base64.c   [plain text]

/* ====================================================================
 * The Apache Software License, Version 1.1
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 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
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 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
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 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
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 * <http://www.apache.org/>.
 *
 * Portions of this software are based upon public domain software
 * originally written at the National Center for Supercomputing Applications,
 * University of Illinois, Urbana-Champaign.
 */

/* base64 encoder/decoder. Originally part of main/util.c
 * but moved here so that support/ab and ap_sha1.c could
 * use it. This meant removing the ap_palloc()s and adding
 * ugly 'len' functions, which is quite a nasty cost.
 */

#include "util.h"

/* aaaack but it's fast and const should make it shared text page. */
static const unsigned char pr2six[256] =
{
    /* ASCII table */
    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 62, 64, 64, 64, 63,
    52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 64, 64, 64, 64, 64, 64,
    64,  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, 64, 64, 64, 64, 64,
    64, 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, 64, 64, 64, 64, 64,
    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64
};

int ap_base64decode_len(const char *bufcoded, int buflen)
{
    int nbytesdecoded;
    register const unsigned char *bufin;
    register int nprbytes;

    bufin = (const unsigned char *) bufcoded;
    while ((pr2six[*bufin] <= 63) && (buflen != 0)) {
        bufin++;
        buflen--;
    }

    nprbytes = bufin - (const unsigned char *) bufcoded;
    nbytesdecoded = (nprbytes * 3) / 4;

    return nbytesdecoded;
}

int ap_base64decode(char *bufplain, const char *bufcoded, int buflen)
{
    int len;
    
    len = ap_base64decode_binary((unsigned char *) bufplain, bufcoded, buflen);
    bufplain[len] = '\0';
    return len;
}

int ap_base64decode_binary(unsigned char *bufplain,
				   const char *bufcoded, int buflen)
{
    int nbytesdecoded;
    register const unsigned char *bufin;
    register unsigned char *bufout;
    register int nprbytes;

    bufin = (const unsigned char *) bufcoded;
    while ((pr2six[*bufin] <= 63) && (buflen != 0)) {
        bufin++;
        buflen--;
    }
    nprbytes = bufin - (const unsigned char *) bufcoded;
    nbytesdecoded = ((nprbytes + 3) / 4) * 3;

    bufout = (unsigned char *) bufplain;
    bufin = (const unsigned char *) bufcoded;

    while (nprbytes > 4) {
	*(bufout++) =
	    (unsigned char) (pr2six[*bufin] << 2 | pr2six[bufin[1]] >> 4);
	*(bufout++) =
	    (unsigned char) (pr2six[bufin[1]] << 4 | pr2six[bufin[2]] >> 2);
	*(bufout++) =
	    (unsigned char) (pr2six[bufin[2]] << 6 | pr2six[bufin[3]]);
	bufin += 4;
	nprbytes -= 4;
    }

    /* Note: (nprbytes == 1) would be an error, so just ingore that case */
    if (nprbytes > 1) {
	*(bufout++) =
	    (unsigned char) (pr2six[*bufin] << 2 | pr2six[bufin[1]] >> 4);
    }
    if (nprbytes > 2) {
	*(bufout++) =
	    (unsigned char) (pr2six[bufin[1]] << 4 | pr2six[bufin[2]] >> 2);
    }
    if (nprbytes > 3) {
	*(bufout++) =
	    (unsigned char) (pr2six[bufin[2]] << 6 | pr2six[bufin[3]]);
    }

    nbytesdecoded -= (4 - nprbytes) & 3;
    return nbytesdecoded;
}

static const char basis_64[] =
    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

int ap_base64encode_len(int len)
{
    return ((len + 2) / 3 * 4) + 1;
}

int ap_base64encode(char *encoded, const char *string, int len)
{
    return ap_base64encode_binary(encoded, (const unsigned char *) string, len);
}

int ap_base64encode_binary(char *encoded,
                                       const unsigned char *string, int len)
{
    int i;
    char *p;

    p = encoded;
    for (i = 0; i < len - 2; i += 3) {
	*p++ = basis_64[(string[i] >> 2) & 0x3F];
	*p++ = basis_64[((string[i] & 0x3) << 4) |
	                ((int) (string[i + 1] & 0xF0) >> 4)];
	*p++ = basis_64[((string[i + 1] & 0xF) << 2) |
	                ((int) (string[i + 2] & 0xC0) >> 6)];
	*p++ = basis_64[string[i + 2] & 0x3F];
    }
    if (i < len) {
	*p++ = basis_64[(string[i] >> 2) & 0x3F];
	if (i == (len - 1)) {
	    *p++ = basis_64[((string[i] & 0x3) << 4)];
	    *p++ = '=';
	}
	else {
	    *p++ = basis_64[((string[i] & 0x3) << 4) |
	                    ((int) (string[i + 1] & 0xF0) >> 4)];
	    *p++ = basis_64[((string[i + 1] & 0xF) << 2)];
	}
	*p++ = '=';
    }

    *p++ = '\0';
    return p - encoded;
}

/* convenience functions for j2 */
char *b64_encode(char *buf, int len) {
    int elen;
    char *out;

    if(len == 0)
        len = strlen(buf);

    elen = ap_base64encode_len(len);
    out = (char *) malloc(sizeof(char) * (elen + 1));

    ap_base64encode(out, buf, len);

    return out;
}

char *b64_decode(char *buf) {
    int elen;
    char *out;

    elen = ap_base64decode_len(buf, -1);
    out = (char *) malloc(sizeof(char) * (elen + 1));

    ap_base64decode(out, buf, -1);

    return out;
}