diff options
Diffstat (limited to 'contrib/less/ch.c')
| -rw-r--r-- | contrib/less/ch.c | 248 |
1 files changed, 144 insertions, 104 deletions
diff --git a/contrib/less/ch.c b/contrib/less/ch.c index eb607d5..8ad028b 100644 --- a/contrib/less/ch.c +++ b/contrib/less/ch.c @@ -1,5 +1,5 @@ /* - * Copyright (C) 1984-2007 Mark Nudelman + * Copyright (C) 1984-2008 Mark Nudelman * * You may distribute under the terms of either the GNU General Public * License or the Less License, as specified in the README file. @@ -37,20 +37,19 @@ public int ignore_eoi; * in order from most- to least-recently used. * The circular list is anchored by the file state "thisfile". */ +struct bufnode { + struct bufnode *next, *prev; + struct bufnode *hnext, *hprev; +}; + #define LBUFSIZE 8192 struct buf { - struct buf *next, *prev; - struct buf *hnext, *hprev; + struct bufnode node; BLOCKNUM block; unsigned int datasize; unsigned char data[LBUFSIZE]; }; - -struct buflist { - /* -- Following members must match struct buf */ - struct buf *buf_next, *buf_prev; - struct buf *buf_hnext, *buf_hprev; -}; +#define bufnode_buf(bn) ((struct buf *) bn) /* * The file state is maintained in a filestate structure. @@ -58,8 +57,8 @@ struct buflist { */ #define BUFHASH_SIZE 64 struct filestate { - struct buf *buf_next, *buf_prev; - struct buflist hashtbl[BUFHASH_SIZE]; + struct bufnode buflist; + struct bufnode hashtbl[BUFHASH_SIZE]; int file; int flags; POSITION fpos; @@ -69,8 +68,8 @@ struct filestate { POSITION fsize; }; -#define ch_bufhead thisfile->buf_next -#define ch_buftail thisfile->buf_prev +#define ch_bufhead thisfile->buflist.next +#define ch_buftail thisfile->buflist.prev #define ch_nbufs thisfile->nbufs #define ch_block thisfile->block #define ch_offset thisfile->offset @@ -79,23 +78,48 @@ struct filestate { #define ch_flags thisfile->flags #define ch_file thisfile->file -#define END_OF_CHAIN ((struct buf *)&thisfile->buf_next) -#define END_OF_HCHAIN(h) ((struct buf *)&thisfile->hashtbl[h]) +#define END_OF_CHAIN (&thisfile->buflist) +#define END_OF_HCHAIN(h) (&thisfile->hashtbl[h]) #define BUFHASH(blk) ((blk) & (BUFHASH_SIZE-1)) -#define FOR_BUFS_IN_CHAIN(h,bp) \ - for (bp = thisfile->hashtbl[h].buf_hnext; \ - bp != END_OF_HCHAIN(h); bp = bp->hnext) +/* + * Macros to manipulate the list of buffers in thisfile->buflist. + */ +#define FOR_BUFS(bn) \ + for (bn = ch_bufhead; bn != END_OF_CHAIN; bn = bn->next) + +#define BUF_RM(bn) \ + (bn)->next->prev = (bn)->prev; \ + (bn)->prev->next = (bn)->next; + +#define BUF_INS_HEAD(bn) \ + (bn)->next = ch_bufhead; \ + (bn)->prev = END_OF_CHAIN; \ + ch_bufhead->prev = (bn); \ + ch_bufhead = (bn); + +#define BUF_INS_TAIL(bn) \ + (bn)->next = END_OF_CHAIN; \ + (bn)->prev = ch_buftail; \ + ch_buftail->next = (bn); \ + ch_buftail = (bn); + +/* + * Macros to manipulate the list of buffers in thisfile->hashtbl[n]. + */ +#define FOR_BUFS_IN_CHAIN(h,bn) \ + for (bn = thisfile->hashtbl[h].hnext; \ + bn != END_OF_HCHAIN(h); bn = bn->hnext) -#define HASH_RM(bp) \ - (bp)->hnext->hprev = (bp)->hprev; \ - (bp)->hprev->hnext = (bp)->hnext; +#define BUF_HASH_RM(bn) \ + (bn)->hnext->hprev = (bn)->hprev; \ + (bn)->hprev->hnext = (bn)->hnext; -#define HASH_INS(bp,h) \ - (bp)->hnext = thisfile->hashtbl[h].buf_hnext; \ - (bp)->hprev = END_OF_HCHAIN(h); \ - thisfile->hashtbl[h].buf_hnext->hprev = (bp); \ - thisfile->hashtbl[h].buf_hnext = (bp); +#define BUF_HASH_INS(bn,h) \ + (bn)->hnext = thisfile->hashtbl[h].hnext; \ + (bn)->hprev = END_OF_HCHAIN(h); \ + thisfile->hashtbl[h].hnext->hprev = (bn); \ + thisfile->hashtbl[h].hnext = (bn); static struct filestate *thisfile; static int ch_ungotchar = -1; @@ -119,17 +143,12 @@ static int ch_addbuf(); /* * Get the character pointed to by the read pointer. - * ch_get() is a macro which is more efficient to call - * than fch_get (the function), in the usual case - * that the block desired is at the head of the chain. */ -#define ch_get() ((ch_block == ch_bufhead->block && \ - ch_offset < ch_bufhead->datasize) ? \ - ch_bufhead->data[ch_offset] : fch_get()) int -fch_get() +ch_get() { register struct buf *bp; + register struct bufnode *bn; register int n; register int slept; register int h; @@ -139,52 +158,69 @@ fch_get() if (thisfile == NULL) return (EOI); + /* + * Quick check for the common case where + * the desired char is in the head buffer. + */ + if (ch_bufhead != END_OF_CHAIN) + { + bp = bufnode_buf(ch_bufhead); + if (ch_block == bp->block && ch_offset < bp->datasize) + return bp->data[ch_offset]; + } + slept = FALSE; /* * Look for a buffer holding the desired block. */ h = BUFHASH(ch_block); - FOR_BUFS_IN_CHAIN(h, bp) + FOR_BUFS_IN_CHAIN(h, bn) { + bp = bufnode_buf(bn); if (bp->block == ch_block) { if (ch_offset >= bp->datasize) /* * Need more data in this buffer. */ - goto read_more; + break; goto found; } } - /* - * Block is not in a buffer. - * Take the least recently used buffer - * and read the desired block into it. - * If the LRU buffer has data in it, - * then maybe allocate a new buffer. - */ - if (ch_buftail == END_OF_CHAIN || ch_buftail->block != -1) + if (bn == END_OF_HCHAIN(h)) { /* - * There is no empty buffer to use. - * Allocate a new buffer if: - * 1. We can't seek on this file and -b is not in effect; or - * 2. We haven't allocated the max buffers for this file yet. + * Block is not in a buffer. + * Take the least recently used buffer + * and read the desired block into it. + * If the LRU buffer has data in it, + * then maybe allocate a new buffer. */ - if ((autobuf && !(ch_flags & CH_CANSEEK)) || - (maxbufs < 0 || ch_nbufs < maxbufs)) - if (ch_addbuf()) - /* - * Allocation failed: turn off autobuf. - */ - autobuf = OPT_OFF; + if (ch_buftail == END_OF_CHAIN || + bufnode_buf(ch_buftail)->block != -1) + { + /* + * There is no empty buffer to use. + * Allocate a new buffer if: + * 1. We can't seek on this file and -b is not in effect; or + * 2. We haven't allocated the max buffers for this file yet. + */ + if ((autobuf && !(ch_flags & CH_CANSEEK)) || + (maxbufs < 0 || ch_nbufs < maxbufs)) + if (ch_addbuf()) + /* + * Allocation failed: turn off autobuf. + */ + autobuf = OPT_OFF; + } + bn = ch_buftail; + bp = bufnode_buf(bn); + BUF_HASH_RM(bn); /* Remove from old hash chain. */ + bp->block = ch_block; + bp->datasize = 0; + BUF_HASH_INS(bn, h); /* Insert into new hash chain. */ } - bp = ch_buftail; - HASH_RM(bp); /* Remove from old hash chain. */ - bp->block = ch_block; - bp->datasize = 0; - HASH_INS(bp, h); /* Insert into new hash chain. */ read_more: pos = (ch_block * LBUFSIZE) + bp->datasize; @@ -309,24 +345,20 @@ fch_get() } found: - if (ch_bufhead != bp) + if (ch_bufhead != bn) { /* * Move the buffer to the head of the buffer chain. * This orders the buffer chain, most- to least-recently used. */ - bp->next->prev = bp->prev; - bp->prev->next = bp->next; - bp->next = ch_bufhead; - bp->prev = END_OF_CHAIN; - ch_bufhead->prev = bp; - ch_bufhead = bp; + BUF_RM(bn); + BUF_INS_HEAD(bn); /* * Move to head of hash chain too. */ - HASH_RM(bp); - HASH_INS(bp, h); + BUF_HASH_RM(bn); + BUF_HASH_INS(bn, h); } if (ch_offset >= bp->datasize) @@ -386,6 +418,7 @@ end_logfile() sync_logfile() { register struct buf *bp; + register struct bufnode *bn; int warned = FALSE; BLOCKNUM block; BLOCKNUM nblocks; @@ -393,24 +426,23 @@ sync_logfile() nblocks = (ch_fpos + LBUFSIZE - 1) / LBUFSIZE; for (block = 0; block < nblocks; block++) { - for (bp = ch_bufhead; ; bp = bp->next) + int wrote = FALSE; + FOR_BUFS(bn) { - if (bp == END_OF_CHAIN) - { - if (!warned) - { - error("Warning: log file is incomplete", - NULL_PARG); - warned = TRUE; - } - break; - } + bp = bufnode_buf(bn); if (bp->block == block) { write(logfile, (char *) bp->data, bp->datasize); + wrote = TRUE; break; } } + if (!wrote && !warned) + { + error("Warning: log file is incomplete", + NULL_PARG); + warned = TRUE; + } } } @@ -424,11 +456,13 @@ buffered(block) BLOCKNUM block; { register struct buf *bp; + register struct bufnode *bn; register int h; h = BUFHASH(block); - FOR_BUFS_IN_CHAIN(h, bp) + FOR_BUFS_IN_CHAIN(h, bn) { + bp = bufnode_buf(bn); if (bp->block == block) return (TRUE); } @@ -510,7 +544,8 @@ ch_end_seek() public int ch_beg_seek() { - register struct buf *bp, *firstbp; + register struct bufnode *bn; + register struct bufnode *firstbn; /* * Try a plain ch_seek first. @@ -522,13 +557,15 @@ ch_beg_seek() * Can't get to position 0. * Look thru the buffers for the one closest to position 0. */ - firstbp = bp = ch_bufhead; - if (bp == END_OF_CHAIN) + firstbn = ch_bufhead; + if (firstbn == END_OF_CHAIN) return (1); - while ((bp = bp->next) != END_OF_CHAIN) - if (bp->block < firstbp->block) - firstbp = bp; - ch_block = firstbp->block; + FOR_BUFS(bn) + { + if (bufnode_buf(bn)->block < bufnode_buf(firstbn)->block) + firstbn = bn; + } + ch_block = bufnode_buf(firstbn)->block; ch_offset = 0; return (0); } @@ -628,7 +665,7 @@ ch_setbufspace(bufspace) public void ch_flush() { - register struct buf *bp; + register struct bufnode *bn; if (thisfile == NULL) return; @@ -646,8 +683,10 @@ ch_flush() /* * Initialize all the buffers. */ - for (bp = ch_bufhead; bp != END_OF_CHAIN; bp = bp->next) - bp->block = -1; + FOR_BUFS(bn) + { + bufnode_buf(bn)->block = -1; + } /* * Figure out the size of the file, if we can. @@ -694,6 +733,7 @@ ch_flush() ch_addbuf() { register struct buf *bp; + register struct bufnode *bn; /* * Allocate and initialize a new buffer and link it @@ -704,11 +744,10 @@ ch_addbuf() return (1); ch_nbufs++; bp->block = -1; - bp->next = END_OF_CHAIN; - bp->prev = ch_buftail; - ch_buftail->next = bp; - ch_buftail = bp; - HASH_INS(bp, 0); + bn = &bp->node; + + BUF_INS_TAIL(bn); + BUF_HASH_INS(bn, 0); return (0); } @@ -722,8 +761,8 @@ init_hashtbl() for (h = 0; h < BUFHASH_SIZE; h++) { - thisfile->hashtbl[h].buf_hnext = END_OF_HCHAIN(h); - thisfile->hashtbl[h].buf_hprev = END_OF_HCHAIN(h); + thisfile->hashtbl[h].hnext = END_OF_HCHAIN(h); + thisfile->hashtbl[h].hprev = END_OF_HCHAIN(h); } } @@ -733,14 +772,13 @@ init_hashtbl() static void ch_delbufs() { - register struct buf *bp; + register struct bufnode *bn; while (ch_bufhead != END_OF_CHAIN) { - bp = ch_bufhead; - bp->next->prev = bp->prev; - bp->prev->next = bp->next; - free(bp); + bn = ch_bufhead; + BUF_RM(bn); + free(bufnode_buf(bn)); } ch_nbufs = 0; init_hashtbl(); @@ -786,7 +824,7 @@ ch_init(f, flags) */ thisfile = (struct filestate *) calloc(1, sizeof(struct filestate)); - thisfile->buf_next = thisfile->buf_prev = END_OF_CHAIN; + thisfile->buflist.next = thisfile->buflist.prev = END_OF_CHAIN; thisfile->nbufs = 0; thisfile->flags = 0; thisfile->fpos = 0; @@ -867,6 +905,7 @@ ch_getflags() ch_dump(struct filestate *fs) { struct buf *bp; + struct bufnode *bn; unsigned char *s; if (fs == NULL) @@ -878,8 +917,9 @@ ch_dump(struct filestate *fs) fs->file, fs->flags, fs->fpos, fs->fsize, fs->block, fs->offset); printf(" %d bufs:\n", fs->nbufs); - for (bp = fs->buf_next; bp != (struct buf *)fs; bp = bp->next) + for (bn = fs->next; bn != &fs->buflist; bn = bn->next) { + bp = bufnode_buf(bn); printf("%x: blk %x, size %x \"", bp, bp->block, bp->datasize); for (s = bp->data; s < bp->data + 30; s++) |
