cur - SvPVX(s->sv));
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// TODO: SvPV_shrink_to_cur?
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} else {
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s->sv = newSVpvn_flags(s->sbuf, s->cur - s->sbuf, s->mortal ? SVs_TEMP : 0);
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}
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if (s->setutf8) SvUTF8_on(s->sv);
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return s->sv;
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}
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#define fustr_init(a,b,c) fustr_init_(aTHX_ a,b,c)
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#define fustr_reserve(a,b) fustr_reserve_(aTHX_ a,b)
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#define fustr_write(a,b,c) fustr_write_(aTHX_ a,b,c)
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#define fustr_write_ch(a,b) fustr_write_ch_(aTHX_ a,b)
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#define fustr_write_buf(a,b) fustr_write_buf_(aTHX_ a,b)
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#define fustr_done(a) fustr_done_(aTHX_ a)
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