/*
 * Copyright (c) 2000-2002, 2004, 2005 Sendmail, Inc. and its suppliers.
 *      All rights reserved.
 * Copyright (c) 1990, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek.
 *
 * By using this file, you agree to the terms and conditions set
 * forth in the LICENSE file which can be found at the top level of
 * the sendmail distribution.
 */

#include <sm/gen.h>
SM_IDSTR(id, "@(#)$Id: strio.c,v 1.44 2005/06/09 21:40:19 ca Exp $")
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>
#include <sm/rpool.h>
#include <sm/io.h>
#include <sm/heap.h>
#include <sm/conf.h>
#include "local.h"

static int      sm_strsetmode __P((SM_FILE_T*, const int *));
static int      sm_strgetmode __P((SM_FILE_T*, int *));

/*
**  Cookie structure for the "strio" file type
*/

struct sm_str_obj
{
        char            *strio_base;
        char            *strio_end;
        size_t          strio_size;
        size_t          strio_offset;
        int             strio_flags;
        const void      *strio_rpool;
};

typedef struct sm_str_obj SM_STR_OBJ_T;

/*
**  SM_STRGROW -- increase storage space for string
**
**      Parameters:
**              s -- current cookie
**              size -- new storage size request
**
**      Returns:
**              true iff successful.
*/

static bool sm_strgrow __P((SM_STR_OBJ_T *, size_t));

static bool
sm_strgrow(s, size)
        SM_STR_OBJ_T *s;
        size_t size;
{
        register void *p;

        if (s->strio_size >= size)
                return true;
        p = sm_realloc(s->strio_base, size);
        if (p == NULL)
                return false;
        s->strio_base = p;
        s->strio_end = s->strio_base + size;
        s->strio_size = size;
        return true;
}

/*
**  SM_STRREAD -- read a portion of the string
**
**      Parameters:
**              fp -- the file pointer
**              buf -- location to place read data
**              n -- number of bytes to read
**
**      Returns:
**              Failure: -1 and sets errno
**              Success: >=0, number of bytes read
*/

ssize_t
sm_strread(fp, buf, n)
        SM_FILE_T *fp;
        char *buf;
        size_t n;
{
        register SM_STR_OBJ_T *s = fp->f_cookie;
        int len;

        if (!(s->strio_flags & SMRD) && !(s->strio_flags & SMRW))
        {
                errno = EBADF;
                return -1;
        }
        len = SM_MIN(s->strio_size - s->strio_offset, n);
        (void) memmove(buf, s->strio_base + s->strio_offset, len);
        s->strio_offset += len;
        return len;
}

/*
**  SM_STRWRITE -- write a portion of the string
**
**      Parameters:
**              fp -- the file pointer
**              buf -- location of data for writing
**              n -- number of bytes to write
**
**      Returns:
**              Failure: -1 and sets errno
**              Success: >=0, number of bytes written
*/

ssize_t
sm_strwrite(fp, buf, n)
        SM_FILE_T *fp;
        char const *buf;
        size_t n;
{
        register SM_STR_OBJ_T *s = fp->f_cookie;

        if (!(s->strio_flags & SMWR) && !(s->strio_flags & SMRW))
        {
                errno = EBADF;
                return -1;
        }
        if (n + s->strio_offset > s->strio_size)
        {
                if (!sm_strgrow(s, n + s->strio_offset))
                        return 0;
        }
        (void) memmove(s->strio_base + s->strio_offset, buf, n);
        s->strio_offset += n;
        return n;
}

/*
**  SM_STRSEEK -- position the offset pointer for the string
**
**      Only SM_IO_SEEK_SET, SM_IO_SEEK_CUR and SM_IO_SEEK_END are valid
**      values for whence.
**
**      Parameters:
**              fp -- the file pointer
**              offset -- number of bytes offset from "base"
**              whence -- determines "base" for 'offset'
**
**      Returns:
**              Failure: -1 and sets errno
**              Success: >=0, number of bytes read
*/

off_t
sm_strseek(fp, offset, whence)
        SM_FILE_T *fp;
        off_t offset;
        int whence;
{
        register off_t ret;
        register SM_STR_OBJ_T *s = fp->f_cookie;

reseek:
        switch (whence)
        {
          case SM_IO_SEEK_SET:
                ret = offset;
                break;
          case SM_IO_SEEK_CUR:
                ret = s->strio_offset + offset;
                break;
          case SM_IO_SEEK_END:
                ret = s->strio_size;
                break;
          default:
                errno = EINVAL;
                return -1;
        }
        if (ret < 0 || ret > (off_t)(size_t)(-1))       /* XXX ugly */
                return -1;
        if ((size_t) ret > s->strio_size)
        {
                if (sm_strgrow(s, (size_t)ret))
                        goto reseek;

                /* errno set by sm_strgrow */
                return -1;
        }
        s->strio_offset = (size_t) ret;
        return ret;
}

/*
**  SM_STROPEN -- open a string file type
**
**      Parameters:
**              fp -- file pointer open to be associated with
**              info -- initial contents (NULL for none)
**              flags -- flags for methods of access (was mode)
**              rpool -- resource pool to use memory from (if applicable)
**
**      Results:
**              Success: 0 (zero)
**              Failure: -1 and sets errno
*/

int
sm_stropen(fp, info, flags, rpool)
        SM_FILE_T *fp;
        const void *info;
        int flags;
        const void *rpool;
{
        register SM_STR_OBJ_T *s;

#if SM_RPOOL
        s = sm_rpool_malloc_x(rpool, sizeof(SM_STR_OBJ_T));
#else /* SM_RPOOL */
        s = sm_malloc(sizeof(SM_STR_OBJ_T));
        if (s == NULL)
                return -1;
#endif /* SM_RPOOL */

        fp->f_cookie = s;
        s->strio_rpool = rpool;
        s->strio_offset = 0;
        s->strio_size = 0;
        s->strio_base = NULL;
        s->strio_end = 0;

        switch (flags)
        {
          case SM_IO_RDWR:
                s->strio_flags = SMRW;
                break;
          case SM_IO_RDONLY:
                s->strio_flags = SMRD;
                break;
          case SM_IO_WRONLY:
                s->strio_flags = SMWR;
                break;
          case SM_IO_APPEND:
                if (s->strio_rpool == NULL)
                        sm_free(s);
                errno = EINVAL;
                return -1;
          default:
                if (s->strio_rpool == NULL)
                        sm_free(s);
                errno = EINVAL;
                return -1;
        }

        if (info != NULL)
        {
                s->strio_base = sm_strdup_x(info);
                if (s->strio_base == NULL)
                {
                        int save_errno = errno;

                        if (s->strio_rpool == NULL)
                                sm_free(s);
                        errno = save_errno;
                        return -1;
                }
                s->strio_size = strlen(info);
                s->strio_end = s->strio_base + s->strio_size;
        }
        return 0;
}

/*
**  SM_STRCLOSE -- close the string file type and free resources
**
**      Parameters:
**              fp -- file pointer
**
**      Results:
**              Success: 0 (zero)
*/

int
sm_strclose(fp)
        SM_FILE_T *fp;
{
        SM_STR_OBJ_T *s = fp->f_cookie;

#if !SM_RPOOL
        sm_free(s->strio_base);
        s->strio_base = NULL;
#endif /* !SM_RPOOL */
        return 0;
}

/*
**  SM_STRSETMODE -- set mode info for the file
**
**       Note: changing the mode can be a safe way to have the "parent"
**       set up a string that the "child" is not to modify
**
**      Parameters:
**              fp -- the file pointer
**              mode -- location of new mode to set
**
**      Results:
**              Success: 0 (zero)
**              Failure: -1 and sets errno
*/

static int
sm_strsetmode(fp, mode)
        SM_FILE_T *fp;
        const int *mode;
{
        register SM_STR_OBJ_T *s = fp->f_cookie;
        int flags;

        switch (*mode)
        {
          case SM_IO_RDWR:
                flags = SMRW;
                break;
          case SM_IO_RDONLY:
                flags = SMRD;
                break;
          case SM_IO_WRONLY:
                flags = SMWR;
                break;
          case SM_IO_APPEND:
                errno = EINVAL;
                return -1;
          default:
                errno = EINVAL;
                return -1;
        }
        s->strio_flags &= ~SMMODEMASK;
        s->strio_flags |= flags;
        return 0;
}

/*
**  SM_STRGETMODE -- get mode info for the file
**
**      Parameters:
**              fp -- the file pointer
**              mode -- location to store current mode
**
**      Results:
**              Success: 0 (zero)
**              Failure: -1 and sets errno
*/

static int
sm_strgetmode(fp, mode)
        SM_FILE_T *fp;
        int *mode;
{
        register SM_STR_OBJ_T *s = fp->f_cookie;

        switch (s->strio_flags & SMMODEMASK)
        {
          case SMRW:
                *mode = SM_IO_RDWR;
                break;
          case SMRD:
                *mode = SM_IO_RDONLY;
                break;
          case SMWR:
                *mode = SM_IO_WRONLY;
                break;
          default:
                errno = EINVAL;
                return -1;
        }
        return 0;
}

/*
**  SM_STRSETINFO -- set info for the file
**
**      Currently only SM_IO_WHAT_MODE is supported for 'what'.
**
**      Parameters:
**              fp -- the file pointer
**              what -- type of information to set
**              valp -- location to data for doing set
**
**      Results:
**              Failure: -1 and sets errno
**              Success: sm_strsetmode() return [0 (zero)]
*/

int
sm_strsetinfo(fp, what, valp)
        SM_FILE_T *fp;
        int what;
        void *valp;
{
        switch(what)
        {
          case SM_IO_WHAT_MODE:
                return sm_strsetmode(fp, (int *) valp);
          default:
                errno = EINVAL;
                return -1;
        }
}

/*
**  SM_STRGETINFO -- get info for the file
**
**      Currently only SM_IO_WHAT_MODE is supported for 'what'.
**
**      Parameters:
**              fp -- the file pointer
**              what -- type of information requested
**              valp -- location to return information in
**
**      Results:
**              Failure: -1 and sets errno
**              Success: sm_strgetmode() return [0 (zero)]
*/

int
sm_strgetinfo(fp, what, valp)
        SM_FILE_T *fp;
        int what;
        void *valp;
{
        switch(what)
        {
          case SM_IO_WHAT_MODE:
                return sm_strgetmode(fp, (int *) valp);
          default:
                errno = EINVAL;
                return -1;
        }
}

/*
**  SM_STRIO_INIT -- initializes a write-only string type
**
**  Original comments below. This function does not appear to be used anywhere.
**  The same functionality can be done by changing the mode of the file.
**  ------------
** sm_strio_init initializes an SM_FILE_T structure as a write-only file
** that writes into the specified buffer:
** - Use sm_io_putc, sm_io_fprintf, etc, to write into the buffer.
**   Attempts to write more than size-1 characters into the buffer will fail
**   silently (no error is reported).
** - Use sm_io_fflush to nul terminate the string in the buffer
**   (the write pointer is not advanced).
** No memory is allocated either by sm_strio_init or by sm_io_{putc,write} etc.
**
**      Parameters:
**              fp -- file pointer
**              buf -- memory location for stored data
**              size -- size of 'buf'
**
**      Results:
**              none.
*/

void
sm_strio_init(fp, buf, size)
        SM_FILE_T *fp;
        char *buf;
        size_t size;
{
        fp->sm_magic = SmFileMagic;
        fp->f_flags = SMWR | SMSTR;
        fp->f_file = -1;
        fp->f_bf.smb_base = fp->f_p = (unsigned char *) buf;
        fp->f_bf.smb_size = fp->f_w = (size ? size - 1 : 0);
        fp->f_lbfsize = 0;
        fp->f_r = 0;
        fp->f_read = NULL;
        fp->f_seek = NULL;
        fp->f_getinfo = NULL;
        fp->f_setinfo = NULL;
}