/*
 * parseutil.c - parse utilities for string and wire conversion
 *
 * (c) NLnet Labs, 2004-2006
 *
 * See the file LICENSE for the license
 */
/**
 * \file
 *
 * Utility functions for parsing, base32(DNS variant) and base64 encoding
 * and decoding, Hex, Time units, Escape codes.
 */

#include "config.h"
#include "sldns/parseutil.h"
#include <sys/time.h>
#include <time.h>
#include <ctype.h>

sldns_lookup_table *
sldns_lookup_by_name(sldns_lookup_table *table, const char *name)
{
        while (table->name != NULL) {
                if (strcasecmp(name, table->name) == 0)
                        return table;
                table++;
        }
        return NULL;
}

sldns_lookup_table *
sldns_lookup_by_id(sldns_lookup_table *table, int id)
{
        while (table->name != NULL) {
                if (table->id == id)
                        return table;
                table++;
        }
        return NULL;
}

/* Number of days per month (except for February in leap years). */
static const int mdays[] = {
        31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};

#define LDNS_MOD(x,y) (((x) % (y) < 0) ? ((x) % (y) + (y)) : ((x) % (y)))
#define LDNS_DIV(x,y) (((x) % (y) < 0) ? ((x) / (y) -  1 ) : ((x) / (y)))

static int
is_leap_year(int year)
{
        return LDNS_MOD(year,   4) == 0 && (LDNS_MOD(year, 100) != 0 
            || LDNS_MOD(year, 400) == 0);
}

static int
leap_days(int y1, int y2)
{
        --y1;
        --y2;
        return (LDNS_DIV(y2,   4) - LDNS_DIV(y1,   4)) - 
               (LDNS_DIV(y2, 100) - LDNS_DIV(y1, 100)) +
               (LDNS_DIV(y2, 400) - LDNS_DIV(y1, 400));
}

/*
 * Code adapted from Python 2.4.1 sources (Lib/calendar.py).
 */
time_t
sldns_mktime_from_utc(const struct tm *tm)
{
        int year = 1900 + tm->tm_year;
        time_t days = 365 * ((time_t) year - 1970) + leap_days(1970, year);
        time_t hours;
        time_t minutes;
        time_t seconds;
        int i;

        for (i = 0; i < tm->tm_mon; ++i) {
                days += mdays[i];
        }
        if (tm->tm_mon > 1 && is_leap_year(year)) {
                ++days;
        }
        days += tm->tm_mday - 1;

        hours = days * 24 + tm->tm_hour;
        minutes = hours * 60 + tm->tm_min;
        seconds = minutes * 60 + tm->tm_sec;

        return seconds;
}

#if SIZEOF_TIME_T <= 4

static void
sldns_year_and_yday_from_days_since_epoch(int64_t days, struct tm *result)
{
        int year = 1970;
        int new_year;

        while (days < 0 || days >= (int64_t) (is_leap_year(year) ? 366 : 365)) {
                new_year = year + (int) LDNS_DIV(days, 365);
                days -= (new_year - year) * 365;
                days -= leap_days(year, new_year);
                year  = new_year;
        }
        result->tm_year = year;
        result->tm_yday = (int) days;
}

/* Number of days per month in a leap year. */
static const int leap_year_mdays[] = {
        31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};

static void
sldns_mon_and_mday_from_year_and_yday(struct tm *result)
{
        int idays = result->tm_yday;
        const int *mon_lengths = is_leap_year(result->tm_year) ? 
                                        leap_year_mdays : mdays;

        result->tm_mon = 0;
        while  (idays >= mon_lengths[result->tm_mon]) {
                idays -= mon_lengths[result->tm_mon++];
        }
        result->tm_mday = idays + 1;
}

static void
sldns_wday_from_year_and_yday(struct tm *result)
{
        result->tm_wday = 4 /* 1-1-1970 was a thursday */
                        + LDNS_MOD((result->tm_year - 1970), 7) * LDNS_MOD(365, 7)
                        + leap_days(1970, result->tm_year)
                        + result->tm_yday;
        result->tm_wday = LDNS_MOD(result->tm_wday, 7);
        if (result->tm_wday < 0) {
                result->tm_wday += 7;
        }
}

static struct tm *
sldns_gmtime64_r(int64_t clock, struct tm *result)
{
        result->tm_isdst = 0;
        result->tm_sec   = (int) LDNS_MOD(clock, 60);
        clock            =       LDNS_DIV(clock, 60);
        result->tm_min   = (int) LDNS_MOD(clock, 60);
        clock            =       LDNS_DIV(clock, 60);
        result->tm_hour  = (int) LDNS_MOD(clock, 24);
        clock            =       LDNS_DIV(clock, 24);

        sldns_year_and_yday_from_days_since_epoch(clock, result);
        sldns_mon_and_mday_from_year_and_yday(result);
        sldns_wday_from_year_and_yday(result);
        result->tm_year -= 1900;

        return result;
}

#endif /* SIZEOF_TIME_T <= 4 */

static int64_t
sldns_serial_arithmetics_time(int32_t time, time_t now)
{
        int32_t offset = (int32_t)((uint32_t) time - (uint32_t) now);
        return (int64_t) now + offset;
}

struct tm *
sldns_serial_arithmetics_gmtime_r(int32_t time, time_t now, struct tm *result)
{
#if SIZEOF_TIME_T <= 4
        int64_t secs_since_epoch = sldns_serial_arithmetics_time(time, now);
        return  sldns_gmtime64_r(secs_since_epoch, result);
#else
        time_t  secs_since_epoch = sldns_serial_arithmetics_time(time, now);
        return  gmtime_r(&secs_since_epoch, result);
#endif
}

int
sldns_hexdigit_to_int(char ch)
{
        switch (ch) {
        case '0': return 0;
        case '1': return 1;
        case '2': return 2;
        case '3': return 3;
        case '4': return 4;
        case '5': return 5;
        case '6': return 6;
        case '7': return 7;
        case '8': return 8;
        case '9': return 9;
        case 'a': case 'A': return 10;
        case 'b': case 'B': return 11;
        case 'c': case 'C': return 12;
        case 'd': case 'D': return 13;
        case 'e': case 'E': return 14;
        case 'f': case 'F': return 15;
        default:
                return -1;
        }
}

uint32_t
sldns_str2period(const char *nptr, const char **endptr, int* overflow)
{
        int sign = 0;
        uint32_t i = 0;
        uint32_t seconds = 0;
        const uint32_t maxint = 0xffffffff;
        *overflow = 0;

        for(*endptr = nptr; **endptr; (*endptr)++) {
                switch (**endptr) {
                        case ' ':
                        case '\t':
                                break;
                        case '-':
                                if(sign == 0) {
                                        sign = -1;
                                } else {
                                        return seconds;
                                }
                                break;
                        case '+':
                                if(sign == 0) {
                                        sign = 1;
                                } else {
                                        return seconds;
                                }
                                break;
                        case 's':
                        case 'S':
                                if(seconds > maxint-i) {
                                        *overflow = 1;
                                        return 0;
                                }
                                seconds += i;
                                i = 0;
                                break;
                        case 'm':
                        case 'M':
                                if(i > maxint/60 || seconds > maxint-(i*60)) {
                                        *overflow = 1;
                                        return 0;
                                }
                                seconds += i * 60;
                                i = 0;
                                break;
                        case 'h':
                        case 'H':
                                if(i > maxint/(60*60) || seconds > maxint-(i*60*60)) {
                                        *overflow = 1;
                                        return 0;
                                }
                                seconds += i * 60 * 60;
                                i = 0;
                                break;
                        case 'd':
                        case 'D':
                                if(i > maxint/(60*60*24) || seconds > maxint-(i*60*60*24)) {
                                        *overflow = 1;
                                        return 0;
                                }
                                seconds += i * 60 * 60 * 24;
                                i = 0;
                                break;
                        case 'w':
                        case 'W':
                                if(i > maxint/(60*60*24*7) || seconds > maxint-(i*60*60*24*7)) {
                                        *overflow = 1;
                                        return 0;
                                }
                                seconds += i * 60 * 60 * 24 * 7;
                                i = 0;
                                break;
                        case '0':
                        case '1':
                        case '2':
                        case '3':
                        case '4':
                        case '5':
                        case '6':
                        case '7':
                        case '8':
                        case '9':
                                if(i > maxint/10 || i*10 > maxint - (**endptr - '0')) {
                                        *overflow = 1;
                                        return 0;
                                }
                                i *= 10;
                                i += (**endptr - '0');
                                break;
                        default:
                                if(seconds > maxint-i) {
                                        *overflow = 1;
                                        return 0;
                                }
                                seconds += i;
                                /* disregard signedness */
                                return seconds;
                }
        }
        if(seconds > maxint-i) {
                *overflow = 1;
                return 0;
        }
        seconds += i;
        /* disregard signedness */
        return seconds;
}

int
sldns_parse_escape(uint8_t *ch_p, const char** str_p)
{
        uint16_t val;

        if ((*str_p)[0] && isdigit((unsigned char)(*str_p)[0]) &&
            (*str_p)[1] && isdigit((unsigned char)(*str_p)[1]) &&
            (*str_p)[2] && isdigit((unsigned char)(*str_p)[2])) {

                val = (uint16_t)(((*str_p)[0] - '0') * 100 +
                                 ((*str_p)[1] - '0') *  10 +
                                 ((*str_p)[2] - '0'));

                if (val > 255) {
                        goto error;
                }
                *ch_p = (uint8_t)val;
                *str_p += 3;
                return 1;

        } else if ((*str_p)[0] && !isdigit((unsigned char)(*str_p)[0])) {

                *ch_p = (uint8_t)*(*str_p)++;
                return 1;
        }
error:
        *str_p = NULL;
        return 0; /* LDNS_WIREPARSE_ERR_SYNTAX_BAD_ESCAPE */
}

/** parse one character, with escape codes */
int
sldns_parse_char(uint8_t *ch_p, const char** str_p)
{
        switch (**str_p) {

        case '\0':      return 0;

        case '\\':      *str_p += 1;
                        return sldns_parse_escape(ch_p, str_p);

        default:        *ch_p = (uint8_t)*(*str_p)++;
                        return 1;
        }
}

size_t sldns_b32_ntop_calculate_size(size_t src_data_length)
{
        return src_data_length == 0 ? 0 : ((src_data_length - 1) / 5 + 1) * 8;
}

size_t sldns_b32_ntop_calculate_size_no_padding(size_t src_data_length)
{
        return ((src_data_length + 3) * 8 / 5) - 4;
}

static int
sldns_b32_ntop_base(const uint8_t* src, size_t src_sz, char* dst, size_t dst_sz,
        int extended_hex, int add_padding)
{
        size_t ret_sz;
        const char* b32 = extended_hex ?  "0123456789abcdefghijklmnopqrstuv"
                                        : "abcdefghijklmnopqrstuvwxyz234567";

        size_t c = 0; /* c is used to carry partial base32 character over 
                       * byte boundaries for sizes with a remainder.
                       * (i.e. src_sz % 5 != 0)
                       */

        ret_sz = add_padding ? sldns_b32_ntop_calculate_size(src_sz)
                             : sldns_b32_ntop_calculate_size_no_padding(src_sz);
        
        /* Do we have enough space? */
        if (dst_sz < ret_sz + 1)
                return -1;

        /* We know the size; terminate the string */
        dst[ret_sz] = '\0';

        /* First process all chunks of five */
        while (src_sz >= 5) {
                /* 00000... ........ ........ ........ ........ */
                dst[0] = b32[(src[0]       ) >> 3];

                /* .....111 11...... ........ ........ ........ */
                dst[1] = b32[(src[0] & 0x07) << 2 | src[1] >> 6];

                /* ........ ..22222. ........ ........ ........ */
                dst[2] = b32[(src[1] & 0x3e) >> 1];

                /* ........ .......3 3333.... ........ ........ */
                dst[3] = b32[(src[1] & 0x01) << 4 | src[2] >> 4];

                /* ........ ........ ....4444 4....... ........ */
                dst[4] = b32[(src[2] & 0x0f) << 1 | src[3] >> 7];

                /* ........ ........ ........ .55555.. ........ */
                dst[5] = b32[(src[3] & 0x7c) >> 2];

                /* ........ ........ ........ ......66 666..... */
                dst[6] = b32[(src[3] & 0x03) << 3 | src[4] >> 5];

                /* ........ ........ ........ ........ ...77777 */
                dst[7] = b32[(src[4] & 0x1f)     ];

                src_sz -= 5;
                src    += 5;
                dst    += 8;
        }
        /* Process what remains */
        switch (src_sz) {
        case 4: /* ........ ........ ........ ......66 666..... */
                dst[6] = b32[(src[3] & 0x03) << 3];

                /* ........ ........ ........ .55555.. ........ */
                dst[5] = b32[(src[3] & 0x7c) >> 2];

                /* ........ ........ ....4444 4....... ........ */
                         c =  src[3]         >> 7 ;
                ATTR_FALLTHROUGH
                /* fallthrough */
        case 3: dst[4] = b32[(src[2] & 0x0f) << 1 | c];

                /* ........ .......3 3333.... ........ ........ */
                         c =  src[2]         >> 4 ;
                ATTR_FALLTHROUGH
                /* fallthrough */
        case 2: dst[3] = b32[(src[1] & 0x01) << 4 | c];

                /* ........ ..22222. ........ ........ ........ */
                dst[2] = b32[(src[1] & 0x3e) >> 1];

                /* .....111 11...... ........ ........ ........ */
                         c =  src[1]         >> 6 ;
                ATTR_FALLTHROUGH
                /* fallthrough */
        case 1: dst[1] = b32[(src[0] & 0x07) << 2 | c];

                /* 00000... ........ ........ ........ ........ */
                dst[0] = b32[ src[0]         >> 3];
        }
        /* Add padding */
        if (add_padding) {
                switch (src_sz) {
                        case 1: dst[2] = '=';
                                dst[3] = '=';
                                ATTR_FALLTHROUGH
                                /* fallthrough */
                        case 2: dst[4] = '=';
                                ATTR_FALLTHROUGH
                                /* fallthrough */
                        case 3: dst[5] = '=';
                                dst[6] = '=';
                                ATTR_FALLTHROUGH
                                /* fallthrough */
                        case 4: dst[7] = '=';
                }
        }
        return (int)ret_sz;
}

int 
sldns_b32_ntop(const uint8_t* src, size_t src_sz, char* dst, size_t dst_sz)
{
        return sldns_b32_ntop_base(src, src_sz, dst, dst_sz, 0, 1);
}

int 
sldns_b32_ntop_extended_hex(const uint8_t* src, size_t src_sz,
                char* dst, size_t dst_sz)
{
        return sldns_b32_ntop_base(src, src_sz, dst, dst_sz, 1, 1);
}

size_t sldns_b32_pton_calculate_size(size_t src_text_length)
{
        return src_text_length * 5 / 8;
}

static int
sldns_b32_pton_base(const char* src, size_t src_sz, uint8_t* dst, size_t dst_sz,
        int extended_hex, int check_padding)
{
        size_t i = 0;
        char ch = '\0';
        uint8_t buf[8];
        uint8_t* start = dst;

        while (src_sz) {
                /* Collect 8 characters in buf (if possible) */
                for (i = 0; i < 8; i++) {

                        do {
                                ch = *src++;
                                --src_sz;

                        } while (isspace((unsigned char)ch) && src_sz > 0);

                        if (ch == '=' || ch == '\0')
                                break;

                        else if (extended_hex)

                                if (ch >= '0' && ch <= '9')
                                        buf[i] = (uint8_t)ch - '0';
                                else if (ch >= 'a' && ch <= 'v')
                                        buf[i] = (uint8_t)ch - 'a' + 10;
                                else if (ch >= 'A' && ch <= 'V')
                                        buf[i] = (uint8_t)ch - 'A' + 10;
                                else
                                        return -1;

                        else if (ch >= 'a' && ch <= 'z')
                                buf[i] = (uint8_t)ch - 'a';
                        else if (ch >= 'A' && ch <= 'Z')
                                buf[i] = (uint8_t)ch - 'A';
                        else if (ch >= '2' && ch <= '7')
                                buf[i] = (uint8_t)ch - '2' + 26;
                        else
                                return -1;
                }
                /* Less that 8 characters. We're done. */
                if (i < 8)
                        break;

                /* Enough space available at the destination? */
                if (dst_sz < 5)
                        return -1;

                /* 00000... ........ ........ ........ ........ */
                /* .....111 11...... ........ ........ ........ */
                dst[0] = buf[0] << 3 | buf[1] >> 2;

                /* .....111 11...... ........ ........ ........ */
                /* ........ ..22222. ........ ........ ........ */
                /* ........ .......3 3333.... ........ ........ */
                dst[1] = buf[1] << 6 | buf[2] << 1 | buf[3] >> 4;

                /* ........ .......3 3333.... ........ ........ */
                /* ........ ........ ....4444 4....... ........ */
                dst[2] = buf[3] << 4 | buf[4] >> 1;

                /* ........ ........ ....4444 4....... ........ */
                /* ........ ........ ........ .55555.. ........ */
                /* ........ ........ ........ ......66 666..... */
                dst[3] = buf[4] << 7 | buf[5] << 2 | buf[6] >> 3;

                /* ........ ........ ........ ......66 666..... */
                /* ........ ........ ........ ........ ...77777 */
                dst[4] = buf[6] << 5 | buf[7];

                dst += 5;
                dst_sz -= 5;
        }
        /* Not ending on a eight byte boundary? */
        if (i > 0 && i < 8) {

                /* Enough space available at the destination? */
                if (dst_sz < (i + 1) / 2)
                        return -1;

                switch (i) {
                case 7: /* ........ ........ ........ ......66 666..... */
                        /* ........ ........ ........ .55555.. ........ */
                        /* ........ ........ ....4444 4....... ........ */
                        dst[3] = buf[4] << 7 | buf[5] << 2 | buf[6] >> 3;
                        ATTR_FALLTHROUGH
                        /* fallthrough */

                case 5: /* ........ ........ ....4444 4....... ........ */
                        /* ........ .......3 3333.... ........ ........ */
                        dst[2] = buf[3] << 4 | buf[4] >> 1;
                        ATTR_FALLTHROUGH
                        /* fallthrough */

                case 4: /* ........ .......3 3333.... ........ ........ */
                        /* ........ ..22222. ........ ........ ........ */
                        /* .....111 11...... ........ ........ ........ */
                        dst[1] = buf[1] << 6 | buf[2] << 1 | buf[3] >> 4;
                        ATTR_FALLTHROUGH
                        /* fallthrough */

                case 2: /* .....111 11...... ........ ........ ........ */
                        /* 00000... ........ ........ ........ ........ */
                        dst[0] = buf[0] << 3 | buf[1] >> 2;

                        break;

                default:
                        return -1;
                }
                dst += (i + 1) / 2;

                if (check_padding) {
                        /* Check remaining padding characters */
                        if (ch != '=')
                                return -1;

                        /* One down, 8 - i - 1 more to come... */
                        for (i = 8 - i - 1; i > 0; i--) {

                                do {
                                        if (src_sz == 0)
                                                return -1;
                                        ch = *src++;
                                        src_sz--;

                                } while (isspace((unsigned char)ch));

                                if (ch != '=')
                                        return -1;
                        }
                }
        }
        return dst - start;
}

int
sldns_b32_pton(const char* src, size_t src_sz, uint8_t* dst, size_t dst_sz)
{
        return sldns_b32_pton_base(src, src_sz, dst, dst_sz, 0, 1);
}

int
sldns_b32_pton_extended_hex(const char* src, size_t src_sz, 
                uint8_t* dst, size_t dst_sz)
{
        return sldns_b32_pton_base(src, src_sz, dst, dst_sz, 1, 1);
}

size_t sldns_b64_ntop_calculate_size(size_t srcsize)
{
        return ((((srcsize + 2) / 3) * 4) + 1);
}

/* RFC 1521, section 5.2.
 *
 * The encoding process represents 24-bit groups of input bits as output
 * strings of 4 encoded characters. Proceeding from left to right, a
 * 24-bit input group is formed by concatenating 3 8-bit input groups.
 * These 24 bits are then treated as 4 concatenated 6-bit groups, each
 * of which is translated into a single digit in the base64 alphabet.
 *
 * This routine does not insert spaces or linebreaks after 76 characters.
 */
static int sldns_b64_ntop_base(uint8_t const *src, size_t srclength,
        char *target, size_t targsize, int base64url, int padding)
{
        char* b64;
        const char pad64 = '=';
        size_t i = 0, o = 0;
        if(base64url)
                b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123"
                        "456789-_";
        else
                b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123"
                        "456789+/";
        if(targsize < sldns_b64_ntop_calculate_size(srclength))
                return -1;
        /* whole chunks: xxxxxxyy yyyyzzzz zzwwwwww */
        while(i+3 <= srclength) {
                if(o+4 > targsize) return -1;
                target[o] = b64[src[i] >> 2];
                target[o+1] = b64[ ((src[i]&0x03)<<4) | (src[i+1]>>4) ];
                target[o+2] = b64[ ((src[i+1]&0x0f)<<2) | (src[i+2]>>6) ];
                target[o+3] = b64[ (src[i+2]&0x3f) ];
                i += 3;
                o += 4;
        }
        /* remainder */
        switch(srclength - i) {
        case 2:
                /* two at end, converted into A B C = */
                target[o] = b64[src[i] >> 2];
                target[o+1] = b64[ ((src[i]&0x03)<<4) | (src[i+1]>>4) ];
                target[o+2] = b64[ ((src[i+1]&0x0f)<<2) ];
                if(padding) {
                        target[o+3] = pad64;
                        /* i += 2; */
                        o += 4;
                } else {
                        o += 3;
                }
                break;
        case 1:
                /* one at end, converted into A B = = */
                target[o] = b64[src[i] >> 2];
                target[o+1] = b64[ ((src[i]&0x03)<<4) ];
                if(padding) {
                        target[o+2] = pad64;
                        target[o+3] = pad64;
                        /* i += 1; */
                        o += 4;
                } else {
                        o += 2;
                }
                break;
        case 0:
        default:
                /* nothing */
                break;
        }
        /* assert: i == srclength */
        if(o+1 > targsize) return -1;
        target[o] = 0;
        return (int)o;
}

int sldns_b64_ntop(uint8_t const *src, size_t srclength, char *target,
        size_t targsize)
{
        return sldns_b64_ntop_base(src, srclength, target, targsize,
                0 /* no base64url */, 1 /* padding */);
}

int sldns_b64url_ntop(uint8_t const *src, size_t srclength, char *target,
        size_t targsize)
{
        return sldns_b64_ntop_base(src, srclength, target, targsize,
                1 /* base64url */, 0 /* no padding */);
}

size_t sldns_b64_pton_calculate_size(size_t srcsize)
{
        return (((((srcsize + 3) / 4) * 3)) + 1);
}

/* padding not required if srcsize is set */
static int sldns_b64_pton_base(char const *src, size_t srcsize, uint8_t *target,
        size_t targsize, int base64url)
{
        const uint8_t pad64 = 64; /* is 64th in the b64 array */
        const char* s = src;
        uint8_t in[4];
        size_t o = 0, incount = 0;
        int check_padding = (srcsize) ? 0 : 1;

        while(*s && (check_padding || srcsize)) {
                /* skip any character that is not base64 */
                /* conceptually we do:
                const char* b64 =      pad'=' is appended to array
                "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
                const char* d = strchr(b64, *s++);
                and use d-b64;
                */
                char d = *s++;
                srcsize--;
                if(d <= 'Z' && d >= 'A')
                        d -= 'A';
                else if(d <= 'z' && d >= 'a')
                        d = d - 'a' + 26;
                else if(d <= '9' && d >= '0')
                        d = d - '0' + 52;
                else if(!base64url && d == '+')
                        d = 62;
                else if(base64url && d == '-')
                        d = 62;
                else if(!base64url && d == '/')
                        d = 63;
                else if(base64url && d == '_')
                        d = 63;
                else if(d == '=') {
                        if(!check_padding)
                                continue;
                        d = 64;
                } else  continue;

                in[incount++] = (uint8_t)d;
                /* work on block of 4, unless padding is not used and there are
                 * less than 4 chars left */
                if(incount != 4 && (check_padding || srcsize))
                        continue;
                assert(!check_padding || incount==4);
                /* process whole block of 4 characters into 3 output bytes */
                if((incount == 2 ||
                        (incount == 4 && in[3] == pad64 && in[2] == pad64))) { /* A B = = */
                        if(o+1 > targsize)
                                return -1;
                        target[o] = (in[0]<<2) | ((in[1]&0x30)>>4);
                        o += 1;
                        break; /* we are done */
                } else if(incount == 3 ||
                        (incount == 4 && in[3] == pad64)) { /* A B C = */
                        if(o+2 > targsize)
                                return -1;
                        target[o] = (in[0]<<2) | ((in[1]&0x30)>>4);
                        target[o+1]= ((in[1]&0x0f)<<4) | ((in[2]&0x3c)>>2);
                        o += 2;
                        break; /* we are done */
                } else {
                        if(incount != 4 || o+3 > targsize)
                                return -1;
                        /* write xxxxxxyy yyyyzzzz zzwwwwww */
                        target[o] = (in[0]<<2) | ((in[1]&0x30)>>4);
                        target[o+1]= ((in[1]&0x0f)<<4) | ((in[2]&0x3c)>>2);
                        target[o+2]= ((in[2]&0x03)<<6) | in[3];
                        o += 3;
                }
                incount = 0;
        }
        return (int)o;
}

int sldns_b64_pton(char const *src, uint8_t *target, size_t targsize)
{
        return sldns_b64_pton_base(src, 0, target, targsize, 0);
}

int sldns_b64url_pton(char const *src, size_t srcsize, uint8_t *target,
        size_t targsize)
{
        if(!srcsize) {
                return 0;
        }
        return sldns_b64_pton_base(src, srcsize, target, targsize, 1);
}

int sldns_b64_contains_nonurl(char const *src, size_t srcsize)
{
        const char* s = src;
        while(*s && srcsize) {
                char d = *s++;
                srcsize--;
                /* the '+' and the '/' and padding '=' is not allowed in b64
                 * url encoding */
                if(d == '+' || d == '/' || d == '=') {
                        return 1;
                }
        }
        return 0;
}