/*

 * Copyright (c) 2009-2016 Petri Lehtinen <petri@digip.org>

 *

 * Jansson is free software; you can redistribute it and/or modify

 * it under the terms of the MIT license. See LICENSE for details.

 */

#ifndef _GNU_SOURCE

#define _GNU_SOURCE

#endif

#include "strbuffer.h"

#include "jansson_private.h"

#include <stdlib.h>

#include <string.h>

#define STRBUFFER_MIN_SIZE 16

#define STRBUFFER_FACTOR   2

#define STRBUFFER_SIZE_MAX ((size_t)-1)

int strbuffer_init(strbuffer_t *strbuff) {

    strbuff->size = STRBUFFER_MIN_SIZE;

    strbuff->length = 0;

    strbuff->value = jsonp_malloc(strbuff->size);

    if (!strbuff->value)

        return -1;

    /* initialize to empty */

    strbuff->value[0] = '\0';

    return 0;

}

void strbuffer_close(strbuffer_t *strbuff) {

    if (strbuff->value)

        jsonp_free(strbuff->value);

    strbuff->size = 0;

    strbuff->length = 0;

    strbuff->value = NULL;

}

void strbuffer_clear(strbuffer_t *strbuff) {

    strbuff->length = 0;

    strbuff->value[0] = '\0';

}

const char *strbuffer_value(const strbuffer_t *strbuff) { return strbuff->value; }

char *strbuffer_steal_value(strbuffer_t *strbuff) {

    char *result = strbuff->value;

    strbuff->value = NULL;

    return result;

}

int strbuffer_append_byte(strbuffer_t *strbuff, char byte) {

    return strbuffer_append_bytes(strbuff, &byte, 1);

}

int strbuffer_append_bytes(strbuffer_t *strbuff, const char *data, size_t size) {

    if (size >= strbuff->size - strbuff->length) {

        size_t new_size;

        char *new_value;

        /* avoid integer overflow */

        if (strbuff->size > STRBUFFER_SIZE_MAX / STRBUFFER_FACTOR ||

            size > STRBUFFER_SIZE_MAX - 1 ||

            strbuff->length > STRBUFFER_SIZE_MAX - 1 - size)

            return -1;

        new_size = max(strbuff->size * STRBUFFER_FACTOR, strbuff->length + size + 1);

        new_value = jsonp_malloc(new_size);

        if (!new_value)

            return -1;

        memcpy(new_value, strbuff->value, strbuff->length);

        jsonp_free(strbuff->value);

        strbuff->value = new_value;

        strbuff->size = new_size;

    }

    memcpy(strbuff->value + strbuff->length, data, size);

    strbuff->length += size;

    strbuff->value[strbuff->length] = '\0';

    return 0;

}

char strbuffer_pop(strbuffer_t *strbuff) {

    if (strbuff->length > 0) {

        char c = strbuff->value[--strbuff->length];

        strbuff->value[strbuff->length] = '\0';

        return c;

    } else

        return '\0';

}