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

```asm
<substring>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x28,%rsp
  test   %rdi,%rdi
  je     L119
  mov    %esi,%r13d
  mov    %edx,%r15d
  xor    %r8d,%r8d
  cmp    %edx,%esi
  jge    L329
  mov    %rdi,%r14
  mov    $0x1,%edi
  call   <malloc@plt>
  mov    %rax,%r8
  movzbl (%r14),%eax
  test   %al,%al
  je     L337
  test   %r15d,%r15d
  jle    L270
  mov    %r14,%rbp
  mov    $0x1,%edx
  xor    %r12d,%r12d
  xor    %ebx,%ebx
  jmp    L241
  nopl   0x0(%rax)
L278:
  cmp    %ebx,%r15d
  je     L390
L241:
  cmp    %ebx,%r13d
  jg     L106
  cmp    %r12d,%edx
  je     L299
L319:
  movslq %r12d,%rcx
  add    $0x1,%r12d
  mov    %al,(%r8,%rcx,1)
L106:
  movzbl 0x1(%rbp),%eax
  add    $0x1,%rbp
  add    $0x1,%ebx
  test   %al,%al
  jne    L278
L463:
  cmp    %ebx,%r13d
  jg     L293
L329:
  add    $0x28,%rsp
  mov    %r8,%rax
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopl   0x0(%rax)
L390:
  movslq %r12d,%rbp
  lea    (%r8,%rbp,1),%rax
  cmp    %edx,%r12d
  je     L193
L223:
  movb   $0x0,(%rax)
  jmp    L463
  nopl   (%rax)
L299:
  lea    (%rdx,%rdx,1),%eax
  mov    %r8,0x18(%rsp)
  mov    %eax,%edi
  mov    %edx,0x10(%rsp)
  mov    %eax,0xc(%rsp)
  call   <malloc@plt>
  mov    0x10(%rsp),%edx
  mov    0x18(%rsp),%r8
  mov    %rax,%rcx
  test   %edx,%edx
  je     L423
  lea    0x1(%r8),%r10
  mov    %rcx,%rsi
  lea    -0x1(%rdx),%eax
  mov    %edx,%edi
  sub    %r10,%rsi
  cmp    $0xe,%rsi
  jbe    L4
  cmp    $0x6,%eax
  jbe    L4
  cmp    $0xe,%eax
  jbe    L87
  mov    %edx,%esi
  mov    %r8,%rdi
  mov    %rcx,%rax
  shr    $0x4,%esi
  sub    %rcx,%rdi
  shl    $0x4,%rsi
  add    %rcx,%rsi
  nopl   0x0(%rax,%rax,1)
L421:
  movdqu (%rax,%rdi,1),%xmm0
  add    $0x10,%rax
  movups %xmm0,-0x10(%rax)
  cmp    %rsi,%rax
  jne    L421
  mov    %edx,%esi
  and    $0xfffffff0,%esi
  mov    %esi,%eax
  cmp    %esi,%edx
  je     L423
  mov    %edx,%edi
  sub    %esi,%edi
  lea    -0x1(%rdi),%r10d
  cmp    $0x6,%r10d
  jbe    L47
L373:
  mov    (%r8,%rsi,1),%r10
  mov    %r10,(%rcx,%rsi,1)
  mov    %edi,%esi
  and    $0xfffffff8,%esi
  add    %esi,%eax
  cmp    %esi,%edi
  je     L423
L47:
  movslq %eax,%rsi
  movzbl (%r8,%rsi,1),%edi
  mov    %dil,(%rcx,%rsi,1)
  lea    0x1(%rax),%esi
  cmp    %esi,%edx
  jle    L423
  movslq %esi,%rsi
  movzbl (%r8,%rsi,1),%edi
  mov    %dil,(%rcx,%rsi,1)
  lea    0x2(%rax),%esi
  cmp    %esi,%edx
  jle    L423
  movslq %esi,%rsi
  movzbl (%r8,%rsi,1),%edi
  mov    %dil,(%rcx,%rsi,1)
  lea    0x3(%rax),%esi
  cmp    %esi,%edx
  jle    L423
  movslq %esi,%rsi
  movzbl (%r8,%rsi,1),%edi
  mov    %dil,(%rcx,%rsi,1)
  lea    0x4(%rax),%esi
  cmp    %esi,%edx
  jle    L423
  movslq %esi,%rsi
  movzbl (%r8,%rsi,1),%edi
  mov    %dil,(%rcx,%rsi,1)
  lea    0x5(%rax),%esi
  cmp    %esi,%edx
  jle    L423
  movslq %esi,%rsi
  add    $0x6,%eax
  movzbl (%r8,%rsi,1),%edi
  mov    %dil,(%rcx,%rsi,1)
  cmp    %eax,%edx
  jle    L423
  cltq
  movzbl (%r8,%rax,1),%edx
  mov    %dl,(%rcx,%rax,1)
L423:
  mov    %r8,%rdi
  mov    %rcx,0x10(%rsp)
  call   <free@plt>
  movzbl 0x0(%rbp),%eax
  mov    0x10(%rsp),%r8
  mov    0xc(%rsp),%edx
  jmp    L319
  nopl   (%rax)
L193:
  lea    0x1(%rdx),%edi
  mov    %r8,0x10(%rsp)
  mov    %edx,%r15d
  mov    %edx,0xc(%rsp)
  call   <malloc@plt>
  mov    0xc(%rsp),%edx
  mov    0x10(%rsp),%r8
  mov    %rax,%r12
  test   %edx,%edx
  je     L49
  lea    0x1(%r8),%rsi
  mov    %r12,%rcx
  lea    -0x1(%rdx),%eax
  sub    %rsi,%rcx
  cmp    $0xe,%rcx
  jbe    L210
  cmp    $0x6,%eax
  jbe    L210
  cmp    $0xe,%eax
  jbe    L60
  mov    %edx,%ecx
  mov    %r8,%rsi
  mov    %r12,%rax
  shr    $0x4,%ecx
  sub    %r12,%rsi
  shl    $0x4,%rcx
  add    %r12,%rcx
  cs nopw 0x0(%rax,%rax,1)
L301:
  movdqu (%rax,%rsi,1),%xmm1
  add    $0x10,%rax
  movups %xmm1,-0x10(%rax)
  cmp    %rcx,%rax
  jne    L301
  mov    %edx,%ecx
  and    $0xfffffff0,%ecx
  mov    %ecx,%eax
  cmp    %ecx,%edx
  je     L49
  mov    %edx,%r15d
  sub    %ecx,%r15d
  lea    -0x1(%r15),%esi
  cmp    $0x6,%esi
  jbe    L316
L467:
  mov    (%r8,%rcx,1),%rsi
  mov    %rsi,(%r12,%rcx,1)
  mov    %r15d,%ecx
  and    $0xfffffff8,%ecx
  add    %ecx,%eax
  cmp    %r15d,%ecx
  je     L49
L316:
  movslq %eax,%rcx
  movzbl (%r8,%rcx,1),%esi
  mov    %sil,(%r12,%rcx,1)
  lea    0x1(%rax),%ecx
  cmp    %ecx,%edx
  jle    L49
  movslq %ecx,%rcx
  movzbl (%r8,%rcx,1),%esi
  mov    %sil,(%r12,%rcx,1)
  lea    0x2(%rax),%ecx
  cmp    %edx,%ecx
  jge    L49
  movslq %ecx,%rcx
  movzbl (%r8,%rcx,1),%esi
  mov    %sil,(%r12,%rcx,1)
  lea    0x3(%rax),%ecx
  cmp    %ecx,%edx
  jle    L49
  movslq %ecx,%rcx
  movzbl (%r8,%rcx,1),%esi
  mov    %sil,(%r12,%rcx,1)
  lea    0x4(%rax),%ecx
  cmp    %edx,%ecx
  jge    L49
  movslq %ecx,%rcx
  movzbl (%r8,%rcx,1),%esi
  mov    %sil,(%r12,%rcx,1)
  lea    0x5(%rax),%ecx
  cmp    %ecx,%edx
  jle    L49
  movslq %ecx,%rcx
  add    $0x6,%eax
  movzbl (%r8,%rcx,1),%esi
  mov    %sil,(%r12,%rcx,1)
  cmp    %eax,%edx
  jle    L49
  cltq
  movzbl (%r8,%rax,1),%edx
  mov    %dl,(%r12,%rax,1)
L49:
  mov    %r8,%rdi
  call   <free@plt>
  lea    (%r12,%rbp,1),%rax
  mov    %r12,%r8
  jmp    L223
  cs nopw 0x0(%rax,%rax,1)
L293:
  lea    0x1(%rbx),%edx
  mov    %r13d,%ecx
  lea    D13(%rip),%rdi
  mov    %r14,%rsi
  call   <printf@plt>
  xor    %r8d,%r8d
  jmp    L329
L4:
  mov    %r8,%rdi
  lea    (%rdx,%rcx,1),%rsi
  mov    %rcx,%rax
  sub    %rcx,%rdi
  nopw   0x0(%rax,%rax,1)
L175:
  movzbl (%rdi,%rax,1),%edx
  add    $0x1,%rax
  mov    %dl,-0x1(%rax)
  cmp    %rsi,%rax
  jne    L175
  jmp    L423
L210:
  mov    %r8,%rcx
  lea    0x1(%r12,%rax,1),%rsi
  mov    %r12,%rax
  sub    %r12,%rcx
  nopl   0x0(%rax,%rax,1)
L108:
  movzbl (%rcx,%rax,1),%edx
  add    $0x1,%rax
  mov    %dl,-0x1(%rax)
  cmp    %rsi,%rax
  jne    L108
  jmp    L49
L119:
  lea    D17(%rip),%rdi
  call   <puts@plt>
  xor    %r8d,%r8d
  jmp    L329
L337:
  xor    %ebx,%ebx
  jmp    L463
L270:
  mov    %r8,%rax
  xor    %ebx,%ebx
  jmp    L223
L87:
  xor    %esi,%esi
  xor    %eax,%eax
  jmp    L373
L60:
  xor    %ecx,%ecx
  xor    %eax,%eax
  jmp    L467
```

tool_calls: name: unpack_data
arguments: data_tag: D13
type: string
name: unpack_data
arguments: data_tag: D17
type: string

tool: D13: %s has a length of %d but was given a start index of %d


tool: D17: substring() was given a null message!

assistant: ```c
char *substring(char *message, int start, int end) {
  if (message == NULL) {
    puts("substring() was given a null message!");
    return NULL;
  }
  if (start == end || start > end) {
    return NULL;
  }
  int messIndex = 0, strIndex = 0, size = 1;
  char *string = (char *)malloc(sizeof(char));
  while (message[messIndex] != 0) {
    if (messIndex >= end) {
      if (strIndex == size) {
        char *tmpString = (char *)malloc(sizeof(char) * (size) + 1);
        for (int i = 0; i < size; i++) {
          tmpString[i] = string[i];
        }
        size = size + 1;
        free(string);
        string = tmpString;
      }
      string[strIndex] = 0;
      break;
    } else if (messIndex >= start) {
      if (strIndex == size) {
        char *tmpString = (char *)malloc(sizeof(char) * (size * 2));
        for (int i = 0; i < size; i++) {
          tmpString[i] = string[i];
        }
        size = size * 2;
        free(string);
        string = tmpString;
      }
      string[strIndex] = message[messIndex];
      strIndex++;
    }
    messIndex++;
  }
  if (messIndex < start) {
    printf("%s has a length of %d but was given a start index of %d\n", message, messIndex + 1, start);
    return NULL;
  }
  return string;
}
```