/*
 * Copyright (c) 2008, Natacha Porté
 * Copyright (c) 2011, Vicent Martí
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#define BUFFER_MAX_ALLOC_SIZE (1024 * 1024 * 16)    // 16mb

#include "buffer.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>

/* MSVC compat */
#if defined(_MSC_VER)
#   define _buf_vsnprintf   _vsnprintf
#else
#   define _buf_vsnprintf   vsnprintf
#endif

int bufprefix( const struct buf* buf, const char* prefix )
{
    size_t i;

    assert( buf && buf->unit );

    for( i = 0; i < buf->size; ++i )
    {
        if( prefix[i] == 0 )
            return 0;

        if( buf->data[i] != prefix[i] )
            return buf->data[i] - prefix[i];
    }

    return 0;
}


/* bufgrow: increasing the allocated size to the given value */
int bufgrow( struct buf* buf, size_t neosz )
{
    size_t  neoasz;
    void*   neodata;

    assert( buf && buf->unit );

    if( neosz > BUFFER_MAX_ALLOC_SIZE )
        return BUF_ENOMEM;

    if( buf->asize >= neosz )
        return BUF_OK;

    neoasz = buf->asize + buf->unit;

    while( neoasz < neosz )
        neoasz += buf->unit;

    neodata = realloc( buf->data, neoasz );

    if( !neodata )
        return BUF_ENOMEM;

    buf->data   = neodata;
    buf->asize  = neoasz;
    return BUF_OK;
}


/* bufnew: allocation of a new buffer */
struct buf* bufnew( size_t unit )
{
    struct buf* ret;

    ret = malloc( sizeof(struct buf) );

    if( ret )
    {
        ret->data   = 0;
        ret->size   = ret->asize = 0;
        ret->unit   = unit;
    }

    return ret;
}


/* bufnullterm: NULL-termination of the string array */
const char* bufcstr( struct buf* buf )
{
    assert( buf && buf->unit );

    if( buf->size < buf->asize && buf->data[buf->size] == 0 )
        return (char*) buf->data;

    if( buf->size + 1 <= buf->asize || bufgrow( buf, buf->size + 1 ) == 0 )
    {
        buf->data[buf->size] = 0;
        return (char*) buf->data;
    }

    return NULL;
}


/* bufprintf: formatted printing to a buffer */
void bufprintf( struct buf* buf, const char* fmt, ... )
{
    va_list ap;
    int n;

    assert( buf && buf->unit );

    if( buf->size >= buf->asize && bufgrow( buf, buf->size + 1 ) < 0 )
        return;

    va_start( ap, fmt );
    n = _buf_vsnprintf( (char*) buf->data + buf->size, buf->asize - buf->size, fmt, ap );
    va_end( ap );

    if( n < 0 )
    {
#ifdef _MSC_VER
        va_start( ap, fmt );
        n = _vscprintf( fmt, ap );
        va_end( ap );
#else
        return;
#endif
    }

    if( (size_t) n >= buf->asize - buf->size )
    {
        if( bufgrow( buf, buf->size + n + 1 ) < 0 )
            return;

        va_start( ap, fmt );
        n = _buf_vsnprintf( (char*) buf->data + buf->size, buf->asize - buf->size, fmt, ap );
        va_end( ap );
    }

    if( n < 0 )
        return;

    buf->size += n;
}


/* bufput: appends raw data to a buffer */
void bufput( struct buf* buf, const void* data, size_t len )
{
    assert( buf && buf->unit );

    if( buf->size + len > buf->asize && bufgrow( buf, buf->size + len ) < 0 )
        return;

    memcpy( buf->data + buf->size, data, len );
    buf->size += len;
}


/* bufputs: appends a NUL-terminated string to a buffer */
void bufputs( struct buf* buf, const char* str )
{
    bufput( buf, str, strlen( str ) );
}


/* bufputc: appends a single uint8_t to a buffer */
void bufputc( struct buf* buf, int c )
{
    assert( buf && buf->unit );

    if( buf->size + 1 > buf->asize && bufgrow( buf, buf->size + 1 ) < 0 )
        return;

    buf->data[buf->size] = c;
    buf->size += 1;
}


/* bufrelease: decrease the reference count and free the buffer if needed */
void bufrelease( struct buf* buf )
{
    if( !buf )
        return;

    free( buf->data );
    free( buf );
}


/* bufreset: frees internal data of the buffer */
void bufreset( struct buf* buf )
{
    if( !buf )
        return;

    free( buf->data );
    buf->data   = NULL;
    buf->size   = buf->asize = 0;
}


/* bufslurp: removes a given number of bytes from the head of the array */
void bufslurp( struct buf* buf, size_t len )
{
    assert( buf && buf->unit );

    if( len >= buf->size )
    {
        buf->size = 0;
        return;
    }

    buf->size -= len;
    memmove( buf->data, buf->data + len, buf->size );
}