wrdk/wiki-app/bigram.c

/*
 * Copyright (c) 2009 Openmoko Inc.
 *
 * This program 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.
 *
 * This program 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 <string.h>
#include <stdlib.h>
#include "msg.h"
#include "bigram.h"
#include "lcd_buf_draw.h"
#ifdef WIKIPCF
extern void showMsg(int currentLevel, char *format, ...);
#include <assert.h>
#else
#include "file-io.h"
#endif

char aBigram[128][2];
int32_t aCharIdx[128];
#ifdef WIKIPCF
void init_bigram(FILE *fd)
{
	init_char_idx();
	ssize_t n = fread(aBigram, 1, sizeof(aBigram), fd);
	assert(sizeof(aBigram) == n);
}
#else

void init_bigram(int fd)
{
	init_char_idx();
	wl_read(fd, aBigram, sizeof(aBigram));
}
#endif

void init_char_idx()
{
	char c;
	int i;
	int idx = 1;

	memset(aCharIdx, 0, sizeof(aCharIdx));
	for (i = 0; i < 128; i++)
	{
		c = (char)i;
		if (is_supported_search_char(c))
		{
			if ('a' <= c && c <= 'z')
				aCharIdx[i] = aCharIdx[(int)'A' + (c - 'a')];
			else
				aCharIdx[i] = idx++;
		}
	}
}

int bigram_char_idx(char c)
{
	return aCharIdx[(int)c];
}

void bigram_encode(char *outStr, char *inStr)
{
	int i;
	int len;
	int rc;
	char c;
	int idxMatchedBigram;

	*outStr = '\0';
	len = strlen(inStr);
	while (len >= 2)
	{
		idxMatchedBigram = -1;
		for (i=0; i < 128; i++)
		{
			if ((rc = memcmp(inStr, &aBigram[i][0], 2)) == 0)
			{
				idxMatchedBigram = i;
				break;
			}
			else if (rc < 0)
				break;
		}
		if (idxMatchedBigram >= 0)
		{
			c = (char)i;
			c |= 0x80;
			*outStr = c;
			outStr++;
			inStr += 2;
			len -= 2;
		}
		else
		{
			*outStr = *inStr;
			outStr++;
			inStr++;
			len--;
		}
	}

	while (len > 0)
	{
		*outStr = *inStr;
		outStr++;
		inStr++;
		len--;
	}
	*outStr = '\0';
}

void bigram_decode(char *outStr, char *inStr, int lenMax)
{
	unsigned char c;

	while (lenMax > 1 && (c = *inStr++) != '\0')
	{
		if (c >= 128)
		{
			*outStr = aBigram[c-128][0];
			outStr++;
			lenMax--;
			if (lenMax > 1)
			{
				*outStr = aBigram[c-128][1];
				outStr++;
				lenMax--;
			}
		}
		else
		{
			*outStr = c;
			outStr++;
			lenMax--;
		}
	}
	*outStr = '\0';
}

int is_supported_search_char(char c)
{
	if (c && (strchr(SUPPORTED_SEARCH_CHARS, c) || ('A' <= c && c <= 'Z')))
		return 1;
	else
		return 0;
}

int search_string_cmp(char *title, char *search, int len)  // assuming search consists of lowercase only
{
	int rc = 0;
	char c = 0;

#if 0  // some debug message
#ifdef WIKIPCF
	char temp[512];
	memcpy(temp, search, len);
	temp[len] = '\0';
	showMsg(3, "[%s][%s]\n", title, temp);
#endif
#endif

	while (!rc && len > 0)
	{
		c = *title;
		if (c && !is_supported_search_char(c))
		{
			title++;
		}
		else
		{
			if ('A' <= c && c <= 'Z')
				c += 32;
			if (c == *search)
			{
				title++;
				search++;
				len--;
			}
			else if (c > *search)
				rc = 1;
			else
				rc = -1;
		}
	}
	return rc;
}