text: /*
   * Copyright 2005-2017 ECMWF.
   *
   * This software is licensed under the terms of the Apache Licence Version 2.0
   * which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
   *
   * In applying this licence, ECMWF does not waive the privileges and immunities granted to it by
   * virtue of its status as an intergovernmental organisation nor does it submit to any jurisdiction.
   */
  
  #include "grib_api_internal.h"
  #define PNG_ANYBITS
  
  /*
     This is used by make_class.pl
  
     START_CLASS_DEF
     CLASS      = accessor
     SUPER      = grib_accessor_class_values
     IMPLEMENTS = init
     IMPLEMENTS = unpack_double
     IMPLEMENTS = pack_double
     IMPLEMENTS = value_count
     MEMBERS=const char*   number_of_values
     MEMBERS=const char*   reference_value
     MEMBERS=const char*   binary_scale_factor
     MEMBERS=const char*   decimal_scale_factor
     MEMBERS=const char*   bits_per_value
     MEMBERS=const char*   ni
     MEMBERS=const char*   nj
     MEMBERS=const char*   list_defining_points
     MEMBERS=const char*   number_of_data_points
     MEMBERS=const char*   scanning_mode
  
     END_CLASS_DEF
  
   */
  
  /* START_CLASS_IMP */
  
  /*
  
  Don't edit anything between START_CLASS_IMP and END_CLASS_IMP
  Instead edit values between START_CLASS_DEF and END_CLASS_DEF
  or edit "accessor.class" and rerun ./make_class.pl
  
  */
  
  static int pack_double(grib_accessor*, const double* val,size_t *len);
  static int unpack_double(grib_accessor*, double* val,size_t *len);
  static int value_count(grib_accessor*,long*);
  static void init(grib_accessor*,const long, grib_arguments* );
  static void init_class(grib_accessor_class*);
  
  typedef struct grib_accessor_data_png_packing {
      grib_accessor          att;
  /* Members defined in gen */
  /* Members defined in values */
  	int  carg;
  	const char* seclen;
  	const char* offsetdata;
  	const char* offsetsection;
  	int dirty;
  /* Members defined in data_png_packing */
  	const char*   number_of_values;
  	const char*   reference_value;
  	const char*   binary_scale_factor;
  	const char*   decimal_scale_factor;
  	const char*   bits_per_value;
  	const char*   ni;
  	const char*   nj;
  	const char*   list_defining_points;
  	const char*   number_of_data_points;
  	const char*   scanning_mode;
  } grib_accessor_data_png_packing;
  
  extern grib_accessor_class* grib_accessor_class_values;
  
  static grib_accessor_class _grib_accessor_class_data_png_packing = {
      &grib_accessor_class_values,                      /* super                     */
      "data_png_packing",                      /* name                      */
      sizeof(grib_accessor_data_png_packing),  /* size                      */
      0,                           /* inited */
      &init_class,                 /* init_class */
      &init,                       /* init                      */
      0,                  /* post_init                      */
      0,                    /* free mem                       */
      0,                       /* describes himself         */
      0,                /* get length of section     */
      0,              /* get length of string      */
      &value_count,                /* get number of values      */
      0,                 /* get number of bytes      */
      0,                /* get offset to bytes           */
      0,            /* get native type               */
      0,                /* get sub_section                */
      0,               /* grib_pack procedures long      */
      0,                 /* grib_pack procedures long      */
      0,                  /* grib_pack procedures long      */
      0,                /* grib_unpack procedures long    */
      &pack_double,                /* grib_pack procedures double    */
      &unpack_double,              /* grib_unpack procedures double  */
      0,                /* grib_pack procedures string    */
      0,              /* grib_unpack procedures string  */
      0,          /* grib_pack array procedures string    */
      0,        /* grib_unpack array procedures string  */
      0,                 /* grib_pack procedures bytes     */
      0,               /* grib_unpack procedures bytes   */
      0,            /* pack_expression */
      0,              /* notify_change   */
      0,                /* update_size   */
      0,            /* preferred_size   */
      0,                    /* resize   */
      0,      /* nearest_smaller_value */
      0,                       /* next accessor    */
      0,                    /* compare vs. another accessor   */
      0,     /* unpack only ith value          */
      0,     /* unpack a subarray         */
      0,              		/* clear          */
      0,               		/* clone accessor          */
  };
  
  
  grib_accessor_class* grib_accessor_class_data_png_packing = &_grib_accessor_class_data_png_packing;
  
  
  static void init_class(grib_accessor_class* c)
  {
  	c->dump	=	(*(c->super))->dump;
  	c->next_offset	=	(*(c->super))->next_offset;
  	c->string_length	=	(*(c->super))->string_length;
  	c->byte_count	=	(*(c->super))->byte_count;
  	c->byte_offset	=	(*(c->super))->byte_offset;
  	c->get_native_type	=	(*(c->super))->get_native_type;
  	c->sub_section	=	(*(c->super))->sub_section;
  	c->pack_missing	=	(*(c->super))->pack_missing;
  	c->is_missing	=	(*(c->super))->is_missing;
  	c->pack_long	=	(*(c->super))->pack_long;
  	c->unpack_long	=	(*(c->super))->unpack_long;
  	c->pack_string	=	(*(c->super))->pack_string;
  	c->unpack_string	=	(*(c->super))->unpack_string;
  	c->pack_string_array	=	(*(c->super))->pack_string_array;
  	c->unpack_string_array	=	(*(c->super))->unpack_string_array;
  	c->pack_bytes	=	(*(c->super))->pack_bytes;
  	c->unpack_bytes	=	(*(c->super))->unpack_bytes;
  	c->pack_expression	=	(*(c->super))->pack_expression;
  	c->notify_change	=	(*(c->super))->notify_change;
  	c->update_size	=	(*(c->super))->update_size;
  	c->preferred_size	=	(*(c->super))->preferred_size;
  	c->resize	=	(*(c->super))->resize;
  	c->nearest_smaller_value	=	(*(c->super))->nearest_smaller_value;
  	c->next	=	(*(c->super))->next;
  	c->compare	=	(*(c->super))->compare;
  	c->unpack_double_element	=	(*(c->super))->unpack_double_element;
  	c->unpack_double_subarray	=	(*(c->super))->unpack_double_subarray;
  	c->clear	=	(*(c->super))->clear;
  	c->make_clone	=	(*(c->super))->make_clone;
  }
  
  /* END_CLASS_IMP */
  
  static void init(grib_accessor* a,const long v, grib_arguments* args)
  {
      grib_accessor_data_png_packing *self =(grib_accessor_data_png_packing*)a;
  
      self->number_of_values      = grib_arguments_get_name(grib_handle_of_accessor(a),args,self->carg++);
      self->reference_value       = grib_arguments_get_name(grib_handle_of_accessor(a),args,self->carg++);
      self->binary_scale_factor   = grib_arguments_get_name(grib_handle_of_accessor(a),args,self->carg++);
      self->decimal_scale_factor  = grib_arguments_get_name(grib_handle_of_accessor(a),args,self->carg++);
      self->bits_per_value           = grib_arguments_get_name(grib_handle_of_accessor(a),args,self->carg++);
  
      self->ni                     = grib_arguments_get_name(grib_handle_of_accessor(a),args,self->carg++);
      self->nj                     = grib_arguments_get_name(grib_handle_of_accessor(a),args,self->carg++);
  
      self->list_defining_points   = grib_arguments_get_name(grib_handle_of_accessor(a),args,self->carg++);
      self->number_of_data_points  = grib_arguments_get_name(grib_handle_of_accessor(a),args,self->carg++);
      self->scanning_mode      = grib_arguments_get_name(grib_handle_of_accessor(a),args,self->carg++);
      a->flags |= GRIB_ACCESSOR_FLAG_DATA;
  }
  
  static int value_count(grib_accessor* a,long* n_vals)
  {
      grib_accessor_data_png_packing *self =(grib_accessor_data_png_packing*)a;
      *n_vals= 0;
      return grib_get_long_internal(grib_handle_of_accessor(a),self->number_of_values,n_vals);
  }
  
  #if HAVE_LIBPNG
  
  #include "png.h"
  
  typedef struct png_read_callback_data {
      unsigned char* buffer;
      size_t         length;
      size_t         offset;
  } png_read_callback_data;
  
  static void png_read_callback(png_structp png,png_bytep data, png_size_t length)
  {
      png_read_callback_data* p = (png_read_callback_data*)png_get_io_ptr(png);
      Assert(p->offset + length <= p->length);
      memcpy(data,p->buffer+p->offset,length);
      p->offset += length;
  }
  
  static void png_write_callback(png_structp png,png_bytep data, png_size_t length)
  {
      png_read_callback_data* p = (png_read_callback_data*)png_get_io_ptr(png);
      Assert(p->offset + length <= p->length);
      memcpy(p->buffer+p->offset,data,length);
      p->offset += length;
  }
  
  static void png_flush_callback(png_structp png)
  {
      /* Empty */
  }
  
  
  static int  unpack_double(grib_accessor* a, double* val, size_t *len)
  {
      grib_accessor_data_png_packing *self =(grib_accessor_data_png_packing*)a;
  
      int err = GRIB_SUCCESS;
      int i,j;
      size_t buflen = grib_byte_count(a);
  
      double bscale = 0;
      double dscale = 0;
      unsigned char* buf = NULL;
      size_t n_vals = 0;
  
      long binary_scale_factor = 0;
      long decimal_scale_factor = 0;
      double reference_value = 0;
      long bits_per_value =0;
      long bits8;
      long nn=0;
  
      png_structp png  = 0;
      png_infop info = 0,theEnd = 0;
      png_bytepp rows = 0;
      int interlace = 0,colour = 0,compression = 0,filter = 0,depth = 0;
  
      png_uint_32 width = 0,height = 0;
  
      png_read_callback_data callback_data;
  
      self->dirty=0;
  
      n_vals = 0;
      err=grib_value_count(a,&nn);
      n_vals=nn;
      if (err) return err;
  
      if((err = grib_get_long_internal(grib_handle_of_accessor(a),self->bits_per_value,&bits_per_value)) != GRIB_SUCCESS)
          return err;
      if((err = grib_get_double_internal(grib_handle_of_accessor(a),self->reference_value, &reference_value)) != GRIB_SUCCESS)
          return err;
      if((err = grib_get_long_internal(grib_handle_of_accessor(a),self->binary_scale_factor, &binary_scale_factor)) != GRIB_SUCCESS)
          return err;
      if((err = grib_get_long_internal(grib_handle_of_accessor(a),self->decimal_scale_factor, &decimal_scale_factor)) != GRIB_SUCCESS)
          return err;
  
      bscale = grib_power(binary_scale_factor,2);
      dscale = grib_power(-decimal_scale_factor,10);
  
      /* TODO: This should be called upstream */
      if(*len < n_vals)
          return GRIB_ARRAY_TOO_SMALL;
  
      /* Special case */
  
      if(bits_per_value == 0)
      {
          for(i = 0; i < n_vals; i++)
              val[i] = reference_value;
          *len = n_vals;
          return GRIB_SUCCESS;
      }
  
      buf = (unsigned char*)grib_handle_of_accessor(a)->buffer->data;
      buf += grib_byte_offset(a);
  
  
      if ( png_sig_cmp(buf,0,8) != 0)
          return GRIB_INVALID_MESSAGE;
  
  
      png = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL,
              NULL, NULL);
      if (!png)
      {
          err = GRIB_DECODING_ERROR;
          goto cleanup;
      }
  
      info = png_create_info_struct(png);
      if (!info)
      {
          err = GRIB_DECODING_ERROR;
          goto cleanup;
      }
  
      theEnd = png_create_info_struct(png);
      if (!theEnd)
      {
          err = GRIB_DECODING_ERROR;
          goto cleanup;
      }
  
      if (setjmp(png_jmpbuf(png)))
      {
          err = GRIB_DECODING_ERROR;
          goto cleanup;
      }
  
      callback_data.buffer = buf;
      callback_data.offset = 0;
      callback_data.length = buflen;
  
      /* printf("buflen=%d\n",buflen); */
  
      png_set_read_fn(png,&callback_data,png_read_callback);
      png_read_png(png, info, PNG_TRANSFORM_IDENTITY, NULL);
  
      Assert(callback_data.offset == callback_data.length);
  
  
      rows = png_get_rows(png, info);
  
      png_get_IHDR(png, info,
              &width, &height,
              &depth, &colour,
              &interlace,
              &compression,
              &filter);
  
  
      if (colour == PNG_COLOR_TYPE_RGB)      depth=24;
      if (colour == PNG_COLOR_TYPE_RGB_ALPHA) depth=32;
      bits8 = ((bits_per_value+7)/8)*8;
  
  #ifdef PNG_ANYBITS
      Assert(depth == bits8);
  #else
      Assert( bits_per_value % 8 == 0 );
  #endif
  
      i = 0;
  
      /* printf("bscale=%g dscale=%g reference_value=%g\n",bscale,dscale,reference_value); */
  
      for(j=0; j<height;j++)
      {
          png_byte* row = rows[j];
          long pos = 0;
          int k;
          for(k = 0 ; k < width; k++)
              val[i++] = (double) (((grib_decode_unsigned_long(row, &pos, bits8)*bscale)+reference_value)*dscale);
      }
      /*-------------------------------------------*/
      *len = n_vals;
  
  cleanup:
      if(png)
          png_destroy_read_struct(&png, info?&info:NULL, theEnd?&theEnd:NULL);
      return err;
  
  }
  
  static int pack_double(grib_accessor* a, const double* val, size_t *len)
  {
      grib_accessor_data_png_packing *self =(grib_accessor_data_png_packing*)a;
  
      int err = GRIB_SUCCESS;
      int i,j;
      size_t buflen = grib_byte_count(a);
  
      unsigned char* buf = NULL;
      unsigned char* encoded = NULL;
      size_t n_vals = 0;
  
      long binary_scale_factor = 0;
      long decimal_scale_factor = 0;
      double reference_value = 0;
      long bits8;
      long bits_per_value =0;
      double max,min;
      long bytes;
      double d;
  
      png_structp png  = 0;
      png_infop info = 0;
      png_bytepp rows = 0;
      int colour = 0,depth = 0;
  
      png_uint_32 width = 0,height = 0;
      unsigned char *p;
      double divisor;
  
      png_read_callback_data callback_data;
      long ni,nj;
      long scanning_mode;
      long list_defining_points;
      long number_of_data_points;
      long nn=0;
  
  
      self->dirty=1;
  
      n_vals = 0;
      err=grib_value_count(a,&nn);
      n_vals=nn;
      if (err) return err;
  
      if((err = grib_get_long_internal(grib_handle_of_accessor(a),self->bits_per_value,&bits_per_value)) != GRIB_SUCCESS)
          return err;
      if((err = grib_get_double_internal(grib_handle_of_accessor(a),self->reference_value, &reference_value)) != GRIB_SUCCESS)
          return err;
      if((err = grib_get_long_internal(grib_handle_of_accessor(a),self->binary_scale_factor, &binary_scale_factor)) != GRIB_SUCCESS)
          return err;
      if((err = grib_get_long_internal(grib_handle_of_accessor(a),self->decimal_scale_factor, &decimal_scale_factor)) != GRIB_SUCCESS)
          return err;
  
      /* Special case */
  
      if(*len == 0) {
          grib_buffer_replace(a, NULL, 0,1,1);
          return GRIB_SUCCESS;
      }
  
      if(bits_per_value == 0)
      {
          int i;
          /* constant field */
          for(i = 1 ; i < n_vals; i++)
              Assert(val[i] == val[0]);
  
          if((err = grib_set_double_internal(grib_handle_of_accessor(a),self->reference_value, val[0])) != GRIB_SUCCESS)
              return err;
          {
              /* Make sure we can decode it again */
              double ref = 1e-100;
              grib_get_double_internal(grib_handle_of_accessor(a),self->reference_value,&ref);
              printf("%g %g %g\n",reference_value,ref,reference_value-ref);
              Assert(ref == reference_value);
          }
  
          if((err = grib_set_long_internal(grib_handle_of_accessor(a),self->number_of_values, n_vals)) !=  GRIB_SUCCESS)
              return err;
  
          grib_buffer_replace(a, NULL, 0,1,1);
  
          return GRIB_SUCCESS;
      }
  
      if((err = grib_get_long_internal(grib_handle_of_accessor(a),self->ni,&ni)) != GRIB_SUCCESS)
          return err;
  
      if((err = grib_get_long_internal(grib_handle_of_accessor(a),self->nj,&nj)) != GRIB_SUCCESS)
          return err;
  
      if((err = grib_get_long_internal(grib_handle_of_accessor(a),self->scanning_mode,&scanning_mode)) != GRIB_SUCCESS)
          return err;
  
      if((err = grib_get_long_internal(grib_handle_of_accessor(a),self->list_defining_points,&list_defining_points)) != GRIB_SUCCESS)
          return err;
  
      if((err = grib_get_long_internal(grib_handle_of_accessor(a),self->number_of_data_points,&number_of_data_points)) != GRIB_SUCCESS)
          return err;
  
      width  = ni;
      height = nj;
  
      if((scanning_mode & (1<<5)) != 0)
      {
          long tmp = width;
          width    = height;
          height   = tmp;
      }
  
      /* The grid is not regular */
      if(list_defining_points != 0)
      {
          width  = *len;
          height = 1;
      }
  
      /* There is a bitmap */
      if(*len != number_of_data_points)
      {
          width  = *len;
          height = 1;
      }
  
      if(width*height != *len)
      {
          fprintf(stderr,"width=%ld height=%ld len=%ld\n", (long)width, (long)height, (long)(*len) );
          Assert(width*height == *len);
      }
  
      d = grib_power(decimal_scale_factor,10) ;
  
      max = val[0];
      min = max;
      for(i=1;i< n_vals;i++)
      {
          if      (val[i] > max) max = val[i];
          else if (val[i] < min) min = val[i];
      }
      min *= d;
      max *= d;
  
      if (grib_get_nearest_smaller_value(grib_handle_of_accessor(a),self->reference_value,min,&reference_value)
              !=GRIB_SUCCESS) {
          grib_context_log(a->context,GRIB_LOG_ERROR,
                  "unable to find nearest_smaller_value of %g for %s",min,self->reference_value);
          return GRIB_INTERNAL_ERROR;
      }
  
      if(reference_value > min)
      {
          fprintf(stderr,"reference_value=%g min_value=%g diff=%g\n",reference_value,min,reference_value-min);
          Assert(reference_value <= min);
      }
  
      binary_scale_factor = grib_get_binary_scale_fact(max,reference_value,bits_per_value,&err);
      divisor = grib_power(-binary_scale_factor,2);
  
  #ifndef PNG_ANYBITS
      Assert(bits_per_value % 8 == 0);
  #endif
      bits8 = (bits_per_value+7)/8*8;
      encoded = grib_context_buffer_malloc_clear(a->context,bits8/8*n_vals);
  
      if(!encoded) {
          err = GRIB_OUT_OF_MEMORY;
          goto cleanup;
      }
  
      buflen = 0;
      p = encoded;
      for(i=0;i< n_vals;i++){
          long blen = bits8;
          unsigned long unsigned_val = (unsigned long)((((val[i]*d)-(reference_value))*divisor)+0.5);
          while(blen >= 8)
          {
              blen   -= 8;
              *p = (unsigned_val >> blen);
              p++;
              buflen++;
          }
      }
      /*       buflen = n_vals*(bits_per_value/8);*/
  
      grib_context_log(a->context, GRIB_LOG_DEBUG,
              "grib_accessor_data_png_packing : pack_double : packing %s, %d values", a->name, n_vals);
      buf = grib_context_buffer_malloc_clear(a->context,buflen);
  
      if(!buf) {
          err = GRIB_OUT_OF_MEMORY;
          goto cleanup;
      }
  
      if((err = grib_set_double_internal(grib_handle_of_accessor(a),self->reference_value, reference_value)) != GRIB_SUCCESS)
          return err;
      {
          /* Make sure we can decode it again */
          double ref = 1e-100;
          grib_get_double_internal(grib_handle_of_accessor(a),self->reference_value,&ref);
          Assert(ref == reference_value);
      }
      if((err = grib_set_long_internal(grib_handle_of_accessor(a),self->binary_scale_factor, binary_scale_factor)) != GRIB_SUCCESS)
          return err;
      if((err = grib_set_long_internal(grib_handle_of_accessor(a),self->decimal_scale_factor, decimal_scale_factor)) != GRIB_SUCCESS)
          return err;
  
      if((err = grib_get_long_internal(grib_handle_of_accessor(a),self->ni,&ni)) != GRIB_SUCCESS)
          return err;
  
      if((err = grib_get_long_internal(grib_handle_of_accessor(a),self->nj,&nj)) != GRIB_SUCCESS)
          return err;
  
      png = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
      if (!png)
      {
          err = GRIB_DECODING_ERROR;
          goto cleanup;
      }
  
      info = png_create_info_struct(png);
      if (!info)
      {
          err = GRIB_DECODING_ERROR;
          goto cleanup;
      }
  
      if (setjmp(png_jmpbuf(png)))
      {
          err = GRIB_DECODING_ERROR;
          goto cleanup;
      }
  
      callback_data.buffer = buf;
      callback_data.offset = 0;
      callback_data.length = buflen;
  
      /* printf("buflen=%d\n",buflen); */
      png_set_write_fn(png,&callback_data,png_write_callback,png_flush_callback);
  
      depth = bits8;
  
      colour = PNG_COLOR_TYPE_GRAY;
      if (bits8 == 24)
      {
          depth=8;
          colour=PNG_COLOR_TYPE_RGB;
      }
  
      if(bits8 == 32 )
      {
          depth=8;
          colour=PNG_COLOR_TYPE_RGB_ALPHA;
      }
  
      png_set_IHDR(png, info, width, height,
              depth, colour, PNG_INTERLACE_NONE,
              PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
  
      /*bytes=bit_depth/8;*/
      bytes = bits8/8;
  
      rows = grib_context_buffer_malloc_clear(a->context,sizeof(png_bytep)*height);
      /*rows  = malloc(height*sizeof(png_bytep));*/
      Assert(rows);
      for (j=0;j<height;j++)
          rows[j] = &encoded[j*width*bytes];
  
      png_set_rows(png, info,rows);
  
      png_write_png(png, info, PNG_TRANSFORM_IDENTITY, NULL);
  
      Assert(callback_data.offset <= callback_data.length);
  
      grib_buffer_replace(a, buf, callback_data.offset,1,1);
  
  cleanup:
      if(png)
          png_destroy_write_struct(&png, info?&info:NULL);
  
  
      grib_context_buffer_free(a->context,buf);
      grib_context_buffer_free(a->context,encoded);
      grib_context_buffer_free(a->context,rows);
  
      if(err == GRIB_SUCCESS)
          err = grib_set_long_internal(grib_handle_of_accessor(a),self->number_of_values, *len);
  
      return err;
  }
  #else
  
  static int  unpack_double(grib_accessor* a, double* val, size_t *len)
  {
      grib_context_log(a->context, GRIB_LOG_ERROR,
              "grib_accessor_data_png_packing: PNG support not enabled.");
      return GRIB_NOT_IMPLEMENTED;
  }
  
  static int pack_double(grib_accessor* a, const double* val, size_t *len)
  {
      grib_context_log(a->context, GRIB_LOG_ERROR,
              "grib_accessor_data_png_packing: PNG support not enabled.");
      return GRIB_NOT_IMPLEMENTED;
  }
  
  #endif
  