user: What is the c source code of the assembly code below:

```asm
<levenshtein>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbx
  mov    %rdx,%rbx
  sub    $0x48,%rsp
  mov    %rdi,-0x60(%rbp)
  mov    (%rdx),%rdi
  mov    %fs:0x28,%rax
  mov    %rax,-0x38(%rbp)
  xor    %eax,%eax
  call   <sqlite3_value_text@plt>
  mov    0x8(%rbx),%rdi
  mov    %rax,%r14
  mov    %rax,-0x50(%rbp)
  call   <sqlite3_value_text@plt>
  test   %r14,%r14
  je     L73
  mov    %rax,%r15
  test   %rax,%rax
  je     L73
  mov    -0x50(%rbp),%rdi
  mov    %rsp,-0x68(%rbp)
  call   <strlen@plt>
  mov    %r15,%rdi
  mov    %eax,%r12d
  call   <strlen@plt>
  lea    0x1(%r12),%esi
  mov    %rsp,%rcx
  mov    %eax,-0x44(%rbp)
  add    $0x1,%eax
  imul   %rsi,%rax
  mov    %rsi,-0x58(%rbp)
  lea    0xf(,%rax,4),%rax
  mov    %rax,%rdx
  and    $0xfffffffffffff000,%rax
  sub    %rax,%rcx
  and    $0xfffffffffffffff0,%rdx
  cmp    %rcx,%rsp
  je     L46
L57:
  sub    $0x1000,%rsp
  orq    $0x0,0xff8(%rsp)
  cmp    %rcx,%rsp
  jne    L57
L46:
  and    $0xfff,%edx
  sub    %rdx,%rsp
  test   %rdx,%rdx
  je     L38
  orq    $0x0,-0x8(%rsp,%rdx,1)
L38:
  lea    0x3(%rsp),%r8
  mov    -0x44(%rbp),%edi
  mov    %r8,%rax
  and    $0xfffffffffffffffc,%r8
  shr    $0x2,%rax
  movl   $0x0,0x0(,%rax,4)
  test   %edi,%edi
  je     L47
  mov    -0x58(%rbp),%rsi
  xor    %ecx,%ecx
  mov    $0x1,%eax
  nopl   (%rax)
L88:
  mov    %eax,%edx
  add    $0x1,%ecx
  add    $0x1,%eax
  imul   %rsi,%rdx
  mov    %ecx,(%r8,%rdx,4)
  cmp    %eax,%edi
  jae    L88
  test   %r12d,%r12d
  je     L60
L37:
  mov    $0x1,%eax
  xchg   %ax,%ax
L122:
  lea    -0x1(%rax),%edx
  mov    %eax,%ecx
  add    $0x1,%eax
  mov    (%r8,%rdx,4),%edx
  add    $0x1,%edx
  mov    %edx,(%r8,%rcx,4)
  cmp    %eax,%r12d
  jae    L122
  mov    -0x44(%rbp),%eax
  test   %eax,%eax
  je     L106
L60:
  mov    $0x1,%r14d
  nopl   0x0(%rax)
L125:
  test   %r12d,%r12d
  je     L56
  mov    -0x58(%rbp),%rax
  lea    -0x1(%r14),%r11d
  mov    %r14d,%r10d
  mov    -0x50(%rbp),%r9
  movzbl (%r15),%r13d
  mov    $0x1,%esi
  imul   %rax,%r11
  imul   %rax,%r10
  nopl   (%rax)
L7:
  mov    %esi,%edi
  lea    -0x1(%rsi),%ebx
  lea    (%rdi,%r11,1),%rax
  mov    (%r8,%rax,4),%ecx
  lea    (%rbx,%r10,1),%rax
  mov    (%r8,%rax,4),%edx
  xor    %eax,%eax
  add    $0x1,%ecx
  add    $0x1,%edx
  cmp    %r13b,(%r9)
  setne  %al
  add    %r11,%rbx
  add    (%r8,%rbx,4),%eax
  cmp    %eax,%ecx
  mov    %eax,%ebx
  cmovbe %ecx,%ebx
  cmp    %eax,%edx
  cmovbe %edx,%eax
  cmp    %edx,%ecx
  cmovb  %ebx,%eax
  add    %r10,%rdi
  add    $0x1,%esi
  add    $0x1,%r9
  mov    %eax,(%r8,%rdi,4)
  cmp    %esi,%r12d
  jae    L7
L56:
  add    $0x1,%r14d
  add    $0x1,%r15
  cmp    %r14d,-0x44(%rbp)
  jae    L125
L106:
  mov    -0x44(%rbp),%edx
  imul   -0x58(%rbp),%rdx
  mov    %r12d,%eax
  mov    -0x60(%rbp),%rdi
  add    %rdx,%rax
  mov    (%r8,%rax,4),%esi
  call   <sqlite3_result_int@plt>
  mov    -0x68(%rbp),%rsp
  jmp    L132
  nopl   0x0(%rax)
L73:
  mov    -0x60(%rbp),%rdi
  call   <sqlite3_result_null@plt>
L132:
  mov    -0x38(%rbp),%rax
  sub    %fs:0x28,%rax
  jne    L168
  lea    -0x28(%rbp),%rsp
  pop    %rbx
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  pop    %rbp
  ret
L47:
  test   %r12d,%r12d
  jne    L37
  jmp    L106
L168:
  call   <__stack_chk_fail@plt>
```

assistant: ```c
extern void levenshtein(sqlite3_context *context, int argc, sqlite3_value **argv) {
  char *s1;
  char *s2;
  s1 = (char *)sqlite3_value_text(argv[0]);
  s2 = (char *)sqlite3_value_text(argv[1]);
  if ((s1 == NULL) || (s2 == NULL)) {
    sqlite3_result_null(context);
  } else {
    unsigned int x;
    unsigned int y;
    unsigned int s1len;
    unsigned int s2len;
    s1len = strlen(s1);
    s2len = strlen(s2);
    unsigned int matrix[s2len + 1][s1len + 1];
    matrix[0][0] = 0;
    for (x = 1; x <= s2len; x++) {
      matrix[x][0] = matrix[x - 1][0] + 1;
    }
    for (y = 1; y <= s1len; y++) {
      matrix[0][y] = matrix[0][y - 1] + 1;
    }
    for (x = 1; x <= s2len; x++) {
      for (y = 1; y <= s1len; y++) {
        matrix[x][y] = ((matrix[x - 1][y] + 1) < (matrix[x][y - 1] + 1) ? ((matrix[x - 1][y] + 1) < (matrix[x - 1][y - 1] + (s1[y - 1] == s2[x - 1] ? 0 : 1)) ? (matrix[x - 1][y] + 1) : (matrix[x - 1][y - 1] + (s1[y - 1] == s2[x - 1] ? 0 : 1))) : ((matrix[x][y - 1] + 1) < (matrix[x - 1][y - 1] + (s1[y - 1] == s2[x - 1] ? 0 : 1)) ? (matrix[x][y - 1] + 1) : (matrix[x - 1][y - 1] + (s1[y - 1] == s2[x - 1] ? 0 : 1))));
      }
    }
    sqlite3_result_int(context, (int)matrix[s2len][s1len]);
  }
}
```