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/* libwapcaplet.h
*
* String internment and management tools.
*
* Copyright 2009 The NetSurf Browser Project.
* Daniel Silverstone <dsilvers@netsurf-browser.org>
*/
#include <string.h>
#include <stdint.h>
#include <assert.h>
#include "libwapcaplet/libwapcaplet.h"
typedef uint32_t lwc_hash;
typedef uint32_t lwc_refcounter;
static inline lwc_hash
lwc_calculate_hash(const char *str, size_t len)
{
lwc_hash z = 0x811c9dc5;
while (len > 0) {
z *= 0x01000193;
z ^= *str++;
len--;
}
return z;
}
struct lwc_string_s {
lwc_string ** prevptr;
lwc_string * next;
size_t len;
lwc_hash hash;
lwc_refcounter refcnt;
lwc_string * insensitive;
};
#define STR_OF(str) ((char *)(str + 1))
#define CSTR_OF(str) ((const char *)(str + 1))
#define NR_BUCKETS (4091)
struct lwc_context_s {
lwc_allocator_fn alloc;
void * alloc_pw;
lwc_string * buckets[NR_BUCKETS];
lwc_refcounter refcnt;
bool refweak;
};
lwc_error
lwc_create_context(lwc_allocator_fn alloc, void *pw,
lwc_context **ret)
{
assert(alloc);
*ret = alloc(NULL, sizeof(lwc_context), pw);
if (*ret == NULL)
return lwc_error_oom;
memset(*ret, 0, sizeof(lwc_context));
(*ret)->alloc = alloc;
(*ret)->alloc_pw = pw;
(*ret)->refcnt = 1;
(*ret)->refweak = true;
return lwc_error_ok;
}
lwc_context *
lwc_context_ref(lwc_context *ctx)
{
assert(ctx);
if (ctx->refweak == true)
ctx->refweak = false;
else
ctx->refcnt++;
return ctx;
}
#define LWC_ALLOC(s) ctx->alloc(NULL, s, ctx->alloc_pw)
#define LWC_FREE(p) ctx->alloc(p, 0, ctx->alloc_pw)
void
lwc_context_unref(lwc_context *ctx)
{
int bucket_nr;
lwc_string *s, *s_next;
assert(ctx);
if (--(ctx->refcnt))
return;
for (bucket_nr = 0; bucket_nr < NR_BUCKETS; ++bucket_nr) {
s = ctx->buckets[bucket_nr];
while (s != NULL) {
s_next = s->next;
LWC_FREE(s);
s = s_next;
}
}
LWC_FREE(ctx);
}
typedef lwc_hash (*lwc_hasher)(const char *, size_t);
typedef int (*lwc_strncmp)(const char *, const char *, size_t);
typedef void (*lwc_memcpy)(char *, const char *, size_t);
static lwc_error
__lwc_context_intern(lwc_context *ctx,
const char *s, size_t slen,
lwc_string **ret,
lwc_hasher hasher,
lwc_strncmp compare,
lwc_memcpy copy)
{
lwc_hash h;
lwc_hash bucket;
lwc_string *str;
assert(ctx);
assert((s != NULL) || (slen == 0));
assert(ret);
h = hasher(s, slen);
bucket = h % NR_BUCKETS;
str = ctx->buckets[bucket];
while (str != NULL) {
if ((str->hash == h) && (str->len == slen)) {
if (compare(CSTR_OF(str), s, slen) == 0) {
str->refcnt++;
*ret = str;
return lwc_error_ok;
}
}
str = str->next;
}
*ret = str = LWC_ALLOC(sizeof(lwc_string) + slen);
if (str == NULL)
return lwc_error_oom;
str->prevptr = &(ctx->buckets[bucket]);
str->next = ctx->buckets[bucket];
if (str->next != NULL)
str->next->prevptr = &(str->next);
ctx->buckets[bucket] = str;
str->len = slen;
str->hash = h;
str->refcnt = 1;
str->insensitive = NULL;
copy(STR_OF(str), s, slen);
return lwc_error_ok;
}
lwc_error
lwc_context_intern(lwc_context *ctx,
const char *s, size_t slen,
lwc_string **ret)
{
return __lwc_context_intern(ctx, s, slen, ret,
lwc_calculate_hash,
strncmp, (lwc_memcpy)memcpy);
}
lwc_error
lwc_context_intern_substring(lwc_context *ctx,
lwc_string *str,
size_t ssoffset, size_t sslen,
lwc_string **ret)
{
assert(ctx);
assert(str);
assert(ret);
if (ssoffset >= str->len)
return lwc_error_range;
if ((ssoffset + sslen) > str->len)
return lwc_error_range;
return lwc_context_intern(ctx, CSTR_OF(str) + ssoffset, sslen, ret);
}
lwc_string *
lwc_context_string_ref(lwc_context *ctx, lwc_string *str)
{
assert(ctx);
assert(str);
str->refcnt++;
return str;
}
void
lwc_context_string_unref(lwc_context *ctx, lwc_string *str)
{
assert(ctx);
assert(str);
if (--(str->refcnt) > 1)
return;
if ((str->refcnt == 1) && (str->insensitive != str))
return;
*(str->prevptr) = str->next;
if (str->next != NULL)
str->next->prevptr = str->prevptr;
if (str->insensitive != NULL && str->refcnt == 0)
lwc_context_string_unref(ctx, str->insensitive);
LWC_FREE(str);
}
/**** Shonky caseless bits ****/
static inline char
dolower(const char c)
{
if (c >= 'A' && c <= 'Z')
return c + 'a' - 'A';
return c;
}
static inline lwc_hash
lwc_calculate_lcase_hash(const char *str, size_t len)
{
lwc_hash z = 0x811c9dc5;
while (len > 0) {
z *= 0x01000193;
z ^= dolower(*str++);
len--;
}
return z;
}
static int
lwc_lcase_strcmp(const char *s1, const char *s2, size_t n)
{
while (n--) {
if (*s1++ != dolower(*s2++))
return 1;
}
return 0;
}
static void
lwc_lcase_memcpy(char *target, const char *source, size_t n)
{
while (n--) {
*target++ = dolower(*source++);
}
}
static lwc_error
lwc_context_intern_caseless(lwc_context *ctx,
lwc_string *str)
{
assert(ctx);
assert(str);
assert(str->insensitive == NULL);
return __lwc_context_intern(ctx, CSTR_OF(str),
str->len, &(str->insensitive),
lwc_calculate_lcase_hash,
lwc_lcase_strcmp,
lwc_lcase_memcpy);
}
lwc_error
lwc_context_string_caseless_isequal(lwc_context *ctx,
lwc_string *str1,
lwc_string *str2,
bool *ret)
{
lwc_error err;
assert(ctx);
assert(str1);
assert(str2);
if (str1->insensitive == NULL) {
err = lwc_context_intern_caseless(ctx, str1);
if (err != lwc_error_ok)
return err;
}
if (str2->insensitive == NULL) {
err = lwc_context_intern_caseless(ctx, str2);
if (err != lwc_error_ok)
return err;
}
*ret = (str1->insensitive == str2->insensitive);
return lwc_error_ok;
}
/**** Simple accessors ****/
const char *
lwc_string_data(lwc_string *str)
{
assert(str);
return CSTR_OF(str);
}
size_t
lwc_string_length(lwc_string *str)
{
assert(str);
return str->len;
}
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