1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */ 23 /* All Rights Reserved */ 24 25 26 /* Copyright (c) 1981 Regents of the University of California */ 27 #ident "%Z%%M% %I% %E% SMI" /* SVr4.0 1.7 */ 28 /* 29 * The editor uses a temporary file for files being edited, in a structure 30 * similar to that of ed. The first block of the file is used for a header 31 * block which guides recovery after editor/system crashes. 32 * Lines are represented in core by a pointer into the temporary file which 33 * is packed into 16 bits (32 on VMUNIX). All but the low bit index the temp 34 * file; the last is used by global commands. The parameters below control 35 * how much the other bits are shifted left before they index the temp file. 36 * Larger shifts give more slop in the temp file but allow larger files 37 * to be edited. 38 * 39 * The editor does not garbage collect the temporary file. When a new 40 * file is edited, the temporary file is rather discarded and a new one 41 * created for the new file. Garbage collection would be rather complicated 42 * in ex because of the general undo, and in any case would require more 43 * work when throwing lines away because marks would have be carefully 44 * checked before reallocating temporary file space. Said another way, 45 * each time you create a new line in the temporary file you get a unique 46 * number back, and this is a property used by marks. 47 * 48 * The following temp file parameters allow 256k bytes in the temporary 49 * file. By changing to the numbers in comments you can get 512k. 50 * For VMUNIX you get more than you could ever want. 51 * VMUNIX uses long (32 bit) integers giving much more 52 * space in the temp file and no waste. This doubles core 53 * requirements but allows files of essentially unlimited size to be edited. 54 */ 55 #ifndef VMUNIX 56 #define BLKMSK 0777 /* 01777 */ 57 #define BNDRY 8 /* 16 */ 58 #define INCRMT 0200 /* 0100 */ 59 #define LBTMSK 0770 /* 0760 */ 60 #define NMBLKS 506 /* 1018 */ 61 #define OFFBTS 7 /* 6 */ 62 #define OFFMSK 0177 /* 077 */ 63 #define SHFT 2 /* 3 */ 64 #else 65 #define BLKMSK 077777 66 #define BNDRY 2 67 #define INCRMT 04000 /* 02000 */ 68 #define LBTMSK 03776 /* 01776 */ 69 #define NMBLKS 077770 70 #define OFFBTS 11 /* 10 */ 71 #define OFFMSK 03777 /* 01777 */ 72 #define SHFT 0 73 #endif 74 75 /* 76 * The editor uses three buffers into the temporary file (ed uses two 77 * and is very similar). These are two read buffers and one write buffer. 78 * Basically, the editor deals with the file as a sequence of BUFSIZE character 79 * blocks. Each block contains some number of lines (and lines 80 * can run across block boundaries. 81 * 82 * New lines are written into the last block in the temporary file 83 * which is in core as obuf. When a line is needed which isn't in obuf, 84 * then it is brought into an input buffer. As there are two, the choice 85 * is to take the buffer into which the last read (of the two) didn't go. 86 * Thus this is a 2 buffer LRU replacement strategy. Measurement 87 * shows that this saves roughly 25% of the buffer reads over a one 88 * input buffer strategy. Since the editor (on our VAX over 1 week) 89 * spends (spent) roughly 30% of its time in the system read routine, 90 * this can be a big help. 91 */ 92 var bool hitin2; /* Last read hit was ibuff2 not ibuff */ 93 var bool ichang2; /* Have actually changed ibuff2 */ 94 var bool ichanged; /* Have actually changed ibuff */ 95 var short iblock; /* Temp file block number of ibuff (or -1) */ 96 var short iblock2; /* Temp file block number of ibuff2 (or -1) */ 97 var short ninbuf; /* Number useful chars left in input buffer */ 98 var short nleft; /* Number usable chars left in output buffer */ 99 var short oblock; /* Temp file block number of obuff (or -1) */ 100 #ifndef VMUNIX 101 var short tline; /* Current temp file ptr */ 102 #else 103 var int tline; 104 #endif 105 106 var unsigned char ibuff[BUFSIZE]; 107 var unsigned char ibuff2[BUFSIZE]; 108 var unsigned char obuff[BUFSIZE]; 109 110 /* 111 * Structure of the descriptor block which resides 112 * in the first block of the temporary file and is 113 * the guiding light for crash recovery. 114 * 115 * As the Blocks field below implies, there are temporary file blocks 116 * devoted to (some) image of the incore array of pointers into the temp 117 * file. Thus, to recover from a crash we use these indices to get the 118 * line pointers back, and then use the line pointers to get the text back. 119 * Except for possible lost lines due to sandbagged I/O, the entire 120 * file (at the time of the last editor "sync") can be recovered from 121 * the temp file. 122 */ 123 124 /* This definition also appears in expreserve.c... beware */ 125 struct header { 126 time_t Time; /* Time temp file last updated */ 127 int Uid; 128 #ifndef VMUNIX 129 short Flines; /* Number of lines in file */ 130 #else 131 int Flines; 132 #endif 133 unsigned char Savedfile[FNSIZE]; /* The current file name */ 134 short Blocks[LBLKS]; /* Blocks where line pointers stashed */ 135 short encrypted; /* Encrypted temp file flag */ 136 }; 137 var struct header H; 138 139 #define uid H.Uid 140 #define flines H.Flines 141 #define savedfile H.Savedfile 142 #define blocks H.Blocks 143