14887Schin /***********************************************************************
24887Schin * *
34887Schin * This software is part of the ast package *
4*12068SRoger.Faulkner@Oracle.COM * Copyright (c) 1985-2010 AT&T Intellectual Property *
54887Schin * and is licensed under the *
64887Schin * Common Public License, Version 1.0 *
78462SApril.Chin@Sun.COM * by AT&T Intellectual Property *
84887Schin * *
94887Schin * A copy of the License is available at *
104887Schin * http://www.opensource.org/licenses/cpl1.0.txt *
114887Schin * (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) *
124887Schin * *
134887Schin * Information and Software Systems Research *
144887Schin * AT&T Research *
154887Schin * Florham Park NJ *
164887Schin * *
174887Schin * Glenn Fowler <gsf@research.att.com> *
184887Schin * David Korn <dgk@research.att.com> *
194887Schin * Phong Vo <kpv@research.att.com> *
204887Schin * *
214887Schin ***********************************************************************/
224887Schin #include "sfhdr.h"
234887Schin
244887Schin /* Read n bytes from a stream into a buffer
254887Schin **
264887Schin ** Written by Kiem-Phong Vo.
274887Schin */
284887Schin
294887Schin #if __STD_C
sfread(Sfio_t * f,Void_t * buf,size_t n)308462SApril.Chin@Sun.COM ssize_t sfread(Sfio_t* f, Void_t* buf, size_t n)
314887Schin #else
324887Schin ssize_t sfread(f,buf,n)
338462SApril.Chin@Sun.COM Sfio_t* f; /* read from this stream. */
344887Schin Void_t* buf; /* buffer to read into */
358462SApril.Chin@Sun.COM size_t n; /* number of bytes to be read. */
364887Schin #endif
374887Schin {
384887Schin reg uchar *s, *begs;
394887Schin reg ssize_t r;
404887Schin reg int local, justseek;
418462SApril.Chin@Sun.COM SFMTXDECL(f);
424887Schin
438462SApril.Chin@Sun.COM SFMTXENTER(f, (ssize_t)(-1));
444887Schin
454887Schin GETLOCAL(f,local);
464887Schin justseek = f->bits&SF_JUSTSEEK; f->bits &= ~SF_JUSTSEEK;
474887Schin
484887Schin if(!buf)
494887Schin SFMTXRETURN(f, (ssize_t)(n == 0 ? 0 : -1) );
504887Schin
514887Schin /* release peek lock */
524887Schin if(f->mode&SF_PEEK)
534887Schin { if(!(f->mode&SF_READ) )
544887Schin SFMTXRETURN(f, (ssize_t)(-1));
554887Schin
564887Schin if(f->mode&SF_GETR)
574887Schin { if(((uchar*)buf + f->val) != f->next &&
584887Schin (!f->rsrv || f->rsrv->data != (uchar*)buf) )
594887Schin SFMTXRETURN(f, (ssize_t)(-1));
604887Schin f->mode &= ~SF_PEEK;
614887Schin SFMTXRETURN(f, 0);
624887Schin }
634887Schin else
644887Schin { if((uchar*)buf != f->next)
654887Schin SFMTXRETURN(f, (ssize_t)(-1));
664887Schin f->mode &= ~SF_PEEK;
674887Schin if(f->mode&SF_PKRD)
684887Schin { /* actually read the data now */
694887Schin f->mode &= ~SF_PKRD;
704887Schin if(n > 0)
714887Schin n = (r = sysreadf(f->file,f->data,n)) < 0 ? 0 : r;
724887Schin f->endb = f->data+n;
734887Schin f->here += n;
744887Schin }
754887Schin f->next += n;
764887Schin f->endr = f->endb;
774887Schin SFMTXRETURN(f, n);
784887Schin }
794887Schin }
804887Schin
814887Schin s = begs = (uchar*)buf;
824887Schin for(;; f->mode &= ~SF_LOCK)
834887Schin { /* check stream mode */
844887Schin if(SFMODE(f,local) != SF_READ && _sfmode(f,SF_READ,local) < 0)
854887Schin { n = s > begs ? s-begs : (size_t)(-1);
864887Schin SFMTXRETURN(f, (ssize_t)n);
874887Schin }
884887Schin
894887Schin SFLOCK(f,local);
904887Schin
914887Schin if((r = f->endb - f->next) > 0) /* has buffered data */
924887Schin { if(r > (ssize_t)n)
934887Schin r = (ssize_t)n;
944887Schin if(s != f->next)
954887Schin memcpy(s, f->next, r);
964887Schin f->next += r;
974887Schin s += r;
984887Schin n -= r;
994887Schin }
1004887Schin
1014887Schin if(n <= 0) /* all done */
1024887Schin break;
1034887Schin
1044887Schin if(!(f->flags&SF_STRING) && !(f->bits&SF_MMAP) )
1054887Schin { f->next = f->endb = f->data;
1064887Schin
1074887Schin /* exact IO is desirable for these cases */
1084887Schin if(SFDIRECT(f,n) ||
1094887Schin ((f->flags&SF_SHARE) && f->extent < 0) )
1104887Schin r = (ssize_t)n;
1114887Schin else if(justseek && n <= f->iosz && f->iosz <= f->size)
1124887Schin r = f->iosz; /* limit buffering */
1134887Schin else r = f->size; /* full buffering */
1144887Schin
1154887Schin /* if read almost full size, then just do it direct */
1164887Schin if(r > (ssize_t)n && (r - r/8) <= (ssize_t)n)
1174887Schin r = (ssize_t)n;
1184887Schin
1194887Schin /* read directly to user's buffer */
1204887Schin if(r == (ssize_t)n && (r = SFRD(f,s,r,f->disc)) >= 0)
1214887Schin { s += r;
1224887Schin n -= r;
1234887Schin if(r == 0 || n == 0) /* eof or eob */
1244887Schin break;
1254887Schin }
1264887Schin else goto do_filbuf;
1274887Schin }
1284887Schin else
1294887Schin { do_filbuf:
1304887Schin if(justseek)
1314887Schin f->bits |= SF_JUSTSEEK;
1324887Schin if(SFFILBUF(f,-1) <= 0)
1334887Schin break;
1344887Schin }
1354887Schin }
1364887Schin
1374887Schin SFOPEN(f,local);
1384887Schin r = s-begs;
1394887Schin SFMTXRETURN(f, r);
1404887Schin }
141