/*
 * Copyright (c) 2002 - 2007 Magnus Lind.
 *
 * This software is provided 'as-is', without any express or implied warranty.
 * In no event will the authors be held liable for any damages arising from
 * the use of this software.
 *
 * Permission is granted to anyone to use this software, alter it and re-
 * distribute it freely for any non-commercial, non-profit purpose subject to
 * the following restrictions:
 *
 *   1. The origin of this software must not be misrepresented; you must not
 *   claim that you wrote the original software. If you use this software in a
 *   product, an acknowledgment in the product documentation would be
 *   appreciated but is not required.
 *
 *   2. Altered source versions must be plainly marked as such, and must not
 *   be misrepresented as being the original software.
 *
 *   3. This notice may not be removed or altered from any distribution.
 *
 *   4. The names of this software and/or it's copyright holders may not be
 *   used to endorse or promote products derived from this software without
 *   specific prior written permission.
 *
 */

#include <stdlib.h>
#include "log.h"
#include "output.h"

#define OUTPUT_FLAG_REVERSE 1

void output_ctx_init(output_ctx ctx, struct membuf *out)    /* IN/OUT */
{
    ctx->bitbuf = 1;
    ctx->pos = membuf_memlen(out);
    ctx->buf = out;
}

unsigned int output_get_pos(output_ctx ctx)     /* IN */
{
    return ctx->pos;
}

void output_byte(output_ctx ctx,        /* IN/OUT */
                 unsigned char byte)    /* IN */
{
    /*LOG(LOG_DUMP, ("output_byte: $%02X\n", byte)); */
    if(ctx->pos < membuf_memlen(ctx->buf))
    {
        char *p;
        p = membuf_get(ctx->buf);
        p[ctx->pos] = byte;
    }
    else
    {
        while(ctx->pos > membuf_memlen(ctx->buf))
        {
            membuf_append_char(ctx->buf, '\0');
        }
        membuf_append_char(ctx->buf, byte);
    }
    ++(ctx->pos);
}

void output_word(output_ctx ctx,        /* IN/OUT */
                 unsigned short int word)       /* IN */
{
    output_byte(ctx, (unsigned char) (word & 0xff));
    output_byte(ctx, (unsigned char) (word >> 8));
}


void output_bits_flush(output_ctx ctx)  /* IN/OUT */
{
    /* flush the bitbuf including
     * the extra 1 bit acting as eob flag */
    output_byte(ctx, (unsigned char) (ctx->bitbuf & 0xFF));
    if (ctx->bitbuf & 0x100)
    {
        output_byte(ctx, 1);
    }
    LOG(LOG_DUMP, ("bitstream flushed 0x%02X\n", ctx->bitbuf & 0xFF));

    /* reset it */
    ctx->bitbuf = 1;
}

static void output_bits_int(output_ctx ctx,        /* IN/OUT */
                            int count,     /* IN */
                            int val)       /* IN */
{
    /* this makes the bits appear in reversed
     * big endian order in the output stream */
#if BITS_AS_BYTES
    while (count > 7)
    {
        /* at least 8 bits or more are left */
        output_byte(ctx, (unsigned char)(val & 0xFF));
        count -= 8;
        val >>= 8;
    }
#endif
    while (count-- > 0)
    {
        ctx->bitbuf <<= 1;
        ctx->bitbuf |= val & 0x1;
        val >>= 1;
        if (ctx->bitbuf & 0x100)
        {
            /* full byte, flush it */
            output_byte(ctx, (unsigned char) (ctx->bitbuf & 0xFF));
            LOG(LOG_DUMP,
               ("bitstream byte 0x%02X\n", ctx->bitbuf & 0xFF));
            ctx->bitbuf = 1;
        }
    }
}

void output_bits(output_ctx ctx,        /* IN/OUT */
                 int count,     /* IN */
                 int val)       /* IN */
{
    LOG(LOG_DUMP, ("output bits: count = %d, val = %d\n", count, val));
    output_bits_int(ctx, count, val);
}

void output_gamma_code(output_ctx ctx,  /* IN/OUT */
                       int code)        /* IN */
{
    LOG(LOG_DUMP, ("output gamma: code = %d\n", code));
    output_bits_int(ctx, 1, 1);
    while (code-- > 0)
    {
        output_bits_int(ctx, 1, 0);
    }
}