65 lines
1.4 KiB
C
65 lines
1.4 KiB
C
/*-------------------------------------------------------------------------
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*
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* beard.c--
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* sample routines to use large objects
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*
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* Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/tutorial/Attic/beard.c,v 1.1 1998/03/01 04:51:01 scrappy Exp $
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*
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*-------------------------------------------------------------------------
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*/
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typedef struct ImageHdr
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{
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int size;
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} ImageHdr;
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#define BUFSIZE 10
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/*
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* beard -
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* clips lower 1/3 of picture and return as large object
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*/
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Oid
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beard(Oid picture)
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{
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Oid beard;
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int pic_fd,
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beard_fd;
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ImageHdr ihdr;
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char buf[BUFSIZE];
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int cc;
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if ((pic_fd = lo_open(picture, INV_READ)) == -1)
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elog(ERROR, "Cannot access picture large object");
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if (lo_read(pic_fd, (char *) &ihdr, sizeof(ihdr)) != sizeof(ihdr))
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elog(ERROR, "Picture large object corrupted");
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beardOffset = (ihdr.size / 3) * 2;
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/*
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* new large object
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*/
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if ((beard = lo_creat(INV_MD)) == 0) /* ?? is this right? */
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elog(ERROR, "Cannot create new large object");
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if ((beard_fd = lo_open(beard, INV_WRITE)) == -1)
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elog(ERROR, "Cannot access beard large object");
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lo_lseek(pic_fd, beardOffset, SET_CUR);
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while ((cc = lo_read(pic_fd, buf, BUFSIZE)) > 0)
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{
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if (lo_write(beard_fd, buf, cc) != cc)
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elog(ERROR, "error while writing large object");
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}
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lo_close(pic_fd);
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lo_close(beard_fd);
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return beard;
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}
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