efi_strings.c

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/*
 * Copyright (C) 2011 Michael Brown <mbrown@fensystems.co.uk>.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 *
 * You can also choose to distribute this program under the terms of
 * the Unmodified Binary Distribution Licence (as given in the file
 * COPYING.UBDL), provided that you have satisfied its requirements.
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
FILE_SECBOOT ( PERMITTED );

#include <stddef.h>
#include <stdarg.h>
#include <stdlib.h>
#include <errno.h>
#include <ipxe/vsprintf.h>
#include <ipxe/efi/efi_strings.h>

/** Context used by efi_vsnprintf() and friends */
struct efi_sputc_context {
        /** printf context */
        struct printf_context ctx;
        /** Buffer for formatted string (used by efi_printf_sputc()) */
        wchar_t *buf;
        /** Buffer length (used by efi_printf_sputc())
         *
         * Note that this is a number of wide characters, not a number
         * of bytes.
         */
        size_t max_wlen;
};

/**
 * Write wide character to buffer
 *
 * @v ctx               Context
 * @v c                 Character
 */
static void efi_printf_sputc ( struct printf_context *ctx, unsigned int c ) {
        struct efi_sputc_context * sctx =
                container_of ( ctx, struct efi_sputc_context, ctx );

        if ( ctx->len < sctx->max_wlen )
                sctx->buf[ctx->len] = c;
}

/**
 * Write a formatted string to a wide-character buffer
 *
 * @v wbuf              Buffer into which to write the string
 * @v wsize             Size of buffer (in wide characters)
 * @v fmt               Format string
 * @v args              Arguments corresponding to the format string
 * @ret wlen            Length of formatted string (in wide characters)
 *
 * If the buffer is too small to contain the string, the returned
 * length is the length that would have been written had enough space
 * been available.
 */
int efi_vsnprintf ( wchar_t *wbuf, size_t wsize, const char *fmt,
                    va_list args ) {
        struct efi_sputc_context sctx;
        size_t wlen;
        size_t wend;

        /* Hand off to vcprintf */
        sctx.ctx.handler = efi_printf_sputc;
        sctx.buf = wbuf;
        sctx.max_wlen = wsize;
        wlen = vcprintf ( &sctx.ctx, fmt, args );

        /* Add trailing NUL */
        if ( wsize ) {
                wend = wsize - 1;
                if ( wlen < wend )
                        wend = wlen;
                wbuf[wend] = '\0';
        }

        return wlen;
}

/**
 * Write a formatted string to a buffer
 *
 * @v wbuf              Buffer into which to write the string
 * @v wsize             Size of buffer (in wide characters)
 * @v fmt               Format string
 * @v ...               Arguments corresponding to the format string
 * @ret wlen            Length of formatted string (in wide characters)
 */
int efi_snprintf ( wchar_t *wbuf, size_t wsize, const char *fmt, ... ) {
        va_list args;
        int i;

        va_start ( args, fmt );
        i = efi_vsnprintf ( wbuf, wsize, fmt, args );
        va_end ( args );
        return i;
}

/**
 * Version of efi_vsnprintf() that accepts a signed buffer size
 *
 * @v wbuf              Buffer into which to write the string
 * @v swsize            Size of buffer (in wide characters)
 * @v fmt               Format string
 * @v args              Arguments corresponding to the format string
 * @ret wlen            Length of formatted string (in wide characters)
 */
int efi_vssnprintf ( wchar_t *wbuf, ssize_t swsize, const char *fmt,
                     va_list args ) {

        /* Treat negative buffer size as zero buffer size */
        if ( swsize < 0 )
                swsize = 0;

        /* Hand off to vsnprintf */
        return efi_vsnprintf ( wbuf, swsize, fmt, args );
}

/**
 * Version of efi_vsnprintf() that accepts a signed buffer size
 *
 * @v wbuf              Buffer into which to write the string
 * @v swsize            Size of buffer (in wide characters)
 * @v fmt               Format string
 * @v ...               Arguments corresponding to the format string
 * @ret wlen            Length of formatted string (in wide characters)
 */
int efi_ssnprintf ( wchar_t *wbuf, ssize_t swsize, const char *fmt, ... ) {
        va_list args;
        int len;

        /* Hand off to vssnprintf */
        va_start ( args, fmt );
        len = efi_vssnprintf ( wbuf, swsize, fmt, args );
        va_end ( args );
        return len;
}

/**
 * Write a formatted string to newly allocated memory
 *
 * @v wstrp             Pointer to hold allocated string
 * @v fmt               Format string
 * @v args              Arguments corresponding to the format string
 * @ret len             Length of formatted string (in wide characters)
 */
int efi_vasprintf ( wchar_t **wstrp, const char *fmt, va_list args ) {
        size_t len;
        va_list args_tmp;

        /* Calculate length needed for string */
        va_copy ( args_tmp, args );
        len = ( efi_vsnprintf ( NULL, 0, fmt, args_tmp ) + 1 );
        va_end ( args_tmp );

        /* Allocate and fill string */
        *wstrp = malloc ( len * sizeof ( **wstrp ) );
        if ( ! *wstrp )
                return -ENOMEM;
        return efi_vsnprintf ( *wstrp, len, fmt, args );
}

/**
 * Write a formatted string to newly allocated memory
 *
 * @v wstrp             Pointer to hold allocated string
 * @v fmt               Format string
 * @v ...               Arguments corresponding to the format string
 * @ret len             Length of formatted string (in wide characters)
 */
int efi_asprintf ( wchar_t **wstrp, const char *fmt, ... ) {
        va_list args;
        int len;

        va_start ( args, fmt );
        len = efi_vasprintf ( wstrp, fmt, args );
        va_end ( args );
        return len;
}