/* 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

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/*

 * Base64 encoding (binary to ascii).

 */

#include "nssb64.h"

#include "nspr.h"

#include "secitem.h"

#include "secerr.h"

/*

 * XXX See the big comment at the top of nssb64d.c about moving the

 * bulk of this code over into NSPR (the PL part).  It all applies

 * here but I didn't want to duplicate it, to avoid divergence problems.

 */

/*

 **************************************************************

 * XXX Beginning of base64 encoding code to be moved into NSPR.

 */

struct PLBase64EncodeStateStr {

    unsigned chunks;

    unsigned saved;

    unsigned char buf[3];

};

/*

 * This typedef would belong in the NSPR header file (i.e. plbase64.h).

 */

typedef struct PLBase64EncoderStr PLBase64Encoder;

/*

 * The following implementation of base64 encoding was based on code

 * found in libmime (specifically, in mimeenc.c).  It has been adapted to

 * use PR types and naming as well as to provide other necessary semantics

 * (like buffer-in/buffer-out in addition to "streaming" without undue

 * performance hit of extra copying if you made the buffer versions

 * use the output_fn).  It also incorporates some aspects of the current

 * NSPR base64 encoding code.  As such, you may find similarities to

 * both of those implementations.  I tried to use names that reflected

 * the original code when possible.  For this reason you may find some

 * inconsistencies -- libmime used lots of "in" and "out" whereas the

 * NSPR version uses "src" and "dest"; sometimes I changed one to the other

 * and sometimes I left them when I thought the subroutines were at least

 * self-consistent.

 */

PR_BEGIN_EXTERN_C

/*

 * Opaque object used by the encoder to store state.

 */

struct PLBase64EncoderStr {

    /*

     * The one or two bytes pending.  (We need 3 to create a "token",

     * and hold the leftovers here.  in_buffer_count is *only* ever

     * 0, 1, or 2.

     */

    unsigned char in_buffer[2];

    int in_buffer_count;

    /*

     * If the caller wants linebreaks added, line_length specifies

     * where they come out.  It must be a multiple of 4; if the caller

     * provides one that isn't, we round it down to the nearest

     * multiple of 4.

     *

     * The value of current_column counts how many characters have been

     * added since the last linebreaks (or since the beginning, on the

     * first line).  It is also always a multiple of 4; it is unused when

     * line_length is 0.

     */

    PRUint32 line_length;

    PRUint32 current_column;

    /*

     * Where to write the encoded data (used when streaming, not when

     * doing all in-memory (buffer) operations).

     *

     * Note that this definition is chosen to be compatible with PR_Write.

     */

    PRInt32 (*output_fn)(void *output_arg, const char *buf, PRInt32 size);

    void *output_arg;

    /*

     * Where the encoded output goes -- either temporarily (in the streaming

     * case, staged here before it goes to the output function) or what will

     * be the entire buffered result for users of the buffer version.

     */

    char *output_buffer;

    PRUint32 output_buflen; /* the total length of allocated buffer */

    PRUint32 output_length; /* the length that is currently populated */

};

PR_END_EXTERN_C

/*

 * Table to convert a binary value to its corresponding ascii "code".

 */

static unsigned char base64_valuetocode[64] =

    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

#define B64_PAD '='

#define B64_CR '\r'

#define B64_LF '\n'

static PRStatus

pl_base64_encode_buffer(PLBase64Encoder *data, const unsigned char *in,

                        PRUint32 size)

{

    const unsigned char *end = in + size;

    char *out = data->output_buffer + data->output_length;

    unsigned int i = data->in_buffer_count;

    PRUint32 n = 0;

    int off;

    PRUint32 output_threshold;

    /* If this input buffer is too small, wait until next time. */

    if (size < (3 - i)) {

        data->in_buffer[i++] = in[0];

        if (size > 1)

            data->in_buffer[i++] = in[1];

        PR_ASSERT(i < 3);

        data->in_buffer_count = i;

        return PR_SUCCESS;

    }

    /* If there are bytes that were put back last time, take them now. */

    if (i > 0) {

        n = data->in_buffer[0];

        if (i > 1)

            n = (n << 8) | data->in_buffer[1];

        data->in_buffer_count = 0;

    }

    /* If our total is not a multiple of three, put one or two bytes back. */

    off = (size + i) % 3;

    if (off > 0) {

        size -= off;

        data->in_buffer[0] = in[size];

        if (off > 1)

            data->in_buffer[1] = in[size + 1];

        data->in_buffer_count = off;

        end -= off;

    }

    output_threshold = data->output_buflen - 3;

    /*

     * Populate the output buffer with base64 data, one line (or buffer)

     * at a time.

     */

    while (in < end) {

        int j, k;

        while (i < 3) {

            n = (n << 8) | *in++;

            i++;

        }

        i = 0;

        if (data->line_length > 0) {

            if (data->current_column >= data->line_length) {

                data->current_column = 0;

                *out++ = B64_CR;

                *out++ = B64_LF;

                data->output_length += 2;

            }

            data->current_column += 4; /* the bytes we are about to add */

        }

        for (j = 18; j >= 0; j -= 6) {

            k = (n >> j) & 0x3F;

            *out++ = base64_valuetocode[k];

        }

        n = 0;

        data->output_length += 4;

        if (data->output_length >= output_threshold) {

            PR_ASSERT(data->output_length <= data->output_buflen);

            if (data->output_fn != NULL) {

                PRInt32 output_result;

                output_result = data->output_fn(data->output_arg,

                                                data->output_buffer,

                                                (PRInt32)data->output_length);

                if (output_result < 0)

                    return PR_FAILURE;

                out = data->output_buffer;

                data->output_length = 0;

            } else {

                /*

                 * Check that we are about to exit the loop.  (Since we

                 * are over the threshold, there isn't enough room in the

                 * output buffer for another trip around.)

                 */

                PR_ASSERT(in == end);

                if (in < end) {

                    PR_SetError(PR_BUFFER_OVERFLOW_ERROR, 0);

                    return PR_FAILURE;

                }

            }

        }

    }

    return PR_SUCCESS;

}

static PRStatus

pl_base64_encode_flush(PLBase64Encoder *data)

{

    int i = data->in_buffer_count;

    if (i == 0 && data->output_length == 0)

        return PR_SUCCESS;

    if (i > 0) {

        char *out = data->output_buffer + data->output_length;

        PRUint32 n;

        int j, k;

        n = ((PRUint32)data->in_buffer[0]) << 16;

        if (i > 1)

            n |= ((PRUint32)data->in_buffer[1] << 8);

        data->in_buffer_count = 0;

        if (data->line_length > 0) {

            if (data->current_column >= data->line_length) {

                data->current_column = 0;

                *out++ = B64_CR;

                *out++ = B64_LF;

                data->output_length += 2;

            }

        }

        /*

         * This will fill in more than we really have data for, but the

         * valid parts will end up in the correct position and the extras

         * will be over-written with pad characters below.

         */

        for (j = 18; j >= 0; j -= 6) {

            k = (n >> j) & 0x3F;

            *out++ = base64_valuetocode[k];

        }

        /* Pad with equal-signs. */

        if (i == 1)

            out[-2] = B64_PAD;

        out[-1] = B64_PAD;

        data->output_length += 4;

    }

    if (data->output_fn != NULL) {

        PRInt32 output_result;

        output_result = data->output_fn(data->output_arg, data->output_buffer,

                                        (PRInt32)data->output_length);

        data->output_length = 0;

        if (output_result < 0)

            return PR_FAILURE;

    }

    return PR_SUCCESS;

}

/*

 * The maximum space needed to hold the output of the encoder given input

 * data of length "size", and allowing for CRLF added at least every

 * line_length bytes (we will add it at nearest lower multiple of 4).

 * There is no trailing CRLF.

 */

static PRUint32

PL_Base64MaxEncodedLength(PRUint32 size, PRUint32 line_length)

{

    PRUint32 tokens, tokens_per_line, full_lines, line_break_chars, remainder;

    /* This is the maximum length we support. */

    if (size > 0x3fffffff) {

        return 0;

    }

    tokens = (size + 2) / 3;

    if (line_length == 0) {

        return tokens * 4;

    }

    if (line_length < 4) { /* too small! */

        line_length = 4;

    }

    tokens_per_line = line_length / 4;

    full_lines = tokens / tokens_per_line;

    remainder = (tokens - (full_lines * tokens_per_line)) * 4;

    line_break_chars = full_lines * 2;

    if (remainder == 0) {

        line_break_chars -= 2;

    }

    return (full_lines * tokens_per_line * 4) + line_break_chars + remainder;

}

/*

 * A distinct internal creation function for the buffer version to use.

 * (It does not want to specify an output_fn, and we want the normal

 * Create function to require that.)  All common initialization of the

 * encoding context should be done *here*.

 *

 * Save "line_length", rounded down to nearest multiple of 4 (if not

 * already even multiple).  Allocate output_buffer, if not provided --

 * based on given size if specified, otherwise based on line_length.

 */

static PLBase64Encoder *

pl_base64_create_encoder(PRUint32 line_length, char *output_buffer,

                         PRUint32 output_buflen)

{

    PLBase64Encoder *data;

    PRUint32 line_tokens;

    data = PR_NEWZAP(PLBase64Encoder);

    if (data == NULL)

        return NULL;

    if (line_length > 0 && line_length < 4) /* too small! */

        line_length = 4;

    line_tokens = line_length / 4;

    data->line_length = line_tokens * 4;

    if (output_buffer == NULL) {

        if (output_buflen == 0) {

            if (data->line_length > 0) /* need to include room for CRLF */

                output_buflen = data->line_length + 2;

            else

                output_buflen = 64; /* XXX what is a good size? */

        }

        output_buffer = (char *)PR_Malloc(output_buflen);

        if (output_buffer == NULL) {

            PR_Free(data);

            return NULL;

        }

    }

    data->output_buffer = output_buffer;

    data->output_buflen = output_buflen;

    return data;

}

/*

 * Function to start a base64 encoding context.

 * An "output_fn" is required; the "output_arg" parameter to that is optional.

 * If linebreaks in the encoded output are desired, "line_length" specifies

 * where to place them -- it will be rounded down to the nearest multiple of 4

 * (if it is not already an even multiple of 4).  If it is zero, no linebreaks

 * will be added.  (FYI, a linebreak is CRLF -- two characters.)

 */

static PLBase64Encoder *

PL_CreateBase64Encoder(PRInt32 (*output_fn)(void *, const char *, PRInt32),

                       void *output_arg, PRUint32 line_length)

{

    PLBase64Encoder *data;

    if (output_fn == NULL) {

        PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);

        return NULL;

    }

    data = pl_base64_create_encoder(line_length, NULL, 0);

    if (data == NULL)

        return NULL;

    data->output_fn = output_fn;

    data->output_arg = output_arg;

    return data;

}

/*

 * Push data through the encoder, causing the output_fn (provided to Create)

 * to be called with the encoded data.

 */

static PRStatus

PL_UpdateBase64Encoder(PLBase64Encoder *data, const unsigned char *buffer,

                       PRUint32 size)

{

    /* XXX Should we do argument checking only in debug build? */

    if (data == NULL || buffer == NULL || size == 0) {

        PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);

        return PR_FAILURE;

    }

    return pl_base64_encode_buffer(data, buffer, size);

}

/*

 * When you're done encoding, call this to free the data.  If "abort_p"

 * is false, then calling this may cause the output_fn to be called

 * one last time (as the last buffered data is flushed out).

 */

static PRStatus

PL_DestroyBase64Encoder(PLBase64Encoder *data, PRBool abort_p)

{

    PRStatus status = PR_SUCCESS;

    /* XXX Should we do argument checking only in debug build? */

    if (data == NULL) {

        PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);

        return PR_FAILURE;

    }

    /* Flush out the last few buffered characters. */

    if (!abort_p)

        status = pl_base64_encode_flush(data);

    if (data->output_buffer != NULL)

        PR_Free(data->output_buffer);

    PR_Free(data);

    return status;

}

/*

 * Perform base64 encoding from an input buffer to an output buffer.

 * The output buffer can be provided (as "dest"); you can also pass in

 * a NULL and this function will allocate a buffer large enough for you,

 * and return it.  If you do provide the output buffer, you must also

 * provide the maximum length of that buffer (as "maxdestlen").

 * The actual encoded length of output will be returned to you in

 * "output_destlen".

 *

 * If linebreaks in the encoded output are desired, "line_length" specifies

 * where to place them -- it will be rounded down to the nearest multiple of 4

 * (if it is not already an even multiple of 4).  If it is zero, no linebreaks

 * will be added.  (FYI, a linebreak is CRLF -- two characters.)

 *

 * Return value is NULL on error, the output buffer (allocated or provided)

 * otherwise.

 */

static char *

PL_Base64EncodeBuffer(const unsigned char *src, PRUint32 srclen,

                      PRUint32 line_length, char *dest, PRUint32 maxdestlen,

                      PRUint32 *output_destlen)

{

    PRUint32 need_length;

    PLBase64Encoder *data = NULL;

    PRStatus status;

    PR_ASSERT(srclen > 0);

    if (srclen == 0) {

        return dest;

    }

    /*

     * How much space could we possibly need for encoding this input?

     */

    need_length = PL_Base64MaxEncodedLength(srclen, line_length);

    if (need_length == 0) {

        PORT_SetError(SEC_ERROR_INVALID_ARGS);

        return NULL;

    }

    /*

     * Make sure we have at least that much, if output buffer provided.

     */

    if (dest != NULL) {

        PR_ASSERT(maxdestlen >= need_length);

        if (maxdestlen < need_length) {

            PR_SetError(PR_BUFFER_OVERFLOW_ERROR, 0);

            return NULL;

        }

    } else {

        maxdestlen = need_length;

    }

    data = pl_base64_create_encoder(line_length, dest, maxdestlen);

    if (data == NULL)

        return NULL;

    status = pl_base64_encode_buffer(data, src, srclen);

    /*

     * We do not wait for Destroy to flush, because Destroy will also

     * get rid of our encoder context, which we need to look at first!

     */

    if (status == PR_SUCCESS)

        status = pl_base64_encode_flush(data);

    if (status != PR_SUCCESS) {

        (void)PL_DestroyBase64Encoder(data, PR_TRUE);

        return NULL;

    }

    dest = data->output_buffer;

    /* Must clear this or Destroy will free it. */

    data->output_buffer = NULL;

    *output_destlen = data->output_length;

    status = PL_DestroyBase64Encoder(data, PR_FALSE);

    if (status == PR_FAILURE) {

        PR_Free(dest);

        return NULL;

    }

    return dest;

}

/*

 * XXX End of base64 encoding code to be moved into NSPR.

 ********************************************************

 */

/*

 * This is the beginning of the NSS cover functions.  These will

 * provide the interface we want to expose as NSS-ish.  For example,

 * they will operate on our Items, do any special handling or checking

 * we want to do, etc.

 */

PR_BEGIN_EXTERN_C

/*

 * A boring cover structure for now.  Perhaps someday it will include

 * some more interesting fields.

 */

struct NSSBase64EncoderStr {

    PLBase64Encoder *pl_data;

};

PR_END_EXTERN_C

/*

 * Function to start a base64 encoding context.

 */

NSSBase64Encoder *

NSSBase64Encoder_Create(PRInt32 (*output_fn)(void *, const char *, PRInt32),

                        void *output_arg)

{

    PLBase64Encoder *pl_data;

    NSSBase64Encoder *nss_data;

    nss_data = PORT_ZNew(NSSBase64Encoder);

    if (nss_data == NULL)

        return NULL;

    pl_data = PL_CreateBase64Encoder(output_fn, output_arg, 64);

    if (pl_data == NULL) {

        PORT_Free(nss_data);

        return NULL;

    }

    nss_data->pl_data = pl_data;

    return nss_data;

}

/*

 * Push data through the encoder, causing the output_fn (provided to Create)

 * to be called with the encoded data.

 */

SECStatus

NSSBase64Encoder_Update(NSSBase64Encoder *data, const unsigned char *buffer,

                        PRUint32 size)

{

    PRStatus pr_status;

    /* XXX Should we do argument checking only in debug build? */

    if (data == NULL) {

        PORT_SetError(SEC_ERROR_INVALID_ARGS);

        return SECFailure;

    }

    pr_status = PL_UpdateBase64Encoder(data->pl_data, buffer, size);

    if (pr_status == PR_FAILURE)

        return SECFailure;

    return SECSuccess;

}

/*

 * When you're done encoding, call this to free the data.  If "abort_p"

 * is false, then calling this may cause the output_fn to be called

 * one last time (as the last buffered data is flushed out).

 */

SECStatus

NSSBase64Encoder_Destroy(NSSBase64Encoder *data, PRBool abort_p)

{

    PRStatus pr_status;

    /* XXX Should we do argument checking only in debug build? */

    if (data == NULL) {

        PORT_SetError(SEC_ERROR_INVALID_ARGS);

        return SECFailure;

    }

    pr_status = PL_DestroyBase64Encoder(data->pl_data, abort_p);

    PORT_Free(data);

    if (pr_status == PR_FAILURE)

        return SECFailure;

    return SECSuccess;

}

/*

 * Perform base64 encoding of binary data "inItem" to an ascii string.

 * The output buffer may be provided (as "outStrOpt"); you can also pass

 * in a NULL and the buffer will be allocated for you.  The result will

 * be null-terminated, and if the buffer is provided, "maxOutLen" must

 * specify the maximum length of the buffer and will be checked to

 * supply sufficient space space for the encoded result.  (If "outStrOpt"

 * is NULL, "maxOutLen" is ignored.)

 *

 * If "outStrOpt" is NULL, allocation will happen out of the passed-in

 * "arenaOpt", if *it* is non-NULL, otherwise standard allocation (heap)

 * will be used.

 *

 * Return value is NULL on error, the output buffer (allocated or provided)

 * otherwise.

 */

char *

NSSBase64_EncodeItem(PLArenaPool *arenaOpt, char *outStrOpt,

                     unsigned int maxOutLen, SECItem *inItem)

{

    char *out_string = outStrOpt;

    PRUint32 max_out_len;

    PRUint32 out_len = 0;

    void *mark = NULL;

    char *dummy;

    PORT_Assert(inItem != NULL && inItem->data != NULL && inItem->len != 0);

    if (inItem == NULL || inItem->data == NULL || inItem->len == 0) {

        PORT_SetError(SEC_ERROR_INVALID_ARGS);

        return NULL;

    }

    max_out_len = PL_Base64MaxEncodedLength(inItem->len, 64);

    if (max_out_len == 0) {

        PORT_SetError(SEC_ERROR_INVALID_ARGS);

        return NULL;

    }

    if (arenaOpt != NULL)

        mark = PORT_ArenaMark(arenaOpt);

    if (out_string == NULL) {

        if (arenaOpt != NULL)

            out_string = PORT_ArenaAlloc(arenaOpt, max_out_len + 1);

        else

            out_string = PORT_Alloc(max_out_len + 1);

        if (out_string == NULL) {

            if (arenaOpt != NULL)

                PORT_ArenaRelease(arenaOpt, mark);

            return NULL;

        }

    } else {

        if ((max_out_len + 1) > maxOutLen) {

            PORT_SetError(SEC_ERROR_OUTPUT_LEN);

            return NULL;

        }

        max_out_len = maxOutLen;

    }

    dummy = PL_Base64EncodeBuffer(inItem->data, inItem->len, 64,

                                  out_string, max_out_len, &out_len);

    if (dummy == NULL) {

        if (arenaOpt != NULL) {

            PORT_ArenaRelease(arenaOpt, mark);

        } else {

            PORT_Free(out_string);

        }

        return NULL;

    }

    if (arenaOpt != NULL)

        PORT_ArenaUnmark(arenaOpt, mark);

    out_string[out_len] = '\0';

    return out_string;

}

/*

 * XXX Everything below is deprecated.  If you add new stuff, put it

 * *above*, not below.

 */

/*

 * XXX The following "BTOA" functions are provided for backward compatibility

 * with current code.  They should be considered strongly deprecated.

 * When we can convert all our code over to using the new NSSBase64Encoder_

 * functions defined above, we should get rid of these altogether.  (Remove

 * protoypes from base64.h as well -- actually, remove that file completely).

 * If someone thinks either of these functions provides such a very useful

 * interface (though, as shown, the same functionality can already be

 * obtained by calling NSSBase64_EncodeItem directly), fine -- but then

 * that API should be provided with a nice new NSSFoo name and using

 * appropriate types, etc.

 */

#include "base64.h"

/*

** Return an PORT_Alloc'd ascii string which is the base64 encoded

** version of the input string.

*/

char *

BTOA_DataToAscii(const unsigned char *data, unsigned int len)

{

    SECItem binary_item;

    binary_item.data = (unsigned char *)data;

    binary_item.len = len;

    return NSSBase64_EncodeItem(NULL, NULL, 0, &binary_item);

}

/*

** Convert from binary encoding of an item to ascii.

*/

char *

BTOA_ConvertItemToAscii(SECItem *binary_item)

{

    return NSSBase64_EncodeItem(NULL, NULL, 0, binary_item);

}