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#include "md5_core.h"
#include "md5_math.h"
#define RA A, B, C, D
#define RB D, A, B, C
#define RC C, D, A, B
#define RD B, C, D, A
#define F(x, y, z) (z ^ (x & (y ^ z)))
#define G(x, y, z) (y ^ (z & (x ^ y)))
#define H(x, y, z) (x ^ y ^ z)
#define I(x, y, z) (y ^ (x | ~z))
#define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
#define STEP(i, f, a, b, c, d) \
do { \
a += f(b, c, d) + data[K(i)] + T(i); \
CYCLIC(a, S(i)); \
a += b; \
} while (0)
#define FF(i, ...) STEP((0x00 | i), F, __VA_ARGS__)
#define GG(i, ...) STEP((0x10 | i), G, __VA_ARGS__)
#define HH(i, ...) STEP((0x20 | i), H, __VA_ARGS__)
#define II(i, ...) STEP((0x30 | i), I, __VA_ARGS__)
#define MD5_ROUND(OP) \
OP(0x0, RA); OP(0x1, RB); OP(0x2, RC); OP(0x3, RD); \
OP(0x4, RA); OP(0x5, RB); OP(0x6, RC); OP(0x7, RD); \
OP(0x8, RA); OP(0x9, RB); OP(0xa, RC); OP(0xb, RD); \
OP(0xc, RA); OP(0xd, RB); OP(0xe, RC); OP(0xf, RD);
namespace md5 {
consteval int K(int index) {
int i = index >> 4;
const int step[] = {1, 5, 3, 7};
const int begin[] = {0, 1, 5, 0};
return (begin[i] + step[i] * index) & 0b1111;
}
consteval int S(int index) {
const int map[][4] = {
{7, 12, 17, 22},
{5, 9, 14, 20},
{4, 11, 16, 23},
{6, 10, 15, 21},
};
return map[index >> 4][index & 0b11];
}
consteval uint32_t T(int index) {
double val = math::sin(index + 1);
return uint32_t(std::abs(val) * 0x100000000);
}
void md5_reset(struct md5_ctx *ctx) {
ctx->A = MD5_A;
ctx->B = MD5_B;
ctx->C = MD5_C;
ctx->D = MD5_D;
ctx->size = 0;
}
void md5_process(struct md5_ctx *ctx, const void *buffer, uint64_t len) {
const auto *data = (uint32_t *)buffer;
const auto *limit = data + (len >> 2);
uint32_t A = ctx->A;
uint32_t B = ctx->B;
uint32_t C = ctx->C;
uint32_t D = ctx->D;
while (data < limit) {
uint32_t A_ = A;
uint32_t B_ = B;
uint32_t C_ = C;
uint32_t D_ = D;
MD5_ROUND(FF)
MD5_ROUND(GG)
MD5_ROUND(HH)
MD5_ROUND(II)
A += A_;
B += B_;
C += C_;
D += D_;
data += 16; // 512 bits
}
ctx->A = A;
ctx->B = B;
ctx->C = C;
ctx->D = D;
ctx->size += len; // processed size
}
} // namespace md5