TencentOS-tiny/components/connectivity/qcloud-iot-hub-sdk-3.1.2/3rdparty/sdk_src/utils/utils_base64.c

/*
 * Tencent is pleased to support the open source community by making IoT Hub available.
 * Copyright (C) 2016 THL A29 Limited, a Tencent company. All rights reserved.

 * Licensed under the MIT License (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://opensource.org/licenses/MIT

 * Unless required by applicable law or agreed to in writing, software distributed under the License is
 * distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

#ifdef __cplusplus
extern "C" {
#endif
    
#include <stdint.h>
#include <stdlib.h>

#include "utils_base64.h"

static const unsigned char base64_enc_map[64] =
{
    'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
    'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',
    'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd',
    'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
    'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x',
    'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7',
    '8', '9', '+', '/'
};

static const unsigned char base64_dec_map[128] =
{
    127, 127, 127, 127, 127, 127, 127, 127, 127, 127,
    127, 127, 127, 127, 127, 127, 127, 127, 127, 127,
    127, 127, 127, 127, 127, 127, 127, 127, 127, 127,
    127, 127, 127, 127, 127, 127, 127, 127, 127, 127,
    127, 127, 127,  62, 127, 127, 127,  63,  52,  53,
    54,  55,  56,  57,  58,  59,  60,  61, 127, 127,
    127,  64, 127, 127, 127,   0,   1,   2,   3,   4,
    5,   6,   7,   8,   9,  10,  11,  12,  13,  14,
    15,  16,  17,  18,  19,  20,  21,  22,  23,  24,
    25, 127, 127, 127, 127, 127, 127,  26,  27,  28,
    29,  30,  31,  32,  33,  34,  35,  36,  37,  38,
    39,  40,  41,  42,  43,  44,  45,  46,  47,  48,
    49,  50,  51, 127, 127, 127, 127, 127
};
    
#define BASE64_SIZE_T_MAX   ( (size_t) -1 ) /* SIZE_T_MAX is not standard */
    
int qcloud_iot_utils_base64encode( unsigned char *dst, size_t dlen, size_t *olen,
                                const unsigned char *src, size_t slen )
{
    size_t i, n;
    unsigned char *p;
    
    if( slen == 0 )
    {
        *olen = 0;
        return( 0 );
    }
    
    n = slen / 3 + ( slen % 3 != 0 );
    
    if( n > ( BASE64_SIZE_T_MAX - 1 ) / 4 )
    {
        *olen = BASE64_SIZE_T_MAX;
        return( QCLOUD_ERR_FAILURE );
    }
    
    n *= 4;
    
    if( ( dlen < n + 1 ) || ( NULL == dst ) )
    {
        *olen = n + 1;
        return( QCLOUD_ERR_FAILURE );
    }
    
    n = ( slen / 3 ) * 3;
    
    int C1, C2, C3;
    for( i = 0, p = dst; i < n; i += 3 )
    {
        C1 = *src++;
        C2 = *src++;
        C3 = *src++;
        
        *p++ = base64_enc_map[(C1 >> 2) & 0x3F];
        *p++ = base64_enc_map[(((C1 &  3) << 4) + (C2 >> 4)) & 0x3F];
        *p++ = base64_enc_map[(((C2 & 15) << 2) + (C3 >> 6)) & 0x3F];
        *p++ = base64_enc_map[C3 & 0x3F];
    }
    
    if( i < slen )
    {
        C1 = *src++;
        C2 = ( ( i + 1 ) < slen ) ? *src++ : 0;
        
        *p++ = base64_enc_map[(C1 >> 2) & 0x3F];
        *p++ = base64_enc_map[(((C1 & 3) << 4) + (C2 >> 4)) & 0x3F];
        
        if( ( i + 1 ) < slen )
            *p++ = base64_enc_map[((C2 & 15) << 2) & 0x3F];
        else *p++ = '=';
        
        *p++ = '=';
    }
    
    *olen = p - dst;
    *p = 0;
    
    return( 0 );
}

int qcloud_iot_utils_base64decode( unsigned char *dst, size_t dlen, size_t *olen,
                                const unsigned char *src, size_t slen )
{
    size_t i, n;
    uint32_t j, x;
    unsigned char *p;
    
    /* First pass: check for validity and get output length */
    for( i = n = j = 0; i < slen; i++ )
    {
        /* Skip spaces before checking for EOL */
        x = 0;
        while( i < slen && src[i] == ' ' )
        {
            ++i;
            ++x;
        }
        
        /* Spaces at end of buffer are OK */
        if( i == slen )
            break;
        
        if( ( slen - i ) >= 2 &&
            src[i] == '\r' && src[i + 1] == '\n' )
            continue;
        
        if( src[i] == '\n' )
            continue;
        
        /* Space inside a line is an error */
        if( x != 0 )
            return( QCLOUD_ERR_FAILURE );
        
        if( src[i] == '=' && ++j > 2 )
            return( QCLOUD_ERR_FAILURE );
        
        if( src[i] > 127 || base64_dec_map[src[i]] == 127 )
            return( QCLOUD_ERR_FAILURE );
        
        if( base64_dec_map[src[i]] < 64 && j != 0 )
            return( QCLOUD_ERR_FAILURE );
        
        n++;
    }
    
    if( n == 0 )
    {
        *olen = 0;
        return( 0 );
    }
    
    n = ( ( n * 6 ) + 7 ) >> 3;
    n -= j;
    
    if( dst == NULL || dlen < n )
    {
        *olen = n;
        return( QCLOUD_ERR_FAILURE );
    }
    
    for( j = 3, n = x = 0, p = dst; i > 0; i--, src++ )
    {
        if( *src == '\r' || *src == '\n' || *src == ' ' )
            continue;
        
        j -= ( base64_dec_map[*src] == 64 );
        x  = ( x << 6 ) | ( base64_dec_map[*src] & 0x3F );
        
        if( ++n == 4 )
        {
            n = 0;
            if( j > 0 ) *p++ = (unsigned char)( x >> 16 );
            if( j > 1 ) *p++ = (unsigned char)( x >>  8 );
            if( j > 2 ) *p++ = (unsigned char)( x       );
        }
    }
    
    *olen = p - dst;
    
    return( 0 );
}
    
#ifdef __cplusplus
}
#endif