83 lines
1.5 KiB
C
83 lines
1.5 KiB
C
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#pragma once
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#include <limits.h>
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#include <stddef.h>
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#include <stdint.h>
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static uint64_t g_rand_seed = 1;
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static void my_srand(uint64_t n)
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{
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g_rand_seed = n == 0 ? 1 : n;
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}
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static uint64_t my_rand64()
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{
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/*
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* Xorshift RNG [1] + multiply
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* [1]: https://www.jstatsoft.org/article/view/v008i14/916 */
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uint64_t x = g_rand_seed;
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x ^= x >> 12ULL;
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x ^= x << 25ULL;
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x ^= x >> 27ULL;
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g_rand_seed = x;
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return x * 2685821657736338717ULL;
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}
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static int my_tolower(int ch)
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{
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return ch >= 'A' && ch <= 'Z'
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? ch - 'A' + 'a'
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: ch;
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}
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static int my_isdigit(int ch)
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{
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return ch >= '0' && ch <= '9';
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}
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static void* my_memset(void *b, int c, size_t len)
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{
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unsigned char* x = b;
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unsigned char ch = (unsigned char)c;
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for (size_t i = 0; i < len; ++i) {
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x[i] = ch;
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}
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return b;
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}
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static void* my_memcpy(void* restrict dst, void const* restrict src, size_t n)
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{
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uint8_t* d = dst;
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uint8_t const* s = src;
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for (size_t i = 0; i < n; ++i) {
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d[i] = s[i];
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}
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return dst;
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}
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int my_memcmp(void const* s1, void const* s2, size_t n)
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{
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/* todo: SIMD optimize or use 64 bit strides initially if optimizer
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doesn't catch this */
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int8_t const* a = s1;
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int8_t const* b = s2;
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for (size_t i = 0; i < n; ++i) {
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int8_t diff = a[i] - b[i];
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if (diff)
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return diff;
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}
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return 0;
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}
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static size_t strlen(char const* s)
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{
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size_t n = 0;
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while (s[n++])
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;
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return n;
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}
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