/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.] */

#include <openssl/asn1.h>

#include <assert.h>

#include <openssl/bio.h>
#include <openssl/mem.h>


/* Must be large enough for biggest tag+length */
#define DEFAULT_ASN1_BUF_SIZE 20

typedef enum 
	{
	ASN1_STATE_START,
	ASN1_STATE_PRE_COPY,
	ASN1_STATE_HEADER,
	ASN1_STATE_HEADER_COPY,
	ASN1_STATE_DATA_COPY,
	ASN1_STATE_POST_COPY,
	ASN1_STATE_DONE
	} asn1_bio_state_t;

typedef struct BIO_ASN1_EX_FUNCS_st
	{
	asn1_ps_func	*ex_func;
	asn1_ps_func	*ex_free_func;
	} BIO_ASN1_EX_FUNCS;

typedef struct BIO_ASN1_BUF_CTX_t
	{
	/* Internal state */
	asn1_bio_state_t state;
	/* Internal buffer */
	unsigned char *buf;
	/* Size of buffer */
	int bufsize;
	/* Current position in buffer */
	int bufpos;
	/* Current buffer length */
	int buflen;
	/* Amount of data to copy */
	int copylen;
	/* Class and tag to use */
	int asn1_class, asn1_tag;
	asn1_ps_func *prefix, *prefix_free, *suffix, *suffix_free;
	/* Extra buffer for prefix and suffix data */
	unsigned char *ex_buf;
	int ex_len;
	int ex_pos;
	void *ex_arg;
	} BIO_ASN1_BUF_CTX;


static int asn1_bio_write(BIO *h, const char *buf,int num);
static int asn1_bio_read(BIO *h, char *buf, int size);
static int asn1_bio_puts(BIO *h, const char *str);
static int asn1_bio_gets(BIO *h, char *str, int size);
static long asn1_bio_ctrl(BIO *h, int cmd, long arg1, void *arg2);
static int asn1_bio_new(BIO *h);
static int asn1_bio_free(BIO *data);
static long asn1_bio_callback_ctrl(BIO *h, int cmd, bio_info_cb fp);

static int asn1_bio_init(BIO_ASN1_BUF_CTX *ctx, int size);
static int asn1_bio_flush_ex(BIO *b, BIO_ASN1_BUF_CTX *ctx,
				asn1_ps_func *cleanup, asn1_bio_state_t next);
static int asn1_bio_setup_ex(BIO *b, BIO_ASN1_BUF_CTX *ctx,
				asn1_ps_func *setup, 
				asn1_bio_state_t ex_state,
				asn1_bio_state_t other_state);

static BIO_METHOD methods_asn1=
	{
	BIO_TYPE_ASN1,
	"asn1",
	asn1_bio_write,
	asn1_bio_read,
	asn1_bio_puts,
	asn1_bio_gets,
	asn1_bio_ctrl,
	asn1_bio_new,
	asn1_bio_free,
	asn1_bio_callback_ctrl,
	};

BIO_METHOD *BIO_f_asn1(void)
	{
	return(&methods_asn1);
	}


static int asn1_bio_new(BIO *b)
	{
	BIO_ASN1_BUF_CTX *ctx;
	ctx = OPENSSL_malloc(sizeof(BIO_ASN1_BUF_CTX));
	if (!ctx)
		return 0;
	if (!asn1_bio_init(ctx, DEFAULT_ASN1_BUF_SIZE))
		{
		OPENSSL_free(ctx);
		return 0;
		}
	b->init = 1;
	b->ptr = (char *)ctx;
	b->flags = 0;
	return 1;
	}

static int asn1_bio_init(BIO_ASN1_BUF_CTX *ctx, int size)
	{
	ctx->buf = OPENSSL_malloc(size);
	if (!ctx->buf)
		return 0;
	ctx->bufsize = size;
	ctx->bufpos = 0;
	ctx->buflen = 0;
	ctx->copylen = 0;
	ctx->asn1_class = V_ASN1_UNIVERSAL;
	ctx->asn1_tag = V_ASN1_OCTET_STRING;
	ctx->ex_buf = 0;
	ctx->ex_pos = 0;
	ctx->ex_len = 0;
	ctx->state = ASN1_STATE_START;
	return 1;
	}

static int asn1_bio_free(BIO *b)
	{
	BIO_ASN1_BUF_CTX *ctx;
	ctx = (BIO_ASN1_BUF_CTX *) b->ptr;
	if (ctx == NULL)
		return 0;
	if (ctx->buf)
		OPENSSL_free(ctx->buf);
	OPENSSL_free(ctx);
	b->init = 0;
	b->ptr = NULL;
	b->flags = 0;
	return 1;
	}

static int asn1_bio_write(BIO *b, const char *in , int inl)
	{
	BIO_ASN1_BUF_CTX *ctx;
	int wrmax, wrlen, ret;
	unsigned char *p;
	if (!in || (inl < 0) || (b->next_bio == NULL))
		return 0;
	ctx = (BIO_ASN1_BUF_CTX *) b->ptr;
	if (ctx == NULL)
		return 0;

	wrlen = 0;
	ret = -1;

	for(;;)
		{
		switch (ctx->state)
			{

			/* Setup prefix data, call it */
			case ASN1_STATE_START:
			if (!asn1_bio_setup_ex(b, ctx, ctx->prefix,
				ASN1_STATE_PRE_COPY, ASN1_STATE_HEADER))
				return 0;
			break;

			/* Copy any pre data first */
			case ASN1_STATE_PRE_COPY:

			ret = asn1_bio_flush_ex(b, ctx, ctx->prefix_free,
							ASN1_STATE_HEADER);

			if (ret <= 0)
				goto done;

			break;

			case ASN1_STATE_HEADER:
			ctx->buflen =
				ASN1_object_size(0, inl, ctx->asn1_tag) - inl;
			assert(ctx->buflen <= ctx->bufsize);
			p = ctx->buf;
			ASN1_put_object(&p, 0, inl,
					ctx->asn1_tag, ctx->asn1_class);
			ctx->copylen = inl;
			ctx->state = ASN1_STATE_HEADER_COPY;

			break;

			case ASN1_STATE_HEADER_COPY:	
			ret = BIO_write(b->next_bio,
					ctx->buf + ctx->bufpos, ctx->buflen);
			if (ret <= 0)
				goto done;

			ctx->buflen -= ret;
			if (ctx->buflen)
				ctx->bufpos += ret;
			else
				{
				ctx->bufpos = 0;
				ctx->state = ASN1_STATE_DATA_COPY;
				}

			break;

			case ASN1_STATE_DATA_COPY:

			if (inl > ctx->copylen)
				wrmax = ctx->copylen;
			else
				wrmax = inl;
			ret = BIO_write(b->next_bio, in, wrmax);
			if (ret <= 0)
				break;
			wrlen += ret;
			ctx->copylen -= ret;
			in += ret;
			inl -= ret;

			if (ctx->copylen == 0)
				ctx->state = ASN1_STATE_HEADER;

			if (inl == 0)
				goto done;

			break;

			default:
			BIO_clear_retry_flags(b);
			return 0;

			}

		}

	done:
	BIO_clear_retry_flags(b);
	BIO_copy_next_retry(b);

	return (wrlen > 0) ? wrlen : ret;

	}

static int asn1_bio_flush_ex(BIO *b, BIO_ASN1_BUF_CTX *ctx,
				asn1_ps_func *cleanup, asn1_bio_state_t next)
	{
	int ret;
	if (ctx->ex_len <= 0)
		return 1;
	for(;;)
		{
		ret = BIO_write(b->next_bio, ctx->ex_buf + ctx->ex_pos,
								ctx->ex_len);
		if (ret <= 0)
			break;
		ctx->ex_len -= ret;
		if (ctx->ex_len > 0)
			ctx->ex_pos += ret;
		else
			{
			if(cleanup)
				cleanup(b, &ctx->ex_buf, &ctx->ex_len,
								&ctx->ex_arg);
			ctx->state = next;
			ctx->ex_pos = 0;
			break;
			}
		}
	return ret;
	}

static int asn1_bio_setup_ex(BIO *b, BIO_ASN1_BUF_CTX *ctx,
				asn1_ps_func *setup, 
				asn1_bio_state_t ex_state,
				asn1_bio_state_t other_state)
	{
	if (setup && !setup(b, &ctx->ex_buf, &ctx->ex_len, &ctx->ex_arg))
		{
		BIO_clear_retry_flags(b);
		return 0;
		}
	if (ctx->ex_len > 0)
		ctx->state = ex_state;
	else
		ctx->state = other_state;
	return 1;
	}

static int asn1_bio_read(BIO *b, char *in , int inl)
	{
	if (!b->next_bio)
		return 0;
	return BIO_read(b->next_bio, in , inl);
	}

static int asn1_bio_puts(BIO *b, const char *str)
	{
	return asn1_bio_write(b, str, strlen(str));
	}

static int asn1_bio_gets(BIO *b, char *str, int size)
	{
	if (!b->next_bio)
		return 0;
	return BIO_gets(b->next_bio, str , size);
	}

static long asn1_bio_callback_ctrl(BIO *b, int cmd, bio_info_cb fp)
	{
	if (b->next_bio == NULL) return(0);
	return BIO_callback_ctrl(b->next_bio,cmd,fp);
	}

static long asn1_bio_ctrl(BIO *b, int cmd, long arg1, void *arg2)
	{
	BIO_ASN1_BUF_CTX *ctx;
	BIO_ASN1_EX_FUNCS *ex_func;
	long ret = 1;
	ctx = (BIO_ASN1_BUF_CTX *) b->ptr;
	if (ctx == NULL)
		return 0;
	switch(cmd)
		{

		case BIO_C_SET_PREFIX:
		ex_func = arg2;
		ctx->prefix  = ex_func->ex_func;
		ctx->prefix_free  = ex_func->ex_free_func;
		break;

		case BIO_C_GET_PREFIX:
		ex_func = arg2;
		ex_func->ex_func = ctx->prefix;
		ex_func->ex_free_func = ctx->prefix_free;
		break;

		case BIO_C_SET_SUFFIX:
		ex_func = arg2;
		ctx->suffix  = ex_func->ex_func;
		ctx->suffix_free  = ex_func->ex_free_func;
		break;

		case BIO_C_GET_SUFFIX:
		ex_func = arg2;
		ex_func->ex_func = ctx->suffix;
		ex_func->ex_free_func = ctx->suffix_free;
		break;

		case BIO_C_SET_EX_ARG:
		ctx->ex_arg = arg2;
		break;

		case BIO_C_GET_EX_ARG:
		*(void **)arg2 = ctx->ex_arg;
		break;

		case BIO_CTRL_FLUSH:
		if (!b->next_bio)
			return 0;

		/* Call post function if possible */
		if (ctx->state == ASN1_STATE_HEADER)
			{
			if (!asn1_bio_setup_ex(b, ctx, ctx->suffix,
				ASN1_STATE_POST_COPY, ASN1_STATE_DONE))
				return 0;
			}

		if (ctx->state == ASN1_STATE_POST_COPY)
			{
			ret = asn1_bio_flush_ex(b, ctx, ctx->suffix_free,
							ASN1_STATE_DONE);
			if (ret <= 0)
				return ret;
			}

		if (ctx->state == ASN1_STATE_DONE)
			return BIO_ctrl(b->next_bio, cmd, arg1, arg2);
		else
			{
			BIO_clear_retry_flags(b);
			return 0;
			}
		break;


		default:
		if (!b->next_bio)
			return 0;
		return BIO_ctrl(b->next_bio, cmd, arg1, arg2);

		}

	return ret;
	}

static int asn1_bio_set_ex(BIO *b, int cmd,
		asn1_ps_func *ex_func, asn1_ps_func *ex_free_func)
	{
	BIO_ASN1_EX_FUNCS extmp;
	extmp.ex_func = ex_func;
	extmp.ex_free_func = ex_free_func;
	return BIO_ctrl(b, cmd, 0, &extmp);
	}

static int asn1_bio_get_ex(BIO *b, int cmd,
		asn1_ps_func **ex_func, asn1_ps_func **ex_free_func)
	{
	BIO_ASN1_EX_FUNCS extmp;
	int ret;
	ret = BIO_ctrl(b, cmd, 0, &extmp);
	if (ret > 0)
		{
		*ex_func = extmp.ex_func;
		*ex_free_func = extmp.ex_free_func;
		}
	return ret;
	}

int BIO_asn1_set_prefix(BIO *b, asn1_ps_func *prefix, asn1_ps_func *prefix_free)
	{
	return asn1_bio_set_ex(b, BIO_C_SET_PREFIX, prefix, prefix_free);
	}

int BIO_asn1_get_prefix(BIO *b, asn1_ps_func **pprefix, asn1_ps_func **pprefix_free)
	{
	return asn1_bio_get_ex(b, BIO_C_GET_PREFIX, pprefix, pprefix_free);
	}

int BIO_asn1_set_suffix(BIO *b, asn1_ps_func *suffix, asn1_ps_func *suffix_free)
	{
	return asn1_bio_set_ex(b, BIO_C_SET_SUFFIX, suffix, suffix_free);
	}

int BIO_asn1_get_suffix(BIO *b, asn1_ps_func **psuffix, asn1_ps_func **psuffix_free)
	{
	return asn1_bio_get_ex(b, BIO_C_GET_SUFFIX, psuffix, psuffix_free);
	}