Examples
This example provides sample code for a stateless converter that performs an algorithm-based convertion of the IBM-850 code set to the ISO8859-1 code set.
The file name for this example is 850_88591.c
#include <stdlib.h>
#include <iconv.h>
#include "850_88591.h"
#define DONE 0
/*
* Name : _iconv_exec()
*
* This contains actual conversion method.
*/
static size_t _iconv_exec(_LC_sample_iconv_t *cd,
unsigned char** inbuf, size_t *inbytesleft,
unsigned char** outbuf, size_t *outbytesleft)
/*
* cd : converter descriptor
* inbuf : input buffer
* outbuf : output buffer
* inbytesleft : number of data(in bytes) in input buffer
* outbytesleft : number of data(in bytes) in output buffer
*/
{
unsigned char *in; /* point the input buffer */
unsigned char *out; /* point the output buffer */
unsigned char *e_in; /* point the end of input buffer*/
unsigned char *e_out; /* point the end of output buffer*/
/*
* If given converter discripter is invalid,
* it sets the errno and returns the number
* of bytes left to be converted.
*/
if (!cd) {
errno = EBADF;
return *inbytesleft;
}
/*
* If the input buffer does not exist or there
* is no character to be converted, it returns
* 0 (no characters to be converted).
*/
if (!inbuf || !(*inbytesleft))
return DONE;
/*
* Set up pointers and initialize other variables
*/
e_in = (in = *inbuf) + *inbytesleft;
e_out = (out = *outbuf) + *outbytesleft;
/*
* Perform code point conversion until all input
* is consumed.
* When error occurs (i.e. buffer overflow), error
* number is set and exit this loop.
*/
while (in < e_in) {
/*
* If there is not enough space left in output buffer
* to hold the converted data, it stops converting and
* sets the errno to E2BIG.
*/
if (e_out <= out) {
errno = E2BIG;
break;
}
/*
* Convert the input data and store it into the output
* buffer, then advance the pointers which point to the
* buffers.
*/
*out++ = table[*in++];
} /* while */
/*
* Update the pointers to the buffers and
* input /output byte counts
*/
*inbuf = in;
*outbuf = out;
*inbytesleft = e_in - in;
*outbytesleft = e_out - out;
/*
* Reurn the number of bytes left to be converted
* (0 for successful conversion completion)
*/
return *inbytesleft;
}
/*
* Name : _iconv_close()
*
* Free the allocated converter descriptor
*/
static void _iconv_close(iconv_t cd)
{
if (!cd)
free(cd);
else
/*
* If given converter is not valid,
* it sets the errno to EBADF
*/
errno = EBADF;
}
/*
* Name : init()
*
* This allocates and initializes the converter descriptor.
*/
static _LC_sample_iconv_t*
init (_LC_core_iconv_t *core_cd, char* toname, char* fromname)
{
_LC_sample_iconv_t *cd; /* converter descriptor */
/*
* Allocate a converter descriptor
*/
if (!(cd = (_LC_sample_iconv_t *)
malloc(sizeof(_LC_sample_iconv_t))))
return (NULL);
/*
*Copy the core part of converter descriptor which is passed *in
*/
cd->core = *core_cd;
/*
* Return the converter descriptor
*/
return cd;
}
/*
* Name : instantiate()
*
* Core part of a converter descriptor is initialized here.
*/
_LC_core_iconv_t* instantiate(void)
{
static _LC_core_iconv_t cd;
/*
* Initialize
* _LC_MAGIC and _LC_VERSION are defined in <lc_core.h>.
* _LC_ICONV and _LC_core_iconv_t are defined in <iconv.h>.
*/
cd.hdr.magic = _LC_MAGIC;
cd.hdr.version = _LC_VERSION;
cd.hdr.type_id = _LC_ICONV;
cd.hdr.size = sizeof (_LC_core_iconv_t);
/*
* Set pointers to each method.
*/
cd.init = init;
cd.exec = _iconv_exec;
cd.close = _iconv_close;
/*
* Returns the core part
*/
return &cd;
}
This example contains a sample header file named 850_88591.h.
#ifndef _ICONV_SAMPLE_H
#define _ICONV_SAMPLE_H
/*
* Define _LC_sample_iconv_t
*/
typedef struct _LC_sample_iconv_rec {
_LC_core_iconv_t core;
} _LC_sample_iconv_t;
static unsigned char table[] = { /*
_______________________________________
| |
| IBM-850 ISO8859-1 |
|_______________________________________|
/* 0x00 */ 0x00,
/* 0x01 */ 0x01,
/* 0x02 */ 0x02,
/* 0x03 */ 0x03,
/* 0x04 */ 0x04,
/* 0x05 */ 0x05,
/* 0x06 */ 0x06,
/* 0x07 */ 0x07,
/* 0x08 */ 0x08,
/* 0x09 */ 0x09,
/* 0x0A */ 0x0A,
/* 0x0B */ 0x0B,
/* 0x0C */ 0x0C,
/* 0x0D */ 0x0D,
.
.
.
/* 0xF3 */ 0xBE,
/* 0xF4 */ 0xB6,
/* 0xF5 */ 0xA7,
/* 0xF6 */ 0xF7,
/* 0xF7 */ 0xB8,
/* 0xF8 */ 0xB0,
/* 0xF9 */ 0xA8,
/* 0xFA */ 0xB7,
/* 0xFB */ 0xB9,
/* 0xFC */ 0xB3,
/* 0xFD */ 0xB2,
/* 0xFE */ 0x1A,
/* 0xFF */ 0xA0,
};
#endifThis example is a sample makefile.
SHELL = /bin/ksh
CFLAGS = $(COMPOPT) $(INCLUDE) $(DEFINES)
INCLUDE = -I.
COMPOPT =
DEFINES = -D_POSIX_SOURCE -D_XOPEN_SOURCE
CC = /bin/xlc
LD = /bin/ld
RM = /bin/rm
SRC = 850_88591.c
TARGET = 850_88591
ENTRY_POINT = instantiate
$(TARGET) :
cc -e $(ENTRY_POINT) -o $(TARGET) $(SRC) -l iconv
clean :
$(RM) -f $(TARGET)
$(RM) -f *.o