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Re: One agnostic random function for big project (4 GB of code)

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On Thursday, December 12, 2019 at 3:49:05 PM UTC, Frederick Gotham wrote:

> Also I might have to write it in C also, and so I want the function names to be the same.


I realise that this is a C++ newsgroup, but anyway here's what I've got so far with porting it to C. There's no namespaces so I've put a UUID suffix on all global identifiers.


#ifndef H_INCLUSION_GUARD_COMPANY_PRODUCT_RANDOM
#define H_INCLUSION_GUARD_COMPANY_PRODUCT_RANDOM

#ifdef __cplusplus
#	error "This is a C header file but you've included it in a C++ source file (or you've used a C++ compiler on a C source file). You can't do that."
#endif

#include <stdbool.h>   /* bool */

#include <stddef.h>    /* NULL, size_t */

#include <limits.h>    /* INT_MAX */

#include <pthread.h>

// The next two lines are declarations of functions found in
// "libdl.so". (Unfortunately the compiler won't let me put
// these declarations inside the body of a function).
extern void *dlopen(char const *, int);
extern void *dlsym(void *,char const *);

typedef int (*RAND_bytes_t_35466a8ef14e4bc2b50bfc28a6d19b66)(char unsigned *, int);

bool g_random_first_time_35466a8ef14e4bc2b50bfc28a6d19b66 = true;

RAND_bytes_t_35466a8ef14e4bc2b50bfc28a6d19b66 g_ptr_to_RAND_bytes_35466a8ef14e4bc2b50bfc28a6d19b66 = NULL;

pthread_mutex_t g_mutex_35466a8ef14e4bc2b50bfc28a6d19b66 = PTHREAD_MUTEX_INITIALIZER;

inline void Company_Product_Random(void *pvoid, size_t len_bytes)  // len_bytes can be 0
{
	pthread_mutex_lock(&g_mutex_35466a8ef14e4bc2b50bfc28a6d19b66);
	
	if ( g_random_first_time_35466a8ef14e4bc2b50bfc28a6d19b66 )
	{
		g_random_first_time_35466a8ef14e4bc2b50bfc28a6d19b66 = false;
		
		void *const handle = dlopen("libcrypto.so", 1);  /* 1 == RTLD_LAZY */

		if ( NULL == handle )
			return;

		g_ptr_to_RAND_bytes_35466a8ef14e4bc2b50bfc28a6d19b66 = \
		    (RAND_bytes_t_35466a8ef14e4bc2b50bfc28a6d19b66)dlsym(handle, "RAND_bytes");  // Linux allows func_pointer = obj_pointer
	}
	
	pthread_mutex_unlock(&g_mutex_35466a8ef14e4bc2b50bfc28a6d19b66);

	if ( NULL == g_ptr_to_RAND_bytes_35466a8ef14e4bc2b50bfc28a6d19b66 )
		return;

	while ( 0 != len_bytes )
	{
		int bytes_this_time;  // RAND_bytes unfortunately takes an 'int' for length

		if ( len_bytes > (size_t)INT_MAX )
			bytes_this_time = INT_MAX;
		else
			bytes_this_time = len_bytes;

		g_ptr_to_RAND_bytes_35466a8ef14e4bc2b50bfc28a6d19b66( (char unsigned *)pvoid, bytes_this_time );

		pvoid = (char*)pvoid + bytes_this_time;  // Cast to char pointer for arithmetic
		len_bytes -= bytes_this_time;
	}
}

#endif  //  ifndef H_INCLUSION_GUARD_COMPANY_PRODUCT_RANDOM

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One agnostic random function for big project (4 GB of code) Frederick Gotham <cauldwell.thomas@gmail.com> - 2019-12-12 03:53 -0800
  Re: One agnostic random function for big project (4 GB of code) Bart <bc@freeuk.com> - 2019-12-12 12:01 +0000
    Re: One agnostic random function for big project (4 GB of code) Frederick Gotham <cauldwell.thomas@gmail.com> - 2019-12-12 04:06 -0800
      Re: One agnostic random function for big project (4 GB of code) boltar@nowhere.co.uk - 2019-12-12 12:22 +0000
      Iceream is your friend (was Re: One agnostic random function for big project (4 GB of code)) Vir Campestris <vir.campestris@invalid.invalid> - 2019-12-13 21:51 +0000
  Re: One agnostic random function for big project (4 GB of code) Paavo Helde <myfirstname@osa.pri.ee> - 2019-12-12 14:31 +0200
    Re: One agnostic random function for big project (4 GB of code) Frederick Gotham <cauldwell.thomas@gmail.com> - 2019-12-12 04:47 -0800
      Re: One agnostic random function for big project (4 GB of code) Paavo Helde <myfirstname@osa.pri.ee> - 2019-12-12 15:15 +0200
        Re: One agnostic random function for big project (4 GB of code) Frederick Gotham <cauldwell.thomas@gmail.com> - 2019-12-12 05:27 -0800
          Re: One agnostic random function for big project (4 GB of code) Paavo Helde <myfirstname@osa.pri.ee> - 2019-12-12 16:25 +0200
            Re: One agnostic random function for big project (4 GB of code) Frederick Gotham <cauldwell.thomas@gmail.com> - 2019-12-12 06:33 -0800
            Re: One agnostic random function for big project (4 GB of code) Paavo Helde <myfirstname@osa.pri.ee> - 2019-12-12 16:40 +0200
              Re: One agnostic random function for big project (4 GB of code) Frederick Gotham <cauldwell.thomas@gmail.com> - 2019-12-12 07:26 -0800
                Re: One agnostic random function for big project (4 GB of code) Paavo Helde <myfirstname@osa.pri.ee> - 2019-12-12 17:37 +0200
                Re: One agnostic random function for big project (4 GB of code) Frederick Gotham <cauldwell.thomas@gmail.com> - 2019-12-12 07:48 -0800
                Re: One agnostic random function for big project (4 GB of code) Frederick Gotham <cauldwell.thomas@gmail.com> - 2019-12-12 08:27 -0800
    Re: One agnostic random function for big project (4 GB of code) Manfred <noname@add.invalid> - 2019-12-12 17:41 +0100

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