/*
  * xconv.c -- An SQLite3 C extension that uses libxconv to convert from
  * ISO 6937 to UTF-8.
  */
#include <string.h>
#include <stdlib.h>
#include <sqlite3ext.h>
#include <xconv.h>

SQLITE_EXTENSION_INIT1

void
sqlite_xconv(sqlite3_context *c, int argc, sqlite3_value **argv)
{
	char *src, *dst;
	size_t dlen;

	if (argc != 1 || !(src = (char *)sqlite3_value_text(argv[0])))
	{
		sqlite3_result_error(c, "xconv requires 1 parameter", -1);
		return;
	}

	dlen = strlen(src) * 2 + 14;
	if (!(dst = (char *)malloc(dlen)))
	{
		sqlite3_result_error(c, "malloc() failed", -1);
		return;
	}

	if (!xconv(src, dst, dlen))
	{
		free(dst);
		dst = strdup(src);
	}

	sqlite3_result_text(c, dst, -1, free);
}

void
sqlite_utf8conv(sqlite3_context *c, int argc, sqlite3_value **argv)
{
	char *src, *dst;

	if (argc != 1 || !(src = (char *)sqlite3_value_text(argv[0])))
	{
		sqlite3_result_error(c, "utf8conv requires 1 parameter", -1);
		return;
	}

	if (src[0] == 0x10)
	{
		if (src[1] == 'i' && src[2] == '7')
		{
			size_t dlen;

			src += 3;
			dlen = strlen(src) * 2 + 14;
			if (!(dst = (char *)malloc(dlen)))
			{
				sqlite3_result_error(c, "malloc() failed", -1);
				return;
			}

			if (!xconv(src, dst, dlen))
			{
				free(dst);
				dst = strdup(src);
			}
		}
		else
			dst = strdup("");
	}
	else
	{
		if (*src < 0x20)
			src += *src == 0x1F ? 2 : 1;

		dst = strdup(src);
	}

	sqlite3_result_text(c, dst, -1, free);
}

#ifdef _WIN32
__declspec(dllexport)
#endif
int sqlite3_xconv_init(sqlite3 *db, char **err,
    const sqlite3_api_routines *api)
{
	int rc1, rc2;

	SQLITE_EXTENSION_INIT2(api);
	rc1 = sqlite3_create_function(db, "xconv", 1,
	    SQLITE_UTF8 | SQLITE_DETERMINISTIC, NULL,
	    sqlite_xconv, NULL, NULL);
	rc2 = sqlite3_create_function(db, "utf8conv", 1,
	    SQLITE_UTF8 | SQLITE_DETERMINISTIC, NULL,
	    sqlite_utf8conv, NULL, NULL);
	return rc1 != SQLITE_OK && rc2 != SQLITE_OK ? rc1 : SQLITE_OK;
}