/*
Copyright (C) 2004, The Perl Foundation.
$Id: fixed_8.c 16304 2006-12-28 22:40:22Z particle $

=head1 NAME

src/encodings/fixed_8.c

=head1 DESCRIPTION

This file implements the encoding functions for fixed-width 8-bit codepoints

=cut

*/

#include "parrot/parrot.h"
#include "fixed_8.h"

#define UNIMPL internal_exception(UNIMPLEMENTED, "unimpl fixed_8")

static STRING *
to_encoding(Interp *interp, STRING *src, STRING *dest)
{
    UNIMPL;
    return NULL;
}


/* codepoints are bytes, so delegate */
static UINTVAL
get_codepoint(Interp *interp, const STRING *source_string,
        UINTVAL offset)
{
    return get_byte(interp, source_string, offset);
}

/* This is the same as set byte */
static void
set_codepoint(Interp *interp, STRING *source_string,
        UINTVAL offset, UINTVAL codepoint)
{
    set_byte(interp, source_string, offset, codepoint);
}

static UINTVAL
get_byte(Interp *interp, const STRING *source_string, UINTVAL offset)
{
    unsigned char *contents = source_string->strstart;
    if (offset >= source_string->bufused) {
/*        internal_exception(0,
                "get_byte past the end of the buffer (%i of %i)",
                offset, source_string->bufused);*/
        return 0;
    }
    return contents[offset];
}

static void
set_byte(Interp *interp, const STRING *source_string,
        UINTVAL offset, UINTVAL byte)
{
    unsigned char *contents;
    if (offset >= source_string->bufused) {
        internal_exception(0, "set_byte past the end of the buffer");
    }
    contents = source_string->strstart;
    contents[offset] = (unsigned char)byte;
}

/* Delegate to get_bytes */
static STRING *
get_codepoints(Interp *interp, STRING *source_string,
        UINTVAL offset, UINTVAL count)
{
    STRING *return_string = get_bytes(interp, source_string,
            offset, count);
    return_string->charset = source_string->charset;
    return return_string;
}

static STRING *
get_bytes(Interp *interp, STRING *source_string,
        UINTVAL offset, UINTVAL count)
{
    STRING *return_string = Parrot_make_COW_reference(interp,
            source_string);
    return_string->encoding = source_string->encoding;
    return_string->charset = source_string->charset;

    return_string->strstart = (char *)return_string->strstart + offset ;
    return_string->bufused = count;

    return_string->strlen = count;
    return_string->hashval = 0;

    return return_string;
}


/* Delegate to get_bytes */
static STRING *
get_codepoints_inplace(Interp *interp, STRING *source_string,
        UINTVAL offset, UINTVAL count, STRING *dest_string)
{

    return get_bytes_inplace(interp, source_string, offset,
            count, dest_string);
}

static STRING *
get_bytes_inplace(Interp *interp, STRING *source_string,
        UINTVAL offset, UINTVAL count, STRING *return_string)
{
    Parrot_reuse_COW_reference(interp, source_string, return_string);

    return_string->strstart = (char *)return_string->strstart + offset ;
    return_string->bufused = count;

    return_string->strlen = count;
    return_string->hashval = 0;

    return return_string;
}

/* Delegate to set_bytes */
static void
set_codepoints(Interp *interp, STRING *source_string,
        UINTVAL offset, UINTVAL count, STRING *new_codepoints)
{
    set_bytes(interp, source_string, offset, count, new_codepoints);
}

static void
set_bytes(Interp *interp, STRING *source_string,
        UINTVAL offset, UINTVAL count, STRING *new_bytes)
{
    string_replace(interp, source_string, offset, count, new_bytes, NULL);
}

/* Unconditionally makes the string be in this encoding, if that's
   valid */
static void
become_encoding(Interp *interp, STRING *source_string)
{
    UNIMPL;
}


static UINTVAL
codepoints(Interp *interp, STRING *source_string)
{
    return bytes(interp, source_string);
}

static UINTVAL
bytes(Interp *interp, STRING *source_string)
{
    return source_string->bufused;
}

/*
 * iterator functions
 */

static UINTVAL
fixed8_get_next(Interp *interp, String_iter *iter)
{
    UINTVAL c = get_byte(interp, iter->str, iter->charpos++);
    iter->bytepos++;
    return c;
}

static void
fixed8_set_next(Interp *interp, String_iter *iter, UINTVAL c)
{
    set_byte(interp, iter->str, iter->charpos++, c);
    iter->bytepos++;
}

static void
fixed8_set_position(Interp *interp, String_iter *iter, UINTVAL pos)
{
    iter->bytepos = iter->charpos = pos;
    assert(pos <= PObj_buflen(iter->str));
}


static void
iter_init(Interp *interp, String *src, String_iter *iter)
{
    iter->str = src;
    iter->bytepos = iter->charpos = 0;
    iter->get_and_advance = fixed8_get_next;
    iter->set_and_advance = fixed8_set_next;
    iter->set_position =    fixed8_set_position;
}

ENCODING *
Parrot_encoding_fixed_8_init(Interp *interp)
{
    ENCODING *return_encoding = Parrot_new_encoding(interp);

    ENCODING base_encoding = {
        "fixed_8",
        1, /* Max bytes per codepoint */
        to_encoding,
        get_codepoint,
        set_codepoint,
        get_byte,
        set_byte,
        get_codepoints,
        get_codepoints_inplace,
        get_bytes,
        get_bytes_inplace,
        set_codepoints,
        set_bytes,
        become_encoding,
        codepoints,
        bytes,
        iter_init

    };
    memcpy(return_encoding, &base_encoding, sizeof (ENCODING));
    Parrot_register_encoding(interp, "fixed_8", return_encoding);
    return return_encoding;
}






/*
 * Local variables:
 *   c-file-style: "parrot"
 * End:
 * vim: expandtab shiftwidth=4:
 */

