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REDESIGNED: Base64 encoding/decoding functions

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Found some issues with output size when padding required, just re-implemented both functions from scratch.
This commit is contained in:
Ray 2025-05-28 17:19:19 +02:00
parent 5ddd13b775
commit d7148f5f9d
2 changed files with 83 additions and 70 deletions
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2
src/raylib.h
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@ -1154,7 +1154,7 @@ RLAPI long GetFileModTime(const char *fileName); // Get file mo
RLAPI unsigned char *CompressData(const unsigned char *data, int dataSize, int *compDataSize); // Compress data (DEFLATE algorithm), memory must be MemFree()
RLAPI unsigned char *DecompressData(const unsigned char *compData, int compDataSize, int *dataSize); // Decompress data (DEFLATE algorithm), memory must be MemFree()
RLAPI char *EncodeDataBase64(const unsigned char *data, int dataSize, int *outputSize); // Encode data to Base64 string (includes NULL terminator), memory must be MemFree()
RLAPI unsigned char *DecodeDataBase64(const char *data, int *outputSize); // Decode Base64 string data, memory must be MemFree()
RLAPI unsigned char *DecodeDataBase64(const char *text, int *outputSize); // Decode Base64 string (expected NULL terminated), memory must be MemFree()
RLAPI unsigned int ComputeCRC32(unsigned char *data, int dataSize); // Compute CRC32 hash code
RLAPI unsigned int *ComputeMD5(unsigned char *data, int dataSize); // Compute MD5 hash code, returns static int[4] (16 bytes)
RLAPI unsigned int *ComputeSHA1(unsigned char *data, int dataSize); // Compute SHA1 hash code, returns static int[5] (20 bytes)

151
src/rcore.c
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@ -2542,96 +2542,109 @@ unsigned char *DecompressData(const unsigned char *compData, int compDataSize, i
// NOTE: Returned string includes NULL terminator, considered on outputSize
char *EncodeDataBase64(const unsigned char *data, int dataSize, int *outputSize)
{
static const unsigned char base64encodeTable[] = {
'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', '+', '/'
};
// Base64 conversion table from RFC 4648 [0..63]
// NOTE: They represent 64 values (6 bits), to encode 3 bytes of data into 4 "sixtets" (6bit characters)
static const char base64EncodeTable[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static const int modTable[] = { 0, 2, 1 };
// Compute expected size and padding
int paddedSize = dataSize;
while (paddedSize%3 != 0) paddedSize++; // Padding bytes to round 4*(dataSize/3) to 4 bytes
int estimatedOutputSize = 4*(paddedSize/3);
int padding = paddedSize - dataSize;
*outputSize = 4*((dataSize + 2)/3) + 1; // Adding +1 for NULL terminator
// Adding null terminator to string
estimatedOutputSize += 1;
char *encodedData = (char *)RL_MALLOC(*outputSize);
// Load some memory to store encoded string
char *encodedData = (char *)RL_CALLOC(estimatedOutputSize, 1);
if (encodedData == NULL) return NULL;
if (encodedData == NULL) return NULL; // Security check
for (int i = 0, j = 0; i < dataSize;)
int outputCount = 0;
for (int i = 0; i < dataSize;)
{
unsigned int octetA = (i < dataSize)? (unsigned char)data[i++] : 0;
unsigned int octetB = (i < dataSize)? (unsigned char)data[i++] : 0;
unsigned int octetC = (i < dataSize)? (unsigned char)data[i++] : 0;
unsigned int octetA = 0;
unsigned int octetB = 0;
unsigned int octetC = 0;
unsigned int octetPack = 0;
unsigned int triple = (octetA << 0x10) + (octetB << 0x08) + octetC;
octetA = data[i]; // Generates 2 sextets
octetB = ((i + 1) < dataSize)? data[i + 1] : 0; // Generates 3 sextets
octetC = ((i + 2) < dataSize)? data[i + 2] : 0; // Generates 4 sextets
encodedData[j++] = base64encodeTable[(triple >> 3*6) & 0x3F];
encodedData[j++] = base64encodeTable[(triple >> 2*6) & 0x3F];
encodedData[j++] = base64encodeTable[(triple >> 1*6) & 0x3F];
encodedData[j++] = base64encodeTable[(triple >> 0*6) & 0x3F];
octetPack = (octetA << 16) | (octetB << 8) | octetC;
encodedData[outputCount + 0] = (unsigned char)(base64EncodeTable[(octetPack >> 18) & 0x3f]);
encodedData[outputCount + 1] = (unsigned char)(base64EncodeTable[(octetPack >> 12) & 0x3f]);
encodedData[outputCount + 2] = (unsigned char)(base64EncodeTable[(octetPack >> 6) & 0x3f]);
encodedData[outputCount + 3] = (unsigned char)(base64EncodeTable[octetPack & 0x3f]);
outputCount += 4;
i += 3;
}
// Add required padding bytes
for (int p = 0; p < padding; p++) encodedData[outputCount - p - 1] = '=';
for (int i = 0; i < modTable[dataSize%3]; i++) encodedData[*outputSize - 1 - i] = '='; // Padding character
// Add null terminator to string
encodedData[outputCount] = '\0';
outputCount++;
encodedData[*outputSize - 1] = '\0';
if (outputCount != estimatedOutputSize) TRACELOG(LOG_WARNING, "BASE64: Output size differs from estimation");
*outputSize = estimatedOutputSize;
return encodedData;
}
// Decode Base64 string data
unsigned char *DecodeDataBase64(const char *data, int *outputSize)
// Decode Base64 string (expected NULL terminated)
unsigned char *DecodeDataBase64(const char *text, int *outputSize)
{
static const unsigned char base64decodeTable[] = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 62, 0, 0, 0, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 0, 0, 0, 0, 0, 0, 0, 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, 0, 0, 0, 0, 0, 0, 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
// Base64 decode table
// NOTE: Following ASCII order [0..255] assigning the expected sixtet value to
// every character in the corresponding ASCII position
static const unsigned char base64DecodeTable[256] = {
['A'] = 0, ['B'] = 1, ['C'] = 2, ['D'] = 3, ['E'] = 4, ['F'] = 5, ['G'] = 6, ['H'] = 7,
['I'] = 8, ['J'] = 9, ['K'] = 10, ['L'] = 11, ['M'] = 12, ['N'] = 13, ['O'] = 14, ['P'] = 15,
['Q'] = 16, ['R'] = 17, ['S'] = 18, ['T'] = 19, ['U'] = 20, ['V'] = 21, ['W'] = 22, ['X'] = 23, ['Y'] = 24, ['Z'] = 25,
['a'] = 26, ['b'] = 27, ['c'] = 28, ['d'] = 29, ['e'] = 30, ['f'] = 31, ['g'] = 32, ['h'] = 33,
['i'] = 34, ['j'] = 35, ['k'] = 36, ['l'] = 37, ['m'] = 38, ['n'] = 39, ['o'] = 40, ['p'] = 41,
['q'] = 42, ['r'] = 43, ['s'] = 44, ['t'] = 45, ['u'] = 46, ['v'] = 47, ['w'] = 48, ['x'] = 49, ['y'] = 50, ['z'] = 51,
['0'] = 52, ['1'] = 53, ['2'] = 54, ['3'] = 55, ['4'] = 56, ['5'] = 57, ['6'] = 58, ['7'] = 59,
['8'] = 60, ['9'] = 61, ['+'] = 62, ['/'] = 63
};
// Get output size of Base64 input data
int outSize = 0;
for (int i = 0; data[4*i] != 0; i++)
// Compute expected size and padding
int dataSize = (int)strlen(text); // WARNING: Expecting NULL terminated strings!
int ending = dataSize - 1;
int padding = 0;
while (text[ending] == '=') { padding++; ending--; }
int estimatedOutputSize = 3*(dataSize/4) - padding;
int maxOutputSize = 3*(dataSize/4);
// Load some memory to store decoded data
// NOTE: Allocated enough size to include padding
unsigned char *decodedData = (unsigned char *)RL_CALLOC(maxOutputSize, 1);
if (decodedData == NULL) return NULL;
int outputCount = 0;
for (int i = 0, j = 0; i < dataSize;)
{
if (data[4*i + 3] == '=')
{
if (data[4*i + 2] == '=') outSize += 1;
else outSize += 2;
}
else outSize += 3;
// Every 4 sixtets must generate 3 octets
unsigned int sixtetA = base64DecodeTable[(unsigned char)text[i]];
unsigned int sixtetB = base64DecodeTable[(unsigned char)text[i + 1]];
unsigned int sixtetC = ((unsigned char)text[i + 2] != '=')? base64DecodeTable[(unsigned char)text[i + 2]] : 0;
unsigned int sixtetD = ((unsigned char)text[i + 3] != '=')? base64DecodeTable[(unsigned char)text[i + 3]] : 0;
unsigned int octetPack = (sixtetA << 18) | (sixtetB << 12) | (sixtetC << 6) | sixtetD;
decodedData[outputCount + 0] = (octetPack >> 16) & 0xff;
decodedData[outputCount + 1] = (octetPack >> 8) & 0xff;
decodedData[outputCount + 2] = octetPack & 0xff;
outputCount += 3;
i += 4;
}
// Allocate memory to store decoded Base64 data
unsigned char *decodedData = (unsigned char *)RL_MALLOC(outSize);
if (estimatedOutputSize != (outputCount - padding)) TRACELOG(LOG_WARNING, "BASE64: Decoded size differs from estimation");
for (int i = 0; i < outSize/3; i++)
{
unsigned char a = base64decodeTable[(int)data[4*i]];
unsigned char b = base64decodeTable[(int)data[4*i + 1]];
unsigned char c = base64decodeTable[(int)data[4*i + 2]];
unsigned char d = base64decodeTable[(int)data[4*i + 3]];
decodedData[3*i] = (a << 2) | (b >> 4);
decodedData[3*i + 1] = (b << 4) | (c >> 2);
decodedData[3*i + 2] = (c << 6) | d;
}
if (outSize%3 == 1)
{
int n = outSize/3;
unsigned char a = base64decodeTable[(int)data[4*n]];
unsigned char b = base64decodeTable[(int)data[4*n + 1]];
decodedData[outSize - 1] = (a << 2) | (b >> 4);
}
else if (outSize%3 == 2)
{
int n = outSize/3;
unsigned char a = base64decodeTable[(int)data[4*n]];
unsigned char b = base64decodeTable[(int)data[4*n + 1]];
unsigned char c = base64decodeTable[(int)data[4*n + 2]];
decodedData[outSize - 2] = (a << 2) | (b >> 4);
decodedData[outSize - 1] = (b << 4) | (c >> 2);
}
*outputSize = outSize;
*outputSize = estimatedOutputSize;
return decodedData;
}