93 lines
2.8 KiB
Markdown
93 lines
2.8 KiB
Markdown
|
---
|
||
|
layout: page
|
||
|
title: character encoding and conversions
|
||
|
---
|
||
|
libcasio has its own portable character encoding conversion, resembling
|
||
|
iconv. It supports Unicode transformation formats (UTF-8, UTF-16, UTF-32)
|
||
|
and CASIO's proprietary character encoding named FONTCHARACTER according to
|
||
|
the SDK it published in 2006 for the fx-9860G.
|
||
|
|
||
|
The character conversion utilities are defined in `<libcasio/char.h>`,
|
||
|
but as usual, including `<libcasio.h>` for everything is recommended.
|
||
|
|
||
|
### Opening and closing a conversion descriptor
|
||
|
The conversion descriptor is the main object that will keep track of
|
||
|
the conversion steps and status. Here are the main functions to manage it:
|
||
|
|
||
|
{% highlight c linenos %}
|
||
|
int casio_open_conv(casio_conv_t *cd, const char *to, const char *from);
|
||
|
int casio_close_conv(casio_conv_t cd);
|
||
|
{% endhighlight %}
|
||
|
|
||
|
The `to` and `from` parameters of the `casio_open_conv()` function are the
|
||
|
string identifiers of the source and destination encodings for the conversion.
|
||
|
For example, use `casio_open_conv(&cd, "utf-8", "utf-32")` to open a descriptor
|
||
|
that will be able to convert UTF-32 encoded data into UTF-8 encoded data.
|
||
|
|
||
|
### Converting formats
|
||
|
Once the conversion descriptor is opened, you can use the `casio_conv()`
|
||
|
function, defined this way:
|
||
|
|
||
|
{% highlight c linenos %}
|
||
|
int casio_conv(casio_conv_t cd,
|
||
|
const char **in_buffer, size_t *in_left,
|
||
|
const char **out_buffer, size_t *out_left);
|
||
|
{% endhighlight %}
|
||
|
|
||
|
In the same fashion than iconv, this function is made for being called
|
||
|
several times, usually because you read from a stream and write to another
|
||
|
stream — although you can use it to convert data all at once.
|
||
|
|
||
|
Here is a simple example using two buffers:
|
||
|
|
||
|
{% highlight c linenos %}
|
||
|
#include <stdio.h>
|
||
|
#include <stdlib.h>
|
||
|
#include <stdint.h>
|
||
|
#include <libcasio.h>
|
||
|
|
||
|
int main(void)
|
||
|
{
|
||
|
int err = 0; casio_conv_t cd = NULL;
|
||
|
uint32_t buf0[] = {'H', 'e', 'l', 'l', 'o'};
|
||
|
size_t buf0_size = 5 * sizeof(uint32_t);
|
||
|
uint32_t buf1[] = {' ', 'w', 'o', 'r', 'l', 'd', '!'};
|
||
|
size_t buf1_size = 7 * sizeof(uint32_t);
|
||
|
char bufdata[30], *buf = &bufdata;
|
||
|
size_t outsize = 29; /* let space for the end zero */
|
||
|
|
||
|
/* Open the conversion descriptor. */
|
||
|
err = casio_open_conv(&cd, "utf-8", "utf-32");
|
||
|
if (err) {
|
||
|
fprintf(stderr, "Could not open the conversion desc.: %s",
|
||
|
casio_strerror(err));
|
||
|
goto fail;
|
||
|
}
|
||
|
|
||
|
/* Convert the first buffer. */
|
||
|
err = casio_conv(cd, &buf0, &buf0_size, &buf, &outsize);
|
||
|
if (err) {
|
||
|
fprintf(stderr, "Could not convert the first buffer: %s",
|
||
|
casio_strerror(err));
|
||
|
goto fail;
|
||
|
}
|
||
|
|
||
|
/* Convert the second buffer. */
|
||
|
err = casio_conv(cd, &buf1, &buf1_size, &buf, &outsize);
|
||
|
if (err) {
|
||
|
fprintf(stderr, "Could not convert the second buffer: %s",
|
||
|
casio_strerror(err));
|
||
|
goto fail;
|
||
|
}
|
||
|
|
||
|
/* Print the buffer. */
|
||
|
*buf = '\0';
|
||
|
fputs(bufdata, stdout);
|
||
|
|
||
|
fail:
|
||
|
/* Close the conversion descriptor. */
|
||
|
casio_close_conv(cd);
|
||
|
return (err != 0);
|
||
|
}
|
||
|
{% endhighlight %}
|