/* 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.
*/


/* MD5Encode filter */
#include "memory_.h"
#include "strimpl.h"
#include "stream.h"
#include "smd5.h"

/* ------ MD5Encode ------ */

private_st_MD5E_state();

/* Initialize the state. */
static int
s_MD5E_init(stream_state * st)
{
    stream_MD5E_state *const ss = (stream_MD5E_state *) st;

    gs_md5_init(&ss->md5);
    return 0;
}

/* Process a buffer. */
static int
s_MD5E_process(stream_state * st, stream_cursor_read * pr,
               stream_cursor_write * pw, bool last)
{
    stream_MD5E_state *const ss = (stream_MD5E_state *) st;
    int status = 0;

    if (pr->ptr < pr->limit) {
        gs_md5_append(&ss->md5, pr->ptr + 1, pr->limit - pr->ptr);
        pr->ptr = pr->limit;
    }
    if (last) {
        if (pw->limit - pw->ptr >= 16) {
            gs_md5_finish(&ss->md5, pw->ptr + 1);
            pw->ptr += 16;
            status = EOFC;
        } else
            status = 1;
    }
    return status;
}

/* Stream template */
const stream_template s_MD5E_template = {
    &st_MD5E_state, s_MD5E_init, s_MD5E_process, 1, 16
};

stream *
s_MD5E_make_stream(gs_memory_t *mem, byte *digest, int digest_size)
{
    stream *s = s_alloc(mem, "s_MD5E_make_stream");
    stream_state *ss = s_alloc_state(mem, s_MD5E_template.stype, "s_MD5E_make_stream");

    if (ss == NULL || s == NULL)
        goto err;
    ss->templat = &s_MD5E_template;
    if (s_init_filter(s, ss, digest, digest_size, NULL) < 0)
goto err;
    s->strm = s;
    return s;
err:
    gs_free_object(mem, ss, "s_MD5E_make_stream");
    gs_free_object(mem, s, "s_MD5E_make_stream");
    return NULL;
}

/* Process a buffer. */
static int
s_MD5C_process(stream_state * st, stream_cursor_read * pr,
               stream_cursor_write * pw, bool last)
{
    stream_MD5E_state *const ss = (stream_MD5E_state *) st;
    int nr = pr->limit - pr->ptr;
    int nw = pw->limit - pw->ptr;
    int n = min(nr, nw);

    gs_md5_append(&ss->md5, pr->ptr + 1, n);
    memcpy(pw->ptr + 1, pr->ptr + 1, n);
    pr->ptr += n;
    pw->ptr += n;
    if (pw->limit == pw->ptr)
        return 1;
    return 0;
}
/* Stream template */
const stream_template s_MD5C_template = {
    &st_MD5E_state, s_MD5E_init, s_MD5C_process, 1, 1024
};

stream *
s_MD5C_make_stream(gs_memory_t *mem, stream *strm)
{
    stream *s = s_alloc(mem, "s_MD5E_make_stream");
    stream_state *ss = s_alloc_state(mem, s_MD5E_template.stype, "s_MD5E_make_stream");
    int buffer_size = 1024;
    byte *buffer = gs_alloc_bytes(mem, buffer_size, "s_MD5E_make_stream(buffer)");

    if (ss == NULL || s == NULL || buffer == NULL)
        goto err;
    ss->templat = &s_MD5C_template;
    if (s_init_filter(s, ss, buffer, buffer_size, NULL) < 0)
        goto err;
    s->strm = strm;
    s->close_strm = true;
    return s;
err:
    gs_free_object(mem, ss, "s_MD5E_make_stream");
    gs_free_object(mem, s, "s_MD5E_make_stream");
    gs_free_object(mem, buffer, "s_MD5E_make_stream");
    return NULL;
}

/* Get a digest. Apply 'flush' before calling. */
int
s_MD5C_get_digest(stream *s, byte *buf, int buf_length)
{
    stream_MD5E_state *const ss = (stream_MD5E_state *)s->state;
    gs_md5_state_t md5;
    byte b[16], *p;
    int l = min(16, buf_length), k;

    if (s->procs.process != s_MD5C_process)
        return 0; /* Must not happen. */
    md5 = ss->md5;
    gs_md5_finish(&md5, b);
    memcpy(buf, b, l);
    for (p = b + l; p < b + sizeof(b); p += l) {
        for (k = 0; k < l && p + k < b + sizeof(b); k++)
            buf[k] ^= p[k];
    }
    return l;
}