root/drivers/staging/media/av7110/av7110_ipack.c
// SPDX-License-Identifier: GPL-2.0
#include "dvb_filter.h"
#include "av7110_ipack.h"
#include <linux/string.h>       /* for memcpy() */
#include <linux/vmalloc.h>

void av7110_ipack_reset(struct ipack *p)
{
        p->found = 0;
        p->cid = 0;
        p->plength = 0;
        p->flag1 = 0;
        p->flag2 = 0;
        p->hlength = 0;
        p->mpeg = 0;
        p->check = 0;
        p->which = 0;
        p->done = 0;
        p->count = 0;
}

int av7110_ipack_init(struct ipack *p, int size,
                      void (*func)(u8 *buf, int size, void *priv))
{
        p->buf = vmalloc(size);
        if (!p->buf)
                return -ENOMEM;
        p->size = size;
        p->func = func;
        p->repack_subids = 0;
        av7110_ipack_reset(p);
        return 0;
}

void av7110_ipack_free(struct ipack *p)
{
        vfree(p->buf);
}

static void send_ipack(struct ipack *p)
{
        int off;
        struct dvb_audio_info ai;
        int ac3_off = 0;
        int streamid = 0;
        int nframes = 0;
        int f = 0;

        switch (p->mpeg) {
        case 2:
                if (p->count < 10)
                        return;
                p->buf[3] = p->cid;
                p->buf[4] = (u8)(((p->count - 6) & 0xff00) >> 8);
                p->buf[5] = (u8)((p->count - 6) & 0x00ff);
                if (p->repack_subids && p->cid == PRIVATE_STREAM1) {
                        off = 9 + p->buf[8];
                        streamid = p->buf[off];
                        if ((streamid & 0xf8) == 0x80) {
                                ai.off = 0;
                                ac3_off = ((p->buf[off + 2] << 8) |
                                           p->buf[off + 3]);
                                if (ac3_off < p->count)
                                        f = dvb_filter_get_ac3info(p->buf + off + 3 + ac3_off,
                                                                   p->count - ac3_off, &ai, 0);
                                if (!f) {
                                        nframes = (p->count - off - 3 - ac3_off) /
                                                ai.framesize + 1;
                                        p->buf[off + 2] = (ac3_off >> 8) & 0xff;
                                        p->buf[off + 3] = (ac3_off) & 0xff;
                                        p->buf[off + 1] = nframes;
                                        ac3_off +=  nframes * ai.framesize - p->count;
                                }
                        }
                }
                p->func(p->buf, p->count, p->data);

                p->buf[6] = 0x80;
                p->buf[7] = 0x00;
                p->buf[8] = 0x00;
                p->count = 9;
                if (p->repack_subids && p->cid == PRIVATE_STREAM1 &&
                    (streamid & 0xf8) == 0x80) {
                        p->count += 4;
                        p->buf[9] = streamid;
                        p->buf[10] = (ac3_off >> 8) & 0xff;
                        p->buf[11] = (ac3_off) & 0xff;
                        p->buf[12] = 0;
                }
                break;

        case 1:
                if (p->count < 8)
                        return;
                p->buf[3] = p->cid;
                p->buf[4] = (u8)(((p->count - 6) & 0xff00) >> 8);
                p->buf[5] = (u8)((p->count - 6) & 0x00ff);
                p->func(p->buf, p->count, p->data);

                p->buf[6] = 0x0f;
                p->count = 7;
                break;
        }
}

void av7110_ipack_flush(struct ipack *p)
{
        if (p->plength != MMAX_PLENGTH - 6 || p->found <= 6)
                return;
        p->plength = p->found - 6;
        p->found = 0;
        send_ipack(p);
        av7110_ipack_reset(p);
}

static void write_ipack(struct ipack *p, const u8 *data, int count)
{
        u8 headr[3] = { 0x00, 0x00, 0x01 };

        if (p->count < 6) {
                memcpy(p->buf, headr, 3);
                p->count = 6;
        }

        if (p->count + count < p->size) {
                memcpy(p->buf + p->count, data, count);
                p->count += count;
        } else {
                int rest = p->size - p->count;

                memcpy(p->buf + p->count, data, rest);
                p->count += rest;
                send_ipack(p);
                if (count - rest > 0)
                        write_ipack(p, data + rest, count - rest);
        }
}

int av7110_ipack_instant_repack(const u8 *buf, int count, struct ipack *p)
{
        int l;
        int c = 0;

        while (c < count && (p->mpeg == 0 ||
                             (p->mpeg == 1 && p->found < 7) ||
                             (p->mpeg == 2 && p->found < 9)) &&
                             (p->found < 5 || !p->done)) {
                switch (p->found) {
                case 0:
                case 1:
                        if (buf[c] == 0x00)
                                p->found++;
                        else
                                p->found = 0;
                        c++;
                        break;
                case 2:
                        if (buf[c] == 0x01)
                                p->found++;
                        else if (buf[c] == 0)
                                p->found = 2;
                        else
                                p->found = 0;
                        c++;
                        break;
                case 3:
                        p->cid = 0;
                        switch (buf[c]) {
                        case PROG_STREAM_MAP:
                        case PRIVATE_STREAM2:
                        case PROG_STREAM_DIR:
                        case ECM_STREAM:
                        case EMM_STREAM:
                        case PADDING_STREAM:
                        case DSM_CC_STREAM:
                        case ISO13522_STREAM:
                                p->done = 1;
                                fallthrough;
                        case PRIVATE_STREAM1:
                        case VIDEO_STREAM_S ... VIDEO_STREAM_E:
                        case AUDIO_STREAM_S ... AUDIO_STREAM_E:
                                p->found++;
                                p->cid = buf[c];
                                c++;
                                break;
                        default:
                                p->found = 0;
                                break;
                        }
                        break;

                case 4:
                        if (count - c > 1) {
                                p->plen[0] = buf[c];
                                c++;
                                p->plen[1] = buf[c];
                                c++;
                                p->found += 2;
                                p->plength = (p->plen[0] << 8) | p->plen[1];
                        } else {
                                p->plen[0] = buf[c];
                                p->found++;
                                return count;
                        }
                        break;
                case 5:
                        p->plen[1] = buf[c];
                        c++;
                        p->found++;
                        p->plength = (p->plen[0] << 8) | p->plen[1];
                        break;
                case 6:
                        if (!p->done) {
                                p->flag1 = buf[c];
                                c++;
                                p->found++;
                                if ((p->flag1 & 0xc0) == 0x80) {
                                        p->mpeg = 2;
                                } else {
                                        p->hlength = 0;
                                        p->which = 0;
                                        p->mpeg = 1;
                                        p->flag2 = 0;
                                }
                        }
                        break;

                case 7:
                        if (!p->done && p->mpeg == 2) {
                                p->flag2 = buf[c];
                                c++;
                                p->found++;
                        }
                        break;

                case 8:
                        if (!p->done && p->mpeg == 2) {
                                p->hlength = buf[c];
                                c++;
                                p->found++;
                        }
                        break;
                }
        }

        if (c == count)
                return count;

        if (!p->plength)
                p->plength = MMAX_PLENGTH - 6;

        if (!(p->done || ((p->mpeg == 2 && p->found >= 9) ||
                          (p->mpeg == 1 && p->found >= 7))))
                return count;

        switch (p->cid) {
        case AUDIO_STREAM_S ... AUDIO_STREAM_E:
        case VIDEO_STREAM_S ... VIDEO_STREAM_E:
        case PRIVATE_STREAM1:
                if (p->mpeg == 2 && p->found == 9) {
                        write_ipack(p, &p->flag1, 1);
                        write_ipack(p, &p->flag2, 1);
                        write_ipack(p, &p->hlength, 1);
                }

                if (p->mpeg == 1 && p->found == 7)
                        write_ipack(p, &p->flag1, 1);

                if (p->mpeg == 2 && (p->flag2 & PTS_ONLY) && p->found < 14) {
                        while (c < count && p->found < 14) {
                                p->pts[p->found - 9] = buf[c];
                                write_ipack(p, buf + c, 1);
                                c++;
                                p->found++;
                        }
                        if (c == count)
                                return count;
                }

                if (p->mpeg == 1 && p->which < 2000) {
                        if (p->found == 7) {
                                p->check = p->flag1;
                                p->hlength = 1;
                        }

                        while (!p->which && c < count && p->check == 0xff) {
                                p->check = buf[c];
                                write_ipack(p, buf + c, 1);
                                c++;
                                p->found++;
                                p->hlength++;
                        }

                        if (c == count)
                                return count;

                        if ((p->check & 0xc0) == 0x40 && !p->which) {
                                p->check = buf[c];
                                write_ipack(p, buf + c, 1);
                                c++;
                                p->found++;
                                p->hlength++;

                                p->which = 1;
                                if (c == count)
                                        return count;
                                p->check = buf[c];
                                write_ipack(p, buf + c, 1);
                                c++;
                                p->found++;
                                p->hlength++;
                                p->which = 2;
                                if (c == count)
                                        return count;
                        }

                        if (p->which == 1) {
                                p->check = buf[c];
                                write_ipack(p, buf + c, 1);
                                c++;
                                p->found++;
                                p->hlength++;
                                p->which = 2;
                                if (c == count)
                                        return count;
                        }

                        if ((p->check & 0x30) && p->check != 0xff) {
                                p->flag2 = (p->check & 0xf0) << 2;
                                p->pts[0] = p->check;
                                p->which = 3;
                        }

                        if (c == count)
                                return count;
                        if (p->which > 2) {
                                if ((p->flag2 & PTS_DTS_FLAGS) == PTS_ONLY) {
                                        while (c < count && p->which < 7) {
                                                p->pts[p->which - 2] = buf[c];
                                                write_ipack(p, buf + c, 1);
                                                c++;
                                                p->found++;
                                                p->which++;
                                                p->hlength++;
                                        }
                                        if (c == count)
                                                return count;
                                } else if ((p->flag2 & PTS_DTS_FLAGS) == PTS_DTS) {
                                        while (c < count && p->which < 12) {
                                                if (p->which < 7)
                                                        p->pts[p->which - 2] = buf[c];
                                                write_ipack(p, buf + c, 1);
                                                c++;
                                                p->found++;
                                                p->which++;
                                                p->hlength++;
                                        }
                                        if (c == count)
                                                return count;
                                }
                                p->which = 2000;
                        }
                }

                while (c < count && p->found < p->plength + 6) {
                        l = count - c;
                        if (l + p->found > p->plength + 6)
                                l = p->plength + 6 - p->found;
                        write_ipack(p, buf + c, l);
                        p->found += l;
                        c += l;
                }
                break;
        }

        if (p->done) {
                if (p->found + count - c < p->plength + 6) {
                        p->found += count - c;
                        c = count;
                } else {
                        c += p->plength + 6 - p->found;
                        p->found = p->plength + 6;
                }
        }

        if (p->plength && p->found == p->plength + 6) {
                send_ipack(p);
                av7110_ipack_reset(p);
                if (c < count)
                        av7110_ipack_instant_repack(buf + c, count - c, p);
        }

        return count;
}