From 3da485fdbf9ab405789a72303bd5dbe4cfa12d87 Mon Sep 17 00:00:00 2001
From: Nguyen Van Duc Tai <bonnhatnguyen0@gmail.com>
Date: Tue, 6 Oct 2026 02:08:50 +0700
Subject: [PATCH] feat(cpp): add fasta benchmark (1.cpp)

---
 bench/algorithm/fasta/1.cpp | 177 ++++++++++++++++++++++++++++++++++++
 bench/bench_cpp.yaml        |   3 +
 2 files changed, 180 insertions(+)
 create mode 100644 bench/algorithm/fasta/1.cpp

diff --git a/bench/algorithm/fasta/1.cpp b/bench/algorithm/fasta/1.cpp
new file mode 100644
index 000000000..f2f3c368a
--- /dev/null
+++ b/bench/algorithm/fasta/1.cpp
@@ -0,0 +1,177 @@
+// The Computer Language Benchmarks Game
+// https://salsa.debian.org/benchmarksgame-team/benchmarksgame/
+//
+// Contributed by @bonnhatnguyen for Programming-Language-Benchmarks
+// Highly optimized C++20 implementation using direct O(1) table lookup
+// and block buffered I/O.
+
+#include <algorithm>
+#include <array>
+#include <cmath>
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <string>
+#include <string_view>
+#include <vector>
+
+constexpr size_t LINE_LENGTH = 60;
+constexpr uint32_t IM = 139968;
+constexpr uint32_t IA = 3877;
+constexpr uint32_t IC = 29573;
+
+struct Rng {
+    uint32_t state = 42;
+
+    inline uint32_t next() noexcept {
+        state = (state * IA + IC) % IM;
+        return state;
+    }
+};
+
+struct AminoAcid {
+    char c;
+    float p;
+};
+
+// Direct 136.7 KB lookup table indexed by random value in [0, IM)
+// Eliminates all search loops and floating-point conversions in the generation phase.
+static char iub_lookup[IM];
+static char homo_lookup[IM];
+
+static void init_lookup_table(char* table, const AminoAcid* aa, size_t count) {
+    float cumulative = 0.0f;
+    uint32_t current_idx = 0;
+    for (size_t i = 0; i < count; ++i) {
+        cumulative += aa[i].p;
+        uint32_t target = static_cast<uint32_t>(std::floor(cumulative * static_cast<float>(IM)));
+        if (i == count - 1 || target >= IM) {
+            target = IM - 1;
+        }
+        while (current_idx <= target && current_idx < IM) {
+            table[current_idx++] = aa[i].c;
+        }
+    }
+}
+
+static constexpr std::string_view ALU =
+    "GGCCGGGCGCGGTGGCTCACGCCTGTAATCCCAGCACTTTGG"
+    "GAGGCCGAGGCGGGCGGATCACCTGAGGTCAGGAGTTCGAGA"
+    "CCAGCCTGGCCAACATGGTGAAACCCCGTCTCTACTAAAAAT"
+    "ACAAAAATTAGCCGGGCGTGGTGGCGCGCGCCTGTAATCCCA"
+    "GCTACTCGGGAGGCTGAGGCAGGAGAATCGCTTGAACCCGGG"
+    "AGGCGGAGGTTGCAGTGAGCCGAGATCGCGCCACTGCACTCC"
+    "AGCCTGGGCGACAGAGCGAGACTCCGTCTCAAAAA";
+
+static constexpr AminoAcid IUB[] = {
+    {'a', 0.27f},
+    {'c', 0.12f},
+    {'g', 0.12f},
+    {'t', 0.27f},
+    {'B', 0.02f},
+    {'D', 0.02f},
+    {'H', 0.02f},
+    {'K', 0.02f},
+    {'M', 0.02f},
+    {'N', 0.02f},
+    {'R', 0.02f},
+    {'S', 0.02f},
+    {'V', 0.02f},
+    {'W', 0.02f},
+    {'Y', 0.02f},
+};
+
+static constexpr AminoAcid HOMOSAPIENS[] = {
+    {'a', 0.3029549426680f},
+    {'c', 0.1979883004921f},
+    {'g', 0.1975473066391f},
+    {'t', 0.3015094502008f},
+};
+
+// High-capacity buffered writer
+constexpr size_t BUFFER_SIZE = 256 * 1024;
+static char out_buf[BUFFER_SIZE];
+static size_t out_pos = 0;
+
+static inline void flush_out() noexcept {
+    if (out_pos > 0) {
+        fwrite(out_buf, 1, out_pos, stdout);
+        out_pos = 0;
+    }
+}
+
+static inline void write_str(std::string_view s) noexcept {
+    for (char c : s) {
+        out_buf[out_pos++] = c;
+        if (out_pos == BUFFER_SIZE) {
+            flush_out();
+        }
+    }
+}
+
+static inline void write_char(char c) noexcept {
+    out_buf[out_pos++] = c;
+    if (out_pos == BUFFER_SIZE) {
+        flush_out();
+    }
+}
+
+static void make_fasta_repeat(std::string_view header, std::string_view seq, size_t n) {
+    write_str(header);
+
+    // Double the sequence to avoid wrapping modulo checks
+    std::string double_seq;
+    double_seq.reserve(seq.size() + LINE_LENGTH);
+    double_seq.append(seq);
+    double_seq.append(seq.substr(0, LINE_LENGTH));
+
+    size_t seq_pos = 0;
+    const size_t seq_len = seq.size();
+
+    while (n > 0) {
+        size_t chunk = std::min(LINE_LENGTH, n);
+        for (size_t i = 0; i < chunk; ++i) {
+            write_char(double_seq[seq_pos + i]);
+        }
+        write_char('\n');
+        seq_pos += chunk;
+        if (seq_pos >= seq_len) {
+            seq_pos -= seq_len;
+        }
+        n -= chunk;
+    }
+}
+
+static void make_fasta_random(std::string_view header, const char* lookup, Rng& rng, size_t n) {
+    write_str(header);
+
+    while (n > 0) {
+        size_t chunk = std::min(LINE_LENGTH, n);
+        for (size_t i = 0; i < chunk; ++i) {
+            uint32_t r = rng.next();
+            write_char(lookup[r]);
+        }
+        write_char('\n');
+        n -= chunk;
+    }
+}
+
+int main(int argc, char** argv) {
+    size_t n = 1000;
+    if (argc > 1) {
+        n = static_cast<size_t>(std::atoi(argv[1]));
+    }
+
+    init_lookup_table(iub_lookup, IUB, sizeof(IUB) / sizeof(IUB[0]));
+    init_lookup_table(homo_lookup, HOMOSAPIENS, sizeof(HOMOSAPIENS) / sizeof(HOMOSAPIENS[0]));
+
+    Rng rng;
+
+    make_fasta_repeat(">ONE Homo sapiens alu\n", ALU, n * 2);
+    make_fasta_random(">TWO IUB ambiguity codes\n", iub_lookup, rng, n * 3);
+    make_fasta_random(">THREE Homo sapiens frequency\n", homo_lookup, rng, n * 5);
+
+    flush_out();
+    return 0;
+}
diff --git a/bench/bench_cpp.yaml b/bench/bench_cpp.yaml
index e17d7c0a5..1772fa3ed 100644
--- a/bench/bench_cpp.yaml
+++ b/bench/bench_cpp.yaml
@@ -18,6 +18,9 @@ problems:
   - name: nsieve
     source:
       - 1.cpp
+  - name: fasta
+    source:
+      - 1.cpp
 compiler_version_command:
 compiler_version_regex:
 runtime_version_parameter: