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/* $Id: ascii.c,v 1.8 2009/06/10 20:18:43 kristaps Exp $ */
/*
* Copyright (c) 2009 Kristaps Dzonsons <kristaps@kth.se>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <assert.h>
#include <err.h>
#include <stdlib.h>
#include <string.h>
#include "term.h"
#define ASCII_PRINT_HI 126
#define ASCII_PRINT_LO 32
struct line {
const char *code;
const char *out;
/* 32- and 64-bit alignment safe. */
size_t codesz;
size_t outsz;
};
struct linep {
const struct line *line;
struct linep *next;
};
#define LINE(w, x, y, z) \
{ (w), (y), (x), (z) },
static const struct line lines[] = {
#include "ascii.in"
};
struct asciitab {
struct linep *lines;
void **htab;
};
static inline int match(const struct line *,
const char *, size_t);
void
term_asciifree(void *arg)
{
struct asciitab *tab;
tab = (struct asciitab *)arg;
free(tab->lines);
free(tab->htab);
free(tab);
}
void *
term_ascii2htab(void)
{
struct asciitab *tab;
void **htab;
struct linep *pp, *p;
int i, len, hash;
/*
* Constructs a very basic chaining hashtable. The hash routine
* is simply the integral value of the first character.
* Subsequent entries are chained in the order they're processed
* (they're in-line re-ordered during lookup).
*/
if (NULL == (tab = malloc(sizeof(struct asciitab))))
err(1, "malloc");
len = sizeof(lines) / sizeof(struct line);
if (NULL == (p = calloc((size_t)len, sizeof(struct linep))))
err(1, "malloc");
htab = calloc(ASCII_PRINT_HI - ASCII_PRINT_LO + 1,
sizeof(struct linep **));
if (NULL == htab)
err(1, "malloc");
for (i = 0; i < len; i++) {
assert(lines[i].codesz > 0);
assert(lines[i].code);
assert(lines[i].out);
p[i].line = &lines[i];
hash = (int)lines[i].code[0] - ASCII_PRINT_LO;
if (NULL == (pp = ((struct linep **)htab)[hash])) {
htab[hash] = &p[i];
continue;
}
for ( ; pp->next; pp = pp->next)
/* Scan ahead. */ ;
pp->next = &p[i];
}
tab->htab = htab;
tab->lines = p;
return(tab);
}
const char *
term_a2ascii(void *arg, const char *p, size_t sz, size_t *rsz)
{
struct asciitab *tab;
struct linep *pp, *prev;
void **htab;
int hash;
tab = (struct asciitab *)arg;
htab = tab->htab;
assert(p);
assert(sz > 0);
if (p[0] < ASCII_PRINT_LO || p[0] > ASCII_PRINT_HI)
return(NULL);
/*
* Lookup the symbol in the symbol hash. See ascii2htab for the
* hashtable specs. This dynamically re-orders the hash chain
* to optimise for repeat hits.
*/
hash = (int)p[0] - ASCII_PRINT_LO;
if (NULL == (pp = ((struct linep **)htab)[hash]))
return(NULL);
if (NULL == pp->next) {
if ( ! match(pp->line, p, sz))
return(NULL);
*rsz = pp->line->outsz;
return(pp->line->out);
}
for (prev = NULL; pp; pp = pp->next) {
if ( ! match(pp->line, p, sz)) {
prev = pp;
continue;
}
/* Re-order the hash chain. */
if (prev) {
prev->next = pp->next;
pp->next = ((struct linep **)htab)[hash];
htab[hash] = pp;
}
*rsz = pp->line->outsz;
return(pp->line->out);
}
return(NULL);
}
static inline int
match(const struct line *line, const char *p, size_t sz)
{
if (line->codesz != sz)
return(0);
return(0 == strncmp(line->code, p, sz));
}
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