www.digitalmars.com         C & C++   DMDScript  

digitalmars.D.learn - c to d: types + struct/union alignment

reply Michael P. <baseball.mjp gmail.com> writes:
I'm converting some C headers into D, and had some questions.
1. What is the equivalent of a 'short int' in D?
e.g: 
struct ScePspSRect {
	short int 	x;
	short int 	y;
	short int 	w;
	short int 	h;
}

2. If I have this union in C:
typedef union ScePspUnion128 {
/*	SceULong128 	qw;*/	/* Missing compiler support. */
/*	SceULong128 	uq;*/
/*	SceLong128 	q;*/
	SceULong64		ul[2];
	SceLong64		l[2];
	unsigned int 	ui[4];
	int 			i[4];
	unsigned short 	us[8];
	short int 		s[8];
	unsigned char 	uc[16];
	char 			c[16];
	float 			f[4];
	ScePspFRect 	fr;
	ScePspIRect 	ir;
	ScePspFVector4 	fv;
	ScePspIVector4 	iv;
	ScePspFQuaternion fq;
	ScePspFColor 	fc;
	ScePspRGBA8888 	rgba8888[4];
	ScePspRGBA4444 	rgba4444[8];
	ScePspRGBA5551 	rgba5551[8];
	ScePspRGB565 	rgb565[8];
} ScePspUnion128 __attribute__((aligned(16)));

Does it convert to this:
union ScePspUnion128 {
/*	SceULong128 	qw;*/	/* Missing compiler support. */
/*	SceULong128 	uq;*/
/*	SceLong128 	q;*/
        align(16)
{
	SceULong64		ul[2];
	SceLong64		l[2];
	uint 	ui[4];
	int 			i[4];
	ushort 	us[8];
	short int 		s[8]; //What type???
	ubyte  	uc[16];
	char 			c[16]; //should it be byte or char?
	float 			f[4];
	ScePspFRect 	fr;
	ScePspIRect 	ir;
	ScePspFVector4 	fv;
	ScePspIVector4 	iv;
	ScePspFQuaternion fq;
	ScePspFColor 	fc;
	ScePspRGBA8888 	rgba8888[4];
	ScePspRGBA4444 	rgba4444[8];
	ScePspRGBA5551 	rgba5551[8];
	ScePspRGB565 	rgb565[8];
}
} 
Are those type changes correct? Can I use the same way to align structs defined
like that?

3.
typedef	uint8_t				u8;
typedef uint16_t			u16;

typedef uint32_t			u32;
typedef uint64_t			u64;

typedef int8_t				s8;
typedef int16_t				s16;

typedef int32_t				s32;
typedef int64_t				s64;

Would it be okay to be make/alias all of the uintxx_t to 'uint' and all of the
intxx_t to 'int'?
P.S. If anyone is wondering, this is taken from the homebrew PSP SDK.
Thanks,
Michael P.
Dec 30 2009
parent reply BCS <none anon.com> writes:
Hello Michael P.,


 I'm converting some C headers into D, and had some questions.
 1. What is the equivalent of a 'short int' in D?
 e.g:
 struct ScePspSRect {
 short int 	x;
 short int 	y;
 short int 	w;
 short int 	h;
 }


short


 3.
 typedef	uint8_t				u8;
 typedef uint16_t			u16;
 typedef uint32_t			u32;
 typedef uint64_t			u64;
 typedef int8_t				s8;
 typedef int16_t				s16;
 typedef int32_t				s32;
 typedef int64_t				s64;
 Would it be okay to be make/alias all of the uintxx_t to 'uint' and
 all of the intxx_t to 'int'?


no, uint16_t is (I assume) 16 bits long and uint32_t is 32 bits long. if 
you get them mixed up (as the aliasing you proposed would do) you will get 
problems passing struct to non-D code.
Dec 30 2009
parent reply Michael P. <baseball.mjp gmail.com> writes:
BCS Wrote:


 Hello Michael P.,
 

 I'm converting some C headers into D, and had some questions.
 1. What is the equivalent of a 'short int' in D?
 e.g:
 struct ScePspSRect {
 short int 	x;
 short int 	y;
 short int 	w;
 short int 	h;
 }


 
 short
 

 3.
 typedef	uint8_t				u8;
 typedef uint16_t			u16;
 typedef uint32_t			u32;
 typedef uint64_t			u64;
 typedef int8_t				s8;
 typedef int16_t				s16;
 typedef int32_t				s32;
 typedef int64_t				s64;
 Would it be okay to be make/alias all of the uintxx_t to 'uint' and
 all of the intxx_t to 'int'?


 
 no, uint16_t is (I assume) 16 bits long and uint32_t is 32 bits long. if 
 you get them mixed up (as the aliasing you proposed would do) you will get 
 problems passing struct to non-D code.
 
 


Okay. I'll look at where they came from and see what they are defined as. They
come from a file called stdint.h.
Also, would short unsigned int be a 'ushort' then?
Dec 30 2009
parent bearophile <bearophileHUGS lycos.com> writes:
Michael P.:

Also, would short unsigned int be a 'ushort' then?<


In D ushort is an unsigned integer 16 bits long. While I think in C short
unsigned int is not guaranteed to be 16 bit wide. The same is true for unsigned
short / uint.

Bye,
bearophile
Dec 30 2009