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// Copyright (c) Meta Platforms, Inc. and affiliates.
// SPDX-License-Identifier: LGPL-2.1-or-later
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include "bitops.h"
#include "string_builder.h"
#include "util.h"
bool string_builder_null_terminate(struct string_builder *sb)
{
if (!string_builder_reserve_for_append(sb, 1))
return false;
sb->str[sb->len] = '\0';
return true;
}
bool string_builder_reserve(struct string_builder *sb, size_t capacity)
{
if (capacity <= sb->capacity)
return true;
char *tmp = realloc(sb->str, capacity);
if (!tmp)
return false;
sb->str = tmp;
sb->capacity = capacity;
return true;
}
bool string_builder_reserve_for_append(struct string_builder *sb, size_t n)
{
if (n == 0)
return true;
size_t capacity;
if (__builtin_add_overflow(sb->len, n, &capacity))
return false;
if (capacity < (SIZE_MAX / 2) + 1)
capacity = next_power_of_two(capacity);
return string_builder_reserve(sb, capacity);
}
bool string_builder_appendc(struct string_builder *sb, char c)
{
if (!string_builder_reserve_for_append(sb, 1))
return false;
sb->str[sb->len++] = c;
return true;
}
bool string_builder_appendn(struct string_builder *sb, const char *str,
size_t len)
{
if (len == 0)
return true;
if (!string_builder_reserve_for_append(sb, len))
return false;
memcpy(&sb->str[sb->len], str, len);
sb->len += len;
return true;
}
bool string_builder_vappendf(struct string_builder *sb, const char *format,
va_list ap)
{
va_list aq;
int len;
again:
va_copy(aq, ap);
len = vsnprintf(add_to_possibly_null_pointer(sb->str, sb->len),
sb->capacity - sb->len, format, aq);
va_end(aq);
if (len < 0)
return false;
if (sb->len + len < sb->capacity) {
sb->len += len;
return true;
}
/*
* vsnprintf() always null-terminates the string, so we have to allocate
* an extra character.
*/
if (!string_builder_reserve_for_append(sb, len + 1))
return false;
goto again;
}
bool string_builder_appendf(struct string_builder *sb, const char *format, ...)
{
va_list ap;
bool ret;
va_start(ap, format);
ret = string_builder_vappendf(sb, format, ap);
va_end(ap);
return ret;
}
bool string_builder_line_break(struct string_builder *sb)
{
if (!sb->len || sb->str[sb->len - 1] == '\n')
return true;
return string_builder_appendc(sb, '\n');
}
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