freebsd-dev/gnu/usr.bin/groff/libbib/linear.cc
1995-01-15 08:10:00 +00:00

485 lines
11 KiB
C++

// -*- C++ -*-
/* Copyright (C) 1989, 1990, 1991, 1992 Free Software Foundation, Inc.
Written by James Clark (jjc@jclark.com)
This file is part of groff.
groff is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 2, or (at your option) any later
version.
groff is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License along
with groff; see the file COPYING. If not, write to the Free Software
Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <errno.h>
#include "posix.h"
#include "lib.h"
#include "errarg.h"
#include "error.h"
#include "cset.h"
#include "cmap.h"
#include "refid.h"
#include "search.h"
class file_buffer {
char *buffer;
char *bufend;
public:
file_buffer();
~file_buffer();
int load(int fd, const char *filename);
const char *get_start() const;
const char *get_end() const;
};
typedef unsigned char uchar;
static uchar map[256];
static uchar inv_map[256][3];
struct map_init {
map_init();
};
static map_init the_map_init;
map_init::map_init()
{
for (int i = 0; i < 256; i++)
map[i] = csalnum(i) ? cmlower(i) : '\0';
for (i = 0; i < 256; i++) {
if (cslower(i)) {
inv_map[i][0] = i;
inv_map[i][1] = cmupper(i);
inv_map[i][2] = '\0';
}
else if (csdigit(i)) {
inv_map[i][0] = i;
inv_map[i][1] = 0;
}
else
inv_map[i][0] = '\0';
}
}
class bmpattern {
char *pat;
int len;
int delta[256];
public:
bmpattern(const char *pattern, int pattern_length);
~bmpattern();
const char *search(const char *p, const char *end) const;
int length() const;
};
bmpattern::bmpattern(const char *pattern, int pattern_length)
: len(pattern_length)
{
pat = new char[len];
int i;
for (i = 0; i < len; i++)
pat[i] = map[uchar(pattern[i])];
for (i = 0; i < 256; i++)
delta[i] = len;
for (i = 0; i < len; i++)
for (const unsigned char *inv = inv_map[uchar(pat[i])]; *inv; inv++)
delta[*inv] = len - i - 1;
}
const char *bmpattern::search(const char *buf, const char *end) const
{
int buflen = end - buf;
if (len > buflen)
return 0;
const char *strend;
if (buflen > len*4)
strend = end - len*4;
else
strend = buf;
const char *k = buf + len - 1;
const int *del = delta;
const char *pattern = pat;
for (;;) {
while (k < strend) {
int t = del[uchar(*k)];
if (!t)
break;
k += t;
k += del[uchar(*k)];
k += del[uchar(*k)];
}
while (k < end && del[uchar(*k)] != 0)
k++;
if (k == end)
break;
int j = len - 1;
const char *s = k;
for (;;) {
if (j == 0)
return s;
if (map[uchar(*--s)] != uchar(pattern[--j]))
break;
}
k++;
}
return 0;
}
bmpattern::~bmpattern()
{
a_delete pat;
}
inline int bmpattern::length() const
{
return len;
}
static const char *find_end(const char *bufend, const char *p);
const char *linear_searcher::search_and_check(const bmpattern *key,
const char *buf, const char *bufend, const char **start) const
{
assert(buf[-1] == '\n');
assert(bufend[-1] == '\n');
const char *ptr = buf;
for (;;) {
const char *found = key->search(ptr, bufend);
if (!found)
break;
if (check_match(buf, bufend, found, key->length(), &ptr, start))
return found;
}
return 0;
}
static const char *skip_field(const char *end, const char *p)
{
for (;;)
if (*p++ == '\n') {
if (p == end || *p == '%')
break;
for (const char *q = p; *q == ' ' || *q == '\t'; q++)
;
if (*q == '\n')
break;
p = q + 1;
}
return p;
}
static const char *find_end(const char *bufend, const char *p)
{
for (;;)
if (*p++ == '\n') {
if (p == bufend)
break;
for (const char *q = p; *q == ' ' || *q == '\t'; q++)
;
if (*q == '\n')
break;
p = q + 1;
}
return p;
}
int linear_searcher::check_match(const char *buf, const char *bufend,
const char *match, int matchlen,
const char **cont, const char **start) const
{
*cont = match + 1;
// The user is required to supply only the first truncate_len characters
// of the key. If truncate_len <= 0, he must supply all the key.
if ((truncate_len <= 0 || matchlen < truncate_len)
&& map[uchar(match[matchlen])] != '\0')
return 0;
// The character before the match must not be an alphanumeric
// character (unless the alphanumeric character follows one or two
// percent characters at the beginning of the line), nor must it be
// a percent character at the beginning of a line, nor a percent
// character following a percent character at the beginning of a
// line.
switch (match - buf) {
case 0:
break;
case 1:
if (match[-1] == '%' || map[uchar(match[-1])] != '\0')
return 0;
break;
case 2:
if (map[uchar(match[-1])] != '\0' && match[-2] != '%')
return 0;
if (match[-1] == '%'
&& (match[-2] == '\n' || match[-2] == '%'))
return 0;
break;
default:
if (map[uchar(match[-1])] != '\0'
&& !(match[-2] == '%'
&& (match[-3] == '\n'
|| (match[-3] == '%' && match[-4] == '\n'))))
return 0;
if (match[-1] == '%'
&& (match[-2] == '\n'
|| (match[-2] == '%' && match[-3] == '\n')))
return 0;
}
const char *p = match;
int had_percent = 0;
for (;;) {
if (*p == '\n') {
if (!had_percent && p[1] == '%') {
if (p[2] != '\0' && strchr(ignore_fields, p[2]) != 0) {
*cont = skip_field(bufend, match + matchlen);
return 0;
}
if (!start)
break;
had_percent = 1;
}
if (p <= buf) {
if (start)
*start = p + 1;
return 1;
}
for (const char *q = p - 1; *q == ' ' || *q == '\t'; q--)
;
if (*q == '\n') {
if (start)
*start = p + 1;
break;
}
p = q;
}
p--;
}
return 1;
}
file_buffer::file_buffer()
: buffer(0), bufend(0)
{
}
file_buffer::~file_buffer()
{
a_delete buffer;
}
const char *file_buffer::get_start() const
{
return buffer ? buffer + 4 : 0;
}
const char *file_buffer::get_end() const
{
return bufend;
}
int file_buffer::load(int fd, const char *filename)
{
struct stat sb;
if (fstat(fd, &sb) < 0)
error("can't fstat `%1': %2", filename, strerror(errno));
else if (!S_ISREG(sb.st_mode))
error("`%1' is not a regular file", filename);
else {
// We need one character extra at the beginning for an additional newline
// used as a sentinel. We get 4 instead so that the read buffer will be
// word-aligned. This seems to make the read slightly faster. We also
// need one character at the end also for an additional newline used as a
// sentinel.
int size = int(sb.st_size);
buffer = new char[size + 4 + 1];
int nread = read(fd, buffer + 4, size);
if (nread < 0)
error("error reading `%1': %2", filename, strerror(errno));
else if (nread != size)
error("size of `%1' decreased", filename);
else {
char c;
nread = read(fd, &c, 1);
if (nread != 0)
error("size of `%1' increased", filename);
else if (memchr(buffer + 4, '\0', size < 1024 ? size : 1024) != 0)
error("database `%1' is a binary file", filename);
else {
close(fd);
buffer[3] = '\n';
bufend = buffer + 4 + size;
if (bufend[-1] != '\n')
*bufend++ = '\n';
return 1;
}
}
a_delete buffer;
buffer = 0;
}
close(fd);
return 0;
}
linear_searcher::linear_searcher(const char *query, int query_len,
const char *ign, int trunc)
: keys(0), nkeys(0), truncate_len(trunc), ignore_fields(ign)
{
const char *query_end = query + query_len;
int nk = 0;
const char *p;
for (p = query; p < query_end; p++)
if (map[uchar(*p)] != '\0'
&& (p[1] == '\0' || map[uchar(p[1])] == '\0'))
nk++;
if (nk == 0)
return;
keys = new bmpattern*[nk];
p = query;
for (;;) {
while (p < query_end && map[uchar(*p)] == '\0')
p++;
if (p == query_end)
break;
const char *start = p;
while (p < query_end && map[uchar(*p)] != '\0')
p++;
keys[nkeys++] = new bmpattern(start, p - start);
}
assert(nkeys <= nk);
if (nkeys == 0) {
a_delete keys;
keys = 0;
}
}
linear_searcher::~linear_searcher()
{
for (int i = 0; i < nkeys; i++)
delete keys[i];
a_delete keys;
}
int linear_searcher::search(const char *buffer, const char *bufend,
const char **startp, int *lengthp) const
{
assert(bufend - buffer > 0);
assert(buffer[-1] == '\n');
assert(bufend[-1] == '\n');
if (nkeys == 0)
return 0;
for (;;) {
const char *refstart;
const char *found = search_and_check(keys[0], buffer, bufend, &refstart);
if (!found)
break;
const char *refend = find_end(bufend, found + keys[0]->length());
for (int i = 1; i < nkeys; i++)
if (!search_and_check(keys[i], refstart, refend))
break;
if (i >= nkeys) {
*startp = refstart;
*lengthp = refend - refstart;
return 1;
}
buffer = refend;
}
return 0;
}
class linear_search_item : public search_item {
file_buffer fbuf;
public:
linear_search_item(const char *filename, int fid);
~linear_search_item();
int load(int fd);
search_item_iterator *make_search_item_iterator(const char *);
friend class linear_search_item_iterator;
};
class linear_search_item_iterator : public search_item_iterator {
linear_search_item *lsi;
int pos;
public:
linear_search_item_iterator(linear_search_item *, const char *query);
~linear_search_item_iterator();
int next(const linear_searcher &, const char **ptr, int *lenp,
reference_id *ridp);
};
search_item *make_linear_search_item(int fd, const char *filename, int fid)
{
linear_search_item *item = new linear_search_item(filename, fid);
if (!item->load(fd)) {
delete item;
return 0;
}
else
return item;
}
linear_search_item::linear_search_item(const char *filename, int fid)
: search_item(filename, fid)
{
}
linear_search_item::~linear_search_item()
{
}
int linear_search_item::load(int fd)
{
return fbuf.load(fd, name);
}
search_item_iterator *linear_search_item::make_search_item_iterator(
const char *query)
{
return new linear_search_item_iterator(this, query);
}
linear_search_item_iterator::linear_search_item_iterator(
linear_search_item *p, const char *)
: lsi(p), pos(0)
{
}
linear_search_item_iterator::~linear_search_item_iterator()
{
}
int linear_search_item_iterator::next(const linear_searcher &searcher,
const char **startp, int *lengthp,
reference_id *ridp)
{
const char *bufstart = lsi->fbuf.get_start();
const char *bufend = lsi->fbuf.get_end();
const char *ptr = bufstart + pos;
if (ptr < bufend && searcher.search(ptr, bufend, startp, lengthp)) {
pos = *startp + *lengthp - bufstart;
if (ridp)
*ridp = reference_id(lsi->filename_id, *startp - bufstart);
return 1;
}
else
return 0;
}