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1f796663cd
This was a tricky merge. In the 1332a directory I did:
{{{
svn merge https://svn.tokutek.com/tokudb/toku/tokudb.1032b+1332@8415 https://svn.tokutek.com/tokudb/toku/tokudb.1032b+1332@8416
}}}
Then I was able to resolve the conflicts.
Then in the main line I did:
{{{
svn merge -r9042:9046 https://svn.tokutek.com/tokudb/toku/tokudb.1332a
}}}
Fixes #1332.
git-svn-id: file:///svn/toku/tokudb@9047 c7de825b-a66e-492c-adef-691d508d4ae1
76 lines
2.6 KiB
C
76 lines
2.6 KiB
C
/* Buffered read. */
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#include "includes.h"
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struct bread {
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int64_t fileoff; // The byte before this offset is the next byte we will read (since we are reading backward)
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int fd;
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int bufoff; // The current offset in the buf. The next byte we will read is buf[bufoff-1] (assuming that bufoff>0).
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char *buf; // A buffer with at least bufoff bytes in it.
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};
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BREAD create_bread_from_fd_initialize_at(int fd) {
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BREAD XMALLOC(result);
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int r = toku_os_get_file_size(fd, &result->fileoff);
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assert(r==0);
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result->fd=fd;
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result->bufoff=0;
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result->buf = 0;
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return result;
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}
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int close_bread_without_closing_fd(BREAD br) {
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toku_free(br->buf);
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toku_free(br);
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return 0;
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}
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ssize_t bread_backwards(BREAD br, void *vbuf, size_t nbytes) {
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char *buf=vbuf;
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ssize_t result=0;
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const int i4 = sizeof(u_int32_t);
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while (nbytes > 0) {
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// read whatever we can out of the buffer.
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if (br->bufoff>0) {
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size_t to_copy = ((size_t)br->bufoff >= nbytes) ? nbytes : (size_t)br->bufoff;
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memcpy(buf+nbytes-to_copy, &br->buf[br->bufoff-to_copy], to_copy);
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nbytes -= to_copy;
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result += to_copy;
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br->bufoff -= to_copy;
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}
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if (nbytes>0) {
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assert(br->bufoff==0);
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u_int32_t compressed_length_n, uncompressed_length_n;
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assert(br->fileoff>=i4); // there better be the three lengths plus the compressed data.
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{ ssize_t r = pread(br->fd, &compressed_length_n, i4, br->fileoff- i4); assert(r==i4); }
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u_int32_t compressed_length = ntohl(compressed_length_n);
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assert(br->fileoff >= compressed_length + 3*i4);
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{ ssize_t r = pread(br->fd, &uncompressed_length_n, i4, br->fileoff-2*i4); assert(r==i4); }
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u_int32_t uncompressed_length = ntohl(uncompressed_length_n);
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char *XMALLOC_N(compressed_length, zbuf);
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{
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ssize_t r = pread(br->fd, zbuf, compressed_length, br->fileoff- compressed_length -2*i4);
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assert(r==(ssize_t)compressed_length);
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}
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{
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u_int32_t compressed_length_n_again;
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ssize_t r = pread(br->fd, &compressed_length_n_again, i4, br->fileoff-compressed_length-3*i4); assert(r==i4);
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assert(compressed_length_n_again == compressed_length_n);
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}
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uLongf destlen = uncompressed_length;
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XREALLOC_N(uncompressed_length, br->buf);
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uncompress((Bytef*)br->buf, &destlen, (Bytef*)zbuf, compressed_length);
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assert(destlen==uncompressed_length);
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toku_free(zbuf);
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br->bufoff = uncompressed_length;
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br->fileoff -= (compressed_length + 3*i4);
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}
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}
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return result;
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}
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int bread_has_more(BREAD br) {
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return (br->fileoff>0) || (br->bufoff>0);
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}
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