X-Git-Url: http://mj.ucw.cz/gitweb/?a=blobdiff_plain;f=lib%2Ffb-file.c;h=9ac57395445301012a958277a617860ba8766d32;hb=5a78c3505ae7fa76a061e26676450049ec5946d5;hp=07b4ec5ddf2d5f79343c979468d60053717724f2;hpb=5b53087fa5a07ff89d34cf3bf3bc1b28809f05c2;p=libucw.git diff --git a/lib/fb-file.c b/lib/fb-file.c index 07b4ec5d..9ac57395 100644 --- a/lib/fb-file.c +++ b/lib/fb-file.c @@ -1,164 +1,308 @@ /* - * Sherlock Library -- Fast Buffered I/O on Files + * UCW Library -- Fast Buffered I/O on Files * - * (c) 1997--2000 Martin Mares + * (c) 1997--2004 Martin Mares + * (c) 2007 Pavel Charvat + * + * This software may be freely distributed and used according to the terms + * of the GNU Lesser General Public License. */ +#include "lib/lib.h" +#include "lib/fastbuf.h" +#include "lib/lfs.h" + #include #include #include #include -#include "lib/lib.h" -#include "lib/fastbuf.h" -#include "lib/lfs.h" +struct fb_file { + struct fastbuf fb; + int fd; /* File descriptor */ + int is_temp_file; /* 0=normal file, 1=temporary file, delete on close, -1=shared FD */ + int keep_back_buf; /* Optimize for backwards reading */ + sh_off_t wpos; /* Real file position */ + uns wlen; /* Window size */ +}; +#define FB_FILE(f) ((struct fb_file *)(f)->is_fastbuf) +#define FB_BUFFER(f) (byte *)(FB_FILE(f) + 1) static int bfd_refill(struct fastbuf *f) { - int l = read(f->fd, f->buffer, f->buflen); - - if (l < 0) - die("Error reading %s: %m", f->name); - f->bptr = f->buffer; - f->bstop = f->buffer + l; - f->pos = f->fdpos; - f->fdpos += l; - return l; + struct fb_file *F = FB_FILE(f); + byte *read_ptr = (f->buffer = FB_BUFFER(f)); + uns blen = f->bufend - f->buffer, back = F->keep_back_buf ? blen >> 2 : 0, read_len = blen; + /* Forward or no seek */ + if (F->wpos <= f->pos) + { + sh_off_t diff = f->pos - F->wpos; + /* Formula for long forward seeks (prefer lseek()) */ + if (diff > ((sh_off_t)blen << 2)) + { +long_seek: + f->bptr = f->buffer + back; + f->bstop = f->buffer + blen; + goto seek; + } + /* Short forward seek (prefer read() to skip data )*/ + else if ((uns)diff >= back) + { + uns skip = diff - back; + F->wpos += skip; + while (skip) + { + int l = read(F->fd, f->buffer, MIN(skip, blen)); + if (unlikely(l <= 0)) + if (l < 0) + die("Error reading %s: %m", f->name); + else + { + F->wpos -= skip; + goto eof; + } + skip -= l; + } + } + /* Reuse part of the previous window and append new data (also F->wpos == f->pos) */ + else + { + uns keep = back - (uns)diff; + if (keep >= F->wlen) + back = diff + (keep = F->wlen); + else + memmove(f->buffer, f->buffer + F->wlen - keep, keep); + read_len -= keep; + read_ptr += keep; + } + f->bptr = f->buffer + back; + f->bstop = f->buffer + blen; + } + /* Backwards seek */ + else + { + sh_off_t diff = F->wpos - f->pos; + /* Formula for long backwards seeks (keep smaller backbuffer than for shorter seeks ) */ + if (diff > ((sh_off_t)blen << 1)) + { + if ((sh_off_t)back > f->pos) + back = f->pos; + goto long_seek; + } + /* Seek into previous window (do nothing... for example brewind) */ + else if ((uns)diff <= F->wlen) + { + f->bstop = f->buffer + F->wlen; + f->bptr = f->bstop - diff; + f->pos = F->wpos; + return 1; + } + back *= 3; + if ((sh_off_t)back > f->pos) + back = f->pos; + f->bptr = f->buffer + back; + read_len = back + diff - F->wlen; + /* Reuse part of previous window */ + if (F->wlen && read_len < blen) + { + uns keep = MIN(F->wlen, blen - read_len); + memmove(f->buffer + read_len, f->buffer, keep); + f->bstop = f->buffer + read_len + keep; + } + else + f->bstop = f->buffer + (read_len = blen); +seek: + /* Do lseek() */ + F->wpos = f->pos + (f->buffer - f->bptr); + if (sh_seek(F->fd, F->wpos, SEEK_SET) < 0) + die("Error seeking %s: %m", f->name); + } + /* Read (part of) buffer */ + do + { + int l = read(F->fd, read_ptr, read_len); + if (unlikely(l < 0)) + die("Error reading %s: %m", f->name); + if (!l) + if (unlikely(read_ptr < f->bptr)) + goto eof; + else + break; /* Incomplete read because of EOF */ + read_ptr += l; + read_len -= l; + F->wpos += l; + } + while (read_ptr <= f->bptr); + if (read_len) + f->bstop = read_ptr; + f->pos += f->bstop - f->bptr; + F->wlen = f->bstop - f->buffer; + return f->bstop - f->bptr; +eof: + /* Seeked behind EOF */ + f->bptr = f->bstop = f->buffer; + F->wlen = 0; + return 0; } static void bfd_spout(struct fastbuf *f) { + /* Do delayed lseek() if needed */ + if (FB_FILE(f)->wpos != f->pos && sh_seek(FB_FILE(f)->fd, f->pos, SEEK_SET) < 0) + die("Error seeking %s: %m", f->name); + int l = f->bptr - f->buffer; - char *c = f->buffer; + byte *c = f->buffer; + /* Write the buffer */ + FB_FILE(f)->wpos = (f->pos += l); + FB_FILE(f)->wlen = 0; while (l) { - int z = write(f->fd, c, l); + int z = write(FB_FILE(f)->fd, c, l); if (z <= 0) die("Error writing %s: %m", f->name); - f->fdpos += z; l -= z; c += z; } - f->bptr = f->buffer; - f->pos = f->fdpos; + f->bptr = f->buffer = FB_BUFFER(f); } -static void +static int bfd_seek(struct fastbuf *f, sh_off_t pos, int whence) { + /* Delay the seek for the next refill() or spout() call (if whence != SEEK_END). */ sh_off_t l; - - if (whence == SEEK_SET && pos == f->fdpos) - return; - - l = sh_seek(f->fd, pos, whence); - if (l < 0) - die("lseek on %s: %m", f->name); - f->fdpos = f->pos = l; + switch (whence) + { + case SEEK_SET: + f->pos = pos; + return 1; + case SEEK_CUR: + l = f->pos + pos; + if ((pos > 0) ^ (l > f->pos)) + return 0; + f->pos = l; + return 1; + case SEEK_END: + l = sh_seek(FB_FILE(f)->fd, pos, SEEK_END); + if (l < 0) + return 0; + FB_FILE(f)->wpos = f->pos = l; + FB_FILE(f)->wlen = 0; + return 1; + default: + ASSERT(0); + } } static void bfd_close(struct fastbuf *f) { - close(f->fd); + switch (FB_FILE(f)->is_temp_file) + { + case 1: + if (unlink(f->name) < 0) + msg(L_ERROR, "unlink(%s): %m", f->name); + case 0: + if (close(FB_FILE(f)->fd)) + die("close(%s): %m", f->name); + } + xfree(f); } -static struct fastbuf * -bfdopen_internal(int fd, uns buflen, byte *name) +static int +bfd_config(struct fastbuf *f, uns item, int value) { - int namelen = strlen(name) + 1; - struct fastbuf *b = xmalloc(sizeof(struct fastbuf) + buflen + namelen); - - b->buflen = buflen; - b->buffer = (char *)(b+1); - b->bptr = b->bstop = b->buffer; - b->bufend = b->buffer + buflen; - b->name = b->bufend; - strcpy(b->name, name); - b->pos = b->fdpos = 0; - b->fd = fd; - b->refill = bfd_refill; - b->spout = bfd_spout; - b->seek = bfd_seek; - b->close = bfd_close; - return b; + switch (item) + { + case BCONFIG_IS_TEMP_FILE: + FB_FILE(f)->is_temp_file = value; + return 0; + case BCONFIG_KEEP_BACK_BUF: + FB_FILE(f)->keep_back_buf = value; + return 0; + default: + return -1; + } } struct fastbuf * -bopen(byte *name, uns mode, uns buffer) +bfdopen_internal(int fd, const char *name, uns buflen) { - int fd = sh_open(name, mode, 0666); - if (fd < 0) - die("Unable to %s file %s: %m", - (mode & O_CREAT) ? "create" : "open", name); - return bfdopen_internal(fd, buffer, name); + ASSERT(buflen); + int namelen = strlen(name) + 1; + struct fb_file *F = xmalloc_zero(sizeof(struct fb_file) + buflen + namelen); + struct fastbuf *f = &F->fb; + + bzero(F, sizeof(*F)); + f->buffer = (byte *)(F+1); + f->bptr = f->bstop = f->buffer; + f->bufend = f->buffer + buflen; + f->name = f->bufend; + memcpy(f->name, name, namelen); + F->fd = fd; + f->refill = bfd_refill; + f->spout = bfd_spout; + f->seek = bfd_seek; + f->close = bfd_close; + f->config = bfd_config; + f->can_overwrite_buffer = 2; + return f; } struct fastbuf * -bfdopen(int fd, uns buffer) +bopen_try(const char *name, uns mode, uns buflen) { - byte x[32]; + return bopen_file_try(name, mode, &(struct fb_params){ .type = FB_STD, .buffer_size = buflen }); +} - sprintf(x, "fd%d", fd); - return bfdopen_internal(fd, buffer, x); +struct fastbuf * +bopen(const char *name, uns mode, uns buflen) +{ + return bopen_file(name, mode, &(struct fb_params){ .type = FB_STD, .buffer_size = buflen }); } -void bbcopy(struct fastbuf *f, struct fastbuf *t, uns l) +struct fastbuf * +bfdopen(int fd, uns buflen) { - uns rf = f->bstop - f->bptr; + return bopen_fd(fd, &(struct fb_params){ .type = FB_STD, .buffer_size = buflen }); +} - if (!l) - return; - if (rf) - { - uns k = (rf <= l) ? rf : l; - bwrite(t, f->bptr, k); - f->bptr += k; - l -= k; - } - while (l >= t->buflen) - { - t->spout(t); - if ((uns) read(f->fd, t->buffer, t->buflen) != t->buflen) - die("bbcopy: %s exhausted", f->name); - f->pos = f->fdpos; - f->fdpos += t->buflen; - f->bstop = f->bptr = f->buffer; - t->bptr = t->bufend; - l -= t->buflen; - } - while (l) - { - uns k = t->bufend - t->bptr; +struct fastbuf * +bfdopen_shared(int fd, uns buflen) +{ + struct fastbuf *f = bfdopen(fd, buflen); + FB_FILE(f)->is_temp_file = -1; + return f; +} - if (!k) - { - t->spout(t); - k = t->bufend - t->bptr; - } - if (k > l) - k = l; - bread(f, t->bptr, k); - t->bptr += k; - l -= k; - } +void +bfilesync(struct fastbuf *b) +{ + bflush(b); + if (fsync(FB_FILE(b)->fd) < 0) + msg(L_ERROR, "fsync(%s) failed: %m", b->name); } #ifdef TEST -int main(int argc, char **argv) +int main(void) { struct fastbuf *f, *t; - int c; - - f = bopen("/etc/profile", O_RDONLY, 16); + f = bopen_tmp(16); t = bfdopen(1, 13); - bbcopy(f, t, 100); + for (uns i = 0; i < 16; i++) + bwrite(f, "", 7); + bprintf(t, "%d\n", (int)btell(f)); + brewind(f); + bbcopy(f, t, ~0U); + bprintf(t, "\n%d %d\n", (int)btell(f), (int)btell(t)); bclose(f); bclose(t); + return 0; } #endif