text: #include "blake3_impl.h"
  #include <string.h>
  
  INLINE uint32_t rotr32(uint32_t w, uint32_t c) {
    return (w >> c) | (w << (32 - c));
  }
  
  INLINE void g(uint32_t *state, size_t a, size_t b, size_t c, size_t d,
                uint32_t x, uint32_t y) {
    state[a] = state[a] + state[b] + x;
    state[d] = rotr32(state[d] ^ state[a], 16);
    state[c] = state[c] + state[d];
    state[b] = rotr32(state[b] ^ state[c], 12);
    state[a] = state[a] + state[b] + y;
    state[d] = rotr32(state[d] ^ state[a], 8);
    state[c] = state[c] + state[d];
    state[b] = rotr32(state[b] ^ state[c], 7);
  }
  
  INLINE void round_fn(uint32_t state[16], const uint32_t *msg, size_t round) {
    // Select the message schedule based on the round.
    const uint8_t *schedule = MSG_SCHEDULE[round];
  
    // Mix the columns.
    g(state, 0, 4, 8, 12, msg[schedule[0]], msg[schedule[1]]);
    g(state, 1, 5, 9, 13, msg[schedule[2]], msg[schedule[3]]);
    g(state, 2, 6, 10, 14, msg[schedule[4]], msg[schedule[5]]);
    g(state, 3, 7, 11, 15, msg[schedule[6]], msg[schedule[7]]);
  
    // Mix the rows.
    g(state, 0, 5, 10, 15, msg[schedule[8]], msg[schedule[9]]);
    g(state, 1, 6, 11, 12, msg[schedule[10]], msg[schedule[11]]);
    g(state, 2, 7, 8, 13, msg[schedule[12]], msg[schedule[13]]);
    g(state, 3, 4, 9, 14, msg[schedule[14]], msg[schedule[15]]);
  }
  
  INLINE void compress_pre(uint32_t state[16], const uint32_t cv[8],
                           const uint8_t block[BLAKE3_BLOCK_LEN],
                           uint8_t block_len, uint64_t counter, uint8_t flags) {
    uint32_t block_words[16];
    block_words[0] = load32(block + 4 * 0);
    block_words[1] = load32(block + 4 * 1);
    block_words[2] = load32(block + 4 * 2);
    block_words[3] = load32(block + 4 * 3);
    block_words[4] = load32(block + 4 * 4);
    block_words[5] = load32(block + 4 * 5);
    block_words[6] = load32(block + 4 * 6);
    block_words[7] = load32(block + 4 * 7);
    block_words[8] = load32(block + 4 * 8);
    block_words[9] = load32(block + 4 * 9);
    block_words[10] = load32(block + 4 * 10);
    block_words[11] = load32(block + 4 * 11);
    block_words[12] = load32(block + 4 * 12);
    block_words[13] = load32(block + 4 * 13);
    block_words[14] = load32(block + 4 * 14);
    block_words[15] = load32(block + 4 * 15);
  
    state[0] = cv[0];
    state[1] = cv[1];
    state[2] = cv[2];
    state[3] = cv[3];
    state[4] = cv[4];
    state[5] = cv[5];
    state[6] = cv[6];
    state[7] = cv[7];
    state[8] = IV[0];
    state[9] = IV[1];
    state[10] = IV[2];
    state[11] = IV[3];
    state[12] = counter_low(counter);
    state[13] = counter_high(counter);
    state[14] = (uint32_t)block_len;
    state[15] = (uint32_t)flags;
  
    round_fn(state, &block_words[0], 0);
    round_fn(state, &block_words[0], 1);
    round_fn(state, &block_words[0], 2);
    round_fn(state, &block_words[0], 3);
    round_fn(state, &block_words[0], 4);
    round_fn(state, &block_words[0], 5);
    round_fn(state, &block_words[0], 6);
  }
  
  void blake3_compress_in_place_portable(uint32_t cv[8],
                                         const uint8_t block[BLAKE3_BLOCK_LEN],
                                         uint8_t block_len, uint64_t counter,
                                         uint8_t flags) {
    uint32_t state[16];
    compress_pre(state, cv, block, block_len, counter, flags);
    cv[0] = state[0] ^ state[8];
    cv[1] = state[1] ^ state[9];
    cv[2] = state[2] ^ state[10];
    cv[3] = state[3] ^ state[11];
    cv[4] = state[4] ^ state[12];
    cv[5] = state[5] ^ state[13];
    cv[6] = state[6] ^ state[14];
    cv[7] = state[7] ^ state[15];
  }
  
  void blake3_compress_xof_portable(const uint32_t cv[8],
                                    const uint8_t block[BLAKE3_BLOCK_LEN],
                                    uint8_t block_len, uint64_t counter,
                                    uint8_t flags, uint8_t out[64]) {
    uint32_t state[16];
    compress_pre(state, cv, block, block_len, counter, flags);
  
    store32(&out[0 * 4], state[0] ^ state[8]);
    store32(&out[1 * 4], state[1] ^ state[9]);
    store32(&out[2 * 4], state[2] ^ state[10]);
    store32(&out[3 * 4], state[3] ^ state[11]);
    store32(&out[4 * 4], state[4] ^ state[12]);
    store32(&out[5 * 4], state[5] ^ state[13]);
    store32(&out[6 * 4], state[6] ^ state[14]);
    store32(&out[7 * 4], state[7] ^ state[15]);
    store32(&out[8 * 4], state[8] ^ cv[0]);
    store32(&out[9 * 4], state[9] ^ cv[1]);
    store32(&out[10 * 4], state[10] ^ cv[2]);
    store32(&out[11 * 4], state[11] ^ cv[3]);
    store32(&out[12 * 4], state[12] ^ cv[4]);
    store32(&out[13 * 4], state[13] ^ cv[5]);
    store32(&out[14 * 4], state[14] ^ cv[6]);
    store32(&out[15 * 4], state[15] ^ cv[7]);
  }
  
  INLINE void hash_one_portable(const uint8_t *input, size_t blocks,
                                const uint32_t key[8], uint64_t counter,
                                uint8_t flags, uint8_t flags_start,
                                uint8_t flags_end, uint8_t out[BLAKE3_OUT_LEN]) {
    uint32_t cv[8];
    memcpy(cv, key, BLAKE3_KEY_LEN);
    uint8_t block_flags = flags | flags_start;
    while (blocks > 0) {
      if (blocks == 1) {
        block_flags |= flags_end;
      }
      blake3_compress_in_place_portable(cv, input, BLAKE3_BLOCK_LEN, counter,
                                        block_flags);
      input = &input[BLAKE3_BLOCK_LEN];
      blocks -= 1;
      block_flags = flags;
    }
    store_cv_words(out, cv);
  }
  
  void blake3_hash_many_portable(const uint8_t *const *inputs, size_t num_inputs,
                                 size_t blocks, const uint32_t key[8],
                                 uint64_t counter, bool increment_counter,
                                 uint8_t flags, uint8_t flags_start,
                                 uint8_t flags_end, uint8_t *out) {
    while (num_inputs > 0) {
      hash_one_portable(inputs[0], blocks, key, counter, flags, flags_start,
                        flags_end, out);
      if (increment_counter) {
        counter += 1;
      }
      inputs += 1;
      num_inputs -= 1;
      out = &out[BLAKE3_OUT_LEN];
    }
  }
  