/*
  * OpenEXR (.exr) image decoder
  * Copyright (c) 2009 Jimmy Christensen
  *
  * 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

  * OpenEXR decoder
  * @author Jimmy Christensen
  *
  * For more information on the OpenEXR format, visit:
  *  http://openexr.com/
  *
  * exr_flt2uint() and exr_halflt2uint() is credited to  Reimar Döffinger
  */
 

 #include <zlib.h>
 

 #include "get_bits.h"

 #include "avcodec.h"
 #include "bytestream.h"

 #include "internal.h"

 #include "mathops.h"

 #include "thread.h"

 #include "libavutil/imgutils.h"

 #include "libavutil/avassert.h"

 #include "libavutil/opt.h"

 
 enum ExrCompr {
     EXR_RAW   = 0,
     EXR_RLE   = 1,
     EXR_ZIP1  = 2,
     EXR_ZIP16 = 3,
     EXR_PIZ   = 4,

     EXR_PXR24 = 5,

     EXR_B44   = 6,
     EXR_B44A  = 7,

 };
 

 enum ExrPixelType {
     EXR_UINT,
     EXR_HALF,
     EXR_FLOAT
 };
 
 typedef struct EXRChannel {
     int               xsub, ysub;
     enum ExrPixelType pixel_type;
 } EXRChannel;
 

 typedef struct EXRThreadData {
     uint8_t *uncompressed_data;
     int uncompressed_size;
 
     uint8_t *tmp;
     int tmp_size;

 
     uint8_t *bitmap;
     uint16_t *lut;

 } EXRThreadData;
 

 typedef struct EXRContext {

     AVClass        *class;

     AVFrame *picture;

     int compr;

     enum ExrPixelType pixel_type;

     int channel_offsets[4]; // 0 = red, 1 = green, 2 = blue and 3 = alpha

     const AVPixFmtDescriptor *desc;

     uint32_t xmax, xmin;
     uint32_t ymax, ymin;
     uint32_t xdelta, ydelta;

     int ysize;
 

     uint64_t scan_line_size;
     int scan_lines_per_block;
 
     const uint8_t *buf, *table;
     int buf_size;
 

     EXRChannel *channels;
     int nb_channels;
 

     EXRThreadData *thread_data;
     int thread_data_size;

 
     const char* layer;

 } EXRContext;
 

 #define OFFSET(x) offsetof(EXRContext, x)
 #define VD AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_DECODING_PARAM
 static const AVOption options[] = {
     { "layer", "Set the decoding layer",   OFFSET(layer),        AV_OPT_TYPE_STRING, { .str = "" }, 0, 0, VD},
     { NULL },
 };
 
 static const AVClass exr_class = {
     .class_name = "EXR",
     .item_name  = av_default_item_name,
     .option     = options,
     .version    = LIBAVUTIL_VERSION_INT,
 };
 

 /**
  * Converts from 32-bit float as uint32_t to uint16_t
  *
  * @param v 32-bit float
  * @return normalized 16-bit unsigned int
  */
 static inline uint16_t exr_flt2uint(uint32_t v)
 {
     unsigned int exp = v >> 23;
     // "HACK": negative values result in exp<  0, so clipping them to 0
     // is also handled by this condition, avoids explicit check for sign bit.
     if (exp<= 127 + 7 - 24) // we would shift out all bits anyway
         return 0;
     if (exp >= 127)
         return 0xffff;
     v &= 0x007fffff;
     return (v + (1 << 23)) >> (127 + 7 - exp);
 }
 
 /**
  * Converts from 16-bit float as uint16_t to uint16_t
  *
  * @param v 16-bit float
  * @return normalized 16-bit unsigned int
  */
 static inline uint16_t exr_halflt2uint(uint16_t v)
 {

     unsigned exp = 14 - (v >> 10);
     if (exp >= 14) {
         if (exp == 14) return (v >> 9) & 1;
         else           return (v & 0x8000) ? 0 : 0xffff;
     }

     v <<= 6;

     return (v + (1 << 16)) >> (exp + 1);

 }
 
 /**
  * Gets the size of the header variable
  *
  * @param **buf the current pointer location in the header where
  * the variable data starts
  * @param *buf_end pointer location of the end of the buffer
  * @return size of variable data
  */
 static unsigned int get_header_variable_length(const uint8_t **buf,
                                                const uint8_t *buf_end)
 {
     unsigned int variable_buffer_data_size = bytestream_get_le32(buf);
     if (variable_buffer_data_size >= buf_end - *buf)
         return 0;
     return variable_buffer_data_size;
 }
 
 /**
  * Checks if the variable name corresponds with it's data type
  *
  * @param *avctx the AVCodecContext
  * @param **buf the current pointer location in the header where
  * the variable name starts
  * @param *buf_end pointer location of the end of the buffer
  * @param *value_name name of the varible to check
  * @param *value_type type of the varible to check
  * @param minimum_length minimum length of the variable data
  * @param variable_buffer_data_size variable length read from the header
  * after it's checked

  * @return negative if variable is invalid

  */

 static int check_header_variable(AVCodecContext *avctx,

                                               const uint8_t **buf,
                                               const uint8_t *buf_end,
                                               const char *value_name,
                                               const char *value_type,
                                               unsigned int minimum_length,
                                               unsigned int *variable_buffer_data_size)
 {
     if (buf_end - *buf >= minimum_length && !strcmp(*buf, value_name)) {
         *buf += strlen(value_name)+1;
         if (!strcmp(*buf, value_type)) {
             *buf += strlen(value_type)+1;
             *variable_buffer_data_size = get_header_variable_length(buf, buf_end);
             if (!*variable_buffer_data_size)

                 av_log(avctx, AV_LOG_ERROR, "Incomplete header\n");

             return 1;
         }
         *buf -= strlen(value_name)+1;
         av_log(avctx, AV_LOG_WARNING, "Unknown data type for header variable %s\n", value_name);
     }

     return -1;

 }
 

 static void predictor(uint8_t *src, int size)
 {
     uint8_t *t = src + 1;
     uint8_t *stop = src + size;
 
     while (t < stop) {
         int d = (int)t[-1] + (int)t[0] - 128;
         t[0] = d;
         ++t;
     }
 }
 
 static void reorder_pixels(uint8_t *src, uint8_t *dst, int size)
 {
     const int8_t *t1 = src;
     const int8_t *t2 = src + (size + 1) / 2;
     int8_t *s = dst;
     int8_t *stop = s + size;
 
     while (1) {
         if (s < stop)
             *(s++) = *(t1++);
         else
             break;
 
         if (s < stop)
             *(s++) = *(t2++);
         else
             break;
     }
 }
 

 static int zip_uncompress(const uint8_t *src, int compressed_size,
                           int uncompressed_size, EXRThreadData *td)

 {

     unsigned long dest_len = uncompressed_size;
 
     if (uncompress(td->tmp, &dest_len, src, compressed_size) != Z_OK ||
         dest_len != uncompressed_size)
         return AVERROR(EINVAL);
 
     predictor(td->tmp, uncompressed_size);
     reorder_pixels(td->tmp, td->uncompressed_data, uncompressed_size);
 
     return 0;
 }
 
 static int rle_uncompress(const uint8_t *src, int compressed_size,
                           int uncompressed_size, EXRThreadData *td)
 {
     int8_t *d = (int8_t *)td->tmp;

     const int8_t *s = (const int8_t *)src;

     int ssize = compressed_size;
     int dsize = uncompressed_size;

     int8_t *dend = d + dsize;
     int count;
 
     while (ssize > 0) {
         count = *s++;
 
         if (count < 0) {
             count = -count;
 
             if ((dsize -= count    ) < 0 ||
                 (ssize -= count + 1) < 0)
                 return -1;
 
             while (count--)
                 *d++ = *s++;
         } else {
             count++;
 
             if ((dsize -= count) < 0 ||
                 (ssize -= 2    ) < 0)
                 return -1;
 
             while (count--)
                 *d++ = *s;
 
             s++;
         }
     }
 

     if (dend != d)
         return AVERROR_INVALIDDATA;
 
     predictor(td->tmp, uncompressed_size);
     reorder_pixels(td->tmp, td->uncompressed_data, uncompressed_size);
 
     return 0;

 }
 

 #define USHORT_RANGE (1 << 16)
 #define BITMAP_SIZE (1 << 13)
 
 static uint16_t reverse_lut(const uint8_t *bitmap, uint16_t *lut)
 {
     int i, k = 0;
 
     for (i = 0; i < USHORT_RANGE; i++) {
         if ((i == 0) || (bitmap[i >> 3] & (1 << (i & 7))))
             lut[k++] = i;
     }
 
     i = k - 1;
 
     memset(lut + k, 0, (USHORT_RANGE - k) * 2);
 
     return i;
 }
 
 static void apply_lut(const uint16_t *lut, uint16_t *dst, int dsize)
 {
     int i;
 
     for (i = 0; i < dsize; ++i)
         dst[i] = lut[dst[i]];
 }
 
 #define HUF_ENCBITS 16  // literal (value) bit length
 #define HUF_DECBITS 14  // decoding bit size (>= 8)
 
 #define HUF_ENCSIZE ((1 << HUF_ENCBITS) + 1)  // encoding table size
 #define HUF_DECSIZE (1 << HUF_DECBITS)     // decoding table size
 #define HUF_DECMASK (HUF_DECSIZE - 1)
 
 typedef struct HufDec {
     int len;
     int lit;
     int *p;
 } HufDec;
 
 static void huf_canonical_code_table(uint64_t *hcode)
 {
     uint64_t c, n[59] = { 0 };
     int i;
 
     for (i = 0; i < HUF_ENCSIZE; ++i)
         n[hcode[i]] += 1;
 
     c = 0;
     for (i = 58; i > 0; --i) {
         uint64_t nc = ((c + n[i]) >> 1);
         n[i] = c;
         c = nc;
     }
 
     for (i = 0; i < HUF_ENCSIZE; ++i) {
         int l = hcode[i];
 
         if (l > 0)
             hcode[i] = l | (n[l]++ << 6);
     }
 }
 
 #define SHORT_ZEROCODE_RUN  59
 #define LONG_ZEROCODE_RUN   63
 #define SHORTEST_LONG_RUN   (2 + LONG_ZEROCODE_RUN - SHORT_ZEROCODE_RUN)
 #define LONGEST_LONG_RUN    (255 + SHORTEST_LONG_RUN)
 
 static int huf_unpack_enc_table(GetByteContext *gb,
                                 int32_t im, int32_t iM, uint64_t *hcode)
 {
     GetBitContext gbit;
 
     init_get_bits8(&gbit, gb->buffer, bytestream2_get_bytes_left(gb));
 
     for (; im <= iM; im++) {
         uint64_t l = hcode[im] = get_bits(&gbit, 6);
 
         if (l == LONG_ZEROCODE_RUN) {
             int zerun = get_bits(&gbit, 8) + SHORTEST_LONG_RUN;
 
             if (im + zerun > iM + 1)
                 return AVERROR_INVALIDDATA;
 
             while (zerun--)
                 hcode[im++] = 0;
 
             im--;
         } else if (l >= (uint64_t) SHORT_ZEROCODE_RUN) {
             int zerun = l - SHORT_ZEROCODE_RUN + 2;
 
             if (im + zerun > iM + 1)
                 return AVERROR_INVALIDDATA;
 
             while (zerun--)
                 hcode[im++] = 0;
 
             im--;
         }
     }
 
     bytestream2_skip(gb, (get_bits_count(&gbit) + 7) / 8);
     huf_canonical_code_table(hcode);
 
     return 0;
 }
 
 static int huf_build_dec_table(const uint64_t *hcode, int im,
                                int iM, HufDec *hdecod)
 {
     for (; im <= iM; im++) {
         uint64_t c = hcode[im] >> 6;
         int i, l = hcode[im] & 63;
 
         if (c >> l)
             return AVERROR_INVALIDDATA;
 
         if (l > HUF_DECBITS) {
             HufDec *pl = hdecod + (c >> (l - HUF_DECBITS));
             if (pl->len)
                 return AVERROR_INVALIDDATA;
 
             pl->lit++;
 
             pl->p = av_realloc_f(pl->p, pl->lit, sizeof(int));
             if (!pl->p)
                 return AVERROR(ENOMEM);
 
             pl->p[pl->lit - 1] = im;
         } else if (l) {
             HufDec *pl = hdecod + (c << (HUF_DECBITS - l));
 
             for (i = 1 << (HUF_DECBITS - l); i > 0; i--, pl++) {
                 if (pl->len || pl->p)
                     return AVERROR_INVALIDDATA;
                 pl->len = l;
                 pl->lit = im;
             }
         }
     }
 
     return 0;
 }
 
 #define get_char(c, lc, gb) {                   \
     c = (c << 8) | bytestream2_get_byte(gb);    \
     lc += 8;                                    \
 }
 
 #define get_code(po, rlc, c, lc, gb, out, oe) { \
     if (po == rlc) {                            \
         if (lc < 8)                             \
             get_char(c, lc, gb);                \
         lc -= 8;                                \
                                                 \
         cs = c >> lc;                           \
                                                 \
         if (out + cs > oe)                      \
             return AVERROR_INVALIDDATA;         \
                                                 \
         s = out[-1];                            \
                                                 \
         while (cs-- > 0)                        \
             *out++ = s;                         \
     } else if (out < oe) {                      \
         *out++ = po;                            \
     } else {                                    \
         return AVERROR_INVALIDDATA;             \
     }                                           \
 }
 
 static int huf_decode(const uint64_t *hcode, const HufDec *hdecod,
                       GetByteContext *gb, int nbits,
                       int rlc, int no, uint16_t *out)
 {
     uint64_t c = 0;
     uint16_t *outb = out;
     uint16_t *oe = out + no;
     const uint8_t *ie = gb->buffer + (nbits + 7) / 8; // input byte size
     uint8_t cs, s;
     int i, lc = 0;
 
     while (gb->buffer < ie) {
         get_char(c, lc, gb);
 
         while (lc >= HUF_DECBITS) {
             const HufDec pl = hdecod[(c >> (lc-HUF_DECBITS)) & HUF_DECMASK];
 
             if (pl.len) {
                 lc -= pl.len;
                 get_code(pl.lit, rlc, c, lc, gb, out, oe);
             } else {
                 int j;
 
                 if (!pl.p)
                     return AVERROR_INVALIDDATA;
 
                 for (j = 0; j < pl.lit; j++) {
                     int l = hcode[pl.p[j]] & 63;
 
                     while (lc < l && bytestream2_get_bytes_left(gb) > 0)
                         get_char(c, lc, gb);
 
                     if (lc >= l) {
                         if ((hcode[pl.p[j]] >> 6) ==
                             ((c >> (lc - l)) & ((1LL << l) - 1))) {
                             lc -= l;
                             get_code(pl.p[j], rlc, c, lc, gb, out, oe);
                             break;
                         }
                     }
                 }
 
                 if (j == pl.lit)
                     return AVERROR_INVALIDDATA;
             }
         }
     }
 
     i = (8 - nbits) & 7;
     c >>= i;
     lc -= i;
 
     while (lc > 0) {
         const HufDec pl = hdecod[(c << (HUF_DECBITS - lc)) & HUF_DECMASK];
 
         if (pl.len) {
             lc -= pl.len;
             get_code(pl.lit, rlc, c, lc, gb, out, oe);
         } else {
             return AVERROR_INVALIDDATA;
         }
     }
 
     if (out - outb != no)
         return AVERROR_INVALIDDATA;
     return 0;
 }
 
 static int huf_uncompress(GetByteContext *gb,
                           uint16_t *dst, int dst_size)
 {
     int32_t src_size, im, iM;
     uint32_t nBits;
     uint64_t *freq;
     HufDec *hdec;
     int ret, i;
 
     src_size = bytestream2_get_le32(gb);
     im = bytestream2_get_le32(gb);
     iM = bytestream2_get_le32(gb);
     bytestream2_skip(gb, 4);
     nBits = bytestream2_get_le32(gb);
     if (im < 0 || im >= HUF_ENCSIZE ||
         iM < 0 || iM >= HUF_ENCSIZE ||
         src_size < 0)
         return AVERROR_INVALIDDATA;
 
     bytestream2_skip(gb, 4);
 
     freq = av_calloc(HUF_ENCSIZE, sizeof(*freq));
     hdec = av_calloc(HUF_DECSIZE, sizeof(*hdec));
     if (!freq || !hdec) {
         ret = AVERROR(ENOMEM);
         goto fail;
     }
 
     if ((ret = huf_unpack_enc_table(gb, im, iM, freq)) < 0)
         goto fail;
 
     if (nBits > 8 * bytestream2_get_bytes_left(gb)) {
         ret = AVERROR_INVALIDDATA;
         goto fail;
     }
 
     if ((ret = huf_build_dec_table(freq, im, iM, hdec)) < 0)
         goto fail;
     ret = huf_decode(freq, hdec, gb, nBits, iM, dst_size, dst);
 
 fail:
     for (i = 0; i < HUF_DECSIZE; i++) {

         if (hdec)

             av_freep(&hdec[i].p);

     }
 
     av_free(freq);
     av_free(hdec);
 
     return ret;
 }
 
 static inline void wdec14(uint16_t l, uint16_t h, uint16_t *a, uint16_t *b)
 {
     int16_t ls = l;
     int16_t hs = h;
     int hi = hs;
     int ai = ls + (hi & 1) + (hi >> 1);
     int16_t as = ai;
     int16_t bs = ai - hi;
 
     *a = as;
     *b = bs;
 }
 
 #define NBITS      16
 #define A_OFFSET  (1 << (NBITS  - 1))
 #define MOD_MASK  ((1 << NBITS) - 1)
 
 static inline void wdec16(uint16_t l, uint16_t h, uint16_t *a, uint16_t *b)
 {
     int m = l;
     int d = h;
     int bb = (m - (d >> 1)) & MOD_MASK;
     int aa = (d + bb - A_OFFSET) & MOD_MASK;
     *b = bb;
     *a = aa;
 }
 
 static void wav_decode(uint16_t *in, int nx, int ox,
                        int ny, int oy, uint16_t mx)
 {
     int w14 = (mx < (1 << 14));
     int n = (nx > ny) ? ny: nx;
     int p = 1;
     int p2;
 
     while (p <= n)
         p <<= 1;
 
     p >>= 1;
     p2  = p;
     p >>= 1;
 
     while (p >= 1) {
         uint16_t *py = in;
         uint16_t *ey = in + oy * (ny - p2);
         uint16_t i00, i01, i10, i11;
         int oy1 = oy * p;
         int oy2 = oy * p2;
         int ox1 = ox * p;
         int ox2 = ox * p2;
 
         for (; py <= ey; py += oy2) {
             uint16_t *px = py;
             uint16_t *ex = py + ox * (nx - p2);
 
             for (; px <= ex; px += ox2) {
                 uint16_t *p01 = px  + ox1;
                 uint16_t *p10 = px  + oy1;
                 uint16_t *p11 = p10 + ox1;
 
                 if (w14) {
                     wdec14(*px,  *p10, &i00, &i10);
                     wdec14(*p01, *p11, &i01, &i11);
                     wdec14(i00, i01, px,  p01);
                     wdec14(i10, i11, p10, p11);
                 } else {
                     wdec16(*px,  *p10, &i00, &i10);
                     wdec16(*p01, *p11, &i01, &i11);
                     wdec16(i00, i01, px,  p01);
                     wdec16(i10, i11, p10, p11);
                 }
             }
 
             if (nx & p) {
                 uint16_t *p10 = px + oy1;
 
                 if (w14)
                     wdec14(*px, *p10, &i00, p10);
                 else
                     wdec16(*px, *p10, &i00, p10);
 
                 *px = i00;
             }
         }
 
         if (ny & p) {
             uint16_t *px = py;
             uint16_t *ex = py + ox * (nx - p2);
 
             for (; px <= ex; px += ox2) {
                 uint16_t *p01 = px + ox1;
 
                 if (w14)
                     wdec14(*px, *p01, &i00, p01);
                 else
                     wdec16(*px, *p01, &i00, p01);
 
                 *px = i00;
             }
         }
 
         p2 = p;
         p >>= 1;
     }
 }
 
 static int piz_uncompress(EXRContext *s, const uint8_t *src, int ssize, int dsize, EXRThreadData *td)
 {
     GetByteContext gb;
     uint16_t maxval, min_non_zero, max_non_zero;
     uint16_t *ptr, *tmp = (uint16_t *)td->tmp;
     int8_t *out;
     int ret, i, j;
 
     if (!td->bitmap)
         td->bitmap = av_malloc(BITMAP_SIZE);
     if (!td->lut)
         td->lut = av_malloc(1 << 17);
     if (!td->bitmap || !td->lut)
         return AVERROR(ENOMEM);
 
     bytestream2_init(&gb, src, ssize);
     min_non_zero = bytestream2_get_le16(&gb);
     max_non_zero = bytestream2_get_le16(&gb);
 
     if (max_non_zero >= BITMAP_SIZE)
         return AVERROR_INVALIDDATA;
 
     memset(td->bitmap, 0, FFMIN(min_non_zero, BITMAP_SIZE));
     if (min_non_zero <= max_non_zero)
         bytestream2_get_buffer(&gb, td->bitmap + min_non_zero,
                                max_non_zero - min_non_zero + 1);
     memset(td->bitmap + max_non_zero, 0, BITMAP_SIZE - max_non_zero);
 
     maxval = reverse_lut(td->bitmap, td->lut);
 
     ret = huf_uncompress(&gb, tmp, dsize / sizeof(int16_t));
     if (ret)
         return ret;
 
     ptr = tmp;
     for (i = 0; i < s->nb_channels; i++) {
         EXRChannel *channel = &s->channels[i];
         int size = channel->pixel_type;
 
         for (j = 0; j < size; j++)
             wav_decode(ptr + j, s->xdelta, size, s->ysize, s->xdelta * size, maxval);
         ptr += s->xdelta * s->ysize * size;
     }
 
     apply_lut(td->lut, tmp, dsize / sizeof(int16_t));
 
     out = td->uncompressed_data;
     for (i = 0; i < s->ysize; i++) {
         for (j = 0; j < s->nb_channels; j++) {
             uint16_t *in = tmp + j * s->xdelta * s->ysize + i * s->xdelta;
             memcpy(out, in, s->xdelta * 2);
             out += s->xdelta * 2;
         }
     }
 
     return 0;
 }
 

 static int pxr24_uncompress(EXRContext *s, const uint8_t *src,
                             int compressed_size, int uncompressed_size,
                             EXRThreadData *td)
 {
     unsigned long dest_len = uncompressed_size;
     const uint8_t *in = td->tmp;
     uint8_t *out;
     int c, i, j;
 
     if (uncompress(td->tmp, &dest_len, src, compressed_size) != Z_OK ||
         dest_len != uncompressed_size)
         return AVERROR(EINVAL);
 
     out = td->uncompressed_data;
     for (i = 0; i < s->ysize; i++) {
         for (c = 0; c < s->nb_channels; c++) {
             EXRChannel *channel = &s->channels[c];
             const uint8_t *ptr[4];
             uint32_t pixel = 0;
 
             switch (channel->pixel_type) {
             case EXR_FLOAT:
                 ptr[0] = in;
                 ptr[1] = ptr[0] + s->xdelta;
                 ptr[2] = ptr[1] + s->xdelta;
                 in = ptr[2] + s->xdelta;
 
                 for (j = 0; j < s->xdelta; ++j) {
                     uint32_t diff = (*(ptr[0]++) << 24) |
                                     (*(ptr[1]++) << 16) |
                                     (*(ptr[2]++) <<  8);
                     pixel += diff;

                     bytestream_put_le32(&out, pixel);

                 }
                 break;
             case EXR_HALF:
                 ptr[0] = in;
                 ptr[1] = ptr[0] + s->xdelta;
                 in = ptr[1] + s->xdelta;

                 for (j = 0; j < s->xdelta; j++) {

                     uint32_t diff = (*(ptr[0]++) << 8) | *(ptr[1]++);
 
                     pixel += diff;

                     bytestream_put_le16(&out, pixel);

                 }
                 break;
             default:
                 av_assert1(0);
             }
         }
     }
 
     return 0;
 }
 

 static int decode_block(AVCodecContext *avctx, void *tdata,
                         int jobnr, int threadnr)
 {
     EXRContext *s = avctx->priv_data;

     AVFrame *const p = s->picture;

     EXRThreadData *td = &s->thread_data[threadnr];
     const uint8_t *channel_buffer[4] = { 0 };
     const uint8_t *buf = s->buf;
     uint64_t line_offset, uncompressed_size;
     uint32_t xdelta = s->xdelta;
     uint16_t *ptr_x;
     uint8_t *ptr;
     int32_t data_size, line;
     const uint8_t *src;
     int axmax = (avctx->width - (s->xmax + 1)) * 2 * s->desc->nb_components;
     int bxmin = s->xmin * 2 * s->desc->nb_components;

     int i, x, buf_size = s->buf_size;
     int av_unused ret;

 
     line_offset = AV_RL64(s->table + jobnr * 8);
     // Check if the buffer has the required bytes needed from the offset
     if (line_offset > buf_size - 8)
         return AVERROR_INVALIDDATA;
 
     src = buf + line_offset + 8;
     line = AV_RL32(src - 8);
     if (line < s->ymin || line > s->ymax)
         return AVERROR_INVALIDDATA;
 
     data_size = AV_RL32(src - 4);
     if (data_size <= 0 || data_size > buf_size)
         return AVERROR_INVALIDDATA;
 

     s->ysize = FFMIN(s->scan_lines_per_block, s->ymax - line + 1);
     uncompressed_size = s->scan_line_size * s->ysize;

     if ((s->compr == EXR_RAW && (data_size != uncompressed_size ||
                                  line_offset > buf_size - uncompressed_size)) ||

         (s->compr != EXR_RAW && (data_size > uncompressed_size ||
                                  line_offset > buf_size - data_size))) {

         return AVERROR_INVALIDDATA;
     }
 
     if (data_size < uncompressed_size) {
         av_fast_padded_malloc(&td->uncompressed_data, &td->uncompressed_size, uncompressed_size);
         av_fast_padded_malloc(&td->tmp, &td->tmp_size, uncompressed_size);
         if (!td->uncompressed_data || !td->tmp)
             return AVERROR(ENOMEM);
 

         switch (s->compr) {
         case EXR_ZIP1:
         case EXR_ZIP16:
             ret = zip_uncompress(src, data_size, uncompressed_size, td);
             break;

         case EXR_PIZ:
             ret = piz_uncompress(s, src, data_size, uncompressed_size, td);
             break;

         case EXR_PXR24:
             ret = pxr24_uncompress(s, src, data_size, uncompressed_size, td);
             break;

         case EXR_RLE:
             ret = rle_uncompress(src, data_size, uncompressed_size, td);

         }
 

         src = td->uncompressed_data;

     }
 

     channel_buffer[0] = src + xdelta * s->channel_offsets[0];
     channel_buffer[1] = src + xdelta * s->channel_offsets[1];
     channel_buffer[2] = src + xdelta * s->channel_offsets[2];
     if (s->channel_offsets[3] >= 0)
         channel_buffer[3] = src + xdelta * s->channel_offsets[3];
 

     ptr = p->data[0] + line * p->linesize[0];
     for (i = 0; i < s->scan_lines_per_block && line + i <= s->ymax; i++, ptr += p->linesize[0]) {
         const uint8_t *r, *g, *b, *a;
 
         r = channel_buffer[0];
         g = channel_buffer[1];
         b = channel_buffer[2];
         if (channel_buffer[3])
             a = channel_buffer[3];
 
         ptr_x = (uint16_t *)ptr;
 
         // Zero out the start if xmin is not 0
         memset(ptr_x, 0, bxmin);
         ptr_x += s->xmin * s->desc->nb_components;

         if (s->pixel_type == EXR_FLOAT) {

             // 32-bit
             for (x = 0; x < xdelta; x++) {
                 *ptr_x++ = exr_flt2uint(bytestream_get_le32(&r));
                 *ptr_x++ = exr_flt2uint(bytestream_get_le32(&g));
                 *ptr_x++ = exr_flt2uint(bytestream_get_le32(&b));
                 if (channel_buffer[3])
                     *ptr_x++ = exr_flt2uint(bytestream_get_le32(&a));
             }
         } else {
             // 16-bit
             for (x = 0; x < xdelta; x++) {
                 *ptr_x++ = exr_halflt2uint(bytestream_get_le16(&r));
                 *ptr_x++ = exr_halflt2uint(bytestream_get_le16(&g));
                 *ptr_x++ = exr_halflt2uint(bytestream_get_le16(&b));
                 if (channel_buffer[3])
                     *ptr_x++ = exr_halflt2uint(bytestream_get_le16(&a));
             }
         }
 
         // Zero out the end if xmax+1 is not w
         memset(ptr_x, 0, axmax);
 
         channel_buffer[0] += s->scan_line_size;
         channel_buffer[1] += s->scan_line_size;
         channel_buffer[2] += s->scan_line_size;
         if (channel_buffer[3])
             channel_buffer[3] += s->scan_line_size;
     }
 
     return 0;
 }
 

 static int decode_frame(AVCodecContext *avctx,
                         void *data,

                         int *got_frame,

                         AVPacket *avpkt)
 {
     const uint8_t *buf      = avpkt->data;
     unsigned int   buf_size = avpkt->size;
     const uint8_t *buf_end  = buf + buf_size;
 
     EXRContext *const s = avctx->priv_data;

     ThreadFrame frame = { .f = data };

     AVFrame *picture  = data;
     uint8_t *ptr;
 

     int i, y, magic_number, version, flags, ret;

     int w = 0;
     int h = 0;
 

     int out_line_size;

     int scan_line_blocks;

     unsigned int current_channel_offset = 0;
 

     s->xmin = ~0;
     s->xmax = ~0;
     s->ymin = ~0;
     s->ymax = ~0;
     s->xdelta = ~0;
     s->ydelta = ~0;

     s->channel_offsets[0] = -1;
     s->channel_offsets[1] = -1;
     s->channel_offsets[2] = -1;

     s->channel_offsets[3] = -1;

     s->pixel_type = -1;

     s->nb_channels = 0;

     s->compr = -1;

     s->buf = buf;
     s->buf_size = buf_size;

     if (buf_size < 10) {

         av_log(avctx, AV_LOG_ERROR, "Too short header to parse\n");

         return AVERROR_INVALIDDATA;

     }
 

     magic_number = bytestream_get_le32(&buf);
     if (magic_number != 20000630) { // As per documentation of OpenEXR it's supposed to be int 20000630 little-endian

         av_log(avctx, AV_LOG_ERROR, "Wrong magic number %d\n", magic_number);

         return AVERROR_INVALIDDATA;

     }
 

     version = bytestream_get_byte(&buf);
     if (version != 2) {

         avpriv_report_missing_feature(avctx, "Version %d", version);

         return AVERROR_PATCHWELCOME;
     }
 
     flags = bytestream_get_le24(&buf);
     if (flags & 0x2) {

         avpriv_report_missing_feature(avctx, "Tile support");

         return AVERROR_PATCHWELCOME;

     }
 
     // Parse the header

     while (buf < buf_end && buf[0]) {

         unsigned int variable_buffer_data_size;
         // Process the channel list

         if (check_header_variable(avctx, &buf, buf_end, "channels", "chlist", 38, &variable_buffer_data_size) >= 0) {

             const uint8_t *channel_list_end;
             if (!variable_buffer_data_size)

                 return AVERROR_INVALIDDATA;

             channel_list_end = buf + variable_buffer_data_size;

             while (channel_list_end - buf >= 19) {

                 EXRChannel *channel;

                 enum ExrPixelType current_pixel_type;

                 int channel_index = -1;

                 int xsub, ysub;

                 const char* b = buf;
 
                 if ( strcmp( s->layer, "" ) != 0 ) {
                     if ( strncmp( b, s->layer, strlen(s->layer) ) == 0 ) {
                         b += strlen(s->layer);
                         if ( *b == '.' ) ++b;   /* skip dot if not given */
                         av_log( avctx, AV_LOG_INFO, "Layer %s.%s matched\n",
                                s->layer, b );
                     }
                 }
 
 
                 if (!strcmp(b, "R")||!strcmp(b, "X")||!strcmp(b,"U"))

                     channel_index = 0;

                 else if (!strcmp(b, "G")||!strcmp(b, "Y")||!strcmp(b,"V"))

                     channel_index = 1;

                 else if (!strcmp(b, "B")||!strcmp(b, "Z")||!strcmp(b,"W"))

                     channel_index = 2;

                 else if (!strcmp(b, "A"))

                     channel_index = 3;

                 else
                     av_log(avctx, AV_LOG_WARNING, "Unsupported channel %.256s\n", buf);

 
                 while (bytestream_get_byte(&buf) && buf < channel_list_end)
                     continue; /* skip */
 
                 if (channel_list_end - * &buf < 4) {

                     av_log(avctx, AV_LOG_ERROR, "Incomplete header\n");

                     return AVERROR_INVALIDDATA;

                 }
 

                 current_pixel_type = bytestream_get_le32(&buf);
                 if (current_pixel_type > 2) {
                     av_log(avctx, AV_LOG_ERROR, "Unknown pixel type\n");

                     return AVERROR_INVALIDDATA;

                 }
 

                 buf += 4;
                 xsub = bytestream_get_le32(&buf);
                 ysub = bytestream_get_le32(&buf);
                 if (xsub != 1 || ysub != 1) {

                     avpriv_report_missing_feature(avctx, "Subsampling %dx%d", xsub, ysub);

                     return AVERROR_PATCHWELCOME;
                 }
 

                 if (channel_index >= 0) {

                     if (s->pixel_type != -1 && s->pixel_type != current_pixel_type) {

                         av_log(avctx, AV_LOG_ERROR, "RGB channels not of the same depth\n");

                         return AVERROR_INVALIDDATA;

                     }

                     s->pixel_type = current_pixel_type;

                     s->channel_offsets[channel_index] = current_channel_offset;
                 }
 

                 s->channels = av_realloc_f(s->channels, ++s->nb_channels, sizeof(EXRChannel));
                 if (!s->channels)
                     return AVERROR(ENOMEM);
                 channel = &s->channels[s->nb_channels - 1];

                 channel->pixel_type = current_pixel_type;

                 channel->xsub = xsub;
                 channel->ysub = ysub;
 

                 current_channel_offset += 1 << current_pixel_type;

             }
 
             /* Check if all channels are set with an offset or if the channels
              * are causing an overflow  */
 
             if (FFMIN3(s->channel_offsets[0],
                        s->channel_offsets[1],
                        s->channel_offsets[2]) < 0) {
                 if (s->channel_offsets[0] < 0)

                     av_log(avctx, AV_LOG_ERROR, "Missing red channel\n");

                 if (s->channel_offsets[1] < 0)

                     av_log(avctx, AV_LOG_ERROR, "Missing green channel\n");

                 if (s->channel_offsets[2] < 0)

                     av_log(avctx, AV_LOG_ERROR, "Missing blue channel\n");

                 return AVERROR_INVALIDDATA;

             }
 
             buf = channel_list_end;
             continue;

         } else if (check_header_variable(avctx, &buf, buf_end, "dataWindow", "box2i", 31, &variable_buffer_data_size) >= 0) {

             if (!variable_buffer_data_size)

                 return AVERROR_INVALIDDATA;

             s->xmin = AV_RL32(buf);
             s->ymin = AV_RL32(buf + 4);
             s->xmax = AV_RL32(buf + 8);
             s->ymax = AV_RL32(buf + 12);
             s->xdelta = (s->xmax - s->xmin) + 1;
             s->ydelta = (s->ymax - s->ymin) + 1;

 
             buf += variable_buffer_data_size;
             continue;

         } else if (check_header_variable(avctx, &buf, buf_end, "displayWindow", "box2i", 34, &variable_buffer_data_size) >= 0) {

             if (!variable_buffer_data_size)

                 return AVERROR_INVALIDDATA;

 
             w = AV_RL32(buf + 8) + 1;
             h = AV_RL32(buf + 12) + 1;
 
             buf += variable_buffer_data_size;
             continue;

         } else if (check_header_variable(avctx, &buf, buf_end, "lineOrder", "lineOrder", 25, &variable_buffer_data_size) >= 0) {

             if (!variable_buffer_data_size)

                 return AVERROR_INVALIDDATA;

             av_log(avctx, AV_LOG_DEBUG, "line order : %d\n", *buf);
             if (*buf > 2) {
                 av_log(avctx, AV_LOG_ERROR, "Unknown line order\n");
                 return AVERROR_INVALIDDATA;

             }
 
             buf += variable_buffer_data_size;
             continue;

         } else if (check_header_variable(avctx, &buf, buf_end, "pixelAspectRatio", "float", 31, &variable_buffer_data_size) >= 0) {

             if (!variable_buffer_data_size)

                 return AVERROR_INVALIDDATA;

 
             avctx->sample_aspect_ratio = av_d2q(av_int2float(AV_RL32(buf)), 255);
 
             buf += variable_buffer_data_size;
             continue;

         } else if (check_header_variable(avctx, &buf, buf_end, "compression", "compression", 29, &variable_buffer_data_size) >= 0) {

             if (!variable_buffer_data_size)

                 return AVERROR_INVALIDDATA;

             if (s->compr == -1)
                 s->compr = *buf;
             else
                 av_log(avctx, AV_LOG_WARNING, "Found more than one compression attribute\n");

 
             buf += variable_buffer_data_size;
             continue;
         }
 
         // Check if there is enough bytes for a header
         if (buf_end - buf <= 9) {

             av_log(avctx, AV_LOG_ERROR, "Incomplete header\n");

             return AVERROR_INVALIDDATA;

         }
 
         // Process unknown variables

         for (i = 0; i < 2; i++) {

             // Skip variable name/type

             while (++buf < buf_end)

                 if (buf[0] == 0x0)
                     break;
         }
         buf++;
         // Skip variable length
         if (buf_end - buf >= 5) {
             variable_buffer_data_size = get_header_variable_length(&buf, buf_end);
             if (!variable_buffer_data_size) {

                 av_log(avctx, AV_LOG_ERROR, "Incomplete header\n");

                 return AVERROR_INVALIDDATA;

             }
             buf += variable_buffer_data_size;
         }
     }
 

     if (s->compr == -1) {
         av_log(avctx, AV_LOG_ERROR, "Missing compression attribute\n");
         return AVERROR_INVALIDDATA;
     }
 

     if (buf >= buf_end) {

         av_log(avctx, AV_LOG_ERROR, "Incomplete frame\n");

         return AVERROR_INVALIDDATA;

     }
     buf++;
 

     switch (s->pixel_type) {
     case EXR_FLOAT:
     case EXR_HALF:

         if (s->channel_offsets[3] >= 0)

             avctx->pix_fmt = AV_PIX_FMT_RGBA64;

         else

             avctx->pix_fmt = AV_PIX_FMT_RGB48;

         break;

     case EXR_UINT:

         avpriv_request_sample(avctx, "32-bit unsigned int");

         return AVERROR_PATCHWELCOME;

     default:

         av_log(avctx, AV_LOG_ERROR, "Missing channel list\n");

         return AVERROR_INVALIDDATA;

     }
 

     switch (s->compr) {
     case EXR_RAW:

     case EXR_RLE:

     case EXR_ZIP1:

         s->scan_lines_per_block = 1;

         break;

     case EXR_PXR24:

     case EXR_ZIP16:

         s->scan_lines_per_block = 16;

         break;

     case EXR_PIZ:
         s->scan_lines_per_block = 32;
         break;

     default:

         avpriv_report_missing_feature(avctx, "Compression %d", s->compr);

         return AVERROR_PATCHWELCOME;

     }
 

     // Verify the xmin, xmax, ymin, ymax and xdelta before setting the actual image size

     if (s->xmin > s->xmax ||
         s->ymin > s->ymax ||
         s->xdelta != s->xmax - s->xmin + 1 ||
         s->xmax >= w || s->ymax >= h) {

         av_log(avctx, AV_LOG_ERROR, "Wrong sizing or missing size information\n");

         return AVERROR_INVALIDDATA;

     }
 

     if ((ret = ff_set_dimensions(avctx, w, h)) < 0)
         return ret;

     s->desc = av_pix_fmt_desc_get(avctx->pix_fmt);
     out_line_size = avctx->width * 2 * s->desc->nb_components;
     s->scan_line_size = s->xdelta * current_channel_offset;
     scan_line_blocks = (s->ydelta + s->scan_lines_per_block - 1) / s->scan_lines_per_block;

 
     if (s->compr != EXR_RAW) {

         size_t thread_data_size, prev_size;

         EXRThreadData *m;
 
         prev_size = s->thread_data_size;
         if (av_size_mult(avctx->thread_count, sizeof(EXRThreadData), &thread_data_size))
             return AVERROR(EINVAL);
 
         m = av_fast_realloc(s->thread_data, &s->thread_data_size, thread_data_size);
         if (!m)

             return AVERROR(ENOMEM);

         s->thread_data = m;
         memset(s->thread_data + prev_size, 0, s->thread_data_size - prev_size);

     }
 

     if ((ret = ff_thread_get_buffer(avctx, &frame, 0)) < 0)

         return ret;

     if (buf_end - buf < scan_line_blocks * 8)
         return AVERROR_INVALIDDATA;
     s->table = buf;

     ptr = picture->data[0];

 
     // Zero out the start if ymin is not 0

     for (y = 0; y < s->ymin; y++) {

         memset(ptr, 0, out_line_size);

         ptr += picture->linesize[0];

     }
 

     s->picture = picture;

     avctx->execute2(avctx, decode_block, s->thread_data, NULL, scan_line_blocks);

 
     // Zero out the end if ymax+1 is not h

     for (y = s->ymax + 1; y < avctx->height; y++) {

         memset(ptr, 0, out_line_size);

         ptr += picture->linesize[0];

     }
 

     picture->pict_type = AV_PICTURE_TYPE_I;

     *got_frame = 1;

 
     return buf_size;
 }
 
 static av_cold int decode_end(AVCodecContext *avctx)
 {
     EXRContext *s = avctx->priv_data;

     int i;

     for (i = 0; i < s->thread_data_size / sizeof(EXRThreadData); i++) {
         EXRThreadData *td = &s->thread_data[i];

         av_freep(&td->uncompressed_data);
         av_freep(&td->tmp);
         av_freep(&td->bitmap);
         av_freep(&td->lut);

     }
 
     av_freep(&s->thread_data);
     s->thread_data_size = 0;

     av_freep(&s->channels);

     return 0;
 }
 
 AVCodec ff_exr_decoder = {
     .name               = "exr",

     .long_name          = NULL_IF_CONFIG_SMALL("OpenEXR image"),

     .type               = AVMEDIA_TYPE_VIDEO,

     .id                 = AV_CODEC_ID_EXR,

     .priv_data_size     = sizeof(EXRContext),
     .close              = decode_end,
     .decode             = decode_frame,

     .capabilities       = CODEC_CAP_DR1 | CODEC_CAP_FRAME_THREADS | CODEC_CAP_SLICE_THREADS,

     .priv_class         = &exr_class,

 };