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/* Copyright (C) 1989-2020 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 3 of the License, 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 this program. If not, see <http://www.gnu.org/licenses/>. */
#include <assert.h>
#include <string.h>
// 'class PTABLE(T)' is the type of a hash table mapping a string
// (const char *) to an object of type T.
//
// 'struct PASSOC(T)' is the type of a association (pair) between a
// string (const char *) and an object of type T.
//
// 'class PTABLE_ITERATOR(T)' is the type of an iterator iterating through a
// 'class PTABLE(T)'.
//
// Nowadays one would use templates for this; this code predates the addition
// of templates to C++.
#define PTABLE(T) T ## _ptable
#define PASSOC(T) T ## _passoc
#define PTABLE_ITERATOR(T) T ## _ptable_iterator
// itable.h declares this too
#ifndef NEXT_PTABLE_SIZE_DEFINED
# define NEXT_PTABLE_SIZE_DEFINED
extern unsigned next_ptable_size(unsigned); // Return the first suitable
// hash table size greater than the given
// value.
#endif
extern unsigned long hash_string(const char *); // Return a hash code of the
// given string. The hash function is
// platform dependent. */
// Declare the types 'class PTABLE(T)', 'struct PASSOC(T)', and 'class
// PTABLE_ITERATOR(T)' for the type 'T'.
#define declare_ptable(T) \
\
struct PASSOC(T) { \
char *key; \
T *val; \
PASSOC(T)(); \
}; \
\
class PTABLE(T); \
\
class PTABLE_ITERATOR(T) { \
PTABLE(T) *p; \
unsigned i; \
public: \
PTABLE_ITERATOR(T)(PTABLE(T) *); /* Initialize an iterator running \
through the given table. */ \
int next(const char **, T **); /* Fetch the next pair, store the key \
and value in arg1 and arg2, \
respectively, and return 1. If \
there is no more pair in the \
table, return 0. */ \
}; \
\
class PTABLE(T) { \
PASSOC(T) *v; \
unsigned size; \
unsigned used; \
enum { \
FULL_NUM = 1, \
FULL_DEN = 4, \
INITIAL_SIZE = 17 \
}; \
public: \
PTABLE(T)(); /* Create an empty table. */ \
~PTABLE(T)(); /* Delete a table, including its \
values. */ \
const char *define(const char *, T *);/* Define the value (arg2) for a key \
(arg1). Return the copy in the \
table of the key (arg1), or \
possibly NULL if the value (arg2) \
is NULL. */ \
T *lookup(const char *); /* Return a pointer to the value of \
the given key, if found in the \
table, or NULL otherwise. */ \
T *lookupassoc(const char **); /* Return a pointer to the value of \
the given key, passed by reference,\
and replace the key argument with \
the copy found in the table, if \
the key is found in the table. \
Return NULL otherwise. */ \
friend class PTABLE_ITERATOR(T); \
};
// Keys (which are strings) are allocated and freed by PTABLE.
// Values must be allocated by the caller (always using new[], not new)
// and are freed by PTABLE.
// Define the implementations of the members of the types 'class PTABLE(T)',
// 'struct PASSOC(T)', 'class PTABLE_ITERATOR(T)' for the type 'T'.
#define implement_ptable(T) \
\
PASSOC(T)::PASSOC(T)() \
: key(0), val(0) \
{ \
} \
\
PTABLE(T)::PTABLE(T)() \
{ \
v = new PASSOC(T)[size = INITIAL_SIZE]; \
used = 0; \
} \
\
PTABLE(T)::~PTABLE(T)() \
{ \
for (unsigned i = 0; i < size; i++) { \
free(v[i].key); \
/* XXX leak, because we don't know whether */ \
/* 'free', 'delete', or 'delete[]' should be used */ \
/* delete[] v[i].val; */ \
} \
delete[] v; \
} \
\
const char *PTABLE(T)::define(const char *key, T *val) \
{ \
assert(key != 0); \
unsigned long h = hash_string(key); \
unsigned n; \
for (n = unsigned(h % size); \
v[n].key != 0; \
n = (n == 0 ? size - 1 : n - 1)) \
if (strcmp(v[n].key, key) == 0) { \
/* XXX leak, because we don't know whether */ \
/* 'free', 'delete', or 'delete[]' should be used */ \
/* delete[] v[n].val; */ \
v[n].val = val; \
return v[n].key; \
} \
if (val == 0) \
return 0; \
if (used*FULL_DEN >= size*FULL_NUM) { \
PASSOC(T) *oldv = v; \
unsigned old_size = size; \
size = next_ptable_size(size); \
v = new PASSOC(T)[size]; \
for (unsigned i = 0; i < old_size; i++) \
if (oldv[i].key != 0) { \
if (oldv[i].val == 0) \
free(oldv[i].key); \
else { \
unsigned j; \
for (j = unsigned(hash_string(oldv[i].key) % size); \
v[j].key != 0; \
j = (j == 0 ? size - 1 : j - 1)) \
; \
v[j].key = oldv[i].key; \
v[j].val = oldv[i].val; \
} \
} \
for (n = unsigned(h % size); \
v[n].key != 0; \
n = (n == 0 ? size - 1 : n - 1)) \
; \
delete[] oldv; \
} \
char *temp = (char*)malloc(strlen(key)+1); \
strcpy(temp, key); \
v[n].key = temp; \
v[n].val = val; \
used++; \
return temp; \
} \
\
T *PTABLE(T)::lookup(const char *key) \
{ \
assert(key != 0); \
for (unsigned n = unsigned(hash_string(key) % size); \
v[n].key != 0; \
n = (n == 0 ? size - 1 : n - 1)) \
if (strcmp(v[n].key, key) == 0) \
return v[n].val; \
return 0; \
} \
\
T *PTABLE(T)::lookupassoc(const char **keyptr) \
{ \
const char *key = *keyptr; \
assert(key != 0); \
for (unsigned n = unsigned(hash_string(key) % size); \
v[n].key != 0; \
n = (n == 0 ? size - 1 : n - 1)) \
if (strcmp(v[n].key, key) == 0) { \
*keyptr = v[n].key; \
return v[n].val; \
} \
return 0; \
} \
\
PTABLE_ITERATOR(T)::PTABLE_ITERATOR(T)(PTABLE(T) *t) \
: p(t), i(0) \
{ \
} \
\
int PTABLE_ITERATOR(T)::next(const char **keyp, T **valp) \
{ \
unsigned size = p->size; \
PASSOC(T) *v = p->v; \
for (; i < size; i++) \
if (v[i].key != 0) { \
*keyp = v[i].key; \
*valp = v[i].val; \
i++; \
return 1; \
} \
return 0; \
}
// Local Variables:
// fill-column: 72
// mode: C++
// End:
// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
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