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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
#include "plbase64.h"
#include "prlog.h" /* For PR_NOT_REACHED */
#include "prmem.h" /* for malloc / PR_MALLOC */
#include <string.h> /* for strlen */
static unsigned char *base = (unsigned char *)"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static void encode3to4(const unsigned char* src, unsigned char* dest) {
PRUint32 b32 = (PRUint32)0;
PRIntn i, j = 18;
for (i = 0; i < 3; i++) {
b32 <<= 8;
b32 |= (PRUint32)src[i];
}
for (i = 0; i < 4; i++) {
dest[i] = base[(PRUint32)((b32 >> j) & 0x3F)];
j -= 6;
}
return;
}
static void encode2to4(const unsigned char* src, unsigned char* dest) {
dest[0] = base[(PRUint32)((src[0] >> 2) & 0x3F)];
dest[1] = base[(PRUint32)(((src[0] & 0x03) << 4) | ((src[1] >> 4) & 0x0F))];
dest[2] = base[(PRUint32)((src[1] & 0x0F) << 2)];
dest[3] = (unsigned char)'=';
return;
}
static void encode1to4(const unsigned char* src, unsigned char* dest) {
dest[0] = base[(PRUint32)((src[0] >> 2) & 0x3F)];
dest[1] = base[(PRUint32)((src[0] & 0x03) << 4)];
dest[2] = (unsigned char)'=';
dest[3] = (unsigned char)'=';
return;
}
static void encode(const unsigned char* src, PRUint32 srclen,
unsigned char* dest) {
while (srclen >= 3) {
encode3to4(src, dest);
src += 3;
dest += 4;
srclen -= 3;
}
switch (srclen) {
case 2:
encode2to4(src, dest);
break;
case 1:
encode1to4(src, dest);
break;
case 0:
break;
default:
PR_NOT_REACHED("coding error");
}
return;
}
/*
* PL_Base64Encode
*
* If the destination argument is NULL, a return buffer is
* allocated, and the data therein will be null-terminated.
* If the destination argument is not NULL, it is assumed to
* be of sufficient size, and the contents will not be null-
* terminated by this routine.
*
* Returns null if the allocation fails.
*/
PR_IMPLEMENT(char*)
PL_Base64Encode(const char* src, PRUint32 srclen, char* dest) {
if (0 == srclen) {
size_t len = strlen(src);
srclen = len;
/* Detect truncation. */
if (srclen != len) {
return (char*)0;
}
}
if ((char*)0 == dest) {
PRUint32 destlen;
/* Ensure all PRUint32 values stay within range. */
if (srclen > (PR_UINT32_MAX / 4) * 3) {
return (char*)0;
}
destlen = ((srclen + 2) / 3) * 4;
dest = (char*)PR_MALLOC(destlen + 1);
if ((char*)0 == dest) {
return (char*)0;
}
dest[destlen] = (char)0; /* null terminate */
}
encode((const unsigned char*)src, srclen, (unsigned char*)dest);
return dest;
}
static PRInt32 codetovalue(unsigned char c) {
if ((c >= (unsigned char)'A') && (c <= (unsigned char)'Z')) {
return (PRInt32)(c - (unsigned char)'A');
} else if ((c >= (unsigned char)'a') && (c <= (unsigned char)'z')) {
return ((PRInt32)(c - (unsigned char)'a') + 26);
} else if ((c >= (unsigned char)'0') && (c <= (unsigned char)'9')) {
return ((PRInt32)(c - (unsigned char)'0') + 52);
} else if ((unsigned char)'+' == c) {
return (PRInt32)62;
} else if ((unsigned char)'/' == c) {
return (PRInt32)63;
} else {
return -1;
}
}
static PRStatus decode4to3(const unsigned char* src, unsigned char* dest) {
PRUint32 b32 = (PRUint32)0;
PRInt32 bits;
PRIntn i;
for (i = 0; i < 4; i++) {
bits = codetovalue(src[i]);
if (bits < 0) {
return PR_FAILURE;
}
b32 <<= 6;
b32 |= bits;
}
dest[0] = (unsigned char)((b32 >> 16) & 0xFF);
dest[1] = (unsigned char)((b32 >> 8) & 0xFF);
dest[2] = (unsigned char)((b32) & 0xFF);
return PR_SUCCESS;
}
static PRStatus decode3to2(const unsigned char* src, unsigned char* dest) {
PRUint32 b32 = (PRUint32)0;
PRInt32 bits;
PRUint32 ubits;
bits = codetovalue(src[0]);
if (bits < 0) {
return PR_FAILURE;
}
b32 = (PRUint32)bits;
b32 <<= 6;
bits = codetovalue(src[1]);
if (bits < 0) {
return PR_FAILURE;
}
b32 |= (PRUint32)bits;
b32 <<= 4;
bits = codetovalue(src[2]);
if (bits < 0) {
return PR_FAILURE;
}
ubits = (PRUint32)bits;
b32 |= (ubits >> 2);
dest[0] = (unsigned char)((b32 >> 8) & 0xFF);
dest[1] = (unsigned char)((b32) & 0xFF);
return PR_SUCCESS;
}
static PRStatus decode2to1(const unsigned char* src, unsigned char* dest) {
PRUint32 b32;
PRUint32 ubits;
PRInt32 bits;
bits = codetovalue(src[0]);
if (bits < 0) {
return PR_FAILURE;
}
ubits = (PRUint32)bits;
b32 = (ubits << 2);
bits = codetovalue(src[1]);
if (bits < 0) {
return PR_FAILURE;
}
ubits = (PRUint32)bits;
b32 |= (ubits >> 4);
dest[0] = (unsigned char)b32;
return PR_SUCCESS;
}
static PRStatus decode(const unsigned char* src, PRUint32 srclen,
unsigned char* dest) {
PRStatus rv;
while (srclen >= 4) {
rv = decode4to3(src, dest);
if (PR_SUCCESS != rv) {
return PR_FAILURE;
}
src += 4;
dest += 3;
srclen -= 4;
}
switch (srclen) {
case 3:
rv = decode3to2(src, dest);
break;
case 2:
rv = decode2to1(src, dest);
break;
case 1:
rv = PR_FAILURE;
break;
case 0:
rv = PR_SUCCESS;
break;
default:
PR_NOT_REACHED("coding error");
}
return rv;
}
/*
* PL_Base64Decode
*
* If the destination argument is NULL, a return buffer is
* allocated and the data therein will be null-terminated.
* If the destination argument is not null, it is assumed
* to be of sufficient size, and the data will not be null-
* terminated by this routine.
*
* Returns null if the allocation fails, or if the source string is
* not well-formed.
*/
PR_IMPLEMENT(char*)
PL_Base64Decode(const char* src, PRUint32 srclen, char* dest) {
PRStatus status;
PRBool allocated = PR_FALSE;
if ((char*)0 == src) {
return (char*)0;
}
if (0 == srclen) {
size_t len = strlen(src);
srclen = len;
/* Detect truncation. */
if (srclen != len) {
return (char*)0;
}
}
if (srclen && (0 == (srclen & 3))) {
if ((char)'=' == src[srclen - 1]) {
if ((char)'=' == src[srclen - 2]) {
srclen -= 2;
} else {
srclen -= 1;
}
}
}
if ((char*)0 == dest) {
/* The following computes ((srclen * 3) / 4) without overflow. */
PRUint32 destlen = (srclen / 4) * 3 + ((srclen % 4) * 3) / 4;
dest = (char*)PR_MALLOC(destlen + 1);
if ((char*)0 == dest) {
return (char*)0;
}
dest[destlen] = (char)0; /* null terminate */
allocated = PR_TRUE;
}
status = decode((const unsigned char*)src, srclen, (unsigned char*)dest);
if (PR_SUCCESS != status) {
if (PR_TRUE == allocated) {
PR_DELETE(dest);
}
return (char*)0;
}
return dest;
}