1 /*********************************************************************** 2 * * 3 * This software is part of the ast package * 4 * Copyright (c) 1985-2008 AT&T Intellectual Property * 5 * and is licensed under the * 6 * Common Public License, Version 1.0 * 7 * by AT&T Intellectual Property * 8 * * 9 * A copy of the License is available at * 10 * http://www.opensource.org/licenses/cpl1.0.txt * 11 * (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) * 12 * * 13 * Information and Software Systems Research * 14 * AT&T Research * 15 * Florham Park NJ * 16 * * 17 * Glenn Fowler <gsf@research.att.com> * 18 * David Korn <dgk@research.att.com> * 19 * Phong Vo <kpv@research.att.com> * 20 * * 21 ***********************************************************************/ 22 #include "sfhdr.h" 23 24 /* Seek function that knows discipline 25 ** 26 ** Written by Kiem-Phong Vo. 27 */ 28 #if __STD_C 29 Sfoff_t sfsk(Sfio_t* f, Sfoff_t addr, int type, Sfdisc_t* disc) 30 #else 31 Sfoff_t sfsk(f,addr,type,disc) 32 Sfio_t* f; 33 Sfoff_t addr; 34 int type; 35 Sfdisc_t* disc; 36 #endif 37 { 38 Sfoff_t p; 39 reg Sfdisc_t* dc; 40 reg ssize_t s; 41 reg int local, mode; 42 SFMTXDECL(f); 43 44 SFMTXENTER(f, (Sfoff_t)(-1)); 45 46 GETLOCAL(f,local); 47 if(!local && !(f->bits&SF_DCDOWN)) 48 { if((mode = f->mode&SF_RDWR) != (int)f->mode && _sfmode(f,mode,0) < 0) 49 SFMTXRETURN(f, (Sfoff_t)(-1)); 50 if(SFSYNC(f) < 0) 51 SFMTXRETURN(f, (Sfoff_t)(-1)); 52 #ifdef MAP_TYPE 53 if(f->mode == SF_READ && (f->bits&SF_MMAP) && f->data) 54 { SFMUNMAP(f, f->data, f->endb-f->data); 55 f->data = NIL(uchar*); 56 } 57 #endif 58 f->next = f->endb = f->endr = f->endw = f->data; 59 } 60 61 if((type &= (SEEK_SET|SEEK_CUR|SEEK_END)) > SEEK_END) 62 SFMTXRETURN(f, (Sfoff_t)(-1)); 63 64 for(;;) 65 { dc = disc; 66 if(f->flags&SF_STRING) 67 { SFSTRSIZE(f); 68 if(type == SEEK_SET) 69 s = (ssize_t)addr; 70 else if(type == SEEK_CUR) 71 s = (ssize_t)(addr + f->here); 72 else s = (ssize_t)(addr + f->extent); 73 } 74 else 75 { SFDISC(f,dc,seekf); 76 if(dc && dc->seekf) 77 { SFDCSK(f,addr,type,dc,p); 78 } 79 else 80 { p = syslseekf(f->file,(sfoff_t)addr,type); 81 } 82 if(p >= 0) 83 SFMTXRETURN(f,p); 84 s = -1; 85 } 86 87 if(local) 88 SETLOCAL(f); 89 switch(_sfexcept(f,SF_SEEK,s,dc)) 90 { 91 case SF_EDISC: 92 case SF_ECONT: 93 if(f->flags&SF_STRING) 94 SFMTXRETURN(f, (Sfoff_t)s); 95 goto do_continue; 96 default: 97 SFMTXRETURN(f, (Sfoff_t)(-1)); 98 } 99 100 do_continue: 101 for(dc = f->disc; dc; dc = dc->disc) 102 if(dc == disc) 103 break; 104 disc = dc; 105 } 106 } 107