80486DX2-66/C-bytebeat-render
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fwrite_le.*: refactor

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Intel A80486DX2-66 2024-05-19 13:58:26 +03:00
parent 7efc6b77f5
commit 9495b0a23e
Signed by: 80486DX2-66
GPG Key ID: 83631EF27054609B
2 changed files with 10 additions and 13 deletions
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5
include/fwrite_le.h
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@ -12,6 +12,11 @@
#define DETECTED_BIG_ENDIAN 1
#define UNSUPPORTED_ENDIANNESS -1
#define ORDER_NATIVE_U32 0x01234567
#define ORDER_LITTLE_ENDIAN_S4 "\x67\x45\x23\x01"
#define ORDER_BIG_ENDIAN_S4 "\x01\x23\x45\x67"
#define ifeq_u32_ret(lhs, rhs, value) if (!memcmp(lhs, rhs, 4)) return value;
int detect_endianness(void);
size_t fwrite_le(void* ptr, size_t size, size_t count, FILE* stream);
void reorder_le_be(

18
src/fwrite_le.c
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@ -1,19 +1,11 @@
#include "fwrite_le.h"
int detect_endianness(void) {
volatile uint32_t i = 0x01234567;
uint8_t* bytes = (uint8_t*)(&i);
if (bytes[0] == 0x01 &&
bytes[1] == 0x23 &&
bytes[2] == 0x45 &&
bytes[3] == 0x67)
return DETECTED_BIG_ENDIAN;
else if (
bytes[0] == 0x67 &&
bytes[1] == 0x45 &&
bytes[2] == 0x23 &&
bytes[3] == 0x01)
return DETECTED_LITTLE_ENDIAN;
volatile uint32_t native_order_value = ORDER_NATIVE_U32;
uint8_t* as_bytes = (uint8_t*)&native_order_value;
ifeq_u32_ret(as_bytes, ORDER_LITTLE_ENDIAN_S4, DETECTED_LITTLE_ENDIAN);
ifeq_u32_ret(as_bytes, ORDER_BIG_ENDIAN_S4, DETECTED_BIG_ENDIAN );
return UNSUPPORTED_ENDIANNESS;
}