flatbuffers::Table* to buffer_pointer - c++

Consider this scenario.
I'm creating a struct(flatbuffers::Table) using CreateXXX generated code. This creates the struct on the FlatBuffer buffer and gives me the offset.
Then I can get the memory block with GetBufferPointer() and transfer it.
Reversely, if I get a memory block, I can use GetXXX to get my struct(flatbuffers::Table) from that.
But after I get this struct, if I need to serialize it again, how can I do it? After the serialization, I should be able to transfer that data and do GetXXX on that data like before.
flatbuffers::Parser parser;
parser.Parse(schema.c_str());
parser.SetRootType("license");
parser.Parse(j.c_str());
auto* buf = parser.builder_.GetBufferPointer();
auto li = flatbuffers::GetRoot<license>(buf);
std::cout << "ID: " << li->id()->c_str() << " Rand: " << li->rand()->c_str() << " Secret: " << li->secret()->c_str() << std::endl;
uint8_t* buf2 = ????????????
auto li2 = flatbuffers::GetRoot<license>(buf2);
std::cout << "ID: " << li2->id()->c_str() << " Rand: " << li2->rand()->c_str() << " Secret: " << li2->secret()->c_str() << std::endl;


The obvious answer is that you keep the original buffer pointer (and size) around. Then you can "re-serialize" it by just writing out the existing buffer.
There is a function GetBufferStartFromRootPointer if you really must use just the root (li in your example).

Related

YAML::Emitter.size() different from strlen(YAML::Emitter.c_str())

Using YAML::Emitter I sometimes get YAML::Emitter.size() to return a bigger size than strlen(YAML::Emitter.c_str()).
e.g.
YAML::Emitter em;
em << something;
if (em.size() > strlen(em.c_str())
{
std::cout << "WOW " << em.size() << " > " << strlen(em.c_str());
}
This creates issues when writing the yaml text to a buffer:
char* buff = malloc(em.size());
memcpy(buff, em.c_str(), em.size());
because the extra characters at the end fail the yaml parser on the other side that reads this buffer.
Thanks!

AccessViolationException when trying to call c# callback

I have this simple code:
typedef void (__stdcall * OrdersCallback)(ordersTest*);
__declspec(dllexport) void InitializeCallbacks(long ordersCallbackAddress_) {
OrdersCallback ordersCallbackFunction;
std::cout << "current ordersCallbackFunction = " << ordersCallbackFunction << " address = " << &ordersCallbackFunction << std::endl;
std::cout << "set ordersCallbackAddress_ = " << ordersCallbackAddress_ << std::endl;
ordersCallbackFunction = (OrdersCallback) ordersCallbackAddress_;
std::cout << "new ordersCallbackFunction = " << ordersCallbackFunction << " address = " << &ordersCallbackFunction << std::endl;
ordersTest test;
test.replID = 123;
std::cout << "use ordersCallbackFunction = " << ordersCallbackFunction << " address = " << &ordersCallbackFunction << std::endl;
ordersCallbackFunction(&test);
}
And when callback is calling AccessViolationException is raised:
current ordersCallbackFunction = 000007F92BC354E0 address = 0000009785D1EC68
set ordersCallbackAddress_ = -2043003524
new ordersCallbackFunction = FFFFFFFF863A3D7C address = 0000009785D1EC68
use ordersCallbackFunction = FFFFFFFF863A3D7C address = 0000009785D1EC68
Unhandled Exception: System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.
I can't understand what's wrong, in another project very similar code works. Thanks!
upd, more code:
[UnmanagedFunctionPointer(CallingConvention.StdCall)]
public delegate void OrdersCallback(ref OrdersTest value);
[DllImport("CGateNativeAdapter.dll"), SuppressUnmanagedCodeSecurity]
public static extern void InitializeCallbacks(
[MarshalAs(UnmanagedType.FunctionPtr)] OrdersCallback ordersSnapshotCallbackPointer);
OrdersCallback ordersCallback =
delegate(ref OrdersTest value)
{
Console.WriteLine("C# Orders call received = " +
" replID = " + value.replID);
};
InitializeCallbacks(ordersCallback);

The most obvious flaw in what you have shown is that you are attempting to pass the 64 bit pointer as 32 bit value which clearly cannot work. The ordersCallbackAddress_ parameter is declared as long, which is 32 bits wide. But you clearly have a 64 bit process. That almost certainly explains the error that your are experiencing.
Remember that in C++ on Windows, long is 32 bits wide. In C# it is 64 bits wide. In any case you should not use integral types to pass pointers. If you have a pointer, design your functions to operate on pointers.
You need to make sure that ordersCallbackAddress_ is declared to be pointer sized. I don't understand why it is not declared as OrdersCallback.
There may be other problems, but you did not show very much code. You did not show struct declarations, or anything on the managed side of the interface.

How to access a field of exif data from a Photoshop filter plug-in (Photoshop SDK)

I'm looking for a very specific piece of information. I could make this a rather detailed question I guess but I'd rather try keeping it short and to the point.
I need to acces a piece of meta data (exif information) from within a Photoshop filter plug-in. I have never dealt with exif data from within a Photoshop plug-in or without and the PS SDK documentation is of a form that leaves a lot of questions. I would eventually get there but was wondering if anyone here has done this before and could help me out with an example. I'd be very grateful for that...
What we need should be documented here in the SDK:
documentation/html/group___resource_suite.html
documentation/html/imageresourcessection.html
The latter document says that the resource ID I need to retrieve the exif data is 1059 (decimal) and that accessing Exif data is supported since PS 7.0 which is good. But the SDK has no information (that I found) as to what you get, pointer? pointer to what? They just tell you to look at the exif spec. So do I get a pointer to the RAW binary exif data and if so how to I extract a field from that.
The specifications for the Exif data are here:
http://exif.org/specifications.html
As an example I'd like to get at this exif field:
Tag Name Field Name Dec Hex Type Count
Image title ImageDescription 270 10E ASCII Any

EDIT: After a deeper research I've found the following (an excerpt from the documentation):
Document: Photoshop API Guide.
Argument: Callbacks.
The callback routines are organized into “suites” collections of
related routines which implement a particular functionality.
The suites are described by a pointer to a record containing:
a 2 byte version number for the suite,
a 2 byte count of the number of routines in the suite,
a series of function pointers for the callback routines.
You are interested in the Property suite.
Current version: 1; Adobe Photoshop: 5.0; Routines: 2.
Properties are identified by a signature and key, which form a pair to
identify the property of interest.
Adobe Photoshop’s signature is always '8BIM' (0x3842494D).
The EXIF property is controlled by The Japan Electronic Industry Development Association (JEIDA) and Electronic Industries Association of Japan (EIAJ) which merged in Novemeber of 2000. The EXIF specification can be downloaded from their web site at the following location.
http://it.jeita.or.jp/jhistory/document/standard/exif_eng/jeida49eng.htm
GetPropertyProc( )
MACPASCAL OSErr (*GetPropertyProc) (OSType signature, OSType key, int32 index, int32 * simpleProperty, Handle * complexProperty);
This routine allows you to get information about the document currently being processed.
property name: propEXIFData
id:EXIF
type:complex (modifiable)
description:Camera and device data.
To recap I'll write some juicy code:
GetPropertyProc getProperty = formatParamBlock->propertyProcs->getPropertyProc;
rc = getProperty(0x3842494D, propEXIFData, 0, &simpProp, &compProp);
if ( rc )
return;
GetPIHandleSizeProc getSize = formatParamBlock->handleProcs->getSizeProc;
int32 size = getSize(compProp);
if ( !size )
return;
LockPIHandleProc lock = formatParamBlock->handleProcs->lockProc;
uint8* exif = (uint8 *)lock(compProp, false);
if ( !exif )
return;

Here's is a code sample using the Exiv2 Library: http://www.exiv2.org/doc/exifprint_8cpp-example.html
// ***************************************************************** -*- C++ -*-
// exifprint.cpp, $Rev: 2286 $
// Sample program to print the Exif metadata of an image
#include <exiv2/exiv2.hpp>
#include <iostream>
#include <iomanip>
#include <cassert>
int main(int argc, char* const argv[])
try {
if (argc != 2) {
std::cout << "Usage: " << argv[0] << " file\n";
return 1;
}
Exiv2::Image::AutoPtr image = Exiv2::ImageFactory::open(argv[1]);
assert(image.get() != 0);
image->readMetadata();
Exiv2::ExifData &exifData = image->exifData();
if (exifData.empty()) {
std::string error(argv[1]);
error += ": No Exif data found in the file";
throw Exiv2::Error(1, error);
}
Exiv2::ExifData::const_iterator end = exifData.end();
for (Exiv2::ExifData::const_iterator i = exifData.begin(); i != end; ++i) {
const char* tn = i->typeName();
std::cout << std::setw(44) << std::setfill(' ') << std::left
<< i->key() << " "
<< "0x" << std::setw(4) << std::setfill('0') << std::right
<< std::hex << i->tag() << " "
<< std::setw(9) << std::setfill(' ') << std::left
<< (tn ? tn : "Unknown") << " "
<< std::dec << std::setw(3)
<< std::setfill(' ') << std::right
<< i->count() << " "
<< std::dec << i->value()
<< "\n";
}
return 0;
}
//catch (std::exception& e) {
//catch (Exiv2::AnyError& e) {
catch (Exiv2::Error& e) {
std::cout << "Caught Exiv2 exception '" << e.what() << "'\n";
return -1;
}

I combined response vulkanino and ThdK. My method uses the function PIGetEXIFData declared in file PropertyUtils.h that returns a binary exif. Next, this exif decoded Exiv2 library
#include <PropertyUtils.h>
#include <PIProperties.h>
#include <exif.hpp>
void printExif() {
Handle handle;
checkSPErr(PIGetEXIFData(handle));
std::string ss;
checkSPErr(HandleToString(handle, ss));
Exiv2::ExifData exifData;
Exiv2::ExifParser::decode(exifData, reinterpret_cast<const Exiv2::byte*>(ss.data()), ss.size());
Exiv2::ExifData::const_iterator end = exifData.end();
for (Exiv2::ExifData::const_iterator i = exifData.begin(); i != end; ++i) {
const char* tn = i->typeName();
std::cout << std::setw(44) << std::setfill(' ') << std::left
<< i->key() << " "
<< "0x" << std::setw(4) << std::setfill('0') << std::right
<< std::hex << i->tag() << " "
<< std::setw(9) << std::setfill(' ') << std::left
<< (tn ? tn : "Unknown") << " "
<< std::dec << std::setw(3)
<< std::setfill(' ') << std::right
<< i->count() << " "
<< std::dec << i->value()
<< "\n";
}
}

Faster Alternative to std::ofstream

I generate a set of data files. As the files are supposed to be readable, they text files (opposed to binary files).
To output information to my files, I used very comfortable std::ofstream object.
In the beginning, when the data to be exported was smaller, the time needed to write to the files was not noticeable. However, as the information to be exported has accumulated, it takes now around 5 minutes to generate them.
As I started being bothered by waiting, my question is obvious: Is there any faster alternative to std::ofstream, please? In case there is faster alternative, will it be worth of rewritting my application? In other words, could the time saved be +50%? Thank you.
Update:
I was asked to show you my code that generates the above files, so here you are - the most time consuming loop:
ofstream fout;
fout.open(strngCollectiveSourceFileName,ios::out);
fout << "#include \"StdAfx.h\"" << endl;
fout << "#include \"Debug.h\"" << endl;
fout << "#include \"glm.hpp\"" << endl;
fout << "#include \"" << strngCollectiveHeaderFileName.substr( strngCollectiveHeaderFileName.rfind(TEXT("\\")) + 1) << "\"" << endl << endl;
fout << "using namespace glm;" << endl << endl << endl;
for (unsigned int nSprite = 0; nSprite < vpTilesetSprites.size(); nSprite++ )
{
for(unsigned int nFrameSet = 0; nFrameSet < vpTilesetSprites[nSprite]->vpFrameSets.size(); nFrameSet++)
{
// display index definition
fout << "// Index Definition: " << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->GetLongDescription() << "\n";
string strngIndexSignature = strngIndexDefinitionSignature;
strngIndexSignature.replace(strngIndexSignature.find(TEXT("#aIndexArrayName#")), strlen(TEXT("#aIndexArrayName#")), TEXT("a") + vpTilesetSprites[nSprite]->GetObjectName() + vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->GetFrameSetName() + TEXT("IndexData") );
strngIndexSignature.replace(strngIndexSignature.find(TEXT("#ClassName#")), strlen(TEXT("#ClassName#")), strngCollectiveArrayClassName );
fout << strngIndexSignature << "[4] = {0, 1, 2, 3};\t\t" << "// " << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->GetShortDescription() << ": Index Definition\n\n";
// display vertex definition
fout << "// Vertex Definition: " << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->GetLongDescription() << "\n";
string strngVertexSignature = strngVertexDefinitionSignature;
strngVertexSignature.replace(strngVertexSignature.find(TEXT("#aVertexArrayName#")), strlen(TEXT("#aVertexArrayName#")), TEXT("a") + vpTilesetSprites[nSprite]->GetObjectName() + vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->GetFrameSetName() + TEXT("VertexData") );
strngVertexSignature.replace(strngVertexSignature.find(TEXT("#ClassName#")), strlen(TEXT("#ClassName#")), strngCollectiveArrayClassName );
fout << strngVertexSignature << "[" << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->GetFramesCount() << "] =\n";
fout << "{\n";
for (int nFrameNo = 0; nFrameNo < vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->GetFramesCount(); nFrameNo++)
{
fout << "\t" << "{{ vec4(" << fixed << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->vpFrames[nFrameNo]->aVertices[0].vPosition.fx << "f, " << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->vpFrames[nFrameNo]->aVertices[0].vPosition.fy << "f, " << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->vpFrames[nFrameNo]->aVertices[0].vPosition.fz << "f, " << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->vpFrames[nFrameNo]->aVertices[0].vPosition.fw << "f), vec2(" << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->vpFrames[nFrameNo]->aVertices[0].vTextureUV.fu << "f, " << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->vpFrames[nFrameNo]->aVertices[0].vTextureUV.fv << "f) }, // " << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->GetShortDescription() << " vertex 1: vec4(x, y, z, w), vec2(u, v) \n";
fout << "\t" << " { vec4(" << fixed << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->vpFrames[nFrameNo]->aVertices[1].vPosition.fx << "f, " << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->vpFrames[nFrameNo]->aVertices[1].vPosition.fy << "f, " << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->vpFrames[nFrameNo]->aVertices[1].vPosition.fz << "f, " << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->vpFrames[nFrameNo]->aVertices[1].vPosition.fw << "f), vec2(" << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->vpFrames[nFrameNo]->aVertices[1].vTextureUV.fu << "f, " << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->vpFrames[nFrameNo]->aVertices[1].vTextureUV.fv << "f) }, // " << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->GetShortDescription() << " vertex 2: vec4(x, y, z, w), vec2(u, v) \n";
fout << "\t" << " { vec4(" << fixed << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->vpFrames[nFrameNo]->aVertices[2].vPosition.fx << "f, " << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->vpFrames[nFrameNo]->aVertices[2].vPosition.fy << "f, " << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->vpFrames[nFrameNo]->aVertices[2].vPosition.fz << "f, " << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->vpFrames[nFrameNo]->aVertices[2].vPosition.fw << "f), vec2(" << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->vpFrames[nFrameNo]->aVertices[2].vTextureUV.fu << "f, " << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->vpFrames[nFrameNo]->aVertices[2].vTextureUV.fv << "f) }, // " << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->GetShortDescription() << " vertex 3: vec4(x, y, z, w), vec2(u, v) \n";
fout << "\t" << " { vec4(" << fixed << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->vpFrames[nFrameNo]->aVertices[3].vPosition.fx << "f, " << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->vpFrames[nFrameNo]->aVertices[3].vPosition.fy << "f, " << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->vpFrames[nFrameNo]->aVertices[3].vPosition.fz << "f, " << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->vpFrames[nFrameNo]->aVertices[3].vPosition.fw << "f), vec2(" << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->vpFrames[nFrameNo]->aVertices[3].vTextureUV.fu << "f, " << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->vpFrames[nFrameNo]->aVertices[3].vTextureUV.fv << "f) }}, // " << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->GetShortDescription() << " vertex 4: vec4(x, y, z, w), vec2(u, v) \n\n";
}
fout << "};\n\n\n\n";
}
}
fout.close();

If you don't want to use C file I/O then you can give a try to; FastFormat. Look at the comparison for more info.

How are vpTilesetSprites and vpTilesetSprites[nSprite] stored? Are they implemented with lists or arrays? There is a lot of indexed access to them, and if they are list-like structures, you'll spend a lot of extra time following needless pointers. Ed S.'s comment is right: giving the long indexed temporary variables and linebreaks could make it easier to read, and maybe faster, too:
fout << "// Index Definition: " << vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->GetLongDescription() << "\n";
string strngIndexSignature = strngIndexDefinitionSignature;
strngIndexSignature.replace(strngIndexSignature.find(TEXT("#aIndexArrayName#")), strlen(TEXT("#aIndexArrayName#")), TEXT("a") + vpTilesetSprites[nSprite]->GetObjectName() + vpTilesetSprites[nSprite]->vpFrameSets[nFrameSet]->GetFrameSetName() + TEXT("IndexData") );
strngIndexSignature.replace(strngIndexSignature.find(TEXT("#ClassName#")), strlen(TEXT("#ClassName#")), strngCollectiveArrayClassName );
vs
string idxsig = strngIndexDefinitionSignature;
sprite sp = vpTilesetSprites[nSprite];
frameset fs = sp->vpFrameSets[nFrameSet];
fout << "// Index Definition: " << fs->GetLongDescription() << "\n";
idxsig.replace(idxsig.find(TEXT("#aIndexArrayName#")), strlen(TEXT("#aIndexArrayName#")),
TEXT("a") + sp->GetObjectName() + fs->getFrameSetName() + TEXT("IndexData"));
idxsig.replace(idxsig.find(TEXT("#ClassName#")), strlen(TEXT("#ClassName#")),
strngCollectiveArrayClassName);
But, the much bigger problem is how you're using strings as templates; you're looking for a given text string (and computing the length of your needle string every single time you need it!) over and over again.
Consider this: You're performing the find and replace operations nSprite * nFrameSet times. Each time through, this loop:
makes a copy of strngIndexDefinitionSignature
creates four temporary string objects when concatenating static and dynamic strings
compute strlen(TEXT("#ClassName#"))
compute strlen(TEXT("#aIndexArrayName#"))
find start point of both
replace both texts with new texts
And that's just the first four lines of your loop.
Can you replace your strngIndexDefinitionSignature with a format string? I assume it currently looks like this:
"flubber #aIndexArrayName# { blubber } #ClassName# blorp"
If you re-write it like this:
"flubber a %s%sIndexData { blubber } %s blorp"
Then your two find and replace lines can be replaced with:
sprintf(out, index_def_sig, sp->GetObjectName(), fs->getFrameSetName(),
strngCollectiveArrayClassName);
This would remove two find() operations, two replace() operations, creating and destroying four temporary string objects, a string duplicate that was promptly over-written with two replace() calls, and two strlen() operations that return the same result every time (but aren't actually needed anyway).
You can then output your string with << as usual. Or, you can change sprintf(3) to fprintf(3), and avoid even the temporary C string.

Assuming you do it in large enough chunks, calling write() directly might be faster; that said, it's more likely that your biggest bottleneck doesn't have anything directly to do with std::ofstream. The most obvious thing is to make sure you aren't using std::endl (because flushing the stream frequently will kill performance). Beyond that, I would suggest profiling your app to see where it's actually spending the time.

The performance of ostream is probably not your actual issue; I suggest using a profiler to determine where your real bottlenecks are. If ostream turns out to be your actual problem, you can drop down to <cstdio> and use fprintf(FILE*, const char*, ...) for formatted output to a file handle.

The best answer will depend on what sort of text you are generating, and how you are generating it. C++ streams can be slow, but that mostly is because they can also do a lot more for you, such as locale-dependent formatting, and so on.
You may find speed ups with streams by bypassing some of the formatting (eg. ostream::write), or by writing characters directly to a streambuf instead (streambuf::sputn). Sometimes increasing the buffer size on the relevant streambuf helps (via streambuf::pubsetbuf).
If this isn't good enough, you might want to try C-style stdio files, eg fopen, fprintf, etc. It takes a little while to get used to the way the text is formatted if you're not used to that method but the performance is usually pretty good.
For the absolute top performance you usually have to go to OS-specific routines. Sometimes the direct low-level file routines are significantly better than the C stdio, but sometimes not - for example, I've seen some people say WriteFile on Win32 is the fastest method on Windows, whereas some Google hits report it as being slower than stdio. Another approach might be a memory-mapped file, eg. mmap + msync - this essentially uses your system memory as the disk and writes the actual data to disk in large blocks, which is likely to be near optimal. However you run the risk of losing all the data if you incur a crash half way for some reason, which may or may not be a problem for you.

TOUGH: Dealing with deeply nested pointers in C++

I define this structure:
struct s_molecule
{
std::string res_name;
std::vector<t_particle> my_particles;
std::vector<t_bond> my_bonds;
std::vector<t_angle> my_angles;
std::vector<t_dihedral> my_dihedrals;
s_molecule& operator=(const s_molecule &to_assign)
{
res_name = to_assign.res_name;
my_particles = to_assign.my_particles;
my_bonds = to_assign.my_bonds;
my_angles = to_assign.my_angles;
my_dihedrals = to_assign.my_dihedrals;
return *this;
}
};
and these structures:
typedef struct s_particle
{
t_coordinates position;
double charge;
double mass;
std::string name;
std::vector<t_lj_param>::iterator my_particle_kind_iter;
s_particle& operator=(const s_particle &to_assign)
{
position = to_assign.position;
charge = to_assign.charge;
mass = to_assign.mass;
name = to_assign.name;
my_particle_kind_iter = to_assign.my_particle_kind_iter;
return *this;
}
} t_particle;
struct s_bond
{
t_particle * particle_1;
t_particle * particle_2;
std::vector<t_bond_param>::iterator my_bond_kind_iter;
s_bond& operator=(const s_bond &to_assign)
{
particle_1 = to_assign.particle_1;
particle_2 = to_assign.particle_2;
my_bond_kind_iter = to_assign.my_bond_kind_iter;
return *this;
}
};
and then in my code I return a pointer to an s_molecule (typedef'd to t_molecule, but still).
Using this pointer I can get this code to work:
for (unsigned int i = 0;
i < current_molecule->my_particles.size();
i++)
{
std::cout << "Particle "
<< current_molecule->my_particles[i].name << std::endl
<< "Charge: "
<< current_molecule->my_particles[i].charge << std::endl
<< "Mass: "
<< current_molecule->my_particles[i].mass << std::endl
<< "Particle Kind Name: "
<< (*current_molecule->my_particles[i].my_particle_kind_iter).atom_kind_name
<< std::endl
<< "x: " << current_molecule->my_particles[i].position.x
<< " y: " << current_molecule->my_particles[i].position.y
#ifdef USE_3D_GEOM
<< "z: " << current_molecule->my_particles[i].position.z
#endif
<< std::endl;
}
If I replace it with:
for (std::vector<t_particle>::iterator it = current_molecule->my_particles.begin();
it !=current_molecule->my_particles.end();
it++)
{
std::cout << "Particle "
<< (*it).name << std::endl
<< "Charge: "
<< (*it).charge << std::endl
<< "Mass: "
<< (*it).mass << std::endl
<< "Particle Kind Name: "
<< (*(*it).my_particle_kind_iter).atom_kind_name
<< std::endl
<< "x: " << (*it).position.x
<< " y: " << (*it).position.y
#ifdef USE_3D_GEOM
<< "z: " << (*it).position.z
#endif
<< std::endl;
}
I now get nasty segfaults...
Not to put too much here, but I'm also getting segfaults when I tried to do this:
std::cout << "Bond ATOMS : "
<< (*current_molecule).my_bonds[0].particle_1->name
<< std::endl
Again, current_molecule is a pointer to a s_molecule structure, which contains arrays of structures, which in turn either directly have vars or are pointers. I can't get these multiple layers of indirection to work. Suggestions on fixing these segfaults.
FYI I'm compiling on Linux Centos 5.4 with g++ and using a custom makefile system.

#sbi Thanks for the good advice! I believe you are right -- the assignment overloaded operator is unnecessary and should be scrapped.
I've followed the approach of commenting out stuff and am very confused. Basically in the function that passes the pointer to my particular molecule to the main function to print, I can see all the data in that molecule (bonds, particles, name, etc) perfectly, printing with cout's.
Once I pass it to the main as a ptr, if I use that ptr with an iterator I get a segfault. In other words. Also for some reason the bond data (which I can freely print in my funct that returns to the pointer) also segfaults if I try to print it, even if I use the [] to index the vector of bonds (which works for the particle vector).
That's the best info I can give for now.

A wild guess: Are you using shared libraries. I remember having difficulties passing STL-containers back and forth across shared library boundaries.

Jason (OP) was asked in a comment by David Rodríguez:
Are you returning a pointer to a local variable?
Jason answered:
No its a ptr to a class variable. The class is very much in existence (it contains the function that returns the molecule).
Unless you're talking of a true class variable (qualified as static), the fact that the class exists doesn't have much to do with it. Instances of a class exist, and they might have ceased to exist even if you just called a function on them.
As such, the question is:
Does the instance of the class that returned the pointer current_molecule still exist?
Or is current_molecule qualified as static, i.e. being a true class variable?
If the answer to both questions is "no", you're in Undefined County.
At this point, it becomes very important that you post source code that can be used by us here to actually reproduce the problem; it might well be located in source you aren't showing us.

Again, this issue was answered here:
Weird Pointer issue in C++
by DeadMG. Sorry for the double post.