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/*
Copyright (C) 2004-2011 John E. Davis
This file is part of the S-Lang Library.
The S-Lang Library 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 of the
License, or (at your option) any later version.
The S-Lang Library 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 library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
USA.
*/
#include "slinclud.h"
#include "slang.h"
#include "_slang.h"
#ifdef upcase
# undef upcase
#endif
/* The Boyer-Moore search algorthm is used below under the following
* conditions:
*
* 1. The search is case-sensitive.
* 3. UTF-8 mode is not active.
* 2. The search key contains only of single byte characters.
* 4. The multi-byte characters in the key are case-less.
*
* Otherwise, the search is case-insensitive and the key consists of
* multi-byte characters. In this case, a modified BM algorithm is used
* _if_ each character in the key is composed of multi-byte characters that
* have upper and lower case versions of the same length.
*
* Otherwise, the search search will be performed in a brute-force manner.
*/
typedef struct
{
SLuchar_Type *key;
unsigned int key_len;
unsigned int fskip_table[256];
unsigned int bskip_table[256];
}
BoyerMoore_Search_Type;
typedef struct
{
SLuchar_Type **lower_chars;
SLuchar_Type **upper_chars;
unsigned int nlower_chars;
unsigned int nupper_chars;
SLsearch_Type *st;
}
BruteForce_Search_Type;
struct _pSLsearch_Type
{
SLuchar_Type *(*search_fun)(SLsearch_Type *, SLuchar_Type *, SLuchar_Type *, SLuchar_Type *, int);
void (*free_fun) (SLsearch_Type *);
int flags;
unsigned int match_len;
union
{
BoyerMoore_Search_Type bm;
BruteForce_Search_Type bf;
}
s;
};
/* Simple BM search--- case-sensitive, or case-less, or no UTF-8, or 7-bit ascii */
static SLuchar_Type *
bm_search_forward (SLsearch_Type *st, SLuchar_Type *beg, SLuchar_Type *end)
{
register unsigned char char1;
unsigned char *pos;
unsigned int *skip_table;
SLuchar_Type *key;
unsigned int key_len;
int case_fold;
BoyerMoore_Search_Type *bm;
bm = &st->s.bm;
key_len = bm->key_len;
st->match_len = 0;
if ((key_len > (unsigned int) (end - beg))
|| (key_len == 0))
return NULL;
case_fold = st->flags & SLSEARCH_CASELESS;
key = bm->key;
skip_table = bm->fskip_table;
char1 = key[key_len - 1];
beg += (key_len - 1);
while(1)
{
SLuchar_Type ch;
unsigned int dbeg;
unsigned int j;
while (beg < end)
{
ch = *beg;
dbeg = skip_table[ch];
if ((dbeg < key_len)
&& ((ch == char1)
|| (case_fold && (char1 == UPPER_CASE(ch)))))
break;
beg += dbeg;
}
if (beg >= end) return NULL;
pos = beg - (key_len - 1);
for (j = 0; j < key_len; j++)
{
ch = pos[j];
if ((key[j] != ch)
&& ((case_fold == 0)
|| (key[j] != UPPER_CASE(ch))))
break;
}
if (j == key_len)
{
st->match_len = key_len;
return pos;
}
beg += 1;
}
}
static SLuchar_Type *
bm_search_backward (SLsearch_Type *st,
SLuchar_Type *beg, SLuchar_Type *start, SLuchar_Type *end)
{
SLuchar_Type char1;
unsigned int j, ofs;
unsigned int key_len;
SLuchar_Type *key;
int case_fold;
unsigned int *skip_table;
BoyerMoore_Search_Type *bm;
st->match_len = 0;
bm = &st->s.bm;
key_len = bm->key_len;
if ((key_len > (unsigned int) (end - beg))
|| (key_len == 0)
|| (end <= beg)
|| (start < beg)
|| (start >= end))
return NULL;
case_fold = st->flags & SLSEARCH_CASELESS;
key = bm->key;
skip_table = bm->bskip_table;
if (start + key_len > end)
start = end - key_len;
char1 = key[0];
while(1)
{
SLuchar_Type ch;
while (beg <= start)
{
ch = *start;
if ((ch == char1)
|| (case_fold && (char1 == UPPER_CASE(ch))))
break;
ofs = skip_table[ch];
start -= ofs;
}
if (beg > start) return NULL;
for (j = 1; j < key_len; j++)
{
ch = start[j];
if ((key[j] != ch)
&& ((case_fold == 0)
|| (key[j] != UPPER_CASE(ch))))
break;
}
if (j == key_len)
{
st->match_len = key_len;
return start;
}
start--;
}
}
static SLuchar_Type *bm_search (SLsearch_Type *st,
SLuchar_Type *pmin, SLuchar_Type *p, SLuchar_Type *pmax,
int dir)
{
if (dir > 0)
return bm_search_forward (st, p, pmax);
else
return bm_search_backward (st, pmin, p, pmax);
}
/* Return value, if non-NULL returns pointer to the end of the string */
static SLuchar_Type *
looking_at_bf (SLuchar_Type *pmin, SLuchar_Type *pmax,
SLuchar_Type **lower_chars, unsigned int nlower_chars,
SLuchar_Type **upper_chars, unsigned int nupper_chars)
{
unsigned int n;
n = 0;
while ((n < nupper_chars) && (n < nlower_chars))
{
SLuchar_Type *up, *lo, *p;
up = upper_chars[n];
lo = lower_chars[n];
n++;
p = pmin;
while ((p < pmax)
&& (*up == *p)
&& (*up != 0))
{
up++;
p++;
}
if (*up == 0)
{
pmin = p;
continue;
}
p = pmin;
while ((p < pmax)
&& (*lo == *p)
&& (*lo != 0))
{
lo++;
p++;
}
if (*lo == 0)
{
pmin = p;
continue;
}
return NULL;
}
return pmin;
}
/* Brute force case-insensitive searches */
static SLuchar_Type *
bf_search_forward (SLsearch_Type *st,
SLuchar_Type *pmin, SLuchar_Type *pmax)
{
SLsearch_Type *bf_st;
SLuchar_Type chup, chlo;
SLuchar_Type **upper_chars;
SLuchar_Type **lower_chars;
unsigned int nupper_chars, nlower_chars;
bf_st = st->s.bf.st;
upper_chars = st->s.bf.upper_chars;
lower_chars = st->s.bf.lower_chars;
nupper_chars = st->s.bf.nupper_chars;
nlower_chars = st->s.bf.nlower_chars;
chup = upper_chars[0][0];
chlo = lower_chars[0][0];
while (1)
{
SLuchar_Type *p;
if (bf_st != NULL)
{
if (NULL == (pmin = SLsearch_forward (bf_st, pmin, pmax)))
{
st->match_len = 0;
return NULL;
}
p = pmin + bf_st->match_len;
}
else
{
while (pmin < pmax)
{
if ((*pmin == chup) || (*pmin == chlo))
break;
pmin++;
}
if (pmin >= pmax)
{
st->match_len = 0;
return NULL;
}
p = pmin;
}
p = looking_at_bf (p, pmax, lower_chars, nlower_chars,
upper_chars, nupper_chars);
if (p != NULL)
{
st->match_len = p - pmin;
return pmin;
}
pmin++;
}
}
static SLuchar_Type *
bf_search_backward (SLsearch_Type *st,
SLuchar_Type *pmin, SLuchar_Type *start, SLuchar_Type *pmax)
{
SLsearch_Type *bf_st;
SLuchar_Type chup, chlo;
SLuchar_Type **upper_chars;
SLuchar_Type **lower_chars;
unsigned int nupper_chars, nlower_chars;
bf_st = st->s.bf.st;
upper_chars = st->s.bf.upper_chars;
lower_chars = st->s.bf.lower_chars;
nupper_chars = st->s.bf.nupper_chars;
nlower_chars = st->s.bf.nlower_chars;
chup = upper_chars[0][0];
chlo = lower_chars[0][0];
while (1)
{
SLuchar_Type *p;
if (bf_st != NULL)
{
if (NULL == (start = SLsearch_backward (bf_st, pmin, start+1, pmax)))
{
st->match_len = 0;
return NULL;
}
p = start + bf_st->match_len;
}
else
{
/* start--; */
while (start >= pmin)
{
if ((*start == chup) || (*start == chlo))
break;
start--;
}
if (start < pmin)
{
st->match_len = 0;
return NULL;
}
p = start;
}
p = looking_at_bf (p, pmax, lower_chars, nlower_chars,
upper_chars, nupper_chars);
if (p != NULL)
{
st->match_len = p - start;
return start;
}
start--;
}
}
static SLuchar_Type *
bf_search (SLsearch_Type *st,
SLuchar_Type *pmin, SLuchar_Type *p, SLuchar_Type *pmax,
int dir)
{
if (dir > 0)
return bf_search_forward (st, p, pmax);
else
return bf_search_backward (st, pmin, p, pmax);
}
SLuchar_Type *SLsearch_forward (SLsearch_Type *st,
SLuchar_Type *pmin, SLuchar_Type *pmax)
{
if (st == NULL)
return NULL;
return st->search_fun (st, pmin, pmin, pmax, 1);
}
SLuchar_Type *SLsearch_backward (SLsearch_Type *st, SLuchar_Type *pmin,
SLuchar_Type *p, SLuchar_Type *pmax)
{
if (st == NULL)
return NULL;
/* For the backward search, the first character of the string
* is assumed satisfy pmin <= BEG < p
* and end satisfies pmin < END <= pmax
*/
return st->search_fun (st, pmin, p-1, pmax, -1);
}
static int Case_Tables_Ok;
static void init_skip_table (SLuchar_Type *key, unsigned int key_len,
unsigned int *skip_table, int dir, int flags)
{
unsigned int i;
for (i = 0; i < 256; i++)
skip_table[i] = key_len;
if (dir < 0)
key += (key_len-1);
/* For a case-insensitive search, the key here will be uppercased */
flags = flags & SLSEARCH_CASELESS;
i = 0;
while (i < key_len)
{
i++;
skip_table[*key] = key_len - i;
if (flags)
skip_table[LOWER_CASE(*key)] = key_len - i;
key += dir;
}
}
static void bm_free (SLsearch_Type *st)
{
SLang_free_slstring ((char *) st->s.bm.key);
}
static void bf_free (SLsearch_Type *st)
{
unsigned int i, n;
SLuchar_Type **a;
if (NULL != (a = st->s.bf.lower_chars))
{
n = st->s.bf.nlower_chars;
for (i = 0; i < n; i++)
SLang_free_slstring ((char *) a[i]);
SLfree ((char *) a);
}
if (NULL != (a = st->s.bf.upper_chars))
{
n = st->s.bf.nupper_chars;
for (i = 0; i < n; i++)
SLang_free_slstring ((char *) a[i]);
SLfree ((char *) a);
}
}
unsigned int SLsearch_match_len (SLsearch_Type *st)
{
if (st == NULL)
return 0;
return st->match_len;
}
void SLsearch_delete (SLsearch_Type *st)
{
if (st == NULL)
return;
(*st->free_fun) (st);
SLfree ((char *)st);
}
/* This is used if the key is not UTF-8, or it is but the search is case-sensitive */
static SLsearch_Type *bm_open_search (SLuchar_Type *key, int flags)
{
SLsearch_Type *st;
unsigned int keylen;
keylen = strlen ((char *)key);
if (NULL == (st = (SLsearch_Type *)SLcalloc (1, sizeof (SLsearch_Type))))
return NULL;
st->free_fun = bm_free;
/* If the search is case-insensitive, then it must either be all ascii, or
* it is not unicode. In either case, the UPPER_CASE and LOWER_CASE macros
* should be ok to use.
*/
if (flags & SLSEARCH_CASELESS)
{
char *keyup = SLmake_nstring ((char *)key, keylen);
if (keyup != NULL)
{
unsigned char *k = (unsigned char *)keyup;
while (*k != 0)
{
*k = UPPER_CASE(*k);
k++;
}
st->s.bm.key = (SLuchar_Type *)SLang_create_slstring (keyup);
SLfree (keyup);
}
else st->s.bm.key = NULL;
}
else st->s.bm.key = (SLuchar_Type*) SLang_create_slstring ((char *)key);
if (st->s.bm.key == NULL)
{
SLsearch_delete (st);
return NULL;
}
st->s.bm.key_len = keylen;
st->flags = flags;
st->search_fun = bm_search;
init_skip_table (st->s.bm.key, st->s.bm.key_len, st->s.bm.fskip_table, 1, flags);
init_skip_table (st->s.bm.key, st->s.bm.key_len, st->s.bm.bskip_table, -1, flags);
return st;
}
static int is_bm_ok (SLuchar_Type *key, unsigned int len, SLuchar_Type **non_ascii)
{
SLuchar_Type *keymax;
/* See if the key is ascii-only */
keymax = key + len;
while (key < keymax)
{
if (*key & 0x80)
{
*non_ascii = key;
return 0;
}
key++;
}
return 1;
}
static SLuchar_Type **make_string_array (SLuchar_Type *u, unsigned int len, unsigned int *nump)
{
SLuchar_Type *umax;
SLuchar_Type **a;
unsigned int num, i;
int ignore_combining = 0;
num = SLutf8_strlen (u, ignore_combining);
if (num == 0)
return NULL; /* should not happen */
if (NULL == (a = (SLuchar_Type **) SLcalloc (sizeof (SLuchar_Type *), num)))
return NULL;
umax = u + len;
for (i = 0; i < num; i++)
{
SLuchar_Type *u1 = SLutf8_skip_char (u, umax);
if (NULL == (a[i] = (SLuchar_Type *)SLang_create_nslstring ((char *)u, u1 - u)))
goto return_error;
u = u1;
}
*nump = num;
return a;
return_error:
for (i = 0; i < num; i++)
SLang_free_slstring ((char *) a[i]);
SLfree ((char *) a);
return NULL;
}
SLsearch_Type *SLsearch_new (SLuchar_Type *key, int flags)
{
SLsearch_Type *st, *bf_st;
SLuchar_Type *key_upper, *key_lower, *non_ascii;
unsigned int len, upper_len, lower_len;
if (Case_Tables_Ok == 0)
SLang_init_case_tables ();
if (key == NULL)
return NULL;
if ((0 == (flags & SLSEARCH_CASELESS))
|| (0 == (flags & SLSEARCH_UTF8)))
return bm_open_search (key, flags);
/* Otherwise the key is UTF-8 and the search is case-insensitive */
len = strlen ((char *)key);
key_upper = SLutf8_strup (key, key + len);
if (key_upper == NULL)
return NULL;
upper_len = strlen ((char *)key_upper);
if (is_bm_ok (key_upper, upper_len, &non_ascii))
{
st = bm_open_search (key_upper, flags);
SLang_free_slstring ((char *)key_upper);
return st;
}
/* Tricky part */
if (NULL == (key_lower = SLutf8_strlo (key, key + len)))
{
SLang_free_slstring ((char *)key_upper);
return NULL;
}
lower_len = strlen ((char *)key_lower);
/* Try a case-less search */
if ((lower_len == upper_len)
&& (0 == strcmp ((char *)key_upper, (char *)key_lower)))
{
flags &= ~SLSEARCH_CASELESS;
st = bm_open_search (key_upper, flags);
SLang_free_slstring ((char *)key_upper);
SLang_free_slstring ((char *)key_lower);
return st;
}
/* Now Perform a brute-force search. */
/* If the first few characters of the search string are ascii, then
* use BM for that portion
*/
bf_st = NULL;
if (non_ascii - key_upper >= 3)
{
SLuchar_Type *key1 = (SLuchar_Type *) SLmake_nstring ((char *)key_upper, non_ascii - key_upper);
/* ok to propagate NULL below */
bf_st = SLsearch_new (key1, flags);
SLfree ((char *)key1);
if (bf_st == NULL)
{
SLang_free_slstring ((char *)key_upper);
SLang_free_slstring ((char *)key_lower);
return NULL;
}
key1 = (SLuchar_Type *) SLang_create_slstring ((char *)non_ascii);
non_ascii = key_lower + (non_ascii - key_upper);
SLang_free_slstring ((char *)key_upper);
key_upper = key1;
key1 = (SLuchar_Type *)SLang_create_slstring ((char *)non_ascii);
SLang_free_slstring ((char *)key_lower);
key_lower = key1;
if ((key_lower == NULL) || (key_upper == NULL))
{
SLang_free_slstring ((char *)key_upper);
SLang_free_slstring ((char *)key_lower);
SLsearch_delete (bf_st);
return NULL;
}
upper_len = strlen ((char *)key_upper);
lower_len = strlen ((char *)key_lower);
}
st = (SLsearch_Type *)SLcalloc (sizeof (SLsearch_Type), 1);
if (st == NULL)
goto return_error;
st->free_fun = bf_free;
st->flags = flags;
st->search_fun = bf_search;
st->s.bf.st = bf_st; bf_st = NULL;
if (NULL == (st->s.bf.lower_chars = make_string_array (key_lower, lower_len, &st->s.bf.nlower_chars)))
goto return_error;
if (NULL == (st->s.bf.upper_chars = make_string_array (key_upper, upper_len, &st->s.bf.nupper_chars)))
goto return_error;
SLang_free_slstring ((char *)key_upper);
SLang_free_slstring ((char *)key_lower);
return st;
return_error:
SLsearch_delete (st);
SLsearch_delete (bf_st);
SLang_free_slstring ((char *)key_upper);
SLang_free_slstring ((char *)key_lower);
return NULL;
}
/* 8bit clean upper and lowercase tables. These are used _only_ when UTF-8
* mode is not active, or when uppercasing ASCII.
*/
unsigned char _pSLChg_LCase_Lut[256] = {0};
unsigned char _pSLChg_UCase_Lut[256] = {0};
void SLang_define_case (int *u, int *l)
{
unsigned char up = (unsigned char) *u, dn = (unsigned char) *l;
_pSLChg_LCase_Lut[up] = dn;
_pSLChg_LCase_Lut[dn] = dn;
_pSLChg_UCase_Lut[dn] = up;
_pSLChg_UCase_Lut[up] = up;
}
void SLang_init_case_tables (void)
{
int i, j;
if (Case_Tables_Ok) return;
for (i = 0; i < 256; i++)
{
_pSLChg_UCase_Lut[i] = i;
_pSLChg_LCase_Lut[i] = i;
}
for (i = 'A'; i <= 'Z'; i++)
{
j = i + 32;
_pSLChg_UCase_Lut[j] = i;
_pSLChg_LCase_Lut[i] = j;
}
#ifdef PC_SYSTEM
/* Initialize for DOS code page 437. */
_pSLChg_UCase_Lut[135] = 128; _pSLChg_LCase_Lut[128] = 135;
_pSLChg_UCase_Lut[132] = 142; _pSLChg_LCase_Lut[142] = 132;
_pSLChg_UCase_Lut[134] = 143; _pSLChg_LCase_Lut[143] = 134;
_pSLChg_UCase_Lut[130] = 144; _pSLChg_LCase_Lut[144] = 130;
_pSLChg_UCase_Lut[145] = 146; _pSLChg_LCase_Lut[146] = 145;
_pSLChg_UCase_Lut[148] = 153; _pSLChg_LCase_Lut[153] = 148;
_pSLChg_UCase_Lut[129] = 154; _pSLChg_LCase_Lut[154] = 129;
_pSLChg_UCase_Lut[164] = 165; _pSLChg_LCase_Lut[165] = 164;
#else
/* ISO Latin */
for (i = 192; i <= 221; i++)
{
j = i + 32;
_pSLChg_UCase_Lut[j] = i;
_pSLChg_LCase_Lut[i] = j;
}
_pSLChg_UCase_Lut[215] = 215; _pSLChg_LCase_Lut[215] = 215;
_pSLChg_UCase_Lut[223] = 223; _pSLChg_LCase_Lut[223] = 223;
_pSLChg_UCase_Lut[247] = 247; _pSLChg_LCase_Lut[247] = 247;
_pSLChg_UCase_Lut[255] = 255; _pSLChg_LCase_Lut[255] = 255;
#endif
Case_Tables_Ok = 1;
}
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