Added UTF-8 conversion functions

This commit is contained in:
Olaf Barthel
2016-04-02 12:27:49 +02:00
parent abba9e78ce
commit d6fe46462f
2 changed files with 400 additions and 0 deletions
+349
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@@ -0,0 +1,349 @@
/*
* :ts=4
*
* SMB file system wrapper for AmigaOS, using the AmiTCP V3 API
*
* Copyright (C) 2000-2016 by Olaf `Olsen' Barthel <obarthel -at- gmx -dot- net>
*
* 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 2 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, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <stddef.h>
#include "utf-8-iso-8859-1-conversion.h"
/* Encode an ISO 8859 Latin 1 character (default character set for
* the Amiga) in UTF-8 representation (rfc2279). Returns the number
* of characters written to the buffer, or -2 for 'buffer overflow'
* in which case no data is written.
*
* If the address of the buffer to write to is NULL, then no data
* will be written; only the number of bytes that would have been
* written if the buffer address were not NULL will be returned.
*/
static int
encode_iso8859_1_as_utf8_char(unsigned char c,unsigned char * string,int size)
{
int len;
if((c & 0x80) == 0)
{
/* ASCII characters can be encoded as a single octet. */
if(string == NULL || size >= 1)
{
len = 1;
if(string != NULL)
string[0] = c;
}
else
{
/* Not enough room... */
len = -2;
}
}
else
{
/* ISO 8859 Latin 1 characters must be encoded as two octets. */
if(string == NULL || size >= 2)
{
len = 2;
if(string != NULL)
{
string[0] = 0xc0 | ((c >> 6) & 0x03);
string[1] = 0x80 | (c & 0x3f);
}
}
else
{
/* Not enough room... */
len = -2;
}
}
return(len);
}
/****************************************************************************/
/* Data used by the decoder. */
struct utf8_decoding_entry
{
unsigned char mask; /* Mask and pattern are used to identify */
unsigned char pattern; /* the type of multi-octet sequence */
int len; /* Number of octets in the sequence */
long first; /* First and last are for checking the */
long last; /* resulting character against its code range */
};
/****************************************************************************/
/* Decode a character in UTF-8 representation (rfc2279) and return
* how many bytes contributed to that character (1-6). Returns
* -1 if the character could not be decoded or -2 if more bytes
* would be required for decoding than the input buffer holds.
* Returns -3 if the character was not encoded as the shortest
* possible UTF-8 sequence.
*
* If an error is indicated, no data will be written.
*
* If the address of the output buffer to write to is NULL, then no
* data will be written; only the number of bytes that would have
* been decoded if the buffer address were not NULL will be returned.
*/
static int
decode_utf8_char(const unsigned char * const string,int size,unsigned long * result_ptr)
{
int len;
if(size > 0)
{
int c,i;
/* Assume a seven bit ASCII character. */
c = string[0];
/* Could this be an UTF-8 encoded character? */
if((c & 0x80) != 0)
{
static const struct utf8_decoding_entry utf8_decoding_table[5] =
{
{ 0xfe,0xfc,6,0x04000000,0x7FFFFFFF }, /* 1111110x (UCS-4 range 04000000-7FFFFFFF) */
{ 0xfc,0xf8,5,0x00200000,0x03FFFFFF }, /* 111110xx (UCS-4 range 00200000-03FFFFFF) */
{ 0xf8,0xf0,4,0x00010000,0x001FFFFF }, /* 11110xxx (UCS-4 range 00010000-001FFFFF) */
{ 0xf0,0xe0,3,0x00000800,0x0000FFFF }, /* 1110xxxx (UCS-4 range 00000800-0000FFFF) */
{ 0xe0,0xc0,2,0x00000080,0x000007FF } /* 110xxxxx (UCS-4 range 00000080-000007FF) */
};
/* Find the bit pattern that corresponds to the
* code; if none matches, then we have an
* invalid code.
*/
len = -1;
for(i = 0 ; i < 5 ; i++)
{
if((c & utf8_decoding_table[i].mask) == utf8_decoding_table[i].pattern)
{
/* Strip the encoding pattern and retain
* the 'payload'.
*/
c &= ~utf8_decoding_table[i].mask;
/* If the character would consist of more octects
* than the input buffer holds, we flag an underflow
* error.
*/
len = utf8_decoding_table[i].len;
if(len <= size)
{
int j,d;
/* The next few octets contain six bits of
* character data each.
*/
for(j = 1 ; j < len ; j++)
{
d = string[j];
/* Each octet must be in the form
* of 10xxxxxx.
*/
if((d & 0xc0) == 0x80)
{
c = (c << 6) | (d & 0x3f);
}
else
{
/* Bad code... */
len = -1;
break;
}
}
if(len > 0)
{
/* Verify that the character was encoded
* in the shortest form possible.
*/
if(c < utf8_decoding_table[i].first ||
c > utf8_decoding_table[i].last)
{
len = -3;
}
}
}
else
{
len = -2;
}
break;
}
}
}
else
{
len = 1;
}
if(len > 0 && result_ptr != NULL)
(*result_ptr) = c;
}
else
{
len = 0;
}
return(len);
}
/****************************************************************************/
/* Encode a string of characters in ISO 8859 Latin-1 encoding into
* UTF-8 representation (rfc2279). Will encode as many characters as
* will fit into the output buffer, and NUL-terminates the result.
* Returns the number of UTF-8 characters in the output buffer.
*/
int
encode_iso8859_1_as_utf8_string(const unsigned char * const from,int from_len,unsigned char * to,int to_size)
{
int i,char_len,total_len;
int result;
total_len = 0;
for(i = 0 ; i < from_len ; i++)
{
result = encode_iso8859_1_as_utf8_char(from[i],to,to_size-1);
if(result < 0)
{
/* Stop on buffer overflow or error. */
goto out;
}
char_len = result;
if(to != NULL)
{
to += char_len;
to_size -= char_len;
}
total_len += char_len;
}
/* Provide for NUL termination. */
if(to != NULL && to_size > 0)
(*to) = '\0';
result = total_len;
out:
return(result);
}
/****************************************************************************/
/* Decode a string of characters encoded in UTF-8 representation (rfc2279).
* Will decode and retain only characters that can be decoded properly
* and which fit into the ASCII/BMP Latin-1 supplementary range. Will
* decode as many characters as will fit into the output buffer, and
* NUL-terminates the result. Returns the number of characters in the
* output buffer, or -1 for decoding error.
*
* Note that decoding will stop once a NUL has been found in the
* input string to be decoded.
*/
int
decode_utf8_as_iso8859_1_string(const unsigned char * const from,int from_len,unsigned char * to,int to_size)
{
unsigned long c;
int i,char_len,total_len;
int result = -1;
total_len = 0;
i = 0;
/* Process the entire input buffer unless we hit
* a NUL first.
*/
while(from_len > 0)
{
char_len = decode_utf8_char(&from[i],from_len,&c);
if(char_len > 0)
{
from_len -= char_len;
i += char_len;
/* Allow only for ASCII/BMP Latin-1 supplementary
* characters.
*/
if(c >= 256)
goto out;
/* Is there still enough room for the character
* and a terminating NUL byte?
*/
if(to == NULL || to_size-1 > 0)
{
/* Add this only if it's not the terminating
* NUL byte.
*/
if(c != '\0')
{
if(to != NULL)
{
(*to++) = c;
to_size--;
}
total_len++;
}
else
{
/* Found a terminating NUL byte. */
break;
}
}
else
{
/* No more room in the buffer. */
if(to != NULL)
break;
}
}
else
{
/* Underflow or invalid code. */
goto out;
}
}
/* Provide for NUL-termination. */
if(to != NULL && to_size > 0)
(*to) = '\0';
result = total_len;
out:
return(result);
}
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@@ -0,0 +1,51 @@
/*
* :ts=4
*
* SMB file system wrapper for AmigaOS, using the AmiTCP V3 API
*
* Copyright (C) 2000-2016 by Olaf `Olsen' Barthel <obarthel -at- gmx -dot- net>
*
* 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 2 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, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef _UTF_8_ISO_8859_1_CONVERSION_H
#define _UTF_8_ISO_8859_1_CONVERSION_H
/****************************************************************************/
/* Encode a string of characters in ISO 8859 Latin-1 encoding into
* UTF-8 representation (rfc2279). Will encode as many characters as
* will fit into the output buffer, and NUL-terminates the result.
* Returns the number of UTF-8 characters in the output buffer.
*/
extern int encode_iso8859_1_as_utf8_string(const unsigned char * const from,int from_len,unsigned char * to,int to_size);
/****************************************************************************/
/* Decode a string of characters encoded in UTF-8 representation (rfc2279).
* Will decode and retain only characters that can be decoded properly
* and which fit into the ASCII/BMP Latin-1 supplementary range. Will
* decode as many characters as will fit into the output buffer, and
* NUL-terminates the result. Returns the number of characters in the
* output buffer, or -1 for decoding error.
*
* Note that decoding will stop once a NUL has been found in the
* input string to be decoded.
*/
extern int decode_utf8_as_iso8859_1_string(const unsigned char * const from,int from_len,unsigned char * to,int to_size);
/****************************************************************************/
#endif /* _UTF_8_ISO_8859_1_CONVERSION_H */