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author | Bart Schaefer <schaefer@zsh.org> | 2022-04-28 21:06:51 -0700 |
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committer | Bart Schaefer <schaefer@zsh.org> | 2022-04-28 21:06:51 -0700 |
commit | df0c783f4bcbeb93bccd24c33160863563e2f3dc (patch) | |
tree | 960205ad79ce029e6ab1bc500431d171fe43e32c /Src | |
parent | 007c7df74a3cf80a3ac3fd07e588be3848193a4e (diff) | |
download | zsh-df0c783f4bcbeb93bccd24c33160863563e2f3dc.tar.gz zsh-df0c783f4bcbeb93bccd24c33160863563e2f3dc.tar.xz zsh-df0c783f4bcbeb93bccd24c33160863563e2f3dc.zip |
50133: use read-ahead and lseek-rewind for efficient line-buffered input
Diffstat (limited to 'Src')
-rw-r--r-- | Src/input.c | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/Src/input.c b/Src/input.c index c59232681..9898a7177 100644 --- a/Src/input.c +++ b/Src/input.c @@ -217,12 +217,34 @@ shinbufrestore(void) static int shingetchar(void) { - int nread; + int nread, rsize = isset(SHINSTDIN) ? 1 : SHINBUFSIZE; if (shinbufptr < shinbufendptr) return STOUC(*shinbufptr++); shinbufreset(); +#ifdef USE_LSEEK + if (rsize == 1 && lseek(SHIN, 0, SEEK_CUR) != (off_t)-1) + rsize = SHINBUFSIZE; + if (rsize > 1) { + do { + errno = 0; + nread = read(SHIN, shinbuffer, rsize); + } while (nread < 0 && errno == EINTR); + if (nread <= 0) + return -1; + if (isset(SHINSTDIN) && + (shinbufendptr = memchr(shinbuffer, '\n', nread))) { + shinbufendptr++; + rsize = (shinbufendptr - shinbuffer); + if (nread > rsize && + lseek(SHIN, -(nread - rsize), SEEK_CUR) < 0) + zerr("lseek(%d, %d): %e", SHIN, -(nread - rsize), errno); + } else + shinbufendptr = shinbuffer + nread; + return STOUC(*shinbufptr++); + } +#endif for (;;) { errno = 0; nread = read(SHIN, shinbufendptr, 1); |