9base

revived minimalist port of Plan 9 userland to Unix
git clone git://git.suckless.org/9base
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binit.c (1983B)

      1 #include	"lib9.h"
      2 #include	<bio.h>
      3 
      4 enum
      5 {
      6 	MAXBUFS	= 20
      7 };
      8 
      9 static	Biobuf*	wbufs[MAXBUFS];
     10 static	int		atexitflag;
     11 
     12 static
     13 void
     14 batexit(void)
     15 {
     16 	Biobuf *bp;
     17 	int i;
     18 
     19 	for(i=0; i<MAXBUFS; i++) {
     20 		bp = wbufs[i];
     21 		if(bp != 0) {
     22 			wbufs[i] = 0;
     23 			Bflush(bp);
     24 		}
     25 	}
     26 }
     27 
     28 static
     29 void
     30 deinstall(Biobuf *bp)
     31 {
     32 	int i;
     33 
     34 	for(i=0; i<MAXBUFS; i++)
     35 		if(wbufs[i] == bp)
     36 			wbufs[i] = 0;
     37 }
     38 
     39 static
     40 void
     41 install(Biobuf *bp)
     42 {
     43 	int i;
     44 
     45 	deinstall(bp);
     46 	for(i=0; i<MAXBUFS; i++)
     47 		if(wbufs[i] == 0) {
     48 			wbufs[i] = bp;
     49 			break;
     50 		}
     51 	if(atexitflag == 0) {
     52 		atexitflag = 1;
     53 		atexit(batexit);
     54 	}
     55 }
     56 
     57 int
     58 Binits(Biobuf *bp, int f, int mode, unsigned char *p, int size)
     59 {
     60 
     61 	p += Bungetsize;	/* make room for Bungets */
     62 	size -= Bungetsize;
     63 
     64 	switch(mode&~(OCEXEC|ORCLOSE|OTRUNC)) {
     65 	default:
     66 		fprint(2, "Bopen: unknown mode %d\n", mode);
     67 		return Beof;
     68 
     69 	case OREAD:
     70 		bp->state = Bractive;
     71 		bp->ocount = 0;
     72 		break;
     73 
     74 	case OWRITE:
     75 		install(bp);
     76 		bp->state = Bwactive;
     77 		bp->ocount = -size;
     78 		break;
     79 	}
     80 	bp->bbuf = p;
     81 	bp->ebuf = p+size;
     82 	bp->bsize = size;
     83 	bp->icount = 0;
     84 	bp->gbuf = bp->ebuf;
     85 	bp->fid = f;
     86 	bp->flag = 0;
     87 	bp->rdline = 0;
     88 	bp->offset = 0;
     89 	bp->runesize = 0;
     90 	return 0;
     91 }
     92 
     93 
     94 int
     95 Binit(Biobuf *bp, int f, int mode)
     96 {
     97 	return Binits(bp, f, mode, bp->b, sizeof(bp->b));
     98 }
     99 
    100 Biobuf*
    101 Bfdopen(int f, int mode)
    102 {
    103 	Biobuf *bp;
    104 
    105 	bp = malloc(sizeof(Biobuf));
    106 	if(bp == 0)
    107 		return 0;
    108 	Binits(bp, f, mode, bp->b, sizeof(bp->b));
    109 	bp->flag = Bmagic;
    110 	return bp;
    111 }
    112 
    113 Biobuf*
    114 Bopen(char *name, int mode)
    115 {
    116 	Biobuf *bp;
    117 	int f;
    118 
    119 	switch(mode&~(OCEXEC|ORCLOSE|OTRUNC)) {
    120 	default:
    121 		fprint(2, "Bopen: unknown mode %d\n", mode);
    122 		return 0;
    123 
    124 	case OREAD:
    125 		f = open(name, mode);
    126 		if(f < 0)
    127 			return 0;
    128 		break;
    129 
    130 	case OWRITE:
    131 		f = create(name, mode, 0666);
    132 		if(f < 0)
    133 			return 0;
    134 	}
    135 	bp = Bfdopen(f, mode);
    136 	if(bp == 0)
    137 		close(f);
    138 	return bp;
    139 }
    140 
    141 int
    142 Bterm(Biobuf *bp)
    143 {
    144 
    145 	deinstall(bp);
    146 	Bflush(bp);
    147 	if(bp->flag == Bmagic) {
    148 		bp->flag = 0;
    149 		close(bp->fid);
    150 		free(bp);
    151 	}
    152 	return 0;
    153 }