/* Copyright (C) 2001-2023 Artifex Software, Inc.

   All Rights Reserved.

   This software is provided AS-IS with no warranty, either express or

   implied.

   This software is distributed under license and may not be copied,

   modified or distributed except as expressly authorized under the terms

   of the license contained in the file LICENSE in this distribution.

   Refer to licensing information at http://www.artifex.com or contact

   Artifex Software, Inc.,  39 Mesa Street, Suite 108A, San Francisco,

   CA 94129, USA, for further information.

*/

/* DataSource procedures */

#include "memory_.h"

#include "gx.h"

#include "gsdsrc.h"

#include "gserrors.h"

#include "stream.h"

/* GC descriptor */

public_st_data_source();

static

ENUM_PTRS_WITH(data_source_enum_ptrs, gs_data_source_t *psrc)

{

    if (psrc->type == data_source_type_string)

        ENUM_RETURN_CONST_STRING_PTR(gs_data_source_t, data.str);

    else if (psrc->type == data_source_type_stream)

        ENUM_RETURN_PTR(gs_data_source_t, data.strm);

    else      /* bytes or floats */

        ENUM_RETURN_PTR(gs_data_source_t, data.str.data);

}

ENUM_PTRS_END

static RELOC_PTRS_WITH(data_source_reloc_ptrs, gs_data_source_t *psrc)

{

    if (psrc->type == data_source_type_string)

        RELOC_CONST_STRING_PTR(gs_data_source_t, data.str);

    else if (psrc->type == data_source_type_stream)

        RELOC_PTR(gs_data_source_t, data.strm);

    else      /* bytes or floats */

        RELOC_PTR(gs_data_source_t, data.str.data);

}

RELOC_PTRS_END

/* Access data from a string or a byte object. */

/* Does check bounds, and returns 0 data oob. Spec calls for rangecheck,

   but CPSI implementation silently gives (bogus) data. */

int

data_source_access_string(const gs_data_source_t * psrc, ulong start,

                          uint length, byte * buf, const byte ** ptr)

{

    const byte *p = psrc->data.str.data + start;

    if (start + length <= psrc->data.str.size) {

        if (ptr)

            *ptr = p;

        else

            memcpy(buf, p, length);

    } else {

        if (start < psrc->data.str.size) {

            uint oklen = psrc->data.str.size - start;

            memcpy(buf, p, oklen);

            memset(buf + oklen, 0, length - oklen);

        } else {

            memset(buf, 0, length);

        }

        *ptr = buf;

    }

    return 0;

}

/* access_bytes is identical to access_string, but has a different */

/* GC procedure. */

int

data_source_access_bytes(const gs_data_source_t * psrc, ulong start,

                         uint length, byte * buf, const byte ** ptr)

{

    const byte *p = psrc->data.str.data + start;

    if (ptr)

        *ptr = p;

    else

        memcpy(buf, p, length);

    return 0;

}

/* Access data from a stream. */

/* Returns gs_error_rangecheck if out of bounds. */

int

data_source_access_stream(const gs_data_source_t * psrc, ulong start,

                          uint length, byte * buf, const byte ** ptr)

{

    stream *s = psrc->data.strm;

    const byte *p;

    if (start >= s->position &&

        (p = start - s->position + s->cbuf) + length <=

        s->cursor.r.limit + 1

        ) {

        if (ptr)

            *ptr = p;

        else

            memcpy(buf, p, length);

    } else {

        uint nread;

        int code = sseek(s, start);

        if (code < 0)

            return_error(gs_error_rangecheck);

        code = sgets(s, buf, length, &nread);

        if (code < 0)

            return_error(gs_error_rangecheck);

        if (nread != length)

            return_error(gs_error_rangecheck);

        if (ptr)

            *ptr = buf;

    }

    return 0;

}