X-Git-Url: http://mj.ucw.cz/gitweb/?a=blobdiff_plain;f=lib%2Ffb-file.c;h=9ac57395445301012a958277a617860ba8766d32;hb=5a78c3505ae7fa76a061e26676450049ec5946d5;hp=5e1a6981eea4a66ad31644d61bc28911ef059e2c;hpb=b563aa00a128ab0bc6b38473e62508ca7a7c6989;p=libucw.git diff --git a/lib/fb-file.c b/lib/fb-file.c index 5e1a6981..9ac57395 100644 --- a/lib/fb-file.c +++ b/lib/fb-file.c @@ -1,7 +1,8 @@ /* - * Sherlock Library -- Fast Buffered I/O on Files + * UCW Library -- Fast Buffered I/O on Files * - * (c) 1997--2002 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. @@ -11,37 +12,153 @@ #include "lib/fastbuf.h" #include "lib/lfs.h" -#include +#include #include #include #include struct fb_file { struct fastbuf fb; - int fd; /* File descriptor, -1 if not a real file */ + 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(FB_FILE(f)->fd, f->buffer, f->bufend-f->buffer); - if (l < 0) - die("Error reading %s: %m", f->name); - f->bptr = f->buffer; - f->bstop = f->buffer + l; - f->pos += 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; - f->pos += l; + /* Write the buffer */ + FB_FILE(f)->wpos = (f->pos += l); + FB_FILE(f)->wlen = 0; while (l) { int z = write(FB_FILE(f)->fd, c, l); @@ -50,21 +167,35 @@ bfd_spout(struct fastbuf *f) l -= z; c += z; } - f->bptr = f->buffer; + 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->pos) - return; - - l = sh_seek(FB_FILE(f)->fd, pos, whence); - if (l < 0) - die("lseek on %s: %m", f->name); - 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 @@ -74,9 +205,10 @@ bfd_close(struct fastbuf *f) { case 1: if (unlink(f->name) < 0) - log(L_ERROR, "unlink(%s): %m", f->name); + msg(L_ERROR, "unlink(%s): %m", f->name); case 0: - close(FB_FILE(f)->fd); + if (close(FB_FILE(f)->fd)) + die("close(%s): %m", f->name); } xfree(f); } @@ -86,23 +218,27 @@ bfd_config(struct fastbuf *f, uns item, int value) { switch (item) { - case BCONFIG_IS_TEMP_FILE: - FB_FILE(f)->is_temp_file = value; - return 0; - default: - return -1; + 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; } } -static struct fastbuf * -bfdopen_internal(int fd, uns buflen, byte *name) +struct fastbuf * +bfdopen_internal(int fd, const char *name, uns buflen) { + ASSERT(buflen); int namelen = strlen(name) + 1; - struct fb_file *F = xmalloc(sizeof(struct fb_file) + buflen + namelen); + struct fb_file *F = xmalloc_zero(sizeof(struct fb_file) + buflen + namelen); struct fastbuf *f = &F->fb; bzero(F, sizeof(*F)); - f->buffer = (char *)(F+1); + f->buffer = (byte *)(F+1); f->bptr = f->bstop = f->buffer; f->bufend = f->buffer + buflen; f->name = f->bufend; @@ -113,61 +249,57 @@ bfdopen_internal(int fd, uns buflen, byte *name) f->seek = bfd_seek; f->close = bfd_close; f->config = bfd_config; + f->can_overwrite_buffer = 2; return f; } struct fastbuf * -bopen(byte *name, uns mode, uns buffer) +bopen_try(const char *name, uns mode, uns buflen) { - struct fastbuf *b; - -#if 0 /* FIXME: Dirty hack for testing fb-mmap */ - if (buffer >= 65536 && (mode == O_RDONLY)) - { - log(L_DEBUG, "bopen_mm hack: %s", name); - if (mode & O_WRONLY) - mode = (mode & ~O_WRONLY) | O_RDWR; - return bopen_mm(name, mode); - } -#endif - - int fd = sh_open(name, mode, 0666); - if (fd < 0) - die("Unable to %s file %s: %m", - (mode & O_CREAT) ? "create" : "open", name); - b = bfdopen_internal(fd, buffer, name); - if (mode & O_APPEND) - bfd_seek(b, 0, SEEK_END); - return b; + return bopen_file_try(name, mode, &(struct fb_params){ .type = FB_STD, .buffer_size = buflen }); } struct fastbuf * -bfdopen(int fd, uns buffer) +bopen(const char *name, uns mode, uns buflen) { - byte x[32]; + return bopen_file(name, mode, &(struct fb_params){ .type = FB_STD, .buffer_size = buflen }); +} - sprintf(x, "fd%d", fd); - return bfdopen_internal(fd, buffer, x); +struct fastbuf * +bfdopen(int fd, uns buflen) +{ + return bopen_fd(fd, &(struct fb_params){ .type = FB_STD, .buffer_size = buflen }); } struct fastbuf * -bfdopen_shared(int fd, uns buffer) +bfdopen_shared(int fd, uns buflen) { - struct fastbuf *f = bfdopen(fd, buffer); + struct fastbuf *f = bfdopen(fd, buflen); FB_FILE(f)->is_temp_file = -1; return f; } +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; - - f = bopen("/etc/profile", O_RDONLY, 16); + f = bopen_tmp(16); t = bfdopen(1, 13); - bbcopy(f, t, 100); - printf("%d %d\n", (int)btell(f), (int)btell(t)); + 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;