alertik/str.c
2024-08-06 22:57:23 -03:00

244 lines
5.5 KiB
C

/*
* Alertik: a tiny 'syslog' server & notification tool for Mikrotik routers.
* This is free and unencumbered software released into the public domain.
*/
/*
* String/append buffer implementation based on Aqua:
* https://gist.github.com/Theldus/09ed2205aa5ba15cdf4571b71cd1c8fc
*/
#include "str.h"
#include "log.h"
/* Malloc is only used if AB_USE_MALLOC is defined. */
#ifdef AB_USE_MALLOC
#if defined(AB_CALLOC) && defined(AB_REALLOC) && defined(AB_FREE)
# define AB_USE_STDLIB
#elif !defined(AB_CALLOC) && !defined(AB_REALLOC) && !defined(AB_FREE)
# define AB_USE_STDLIB
#else
#error "For custom memory allocators, you should define all three routines!"
#error "Please define: AB_CALLOC, AB_REALLOC and AB_FREE!"
#endif
#endif
#ifndef AB_CALLOC
#define AB_CALLOC(nmemb,sz) calloc((nmemb),(sz))
#define AB_REALLOC(p,newsz) realloc((p),(newsz))
#define AB_FREE(p) free((p))
#endif
#ifdef AB_USE_STDLIB
#include <stdlib.h>
#endif
#include <stdarg.h>
#include <stdio.h>
#include <string.h>
/* ========================================================================= */
/* BUFFER ROUTINES */
/* ========================================================================= */
#ifdef AB_USE_MALLOC
/**
* @brief Rounds up to the next power of two.
*
* @param target Target number to be rounded.
*
* @return Returns the next power of two.
*/
static size_t next_power(size_t target)
{
target--;
target |= target >> 1;
target |= target >> 2;
target |= target >> 4;
target |= target >> 8;
target |= target >> 16;
target++;
return (target);
}
#endif
/**
* @brief Checks if the new size fits in the append buffer, if not,
* reallocates the buffer size by @p incr bytes.
*
* If the macro AB_USE_MALLOC is not defined (default), this only
* checks if the new size fits the buffer.
*
* @param sh Aqua highlight context.
* @param incr Size (in bytes) to be incremented.
*
* @return Returns 0 if success, -1 otherwise.
*
* @note The new size is the next power of two, that is capable
* to hold the required buffer size.
*/
static int increase_buff(struct str_ab *sh, size_t incr)
{
#ifndef AB_USE_MALLOC
if (sh->pos + incr >= MAX_LINE) {
log_msg("(increase buffer) Unable to fit appended message!\n");
log_msg("(static storage) incr: %zu, buff_len: %zu, pos: %zu\n",
incr, sh->pos, sh->buff_len);
return (-1);
}
#else
char *new;
size_t new_size;
if (sh->pos + incr >= sh->buff_len)
{
new_size = next_power(sh->buff_len + incr);
new = AB_REALLOC(sh->buff, new_size);
if (new == NULL)
{
AB_FREE(sh->buff);
sh->buff = NULL;
log_msg("(increase buffer) Unable to fit appended message!\n");
log_msg("(realloc storage) incr: %zu, buff_len: %zu, pos: %zu\n",
incr, sh->pos, sh->buff_len);
return (-1);
}
sh->buff_len = new_size;
sh->buff = new;
}
#endif
return (0);
}
/**
* @brief Initializes the append buffer context.
*
* @param ab Append buffer structure.
*
* @return Returns 0 if success, -1 otherwise.
*/
int ab_init(struct str_ab *ab)
{
if (!ab)
return (-1);
memset(ab, 0, sizeof(*ab));
#ifndef AB_USE_MALLOC
ab->buff_len = MAX_LINE;
#else
ab->buff = AB_CALLOC(MAX_LINE, 1);
if (!ab->buff)
return (-1);
ab->buff_len = MAX_LINE;
#endif
return (0);
}
/**
* @brief Append a given char @p c into the buffer.
*
* @param sh Aqua highlight context.
* @param c Char to be appended.
*
* @return Returns 0 if success, -1 otherwise.
*/
int ab_append_chr(struct str_ab *sh, char c)
{
if (increase_buff(sh, 2) < 0)
return (-1);
sh->buff[sh->pos + 0] = c;
sh->buff[sh->pos + 1] = '\0';
sh->pos++;
return (0);
}
/**
* @brief Appends a given string pointed by @p s of size @p len
* into the current buffer.
*
* If @p len is 0, the string is assumed to be null-terminated
* and its length is obtained.
*
* @param ab Append buffer context.
* @param s String to be append into the buffer.
* @param len String size, if 0, it's length is obtained.
*
* @return Returns 0 if success, -1 otherwise.
*/
int ab_append_str(struct str_ab *ab, const char *s, size_t len)
{
if (!len)
len = strlen(s);
if (increase_buff(ab, len + 1) < 0)
return (-1);
memcpy(ab->buff + ab->pos, s, len);
ab->pos += len;
ab->buff[ab->pos] = '\0';
return (0);
}
/**
* @brief Appends a given formatted string pointed by @p fmt.
*
* @param ab Append buffer context.
* @param fmt Formatted string to be appended.
*
* @return Returns 0 if success, -1 otherwise.
*/
int ab_append_fmt(struct str_ab *ab, const char *fmt, ...)
{
int str_len, ab_len, orig_ab_pos;
char *buff_st;
va_list ap;
buff_st = ab->buff + ab->pos;
ab_len = ab->buff_len - ab->pos;
va_start(ap, fmt);
str_len = vsnprintf(buff_st, ab_len, fmt, ap);
if (str_len < 0) {
log_msg("Unable to fit appended message!\n");
return (-1);
}
va_end(ap);
/* If it fits, just happily returns. */
if (str_len + 1 <= ab_len) {
ab->pos += str_len;
return (0);
}
/* Otherwise, adjust current pos and try to increase buffer. */
else {
orig_ab_pos = ab->pos;
/* temporarily advance our buffer
* to trick our increase buffer. */
ab->pos = ab->buff_len;
if (increase_buff(ab, (str_len + 1) - ab_len))
return (-1);
ab->pos = orig_ab_pos;
}
buff_st = ab->buff + ab->pos;
ab_len = ab->buff_len - ab->pos;
va_start(ap, fmt);
str_len = vsnprintf(buff_st, ab_len, fmt, ap);
if (str_len < 0 || (str_len + 1) > ab_len) {
log_msg("Unable to fit appended message!\n");
return (-1);
}
va_end(ap);
ab->pos += str_len;
return (0);
}