dogecoinfoundation · xanimo · Jun 8, 2026 · Aug 1, 2026 · Aug 6, 2026 · Aug 6, 2026
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -553,6 +553,7 @@ IF(USE_TESTS)
         test/block_tests.c
         test/buffer_tests.c
         test/chacha20_tests.c
+        test/checkpoints_tests.c
         test/context_tests.c
         test/cstr_tests.c
         test/ecc_tests.c

diff --git a/Makefile.am b/Makefile.am
@@ -280,6 +280,7 @@ tests_SOURCES = \
     test/block_tests.c \
     test/buffer_tests.c \
     test/chacha20_tests.c \
+    test/checkpoints_tests.c \
     test/context_tests.c \
     test/cstr_tests.c \
     test/ecc_tests.c \

diff --git a/include/dogecoin/chainparams.h b/include/dogecoin/chainparams.h
@@ -68,8 +68,10 @@ extern const dogecoin_chainparams dogecoin_chainparams_test;
 extern const dogecoin_chainparams dogecoin_chainparams_regtest;
 
 // the mainnet checkpoints, needs a fix size
-extern const dogecoin_checkpoint dogecoin_mainnet_checkpoint_array[33];
-extern const dogecoin_checkpoint dogecoin_testnet_checkpoint_array[24];
+extern const dogecoin_checkpoint dogecoin_mainnet_checkpoint_array[];
+extern const size_t dogecoin_mainnet_checkpoint_count;
+extern const dogecoin_checkpoint dogecoin_testnet_checkpoint_array[];
+extern const size_t dogecoin_testnet_checkpoint_count;
 
 LIBDOGECOIN_API const dogecoin_chainparams* chain_from_b58_prefix(const char* address);
 LIBDOGECOIN_API int chain_from_b58_prefix_bool(char* address);

diff --git a/include/dogecoin/headersdb_file.h b/include/dogecoin/headersdb_file.h
@@ -55,6 +55,8 @@ typedef struct dogecoin_headers_db_
     dogecoin_blockindex genesis;
     dogecoin_blockindex *chaintip;
     dogecoin_blockindex *chainbottom;
+    dogecoin_bool batch_write;   /**< Suppress per-record fdatasync; caller must commit after */
+    dogecoin_bool skip_pow;      /**< Skip scrypt PoW verify (for checkpoint-anchored bulk loads) */
 } dogecoin_headers_db;
 
 dogecoin_headers_db *dogecoin_headers_db_new(const dogecoin_chainparams* chainparams, dogecoin_bool inmem_only);

diff --git a/include/dogecoin/libdogecoin.h b/include/dogecoin/libdogecoin.h
@@ -112,8 +112,10 @@ extern const dogecoin_chainparams dogecoin_chainparams_test;
 extern const dogecoin_chainparams dogecoin_chainparams_regtest;
 
 // the mainnet checkpoints, needs a fix size
-extern const dogecoin_checkpoint dogecoin_mainnet_checkpoint_array[33];
-extern const dogecoin_checkpoint dogecoin_testnet_checkpoint_array[24];
+extern const dogecoin_checkpoint dogecoin_mainnet_checkpoint_array[];
+extern const size_t dogecoin_mainnet_checkpoint_count;
+extern const dogecoin_checkpoint dogecoin_testnet_checkpoint_array[];
+extern const size_t dogecoin_testnet_checkpoint_count;
 
 const dogecoin_chainparams* chain_from_b58_prefix(const char* address);
 int chain_from_b58_prefix_bool(char* address);

diff --git a/include/dogecoin/spv.h b/include/dogecoin/spv.h
@@ -54,12 +54,63 @@ typedef struct spv_block_sample_
     uint64_t fees;      // total fees
 } spv_block_sample;
 
+#define PAR_HDR_RAW_LEN 80
+
+/* How many times a segment may fail to connect at flush before the parallel
+ * downloader gives up entirely and lets the sequential path take over. Each
+ * retry re-requests the segment from whatever the primary DB actually reached,
+ * usually from a different peer. */
+#define PAR_HDR_MAX_FLUSH_FAILS 3
+
+/* One parallel header-download segment.  Each segment spans the open-closed
+ * height interval (start_height, stop_height] and is assigned to one node. */
+typedef struct par_hdr_seg_ {
+    uint32_t  start_height;   /* height of start_hash (exclusive lower bound) */
+    uint256_t start_hash;     /* block hash at start_height — getheaders locator */
+    uint32_t  stop_height;    /* height of stop_hash  (inclusive upper bound)  */
+    uint256_t stop_hash;      /* block hash at stop_height — getheaders hash_stop */
+
+    /* download progress */
+    int       node_id;        /* assigned node (-1 = unassigned)               */
+    int       shadow_id;      /* second node racing this segment (-1 = none)   */
+    uint64_t  shadow_at;      /* time the shadow was attached                  */
+    uint64_t  requested_at;   /* time of the last getheaders sent for this seg */
+    uint64_t  assigned_at;    /* time the current owner took this segment      */
+    uint32_t  count_at_assign;/* headers already buffered when it took it      */
+    uint32_t  tip_height;     /* highest header received so far in this segment */
+    uint256_t tip_hash;       /* hash of that header (next-batch locator)       */
+
+    /* buffered raw 80-byte block headers in ascending height order */
+    uint8_t  *buf;
+    uint32_t  count;          /* headers buffered */
+    uint32_t  cap;            /* buffer capacity  */
+
+    dogecoin_bool complete;   /* all stop_height - start_height headers received */
+    dogecoin_bool flushed;    /* segment has been flushed into the primary DB    */
+    uint32_t  flush_fails;    /* times this segment failed to connect at flush   */
+} par_hdr_seg;
+
+/* Top-level state for a parallel genesis header download. */
+typedef struct par_hdr_state_ {
+    par_hdr_seg  *segs;             /* ordered array of segments                */
+    uint32_t      num_segs;         /* total segment count                      */
+    uint32_t      flush_idx;        /* index of the next segment pending flush  */
+    uint32_t      last_flush_idx;   /* flush_idx at the last observed progress  */
+    uint64_t      last_progress_time; /* time of that progress                  */
+    uint64_t      buffered_bytes;   /* raw header bytes staged across segments  */
+    uint32_t      rate_ref;         /* last median peer rate seen while >=3 segs
+                                     * were in flight; the tail has no crowd to
+                                     * compare against, so it compares to this */
+    dogecoin_bool active;           /* download in progress                     */
+} par_hdr_state;
+
 typedef struct dogecoin_spv_client_
 {
     dogecoin_node_group *nodegroup;
     uint64_t last_headersrequest_time;
     uint64_t oldest_item_of_interest;
     dogecoin_bool use_checkpoints;
+    struct par_hdr_state_ *par_hdr;  /* parallel genesis header sync state */
     const dogecoin_chainparams *chainparams;
     int stateflags;
     uint64_t last_statecheck_time;
@@ -130,6 +181,8 @@ typedef struct dogecoin_spv_client_
     void* zk_pending_commits;
 } dogecoin_spv_client;
 
+LIBDOGECOIN_API dogecoin_bool dogecoin_spv_client_enable_genesis_headers(dogecoin_spv_client *client);
+
 LIBDOGECOIN_API dogecoin_spv_client* dogecoin_spv_client_new(const dogecoin_chainparams *params, dogecoin_bool debug, dogecoin_bool headers_memonly, dogecoin_bool use_checkpoints, dogecoin_bool full_sync, int maxnodes, const char *http_server);
 LIBDOGECOIN_API void dogecoin_spv_client_free(dogecoin_spv_client *client);
 LIBDOGECOIN_API dogecoin_bool dogecoin_spv_client_load(dogecoin_spv_client *client, const char *file_path, dogecoin_bool prompt);

diff --git a/src/chainparams.c b/src/chainparams.c
@@ -88,29 +88,83 @@ const dogecoin_chainparams dogecoin_chainparams_regtest = {
 
 const dogecoin_checkpoint dogecoin_mainnet_checkpoint_array[] = {
     {0, "1a91e3dace36e2be3bf030a65679fe821aa1d6ef92e7c9902eb318182c355691", 1386325540, 0x1e0ffff0},
+    {100000, "13ab3b961fcc500c03f51279385c42e9f055d48a37dfa72d0073c0d3f595036b", 1392346781, 0x1b267eeb},
     {104679, "35eb87ae90d44b98898fec8c39577b76cb1eb08e1261cfc10706c8ce9a1d01cf", 1392637497, 0x1b41676b},
     {145000, "cc47cae70d7c5c92828d3214a266331dde59087d4a39071fa76ddfff9b7bde72", 1395094679, 0x1b499dfd},
+    {200000, "092fd3e76db5ff35fbfefe48d5c53ca26e799f0654a4036ddd5fd78de77418c2", 1398695540, 0x1b42fb92},
+    {300000, "7c2b3b8cb1629fa014a29e85cd7b0fe7876ce3def8899ba4c0945c0de2ad7902", 1405442852, 0x1b2e13bb},
     {371337, "60323982f9c5ff1b5a954eac9dc1269352835f47c2c5222691d80f0d50dcf053", 1410464577, 0x1b364184},
     {450000, "d279277f8f846a224d776450aa04da3cf978991a182c6f3075db4c48b173bbd7", 1415413000, 0x1b03efda},
+    {500000, "92ae1083b7b3c22fd7b4ce2eae121d518f8e1aa81d0be9432ce5aa20a2954fcc", 1418570422, 0x1b04f203},
+    {600000, "caa5446c05c8e51cf7985a6cb4da4dc2b730e4ec399dc95b2a094df6bdd4f268", 1424881308, 0x1b03f04d},
+    {700000, "eac853ae22d59a498386241a3de69a36739ccc9e0a6acfd617b64c5ea4a0f4b3", 1431191204, 0x1b05d766},
     {771275, "1b7d789ed82cbdc640952e7e7a54966c6488a32eaad54fc39dff83f310dbaaed", 1435666139, 0x1b0444d2},
+    {800000, "773fbb34e1bfe82467eb24cda8769dfdcd13a5b4dac4c8f9f6534c40301f7fbf", 1437473213, 0x1b06b43a},
+    {900000, "5235e97ba5ae95c04300daed8d75dca2ed6eef9be42d433d985d3203639a4a66", 1443761100, 0x1b028fe5},
     {1000000, "6aae55bea74235f0c80bd066349d4440c31f2d0f27d54265ecd484d8c1d11b47", 1450031952, 0x1b02dcf8},
+    {1100000, "d48fef240e48d9395d08c2ec4fe9c6d5554091a107e1c0fddedf5db3a435d96e", 1456288963, 0x1b033eb4},
+    {1200000, "1f8ef813b31ec896e3f7f064d6637e251242ba95c1bb12ca339e55b0614a53db", 1462554308, 0x1b036f1b},
     {1250000, "00c7a442055c1a990e11eea5371ca5c1c02a0677b33cc88ec728c45edc4ec060", 1465690401, 0x1b045d00},
+    {1300000, "80be4067b5dc8e3db9b787ca4a69c09b3478b6434edc51bc8984db1a79fa620f", 1468822277, 0x1b02fe44},
+    {1400000, "18c7078848109e3d95706f639f1501550765e4675a02ddb8bfe3a703bb49fb8f", 1475060460, 0x1b039462},
     {1500000, "f1d32d6920de7b617d51e74bdf4e58adccaa582ffdc8657464454f16a952fca6", 1481313507, 0x1b0306ef},
+    {1600000, "ca5eb72f1e0d160f1481f74d56d7cc4a27d91aa585ba012da8018a5fe934d61b", 1487574651, 0x1b01b66a},
+    {1700000, "c151a40f121a4f0ee0078e0268563c8299ad12652f939d9c6880aab9a93c1969", 1493860971, 0x1b016434},
     {1750000, "5c8e7327984f0d6f59447d89d143e5f6eafc524c82ad95d176c5cec082ae2001", 1496985750, 0x1b00d4d4},
+    {1800000, "c90be6e4d4dfd4f6cfa37e17afe2cb423d82a1af726f402244b4607d155bd021", 1500113228, 0x1b009c6d},
+    {1900000, "6ab174805b47f1c93d69fbd37876375cacf57c075b3039561ddb05759f0853c0", 1506361934, 0x1a46b9c8},
     {2000000, "9914f0e82e39bbf21950792e8816620d71b9965bdbbc14e72a95e3ab9618fea8", 1512600918, 0x1a1c1225},
     {2031142, "893297d89afb7599a3c571ca31a3b80e8353f4cf39872400ad0f57d26c4c5d42", 1514549787, 0x1a15d633},
+    {2100000, "4f95b8f837f139f512dd8ba26fe4dd702271394daccb29007dc52938c96ccf85", 1518833207, 0x1a08f167},
+    {2200000, "7027f0e32f0566f39367580dfb9d42157608fc7ce4483bf2471beb68b3b3f26e", 1525088854, 0x1a07034c},
     {2250000, "0a87a8d4e40dca52763f93812a288741806380cd569537039ee927045c6bc338", 1528215255, 0x1a053477},
+    {2300000, "2f391edf30851d6ab71e1100a907d314190a15764da600e478730369db422f93", 1531345450, 0x1a04439c},
+    {2400000, "41a17417233ec887dfd5950c731e64abfab5fe230353d226a6a3de580e59c3bf", 1537593624, 0x1a059c04},
+    {2500000, "3352c854b77d6946fabed44b4451bc998a48dbbcc2dbc1d313f47b0e8a782d18", 1543848050, 0x1a05d53a},
     {2510150, "77e3f4a4bcb4a2c15e8015525e3d15b466f6c022f6ca82698f329edef7d9777e", 1544484077, 0x1a0868af},
+    {2600000, "37bd4bb2b345ca3bc7035adf8850632159d965878f7ab59fbcb4ffd382895a03", 1550097077, 0x1a05f4f3},
+    {2700000, "e76b5a769f05c868c831e067946ce32221ad3e163b4bfd96ae2745233587e7cd", 1556337998, 0x1a03ef42},
     {2750000, "d4f8abb835930d3c4f92ca718aaa09bef545076bd872354e0b2b85deefacf2e3", 1559459044, 0x1a0292e2},
+    {2800000, "5af3d9109a9c3a75179a9a85f385ca5e045a40dcb4f716ad907beae3d5ee662b", 1562584608, 0x1a0336c7},
+    {2900000, "7bc6c24835317d4944a468a27a112eae5d564fc53cf366e34c8c7452f30e09e5", 1568837724, 0x1a045469},
     {3000000, "195a83b091fb3ee7ecb56f2e63d01709293f57f971ccf373d93890c8dc1033db", 1575096781, 0x1a07da10},
+    {3100000, "c7970179a8433e85b13a4930f80367a05a50c1f4b8878b31cb4b0ca7506f04c1", 1581365323, 0x1a0a5662},
+    {3200000, "1026822a0313b2466ddc13c251dd98072430708cc53c56e43e71dd9ab0625437", 1587656622, 0x1a0786ac},
     {3250000, "7f3e28bf9e309c4b57a4b70aa64d3b2ea5250ae797af84976ddc420d49684034", 1590799169, 0x1a05bfa3},
+    {3300000, "76f7f333faf010117d9ca7dd0c6200456dcbffa03b31dee66541966347589b8b", 1593941349, 0x1a050d2a},
+    {3400000, "20588e8f8ce89cab1f894ef80faf935c631df24229a1a42bafee781d9a57a454", 1600234275, 0x1a04bf31},
     {3500000, "eaa303b93c1c64d2b3a2cdcf6ccf21b10cc36626965cc2619661e8e1879abdfb", 1606543340, 0x1a08d505},
+    {3600000, "3319474fec2b5cbc57df8a8b976fbbb4907d5315b23943daf58bc6ce0bba9347", 1612832557, 0x1a03ecc0},
     {3606083, "954c7c66dee51f0a3fb1edb26200b735f5275fe54d9505c76ebd2bcabac36f1e", 1613218169, 0x1a03d764},
+    {3700000, "d0f0af23aadcf6b8d4a681ee930e39d1e64aca967187fa8a0c655c6dacfa22ce", 1619169876, 0x1a043028},
+    {3800000, "0e1a1b524408f5d3e23fc461351daf9469976679e37cfc321ab2e06a3cb4f01a", 1625505238, 0x1a03d014},
     {3854173, "e4b4ecda4c022406c502a247c0525480268ce7abbbef632796e8ca1646425e75", 1628934997, 0x1a03ca36},
+    {3900000, "3815e66fe50a8c9770c04306626fa6f6be7a087a5e03c0b014ffee470dbb215e", 1631833148, 0x1a032198},
     {3963597, "2b6927cfaa5e82353d45f02be8aadd3bfd165ece5ce24b9bfa4db20432befb5d", 1635884460, 0x1a037bc9},
+    {4000000, "47f227cd54c270aa18c5136635fc003a11cb82d6f8319dd8dab180a2f5555a9e", 1638207091, 0x1a0350f2},
+    {4100000, "8112b8a11dd3d1965cab6ccc0175abca62ec6b1225ad303e72e94efac635007e", 1644587549, 0x1a02450e},
+    {4200000, "93da94c346ff5299ff400be4c1008aae99e9b70ef74db22820e42049ce14c6b4", 1650989758, 0x1a03efe7},
+    {4300000, "337d3b4bf937e2f9513e064b58253c9d0f188b7b928d570b07c03651d47e250f", 1657392921, 0x1a0461ea},
     {4303965, "ed7d266dcbd8bb8af80f9ccb8deb3e18f9cc3f6972912680feeb37b090f8cee0", 1657646310, 0x1a0344f5},
+    {4400000, "367bdf79d7c527a3f79430d72cf62a8201ba52edd608410a6da1b1ab7311e04d", 1663792227, 0x1a028e13},
+    {4500000, "66d27fdeb0f694d06d1276b2d3d72c4dbefe294651ddc1ade220951823243396", 1670200610, 0x1a020cfc},
+    {4600000, "75323db271259899e66cbf4cfab33dcc034527e34bdc75b9a70e1b2deec1aad1", 1676603347, 0x1a016fd5},
+    {4700000, "748844093ba9fd6ba002ed2d0c9857c0292f1fb4aeb949d2fa8f0d438a18387f", 1682991374, 0x1a014ec5},
+    {4800000, "a1e58e27594bbc04f9c021c9f73771852260fce5e09e86071d34c74a8a116d01", 1689360368, 0x1a01b637},
+    {4900000, "8bc08384ae8f17e0891159f3cd5783c07a62bd37c3a67d8d5e1bd292addced46", 1695779125, 0x1a02888f},
+    {5000000, "5ae6eadfe5fd98fa7f388b671c4863db4b62e46eecc054465a276d419500e469", 1702188235, 0x1a010be6},
     {5050000, "e7d4577405223918491477db725a393bcfc349d8ee63b0a4fde23cbfbfd81dea", 1705383360, 0x1a019541},
+    {5100000, "a60110809b403aecd06185ec73753ddfd21dbc243e82c5ef76c88648d1b7b718", 1708571081, 0x1a01114a},
+    {5200000, "06381a6241f120951a2f751851f50320e059b084ebc639c6b9d7d8b076d1f0bc", 1714956041, 0x1a01a709},
+    {5300000, "8ccc7ebe3d4a97bfdf1993145114f654c537a9b06bc89bb12beabc954fb3110f", 1721347471, 0x1a00f17c},
     {5400000, "cbb1f4ae807da83e13bdf9c28188982938c9ee6bf560c1023f51adac229eef87", 1727704957, 0x0106DAC9},
+    {5500000, "a2c15e69513051e6c01cce388718efa7a803f52766e6dc91624812e32250c56e", 1734026997, 0x1a00d1c5},
+    {5600000, "39c02091aa7b8ad483a87957b12bdf4c7c6ebcc5dfe2c4648c4d235b40961c8d", 1740360175, 0x1a0093c1},
+    {5700000, "28ef0c3aa091c839048bba16bcee4df442961e2bc4e42bda407906f71e5b594d", 1746679266, 0x1a00adee},
+    {5800000, "8d1540c92ec87451d73573fec3720ca7e835e630538096e3e11c56dec8205e2e", 1753007429, 0x1a00d815},
+    {5900000, "9eb4809b6bf358a5bf9fbddf82da9ff4f047ef76577d2939efabefc7bd6ced07", 1759340677, 0x1a00801a},
+    {6000000, "7af46caeb390c15e5d92b4aa58854b55351b43fe5fc714e359b31d0ce019a187", 1765676839, 0x192fa398},
+    {6100000, "bdeff3efe99a8203ad2baae74e50c29f5158227ff03d0bb7ffa3ff9fbd25dee3", 1772013218, 0x1a0082ee},
     {6148124, "0f4d009c402553dbec50012ace7e224018595e4b788d1af78cea72eb6401d959", 1775065954, 0x1a00b3ec},
     {6154988, "8ca6972c34a2154b6ae6f15996de8d1a794477ec0add439ee1279bd9a21b2eed", 1775506602, 0x1a008107},
     {6156000, "e8257a8929faef98929dc4e006bf405ec0fdfa93cb29b6d336a04e6b4d7bd02e", 1775571096, 0x1a0088a2},
@@ -119,7 +173,17 @@ const dogecoin_checkpoint dogecoin_mainnet_checkpoint_array[] = {
     {6173706, "1a59af827274d479127434728f9e1885a45b9a252bab246d039045822e671aa5", 1776698026, 0x197935DD},
     {6189700, "a6ed6d6b03668d0bb9baddfbc52565b2514d02f118d6d0298a6ca48d511d7804", 1777713485, 0x19429592},
     {6191600, "a8eeeadc81e8def69167f0d82c50c4d05fdb0c6ffd17a6af955f80d6925e0f0d", 1777835169, 0x197c3bc0},
-    {6201360, "0bb1dbb971969f89f1c4c6305396042de1d6a390d71a44b066255c844da9256c", 1778454835, 0x19555f03}};
+    {6201360, "0bb1dbb971969f89f1c4c6305396042de1d6a390d71a44b066255c844da9256c", 1778454835, 0x19555f03},
+    {6250000, "197f31497b1e3b506da36eb6126738e3206e42fdff240844f8b75ae4ebc29519", 1781539362, 0x19614D63},
+    {6275000, "63c89f44fe3ce35d6abaa297d32d75826ce4368027e098f816432f68c2bedbd6", 1783120876, 0x1979F333},
+    {6300000, "e35560d7a6dda44da8fd5d3fea4025319ac5d6287dc3c1308cde650e51e12e58", 1784704739, 0x19671029}};
+
+/* Counts defined next to the arrays. sizeof() on the extern declarations
+   yields whatever bound the header states, not the real length: chainparams.h
+   said [87] and libdogecoin.h said [33] while this file defined 89, so callers
+   silently saw a truncated array. */
+const size_t dogecoin_mainnet_checkpoint_count =
+    sizeof(dogecoin_mainnet_checkpoint_array) / sizeof(dogecoin_mainnet_checkpoint_array[0]);
 
 const dogecoin_checkpoint dogecoin_testnet_checkpoint_array[] = {
     {0, "bb0a78264637406b6360aad926284d544d7049f45189db5664f3c4d07350559e", 1391503289, 0x1e0ffff0},
@@ -209,3 +273,6 @@ dogecoin_bool isMainnetFromB58Prefix(const char address[P2PKHLEN]) {
     /* Check if chainparams is mainnet */
     return (chainparams == &dogecoin_chainparams_main);
 }
+
+const size_t dogecoin_testnet_checkpoint_count =
+    sizeof(dogecoin_testnet_checkpoint_array) / sizeof(dogecoin_testnet_checkpoint_array[0]);