feat: c impl

Author: ProgramRipper

main.c

@@ -0,0 +1,146 @@
+#include "math.h"
+#include "stdint.h"
+#include "stdio.h"
+#include "stdlib.h"
+#include "string.h"
+
+static const uint32_t
+    POLY = 0xEDB88320,
+    table[256] = {
+        0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA, 0x076DC419, 0x706AF48F,
+        0xE963A535, 0x9E6495A3, 0x0EDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988,
+        0x09B64C2B, 0x7EB17CBD, 0xE7B82D07, 0x90BF1D91, 0x1DB71064, 0x6AB020F2,
+        0xF3B97148, 0x84BE41DE, 0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7,
+        0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC, 0x14015C4F, 0x63066CD9,
+        0xFA0F3D63, 0x8D080DF5, 0x3B6E20C8, 0x4C69105E, 0xD56041E4, 0xA2677172,
+        0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B, 0x35B5A8FA, 0x42B2986C,
+        0xDBBBC9D6, 0xACBCF940, 0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59,
+        0x26D930AC, 0x51DE003A, 0xC8D75180, 0xBFD06116, 0x21B4F4B5, 0x56B3C423,
+        0xCFBA9599, 0xB8BDA50F, 0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924,
+        0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D, 0x76DC4190, 0x01DB7106,
+        0x98D220BC, 0xEFD5102A, 0x71B18589, 0x06B6B51F, 0x9FBFE4A5, 0xE8B8D433,
+        0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818, 0x7F6A0DBB, 0x086D3D2D,
+        0x91646C97, 0xE6635C01, 0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E,
+        0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457, 0x65B0D9C6, 0x12B7E950,
+        0x8BBEB8EA, 0xFCB9887C, 0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65,
+        0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2, 0x4ADFA541, 0x3DD895D7,
+        0xA4D1C46D, 0xD3D6F4FB, 0x4369E96A, 0x346ED9FC, 0xAD678846, 0xDA60B8D0,
+        0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9, 0x5005713C, 0x270241AA,
+        0xBE0B1010, 0xC90C2086, 0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
+        0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4, 0x59B33D17, 0x2EB40D81,
+        0xB7BD5C3B, 0xC0BA6CAD, 0xEDB88320, 0x9ABFB3B6, 0x03B6E20C, 0x74B1D29A,
+        0xEAD54739, 0x9DD277AF, 0x04DB2615, 0x73DC1683, 0xE3630B12, 0x94643B84,
+        0x0D6D6A3E, 0x7A6A5AA8, 0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1,
+        0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE, 0xF762575D, 0x806567CB,
+        0x196C3671, 0x6E6B06E7, 0xFED41B76, 0x89D32BE0, 0x10DA7A5A, 0x67DD4ACC,
+        0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5, 0xD6D6A3E8, 0xA1D1937E,
+        0x38D8C2C4, 0x4FDFF252, 0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B,
+        0xD80D2BDA, 0xAF0A1B4C, 0x36034AF6, 0x41047A60, 0xDF60EFC3, 0xA867DF55,
+        0x316E8EEF, 0x4669BE79, 0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236,
+        0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F, 0xC5BA3BBE, 0xB2BD0B28,
+        0x2BB45A92, 0x5CB36A04, 0xC2D7FFA7, 0xB5D0CF31, 0x2CD99E8B, 0x5BDEAE1D,
+        0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x026D930A, 0x9C0906A9, 0xEB0E363F,
+        0x72076785, 0x05005713, 0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38,
+        0x92D28E9B, 0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21, 0x86D3D2D4, 0xF1D4E242,
+        0x68DDB3F8, 0x1FDA836E, 0x81BE16CD, 0xF6B9265B, 0x6FB077E1, 0x18B74777,
+        0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C, 0x8F659EFF, 0xF862AE69,
+        0x616BFFD3, 0x166CCF45, 0xA00AE278, 0xD70DD2EE, 0x4E048354, 0x3903B3C2,
+        0xA7672661, 0xD06016F7, 0x4969474D, 0x3E6E77DB, 0xAED16A4A, 0xD9D65ADC,
+        0x40DF0B66, 0x37D83BF0, 0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9,
+        0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6, 0xBAD03605, 0xCDD70693,
+        0x54DE5729, 0x23D967BF, 0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94,
+        0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D};
+
+typedef struct {
+  uint32_t crc;
+  uint8_t index;
+} crc_t;
+
+crc_t crc32(const unsigned char str[]) {
+  crc_t result = {0xFFFFFFFF, 0xFF};
+
+  for (const unsigned char *i = str; *i != 0; i += sizeof(unsigned char)) {
+    result.index = result.crc & 0xFF ^ *i;
+    result.crc = result.crc >> 8 ^ table[result.index];
+  }
+
+  return result;
+}
+
+uint8_t last_index(const uint32_t crc) {
+  for (uint8_t i = 0; i < sizeof(table); i++) {
+    if (crc == table[i] >> 24) {
+      return i;
+    }
+  }
+}
+
+int16_t check(uintmax_t high, uint8_t indexes[4]) {
+  unsigned char buf[17] = {0};
+  sprintf(buf, "%ju", high);
+  crc_t result = crc32(buf);
+  uint8_t index = result.index;
+
+  if (index != indexes[3]) {
+    return -1;
+  }
+
+  uint32_t crc = result.crc;
+  int16_t low = 0;
+  uint8_t num;
+
+  for (int8_t i = 2; i > -1; i--) {
+    num = (crc & 0xFF ^ indexes[i]) - 48;
+    if (!(0 <= num && num < 10)) {
+      return -1;
+    }
+    low += num * pow(10, i);
+    crc = table[indexes[i]] ^ crc >> 8;
+  }
+
+  return low;
+}
+
+uintmax_t crack(uint32_t crc) {
+  uint8_t indexes[4];
+
+  crc ^= 0xFFFFFFFF;
+  for (uint16_t i = 1; i < 1000; i++) {
+    unsigned char buf[4] = {0};
+    sprintf(buf, "%u", i);
+    if (crc == crc32(buf).crc) {
+      return i;
+    }
+  }
+
+  for (int8_t i = 3; i > -1; i--) {
+    indexes[3 - i] = last_index(crc >> (i << 3));
+    crc ^= table[indexes[3 - i]] >> ((3 - i) << 3);
+  }
+
+  int16_t low;
+  uintmax_t i = 0;
+
+  do {
+    if ((low = check(++i, indexes)) >= 0) {
+      return i * 1000 + low;
+    }
+  } while (i < UINTMAX_MAX / 1000);
+
+  return 0;
+}
+
+int main(int args, char *argv[]) {
+  uint32_t crc;
+
+  if (args > 1) {
+    sscanf(argv[1], "%u", &crc);
+  } else {
+    if (scanf("%u", &crc) != 1) {
+      return -1;
+    };
+  }
+  printf("%ju\n", crack(crc));
+
+  return 0;
+}

main.py

@@ -46,7 +46,7 @@ def check(high: int, indexes: list) -> int | None:
 
 def main(crc: str | int) -> int:  # type: ignore
     indexes = [0] * 4
-    crc = (crc if isinstance(crc, int) else int(crc, 16)) ^ 0xFFFFFFFF
+    crc: int = (crc if isinstance(crc, int) else int(crc, 16)) ^ 0xFFFFFFFF
     for i in range(1, 1000):
         if crc == crc32(str(i))[0]:
             return i