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//===-- Standalone implementation of a char vector --------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIBC_SRC_SUPPORT_CHARVECTOR_H
#define LLVM_LIBC_SRC_SUPPORT_CHARVECTOR_H
#include "src/__support/common.h"
#include <stddef.h>
#include <stdlib.h> // For allocation.
namespace __llvm_libc {
// This is very simple alternate of the std::string class. There is no
// bounds check performed in any of the methods. The callers are expected to
// do the checks before invoking the methods.
//
// This class will be extended as needed in future.
class CharVector {
static constexpr size_t INIT_BUFF_SIZE = 64;
char local_buffer[INIT_BUFF_SIZE];
char *cur_str = local_buffer;
size_t cur_buff_size = INIT_BUFF_SIZE;
size_t index = 0;
public:
CharVector() = default;
LIBC_INLINE ~CharVector() {
if (cur_str != local_buffer)
free(cur_str);
}
// append returns true on success and false on allocation failure.
LIBC_INLINE bool append(char new_char) {
// Subtract 1 for index starting at 0 and another for the null terminator.
if (index >= cur_buff_size - 2) {
// If the new character would cause the string to be longer than the
// buffer's size, attempt to allocate a new buffer.
cur_buff_size = cur_buff_size * 2;
if (cur_str == local_buffer) {
char *new_str;
new_str = reinterpret_cast<char *>(malloc(cur_buff_size));
if (new_str == NULL) {
return false;
}
// TODO: replace with inline memcpy
for (size_t i = 0; i < index; ++i)
new_str[i] = cur_str[i];
cur_str = new_str;
} else {
cur_str = reinterpret_cast<char *>(realloc(cur_str, cur_buff_size));
if (cur_str == NULL) {
return false;
}
}
}
cur_str[index] = new_char;
++index;
return true;
}
LIBC_INLINE char *c_str() {
cur_str[index] = '\0';
return cur_str;
}
LIBC_INLINE size_t length() { return index; }
};
} // namespace __llvm_libc
#endif // LLVM_LIBC_SRC_SUPPORT_CHARVECTOR_H
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