text: /* 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 <stdio.h>
  #include <errno.h>
  #include "internal/cryptlib.h"
  #include <openssl/buffer.h>
  #include <openssl/evp.h>
  #include "internal/bio.h"
  
  static int b64_write(BIO *h, const char *buf, int num);
  static int b64_read(BIO *h, char *buf, int size);
  static int b64_puts(BIO *h, const char *str);
  /*
   * static int b64_gets(BIO *h, char *str, int size);
   */
  static long b64_ctrl(BIO *h, int cmd, long arg1, void *arg2);
  static int b64_new(BIO *h);
  static int b64_free(BIO *data);
  static long b64_callback_ctrl(BIO *h, int cmd, bio_info_cb *fp);
  #define B64_BLOCK_SIZE  1024
  #define B64_BLOCK_SIZE2 768
  #define B64_NONE        0
  #define B64_ENCODE      1
  #define B64_DECODE      2
  
  typedef struct b64_struct {
      /*
       * BIO *bio; moved to the BIO structure
       */
      int buf_len;
      int buf_off;
      int tmp_len;                /* used to find the start when decoding */
      int tmp_nl;                 /* If true, scan until '\n' */
      int encode;
      int start;                  /* have we started decoding yet? */
      int cont;                   /* <= 0 when finished */
      EVP_ENCODE_CTX *base64;
      char buf[EVP_ENCODE_LENGTH(B64_BLOCK_SIZE) + 10];
      char tmp[B64_BLOCK_SIZE];
  } BIO_B64_CTX;
  
  static const BIO_METHOD methods_b64 = {
      BIO_TYPE_BASE64, "base64 encoding",
      b64_write,
      b64_read,
      b64_puts,
      NULL,                       /* b64_gets, */
      b64_ctrl,
      b64_new,
      b64_free,
      b64_callback_ctrl,
  };
  
  
  const BIO_METHOD *BIO_f_base64(void)
  {
      return &methods_b64;
  }
  
  static int b64_new(BIO *bi)
  {
      BIO_B64_CTX *ctx;
  
      ctx = OPENSSL_zalloc(sizeof(*ctx));
      if (ctx == NULL)
          return (0);
  
      ctx->cont = 1;
      ctx->start = 1;
      ctx->base64 = EVP_ENCODE_CTX_new();
      BIO_set_data(bi, ctx);
      BIO_set_init(bi, 1);
  
      return 1;
  }
  
  static int b64_free(BIO *a)
  {
      BIO_B64_CTX *ctx;
      if (a == NULL)
          return 0;
  
      ctx = BIO_get_data(a);
      if (ctx == NULL)
          return 0;
  
      EVP_ENCODE_CTX_free(ctx->base64);
      OPENSSL_free(ctx);
      BIO_set_data(a, NULL);
      BIO_set_init(a, 0);
  
      return 1;
  }
  
  static int b64_read(BIO *b, char *out, int outl)
  {
      int ret = 0, i, ii, j, k, x, n, num, ret_code = 0;
      BIO_B64_CTX *ctx;
      unsigned char *p, *q;
      BIO *next;
  
      if (out == NULL)
          return (0);
      ctx = (BIO_B64_CTX *)BIO_get_data(b);
  
      next = BIO_next(b);
      if ((ctx == NULL) || (next == NULL))
          return 0;
  
      BIO_clear_retry_flags(b);
  
      if (ctx->encode != B64_DECODE) {
          ctx->encode = B64_DECODE;
          ctx->buf_len = 0;
          ctx->buf_off = 0;
          ctx->tmp_len = 0;
          EVP_DecodeInit(ctx->base64);
      }
  
      /* First check if there are bytes decoded/encoded */
      if (ctx->buf_len > 0) {
          OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
          i = ctx->buf_len - ctx->buf_off;
          if (i > outl)
              i = outl;
          OPENSSL_assert(ctx->buf_off + i < (int)sizeof(ctx->buf));
          memcpy(out, &(ctx->buf[ctx->buf_off]), i);
          ret = i;
          out += i;
          outl -= i;
          ctx->buf_off += i;
          if (ctx->buf_len == ctx->buf_off) {
              ctx->buf_len = 0;
              ctx->buf_off = 0;
          }
      }
  
      /*
       * At this point, we have room of outl bytes and an empty buffer, so we
       * should read in some more.
       */
  
      ret_code = 0;
      while (outl > 0) {
          if (ctx->cont <= 0)
              break;
  
          i = BIO_read(next, &(ctx->tmp[ctx->tmp_len]),
                       B64_BLOCK_SIZE - ctx->tmp_len);
  
          if (i <= 0) {
              ret_code = i;
  
              /* Should we continue next time we are called? */
              if (!BIO_should_retry(next)) {
                  ctx->cont = i;
                  /* If buffer empty break */
                  if (ctx->tmp_len == 0)
                      break;
                  /* Fall through and process what we have */
                  else
                      i = 0;
              }
              /* else we retry and add more data to buffer */
              else
                  break;
          }
          i += ctx->tmp_len;
          ctx->tmp_len = i;
  
          /*
           * We need to scan, a line at a time until we have a valid line if we
           * are starting.
           */
          if (ctx->start && (BIO_get_flags(b) & BIO_FLAGS_BASE64_NO_NL)) {
              /* ctx->start=1; */
              ctx->tmp_len = 0;
          } else if (ctx->start) {
              q = p = (unsigned char *)ctx->tmp;
              num = 0;
              for (j = 0; j < i; j++) {
                  if (*(q++) != '\n')
                      continue;
  
                  /*
                   * due to a previous very long line, we need to keep on
                   * scanning for a '\n' before we even start looking for
                   * base64 encoded stuff.
                   */
                  if (ctx->tmp_nl) {
                      p = q;
                      ctx->tmp_nl = 0;
                      continue;
                  }
  
                  k = EVP_DecodeUpdate(ctx->base64,
                                       (unsigned char *)ctx->buf,
                                       &num, p, q - p);
                  if ((k <= 0) && (num == 0) && (ctx->start))
                      EVP_DecodeInit(ctx->base64);
                  else {
                      if (p != (unsigned char *)
                          &(ctx->tmp[0])) {
                          i -= (p - (unsigned char *)
                                &(ctx->tmp[0]));
                          for (x = 0; x < i; x++)
                              ctx->tmp[x] = p[x];
                      }
                      EVP_DecodeInit(ctx->base64);
                      ctx->start = 0;
                      break;
                  }
                  p = q;
              }
  
              /* we fell off the end without starting */
              if ((j == i) && (num == 0)) {
                  /*
                   * Is this is one long chunk?, if so, keep on reading until a
                   * new line.
                   */
                  if (p == (unsigned char *)&(ctx->tmp[0])) {
                      /* Check buffer full */
                      if (i == B64_BLOCK_SIZE) {
                          ctx->tmp_nl = 1;
                          ctx->tmp_len = 0;
                      }
                  } else if (p != q) { /* finished on a '\n' */
                      n = q - p;
                      for (ii = 0; ii < n; ii++)
                          ctx->tmp[ii] = p[ii];
                      ctx->tmp_len = n;
                  }
                  /* else finished on a '\n' */
                  continue;
              } else {
                  ctx->tmp_len = 0;
              }
          } else if ((i < B64_BLOCK_SIZE) && (ctx->cont > 0)) {
              /*
               * If buffer isn't full and we can retry then restart to read in
               * more data.
               */
              continue;
          }
  
          if (BIO_get_flags(b) & BIO_FLAGS_BASE64_NO_NL) {
              int z, jj;
  
              jj = i & ~3;        /* process per 4 */
              z = EVP_DecodeBlock((unsigned char *)ctx->buf,
                                  (unsigned char *)ctx->tmp, jj);
              if (jj > 2) {
                  if (ctx->tmp[jj - 1] == '=') {
                      z--;
                      if (ctx->tmp[jj - 2] == '=')
                          z--;
                  }
              }
              /*
               * z is now number of output bytes and jj is the number consumed
               */
              if (jj != i) {
                  memmove(ctx->tmp, &ctx->tmp[jj], i - jj);
                  ctx->tmp_len = i - jj;
              }
              ctx->buf_len = 0;
              if (z > 0) {
                  ctx->buf_len = z;
              }
              i = z;
          } else {
              i = EVP_DecodeUpdate(ctx->base64,
                                   (unsigned char *)ctx->buf, &ctx->buf_len,
                                   (unsigned char *)ctx->tmp, i);
              ctx->tmp_len = 0;
          }
          ctx->buf_off = 0;
          if (i < 0) {
              ret_code = 0;
              ctx->buf_len = 0;
              break;
          }
  
          if (ctx->buf_len <= outl)
              i = ctx->buf_len;
          else
              i = outl;
  
          memcpy(out, ctx->buf, i);
          ret += i;
          ctx->buf_off = i;
          if (ctx->buf_off == ctx->buf_len) {
              ctx->buf_len = 0;
              ctx->buf_off = 0;
          }
          outl -= i;
          out += i;
      }
      /* BIO_clear_retry_flags(b); */
      BIO_copy_next_retry(b);
      return ((ret == 0) ? ret_code : ret);
  }
  
  static int b64_write(BIO *b, const char *in, int inl)
  {
      int ret = 0;
      int n;
      int i;
      BIO_B64_CTX *ctx;
      BIO *next;
  
      ctx = (BIO_B64_CTX *)BIO_get_data(b);
      next = BIO_next(b);
      if ((ctx == NULL) || (next == NULL))
          return 0;
  
      BIO_clear_retry_flags(b);
  
      if (ctx->encode != B64_ENCODE) {
          ctx->encode = B64_ENCODE;
          ctx->buf_len = 0;
          ctx->buf_off = 0;
          ctx->tmp_len = 0;
          EVP_EncodeInit(ctx->base64);
      }
  
      OPENSSL_assert(ctx->buf_off < (int)sizeof(ctx->buf));
      OPENSSL_assert(ctx->buf_len <= (int)sizeof(ctx->buf));
      OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
      n = ctx->buf_len - ctx->buf_off;
      while (n > 0) {
          i = BIO_write(next, &(ctx->buf[ctx->buf_off]), n);
          if (i <= 0) {
              BIO_copy_next_retry(b);
              return (i);
          }
          OPENSSL_assert(i <= n);
          ctx->buf_off += i;
          OPENSSL_assert(ctx->buf_off <= (int)sizeof(ctx->buf));
          OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
          n -= i;
      }
      /* at this point all pending data has been written */
      ctx->buf_off = 0;
      ctx->buf_len = 0;
  
      if ((in == NULL) || (inl <= 0))
          return (0);
  
      while (inl > 0) {
          n = (inl > B64_BLOCK_SIZE) ? B64_BLOCK_SIZE : inl;
  
          if (BIO_get_flags(b) & BIO_FLAGS_BASE64_NO_NL) {
              if (ctx->tmp_len > 0) {
                  OPENSSL_assert(ctx->tmp_len <= 3);
                  n = 3 - ctx->tmp_len;
                  /*
                   * There's a theoretical possibility for this
                   */
                  if (n > inl)
                      n = inl;
                  memcpy(&(ctx->tmp[ctx->tmp_len]), in, n);
                  ctx->tmp_len += n;
                  ret += n;
                  if (ctx->tmp_len < 3)
                      break;
                  ctx->buf_len =
                      EVP_EncodeBlock((unsigned char *)ctx->buf,
                                      (unsigned char *)ctx->tmp, ctx->tmp_len);
                  OPENSSL_assert(ctx->buf_len <= (int)sizeof(ctx->buf));
                  OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
                  /*
                   * Since we're now done using the temporary buffer, the
                   * length should be 0'd
                   */
                  ctx->tmp_len = 0;
              } else {
                  if (n < 3) {
                      memcpy(ctx->tmp, in, n);
                      ctx->tmp_len = n;
                      ret += n;
                      break;
                  }
                  n -= n % 3;
                  ctx->buf_len =
                      EVP_EncodeBlock((unsigned char *)ctx->buf,
                                      (const unsigned char *)in, n);
                  OPENSSL_assert(ctx->buf_len <= (int)sizeof(ctx->buf));
                  OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
                  ret += n;
              }
          } else {
              EVP_EncodeUpdate(ctx->base64,
                               (unsigned char *)ctx->buf, &ctx->buf_len,
                               (unsigned char *)in, n);
              OPENSSL_assert(ctx->buf_len <= (int)sizeof(ctx->buf));
              OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
              ret += n;
          }
          inl -= n;
          in += n;
  
          ctx->buf_off = 0;
          n = ctx->buf_len;
          while (n > 0) {
              i = BIO_write(next, &(ctx->buf[ctx->buf_off]), n);
              if (i <= 0) {
                  BIO_copy_next_retry(b);
                  return ((ret == 0) ? i : ret);
              }
              OPENSSL_assert(i <= n);
              n -= i;
              ctx->buf_off += i;
              OPENSSL_assert(ctx->buf_off <= (int)sizeof(ctx->buf));
              OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
          }
          ctx->buf_len = 0;
          ctx->buf_off = 0;
      }
      return (ret);
  }
  
  static long b64_ctrl(BIO *b, int cmd, long num, void *ptr)
  {
      BIO_B64_CTX *ctx;
      long ret = 1;
      int i;
      BIO *next;
  
      ctx = (BIO_B64_CTX *)BIO_get_data(b);
      next = BIO_next(b);
      if ((ctx == NULL) || (next == NULL))
          return 0;
  
      switch (cmd) {
      case BIO_CTRL_RESET:
          ctx->cont = 1;
          ctx->start = 1;
          ctx->encode = B64_NONE;
          ret = BIO_ctrl(next, cmd, num, ptr);
          break;
      case BIO_CTRL_EOF:         /* More to read */
          if (ctx->cont <= 0)
              ret = 1;
          else
              ret = BIO_ctrl(next, cmd, num, ptr);
          break;
      case BIO_CTRL_WPENDING:    /* More to write in buffer */
          OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
          ret = ctx->buf_len - ctx->buf_off;
          if ((ret == 0) && (ctx->encode != B64_NONE)
              && (EVP_ENCODE_CTX_num(ctx->base64) != 0))
              ret = 1;
          else if (ret <= 0)
              ret = BIO_ctrl(next, cmd, num, ptr);
          break;
      case BIO_CTRL_PENDING:     /* More to read in buffer */
          OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
          ret = ctx->buf_len - ctx->buf_off;
          if (ret <= 0)
              ret = BIO_ctrl(next, cmd, num, ptr);
          break;
      case BIO_CTRL_FLUSH:
          /* do a final write */
   again:
          while (ctx->buf_len != ctx->buf_off) {
              i = b64_write(b, NULL, 0);
              if (i < 0)
                  return i;
          }
          if (BIO_get_flags(b) & BIO_FLAGS_BASE64_NO_NL) {
              if (ctx->tmp_len != 0) {
                  ctx->buf_len = EVP_EncodeBlock((unsigned char *)ctx->buf,
                                                 (unsigned char *)ctx->tmp,
                                                 ctx->tmp_len);
                  ctx->buf_off = 0;
                  ctx->tmp_len = 0;
                  goto again;
              }
          } else if (ctx->encode != B64_NONE
                     && EVP_ENCODE_CTX_num(ctx->base64) != 0) {
              ctx->buf_off = 0;
              EVP_EncodeFinal(ctx->base64,
                              (unsigned char *)ctx->buf, &(ctx->buf_len));
              /* push out the bytes */
              goto again;
          }
          /* Finally flush the underlying BIO */
          ret = BIO_ctrl(next, cmd, num, ptr);
          break;
  
      case BIO_C_DO_STATE_MACHINE:
          BIO_clear_retry_flags(b);
          ret = BIO_ctrl(next, cmd, num, ptr);
          BIO_copy_next_retry(b);
          break;
  
      case BIO_CTRL_DUP:
          break;
      case BIO_CTRL_INFO:
      case BIO_CTRL_GET:
      case BIO_CTRL_SET:
      default:
          ret = BIO_ctrl(next, cmd, num, ptr);
          break;
      }
      return ret;
  }
  
  static long b64_callback_ctrl(BIO *b, int cmd, bio_info_cb *fp)
  {
      long ret = 1;
      BIO *next = BIO_next(b);
  
      if (next == NULL)
          return 0;
      switch (cmd) {
      default:
          ret = BIO_callback_ctrl(next, cmd, fp);
          break;
      }
      return (ret);
  }
  
  static int b64_puts(BIO *b, const char *str)
  {
      return b64_write(b, str, strlen(str));
  }
  