user: 请显示与下面列出的汇编代码相匹配的C语言实现:

```asm
<expr_get_curr_symbol>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  mov    %rcx,%r12
  push   %rbp
  push   %rbx
  sub    $0x8,%rsp
  test   %rdi,%rdi
  je     L246
  cmpb   $0x0,(%rdi)
  mov    %rdi,%rbx
  je     L246
  mov    %rsi,%rbp
  test   %rsi,%rsi
  je     L246
  mov    %rdx,%r15
  test   %rdx,%rdx
  je     L246
  test   %rcx,%rcx
  je     L222
  cmp    %rsi,%rdi
  jae    L246
  movq   $0x0,(%rcx)
  movabs $0xfffffffeffffd9ff,%rax
  nopl   (%rax)
L193:
  movsbl (%rbx),%edi
  cmp    $0x20,%dil
  jbe    L33
  cmp    %rbx,%rbp
  je     L222
  lea    0x1(%rbx),%r14
  mov    %rbx,%r13
  cmp    $0x2d,%dil
  je     L239
L90:
  call   <isdigit@plt>
  test   %rax,%rax
  je     L270
  mov    %r14,(%r15)
  cmp    %r14,%rbp
  jne    L269
  jmp    L176
  nopw   0x0(%rax,%rax,1)
L160:
  mov    (%r15),%rax
  lea    0x1(%rax),%r14
  mov    %r14,(%r15)
  cmp    %rbp,%r14
  je     L176
L269:
  movsbl (%r14),%edi
  call   <isdigit@plt>
  test   %rax,%rax
  jne    L160
  mov    (%r15),%rbp
L176:
  sub    %rbx,%rbp
  mov    %rbx,%r13
  lea    0x1(%rbp),%rdi
L164:
  mov    %rbp,(%r12)
  call   <expr_alloc@plt>
  xor    %esi,%esi
  mov    %rax,%r14
  mov    (%r12),%rax
  mov    %r14,%rdi
  lea    0x1(%rax),%rdx
  call   <memset@plt>
  mov    (%r12),%rdx
  mov    %r13,%rsi
  mov    %r14,%rdi
  call   <memcpy@plt>
  jmp    L281
  nopl   0x0(%rax)
L33:
  bt     %rdi,%rax
  jb     L77
  add    $0x1,%rbx
  cmp    %rbx,%rbp
  jne    L193
L222:
  xor    %r14d,%r14d
L281:
  add    $0x8,%rsp
  mov    %r14,%rax
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopl   0x0(%rax)
L246:
  test   %r12,%r12
  je     L222
  movq   $0x0,(%r12)
  jmp    L222
  nop
L65:
  mov    $0x2d,%edi
  call   <isdigit@plt>
  test   %rax,%rax
  jne    L190
L270:
  mov    %r14,(%r15)
  mov    $0x2,%edi
  mov    $0x1,%ebp
  jmp    L164
  nopl   0x0(%rax)
L239:
  cmp    %r14,%rbp
  je     L65
  movsbl 0x1(%rbx),%edi
  call   <isdigit@plt>
  test   %rax,%rax
  jne    L59
  movsbl (%rbx),%edi
  call   <isdigit@plt>
  test   %rax,%rax
  je     L270
  mov    %r14,(%r15)
  jmp    L269
L59:
  mov    %r14,%r13
  movsbl 0x1(%rbx),%edi
  lea    0x2(%rbx),%r14
  jmp    L90
L190:
  mov    %rbp,(%r15)
  jmp    L176
L77:
  cmp    %rbx,%rbp
  je     L222
  lea    0x1(%rbx),%r14
  mov    %rbx,%r13
  jmp    L90
```

assistant: ```c
char *expr_get_curr_symbol(const char *buffer, const char *buffer_end, const char **next, size_t *symbol_size) {
  const char *bp, *tbp;
  char *symbol = NULL;
  int neg = 0;
  if (buffer == NULL || *buffer == 0 || buffer_end == NULL || next == NULL || symbol_size == NULL || buffer >= buffer_end) {
    if (symbol_size != NULL) {
      *symbol_size = 0;
    }
    return NULL;
  }
  *symbol_size = 0;
  bp = buffer;
  while (bp != buffer_end && ((*bp) == ' ' || (*bp) == '\n' || (*bp) == '\r' || (*bp) == '\t')) {
    bp++;
  }
  if (bp == buffer_end) {
    return NULL;
  }
  if (*bp == '-' && (bp + 1) != buffer_end && isdigit(*(bp + 1))) {
    bp += 1;
    neg = 1;
  }
  if (isdigit(*bp)) {
    (*next) = bp + 1;
    while ((*next) != buffer_end && isdigit(**next)) {
      (*next)++;
    }
    bp -= neg;
  } else {
    (*next) = bp + 1;
  }
  *symbol_size = (*next) - bp;
  symbol = (char *)expr_alloc(*symbol_size + 1);
  memset(symbol, 0, *symbol_size + 1);
  memcpy(symbol, bp, *symbol_size);
  return symbol;
}
```