customdata_file.cc

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/* SPDX-FileCopyrightText: 2023 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */

 
#include <cstdio>
#include <cstdlib>
#include <cstring>
 
#include "MEM_guardedalloc.h"
 
#include "BLI_endian_defines.h"
#include "BLI_fileops.h"
#include "BLI_string.h"
#include "BLI_utildefines.h"
 
#include "BKE_customdata_file.h"
 
/************************* File Format Definitions ***************************/
 
#define CDF_ENDIAN_LITTLE 0
#define CDF_ENDIAN_BIG 1
 
#define CDF_DATA_FLOAT 0
 
struct CDataFileHeader {
  char ID[4];      /* "BCDF" */
  char endian;     /* little, big */
  char version;    /* non-compatible versions */
  char subversion; /* compatible sub versions */
  char pad;        /* padding */
 
  int structbytes; /* size of this struct in bytes */
  int type;        /* image, mesh */
  int totlayer;    /* number of layers in the file */
};
 
struct CDataFileImageHeader {
  int structbytes; /* size of this struct in bytes */
  int width;       /* image width */
  int height;      /* image height */
  int tile_size;   /* tile size (required power of 2) */
};
 
struct CDataFileMeshHeader {
  int structbytes; /* size of this struct in bytes */
};
 
struct CDataFileLayer {
  int structbytes;               /* size of this struct in bytes */
  int datatype;                  /* only float for now */
  uint64_t datasize;             /* size of data in layer */
  int type;                      /* layer type */
  char name[CDF_LAYER_NAME_MAX]; /* layer name */
};
 
/**************************** Other Definitions ******************************/
 
#define CDF_VERSION 0
#define CDF_SUBVERSION 0
#define CDF_TILE_SIZE 64
 
struct CDataFile {
  int type;
 
  CDataFileHeader header;
  union {
    CDataFileImageHeader image;
    CDataFileMeshHeader mesh;
  } btype;
 
  CDataFileLayer *layer;
  int totlayer;
 
  FILE *readf;
  FILE *writef;
  size_t dataoffset;
};
 
/********************************* Create/Free *******************************/
 
static int cdf_endian()
{
  BLI_STATIC_ASSERT(ENDIAN_ORDER == L_ENDIAN, "Blender only builds on little endian systems")
  return CDF_ENDIAN_LITTLE;
}
 
CDataFile *cdf_create(int type)
{
  CDataFile *cdf = MEM_callocN<CDataFile>("CDataFile");
 
  cdf->type = type;
 
  return cdf;
}
 
void cdf_free(CDataFile *cdf)
{
  cdf_read_close(cdf);
  cdf_write_close(cdf);
 
  if (cdf->layer) {
    MEM_freeN(cdf->layer);
  }
 
  MEM_freeN(cdf);
}
 
/********************************* Read/Write ********************************/
 
static bool cdf_read_header(CDataFile *cdf)
{
  CDataFileHeader *header;
  CDataFileImageHeader *image;
  CDataFileMeshHeader *mesh;
  CDataFileLayer *layer;
  FILE *f = cdf->readf;
  size_t offset = 0;
  int a;
 
  header = &cdf->header;
 
  if (!fread(header, sizeof(CDataFileHeader), 1, cdf->readf)) {
    return false;
  }
 
  if (memcmp(header->ID, "BCDF", sizeof(header->ID)) != 0) {
    return false;
  }
  if (header->version > CDF_VERSION) {
    return false;
  }
  if (header->endian != cdf_endian()) {
    return false;
  }
 
  header->endian = cdf_endian();
 
  /* NOTE: this is endianness-sensitive.
   * Some non-char `header` data would need to be switched. */
 
  if (!ELEM(header->type, CDF_TYPE_IMAGE, CDF_TYPE_MESH)) {
    return false;
  }
 
  offset += header->structbytes;
  header->structbytes = sizeof(CDataFileHeader);
 
  if (BLI_fseek(f, offset, SEEK_SET) != 0) {
    return false;
  }
 
  if (header->type == CDF_TYPE_IMAGE) {
    image = &cdf->btype.image;
    if (!fread(image, sizeof(CDataFileImageHeader), 1, f)) {
      return false;
    }
 
    /* NOTE: this is endianness-sensitive.
     * Some non-char `image` data would need to be switched. */
 
    offset += image->structbytes;
    image->structbytes = sizeof(CDataFileImageHeader);
  }
  else if (header->type == CDF_TYPE_MESH) {
    mesh = &cdf->btype.mesh;
    if (!fread(mesh, sizeof(CDataFileMeshHeader), 1, f)) {
      return false;
    }
 
    /* NOTE: this is endianness-sensitive.
     * Some non-char `mesh` data would need to be switched. */
 
    offset += mesh->structbytes;
    mesh->structbytes = sizeof(CDataFileMeshHeader);
  }
 
  if (BLI_fseek(f, offset, SEEK_SET) != 0) {
    return false;
  }
 
  cdf->layer = MEM_calloc_arrayN<CDataFileLayer>(header->totlayer, "CDataFileLayer");
  cdf->totlayer = header->totlayer;
 
  if (!cdf->layer) {
    return false;
  }
 
  for (a = 0; a < header->totlayer; a++) {
    layer = &cdf->layer[a];
 
    if (!fread(layer, sizeof(CDataFileLayer), 1, f)) {
      return false;
    }
 
    /* NOTE: this is endianness-sensitive.
     * Some non-char `layer` data would need to be switched. */
 
    if (layer->datatype != CDF_DATA_FLOAT) {
      return false;
    }
 
    offset += layer->structbytes;
    layer->structbytes = sizeof(CDataFileLayer);
 
    if (BLI_fseek(f, offset, SEEK_SET) != 0) {
      return false;
    }
  }
 
  cdf->dataoffset = offset;
 
  return true;
}
 
static bool cdf_write_header(CDataFile *cdf)
{
  CDataFileHeader *header;
  CDataFileImageHeader *image;
  CDataFileMeshHeader *mesh;
  CDataFileLayer *layer;
  FILE *f = cdf->writef;
  int a;
 
  header = &cdf->header;
 
  if (!fwrite(header, sizeof(CDataFileHeader), 1, f)) {
    return false;
  }
 
  if (header->type == CDF_TYPE_IMAGE) {
    image = &cdf->btype.image;
    if (!fwrite(image, sizeof(CDataFileImageHeader), 1, f)) {
      return false;
    }
  }
  else if (header->type == CDF_TYPE_MESH) {
    mesh = &cdf->btype.mesh;
    if (!fwrite(mesh, sizeof(CDataFileMeshHeader), 1, f)) {
      return false;
    }
  }
 
  for (a = 0; a < header->totlayer; a++) {
    layer = &cdf->layer[a];
 
    if (!fwrite(layer, sizeof(CDataFileLayer), 1, f)) {
      return false;
    }
  }
 
  return true;
}
 
bool cdf_read_open(CDataFile *cdf, const char *filepath)
{
  FILE *f;
 
  f = BLI_fopen(filepath, "rb");
  if (!f) {
    return false;
  }
 
  cdf->readf = f;
 
  if (!cdf_read_header(cdf)) {
    cdf_read_close(cdf);
    return false;
  }
 
  if (cdf->header.type != cdf->type) {
    cdf_read_close(cdf);
    return false;
  }
 
  return true;
}
 
bool cdf_read_layer(CDataFile *cdf, const CDataFileLayer *blay)
{
  size_t offset;
  int a;
 
  /* seek to right location in file */
  offset = cdf->dataoffset;
  for (a = 0; a < cdf->totlayer; a++) {
    if (&cdf->layer[a] == blay) {
      break;
    }
 
    offset += cdf->layer[a].datasize;
  }
 
  return (BLI_fseek(cdf->readf, offset, SEEK_SET) == 0);
}
 
bool cdf_read_data(CDataFile *cdf, uint size, void *data)
{
  /* read data */
  if (!fread(data, size, 1, cdf->readf)) {
    return false;
  }
 
  /* NOTE: this is endianness-sensitive.
   * `data` would need to be switched. */
 
  return true;
}
 
void cdf_read_close(CDataFile *cdf)
{
  if (cdf->readf) {
    fclose(cdf->readf);
    cdf->readf = nullptr;
  }
}
 
bool cdf_write_open(CDataFile *cdf, const char *filepath)
{
  CDataFileHeader *header;
  CDataFileImageHeader *image;
  CDataFileMeshHeader *mesh;
  FILE *f;
 
  f = BLI_fopen(filepath, "wb");
  if (!f) {
    return false;
  }
 
  cdf->writef = f;
 
  /* Fill header. */
  header = &cdf->header;
  /* Copy "BCDF" (string terminator out of range). */
  header->ID[0] = 'B';
  header->ID[1] = 'C';
  header->ID[2] = 'D';
  header->ID[3] = 'F';
  header->endian = cdf_endian();
  header->version = CDF_VERSION;
  header->subversion = CDF_SUBVERSION;
 
  header->structbytes = sizeof(CDataFileHeader);
  header->type = cdf->type;
  header->totlayer = cdf->totlayer;
 
  if (cdf->type == CDF_TYPE_IMAGE) {
    /* fill image header */
    image = &cdf->btype.image;
    image->structbytes = sizeof(CDataFileImageHeader);
    image->tile_size = CDF_TILE_SIZE;
  }
  else if (cdf->type == CDF_TYPE_MESH) {
    /* fill mesh header */
    mesh = &cdf->btype.mesh;
    mesh->structbytes = sizeof(CDataFileMeshHeader);
  }
 
  cdf_write_header(cdf);
 
  return true;
}
 
bool cdf_write_layer(CDataFile * /*cdf*/, CDataFileLayer * /*blay*/)
{
  return true;
}
 
bool cdf_write_data(CDataFile *cdf, uint size, const void *data)
{
  /* write data */
  if (!fwrite(data, size, 1, cdf->writef)) {
    return false;
  }
 
  return true;
}
 
void cdf_write_close(CDataFile *cdf)
{
  if (cdf->writef) {
    fclose(cdf->writef);
    cdf->writef = nullptr;
  }
}
 
void cdf_remove(const char *filepath)
{
  BLI_delete(filepath, false, false);
}
 
/********************************** Layers ***********************************/
 
CDataFileLayer *cdf_layer_find(CDataFile *cdf, int type, const char *name)
{
  CDataFileLayer *layer;
  int a;
 
  for (a = 0; a < cdf->totlayer; a++) {
    layer = &cdf->layer[a];
 
    if (layer->type == type && STREQ(layer->name, name)) {
      return layer;
    }
  }
 
  return nullptr;
}
 
CDataFileLayer *cdf_layer_add(CDataFile *cdf, int type, const char *name, size_t datasize)
{
  CDataFileLayer *newlayer, *layer;
 
  /* expand array */
  newlayer = MEM_calloc_arrayN<CDataFileLayer>(size_t(cdf->totlayer) + 1, "CDataFileLayer");
  if (cdf->totlayer > 0) {
    memcpy(newlayer, cdf->layer, sizeof(CDataFileLayer) * cdf->totlayer);
  }
  cdf->layer = newlayer;
 
  cdf->totlayer++;
 
  /* fill in new layer */
  layer = &cdf->layer[cdf->totlayer - 1];
  layer->structbytes = sizeof(CDataFileLayer);
  layer->datatype = CDF_DATA_FLOAT;
  layer->datasize = datasize;
  layer->type = type;
  STRNCPY(layer->name, name);
 
  return layer;
}