Files
foobar2000-sdk/pfc/base64.cpp
2021-12-14 00:28:25 -07:00

119 lines
4.0 KiB
C++

#include "pfc.h"
namespace bitWriter {
static void set_bit(t_uint8 * p_stream,size_t p_offset, bool state) {
t_uint8 mask = 1 << (7-(p_offset&7));
t_uint8 & byte = p_stream[p_offset>>3];
byte = (byte & ~mask) | (state ? mask : 0);
}
static void set_bits(t_uint8 * stream, t_size offset, t_size word, t_size bits) {
for(t_size walk = 0; walk < bits; ++walk) {
t_uint8 bit = (t_uint8)((word >> (bits - walk - 1))&1);
set_bit(stream, offset+walk, bit != 0);
}
}
};
namespace pfc {
static const char alphabet[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static const uint8_t alphabetRev[256] =
{0x40,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF
,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF
,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0x3E,0xFF,0xFF,0xFF,0x3F
,0x34,0x35,0x36,0x37,0x38,0x39,0x3A,0x3B,0x3C,0x3D,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF
,0xFF,0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0A,0x0B,0x0C,0x0D,0x0E
,0x0F,0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17,0x18,0x19,0xFF,0xFF,0xFF,0xFF,0xFF
,0xFF,0x1A,0x1B,0x1C,0x1D,0x1E,0x1F,0x20,0x21,0x22,0x23,0x24,0x25,0x26,0x27,0x28
,0x29,0x2A,0x2B,0x2C,0x2D,0x2E,0x2F,0x30,0x31,0x32,0x33,0xFF,0xFF,0xFF,0xFF,0xFF
,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF
,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF
,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF
,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF
,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF
,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF
,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF
,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF
};
size_t base64_strlen( const char * text ) {
size_t ret = 0;
for ( size_t w = 0; ;++w ) {
uint8_t c = (uint8_t) text[w];
if (c == 0) break;
if ( alphabetRev[c] != 0xFF ) ++ret;
}
return ret;
}
t_size base64_decode_estimate(const char * text) {
t_size textLen = base64_strlen(text);
return textLen * 3 / 4;
}
void base64_decode(const char * text, void * out) {
size_t outWritePtr = 0;
size_t inTemp = 0;
uint8_t temp[3];
for ( size_t textWalk = 0 ; ; ++ textWalk ) {
const uint8_t c = (uint8_t) text[textWalk];
if (c == 0) break;
const uint8_t v = alphabetRev[ c ];
if ( v != 0xFF ) {
PFC_ASSERT( inTemp + 6 <= 24 );
bitWriter::set_bits(temp,inTemp,v,6);
inTemp += 6;
if ( inTemp == 24 ) {
memcpy( (uint8_t*) out + outWritePtr, temp, 3 );
outWritePtr += 3;
inTemp = 0;
}
}
}
if ( inTemp > 0 ) {
size_t delta = inTemp / 8;
memcpy( (uint8_t*) out + outWritePtr, temp, delta );
outWritePtr += delta;
inTemp = 0;
}
#if PFC_DEBUG
size_t estimated = base64_decode_estimate( text ) ;
PFC_ASSERT( outWritePtr == estimated );
#endif
}
void base64_encode(pfc::string_base & out, const void * in, t_size inSize) {
out.reset(); base64_encode_append(out, in, inSize);
}
void base64_encode_append(pfc::string_base & out, const void * in, t_size inSize) {
int shift = 0;
int accum = 0;
const t_uint8 * inPtr = reinterpret_cast<const t_uint8*>(in);
for(t_size walk = 0; walk < inSize; ++walk) {
accum <<= 8;
shift += 8;
accum |= inPtr[walk];
while ( shift >= 6 ) {
shift -= 6;
out << format_char( alphabet[(accum >> shift) & 0x3F] );
}
}
if (shift == 4) {
out << format_char( alphabet[(accum & 0xF)<<2] ) << "=";
} else if (shift == 2) {
out << format_char( alphabet[(accum & 0x3)<<4] ) << "==";
}
}
void base64_decode_to_string( pfc::string_base & out, const char * text ) {
char * ptr = out.lock_buffer( base64_decode_estimate( text ) );
base64_decode(text, ptr);
out.unlock_buffer();
}
void base64_encode_from_string( pfc::string_base & out, const char * in ) {
base64_encode( out, in, strlen(in) );
}
}