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105 lines
3.1 KiB
C
105 lines
3.1 KiB
C
/* Measure the extent to which we can compress a file.
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* Works on version 8. */
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#define _XOPEN_SOURCE 500
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#include <arpa/inet.h>
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#include <assert.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <string.h>
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#include <sys/stat.h>
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#include <unistd.h>
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#include <zlib.h>
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#include <toku_portability.h>
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toku_off_t fd_size (int fd) {
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int64_t file_size;
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int r = toku_os_get_file_size(fd, &file_size);
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assert(r==0);
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return file_size;
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}
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#define NSIZE (1<<20)
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unsigned char fbuf[NSIZE];
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unsigned char cbuf[NSIZE+500];
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void
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measure_header (int fd, toku_off_t off, // read header from this offset
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toku_off_t *usize, // size uncompressed (but not including any padding)
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toku_off_t *csize) // compressed size
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{
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int r;
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r=pread(fd, fbuf, 12, off);
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assert(r==12);
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assert(memcmp(fbuf,"tokudata",8)==0);
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int bsize = toku_dtoh32(*(u_int32_t*)(fbuf+8));
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//printf("Bsize=%d\n", bsize);
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(*usize)+=bsize;
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assert(bsize<=NSIZE);
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r=pread(fd, fbuf, bsize, off);
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assert(r==bsize);
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uLongf destLen=sizeof(cbuf);
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r=compress2(cbuf, &destLen,
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fbuf+20, bsize-=20, // skip magic nodesize and version
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1);
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assert(r==Z_OK);
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destLen+=16; // account for the size and magic and version
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//printf("Csize=%ld\n", destLen);
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(*csize)+=destLen;
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}
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void
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measure_node (int fd, toku_off_t off, // read header from this offset
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toku_off_t *usize, // size uncompressed (but not including any padding)
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toku_off_t *csize) // compressed size
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{
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int r;
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r=pread(fd, fbuf, 24, off);
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assert(r==24);
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//printf("fbuf[0..7]=%c%c%c%c%c%c%c%c\n", fbuf[0], fbuf[1], fbuf[2], fbuf[3], fbuf[4], fbuf[5], fbuf[6], fbuf[7]);
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assert(memcmp(fbuf,"tokuleaf",8)==0 || memcmp(fbuf, "tokunode", 8)==0);
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assert(8==toku_dtoh32(*(u_int32_t*)(fbuf+8))); // check file version
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int bsize = toku_dtoh32(*(u_int32_t*)(fbuf+20));
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//printf("Bsize=%d\n", bsize);
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(*usize)+=bsize;
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assert(bsize<=NSIZE);
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r=pread(fd, fbuf, bsize, off);
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assert(r==bsize);
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uLongf destLen=sizeof(cbuf);
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r=compress2(cbuf, &destLen,
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fbuf+28, bsize-=28, // skip constant header stuff
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1);
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destLen += 24; // add in magic (8), version(4), lsn (8), and size (4). Actually lsn will be compressed, but ignore that for now.
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assert(r==Z_OK);
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//printf("Csize=%ld\n", destLen);
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(*csize)+=destLen;
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}
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/* The single argument is the filename to measure. */
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int main (int argc, const char *argv[]) {
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assert(argc==2);
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const char *fname=argv[1];
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int fd = open(fname, O_RDONLY);
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assert(fd>=0);
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toku_off_t fsize = fd_size(fd);
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printf("fsize (uncompressed with padding)=%lld\n", (long long)fsize);
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toku_off_t usize=0, csize=0;
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measure_header(fd, 0, &usize, &csize);
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toku_off_t i;
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for (i=NSIZE; i+24<fsize; i+=NSIZE) {
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measure_node(fd, i, &usize, &csize);
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}
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printf("usize (uncompressed with no padding)=%10lld (ratio=%5.2f)\n", (long long)usize, (double)fsize/(double)usize);
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printf("csize (compressed) =%10lld (ratio=%5.2f)\n", (long long)csize, (double)fsize/(double)csize);
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close(fd);
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return 0;
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}
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