/**

 * @file

 * Common code for Vorbis I encoder and decoder

 * @author Denes Balatoni  ( dbalatoni programozo hu )

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * FFmpeg is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

/**

 * @file

 * Common code for Vorbis I encoder and decoder

 * @author Denes Balatoni  ( dbalatoni programozo hu )

 */

#include "libavutil/common.h"

#include "libavutil/error.h"

#include "libavutil/log.h"

#include "libavutil/macros.h"

#include "vorbis.h"

#include "vorbis_data.h"

/* Helper functions */

// x^(1/n)

unsigned int ff_vorbis_nth_root(unsigned int x, unsigned int n)

{

    unsigned int ret = 0, i, j;

    do {

        ++ret;

        for (i = 0, j = ret; i < n - 1; i++)

            j *= ret;

    } while (j <= x);

    return ret - 1;

}

// Generate vlc codes from vorbis huffman code lengths

// the two bits[p] > 32 checks should be redundant, all calling code should

// already ensure that, but since it allows overwriting the stack it seems

// reasonable to check redundantly.

int ff_vorbis_len2vlc(uint8_t *bits, uint32_t *codes, unsigned num)

{

    uint32_t exit_at_level[33] = { 404 };

    unsigned i, j, p, code;

    for (p = 0; (p < num) && (bits[p] == 0); ++p)

        ;

    if (p == num)

        return 0;

    codes[p] = 0;

    if (bits[p] > 32)

        return AVERROR_INVALIDDATA;

    for (i = 0; i < bits[p]; ++i)

        exit_at_level[i+1] = 1u << i;

    ++p;

    for (i = p; (i < num) && (bits[i] == 0); ++i)

        ;

    if (i == num)

        return 0;

    for (; p < num; ++p) {

        if (bits[p] > 32)

             return AVERROR_INVALIDDATA;

        if (bits[p] == 0)

             continue;

        // find corresponding exit(node which the tree can grow further from)

        for (i = bits[p]; i > 0; --i)

            if (exit_at_level[i])

                break;

        if (!i) // overspecified tree

             return AVERROR_INVALIDDATA;

        code = exit_at_level[i];

        exit_at_level[i] = 0;

        // construct code (append 0s to end) and introduce new exits

        for (j = i + 1 ;j <= bits[p]; ++j)

            exit_at_level[j] = code + (1u << (j - 1));

        codes[p] = code;

    }

    //no exits should be left (underspecified tree - ie. unused valid vlcs - not allowed by SPEC)

    for (p = 1; p < 33; p++)

        if (exit_at_level[p])

            return AVERROR_INVALIDDATA;

    return 0;

}

int ff_vorbis_ready_floor1_list(void *logctx,

                                vorbis_floor1_entry *list, int values)

{

    int i;

    list[0].sort = 0;

    list[1].sort = 1;

    for (i = 2; i < values; i++) {

        int j;

        list[i].low  = 0;

        list[i].high = 1;

        list[i].sort = i;

        for (j = 2; j < i; j++) {

            int tmp = list[j].x;

            if (tmp < list[i].x) {

                if (tmp > list[list[i].low].x)

                    list[i].low  =  j;

            } else {

                if (tmp < list[list[i].high].x)

                    list[i].high = j;

            }

        }

    }

    for (i = 0; i < values - 1; i++) {

        int j;

        for (j = i + 1; j < values; j++) {

            if (list[i].x == list[j].x) {

                av_log(logctx, AV_LOG_ERROR,

                       "Duplicate value found in floor 1 X coordinates\n");

                return AVERROR_INVALIDDATA;

            }

            if (list[list[i].sort].x > list[list[j].sort].x) {

                int tmp = list[i].sort;

                list[i].sort = list[j].sort;

                list[j].sort = tmp;

            }

        }

    }

    return 0;

}

static inline void render_line_unrolled(intptr_t x, int y, int x1,

                                        intptr_t sy, int ady, int adx,

                                        float *buf)

{

    int err = -adx;

    x -= x1 - 1;

    buf += x1 - 1;

    while (++x < 0) {

        err += ady;

        if (err >= 0) {

            err += ady - adx;

            y   += sy;

            buf[x++] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];

        }

        buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];

    }

    if (x <= 0) {

        if (err + ady >= 0)

            y += sy;

        buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];

    }

}

static void render_line(int x0, int y0, int x1, int y1, float *buf)

{

    int dy  = y1 - y0;

    int adx = x1 - x0;

    int ady = FFABS(dy);

    int sy  = dy < 0 ? -1 : 1;

    buf[x0] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y0)];

    if (ady*2 <= adx) { // optimized common case

        render_line_unrolled(x0, y0, x1, sy, ady, adx, buf);

    } else {

        int base  = dy / adx;

        int x     = x0;

        int y     = y0;

        int err   = -adx;

        ady -= FFABS(base) * adx;

        while (++x < x1) {

            y += base;

            err += ady;

            if (err >= 0) {

                err -= adx;

                y   += sy;

            }

            buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];

        }

    }

}

void ff_vorbis_floor1_render_list(vorbis_floor1_entry * list, int values,

                                  uint16_t *y_list, int *flag,

                                  int multiplier, float *out, int samples)

{

    int lx, ly, i;

    lx = 0;

    ly = y_list[0] * multiplier;

    for (i = 1; i < values; i++) {

        int pos = list[i].sort;

        if (flag[pos]) {

            int x1 = list[pos].x;

            int y1 = y_list[pos] * multiplier;

            if (lx < samples)

                render_line(lx, ly, FFMIN(x1,samples), y1, out);

            lx = x1;

            ly = y1;

        }

        if (lx >= samples)

            break;

    }

    if (lx < samples)

        render_line(lx, ly, samples, ly, out);

}