VSHelper.h

//  Copyright (c) 2012-2013 Fredrik Mellbin
//
//  Permission is hereby granted, free of charge, to any person obtaining a copy
//  of this software and associated documentation files (the "Software"), to deal
//  in the Software without restriction, including without limitation the rights
//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
//  copies of the Software, and to permit persons to whom the Software is
//  furnished to do so, subject to the following conditions:
//
//  The above copyright notice and this permission notice shall be included in
//  all copies or substantial portions of the Software.
//
//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
//  THE SOFTWARE.

#ifndef VSHELPER_H
#define VSHELPER_H

#include <limits.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#ifdef _WIN32
#include <malloc.h>
#endif
#include "VapourSynth.h"

// Visual Studio doesn't recognize inline in c mode
#if defined(_MSC_VER) && !defined(__cplusplus)
#define inline _inline
#endif

// A kinda portable definition of the C99 restrict keyword (or its inofficial C++ equivalent)
#if __STDC_VERSION__ >= 199901L // Available in C99
#define VS_RESTRICT restrict
#elif defined(__cplusplus) || defined(_MSC_VER) // Almost all relevant C++ compilers support it so just assume it works
#define VS_RESTRICT __restrict
#else // Not supported
#define VS_RESTRICT
#endif

#ifdef _WIN32
#define VS_ALIGNED_MALLOC(pptr, size, alignment) *(pptr) = _aligned_malloc((size), (alignment))
#define VS_ALIGNED_FREE(ptr) _aligned_free((ptr))
#else
#define VS_ALIGNED_MALLOC(pptr, size, alignment) posix_memalign((void**)(pptr), (alignment), (size))
#define VS_ALIGNED_FREE(ptr) free((ptr))
#endif

#ifdef __cplusplus
// A nicer templated malloc for all the C++ users out there
template<class T>
static inline T* vs_aligned_malloc(size_t size, size_t alignment) {
#ifdef _WIN32
    return (T*)_aligned_malloc(size, alignment);
#else
    void *tmp;
    if (posix_memalign(&tmp, alignment, size))
        tmp = 0;
    return (T*)tmp;
#endif
}

static inline void vs_aligned_free(void *ptr) {
    VS_ALIGNED_FREE(ptr);
}
#endif //__cplusplus

// convenience function for checking if the format never changes between frames
static inline int isConstantFormat(const VSVideoInfo *vi) {
    return vi->height > 0 && vi->width > 0 && vi->format;
}

// convenience function to check for if two clips have the same format (unknown/changeable will be considered the same too)
static inline int isSameFormat(const VSVideoInfo *v1, const VSVideoInfo *v2) {
    return v1->height == v2->height && v1->width == v2->width && v1->format == v2->format;
}

// multiplies and divides a rational number, such as a frame duration, in place and reduces the result
static inline int muldivRational(int64_t *num, int64_t *den, int64_t mul, int64_t div) {
    int64_t a, b;
    *num *= mul;
    *den *= div;
    a = *num;
    b = *den;
    while (b != 0) {
        int64_t t = a;
        a = b;
        b = t % b;
    }
    if (a < 0)
        a = -a;
    *num /= a;
    *den /= a;
    return 0;
}

// converts an int64 to int with saturation, useful to silence warnings when reading int properties among other things
static inline int int64ToIntS(int64_t i) {
    if (i > INT_MAX)
        return INT_MAX;
    else if (i < INT_MIN)
        return INT_MIN;
    else return (int)i;
}

static inline void vs_bitblt(void *dstp, int dst_stride, const void *srcp, int src_stride, int row_size, int height) {
    if (height > 0) {
        if (src_stride == dst_stride && src_stride == row_size) {
            memcpy(dstp, srcp, row_size * height);
        } else {
            int i;
            uint8_t *srcp8 = (uint8_t *)srcp;
            uint8_t *dstp8 = (uint8_t *)dstp;
            for (i = 0; i < height; i++) {
                memcpy(dstp8, srcp8, row_size);
                srcp8 += src_stride;
                dstp8 += dst_stride;
            }
        }
    }
}

// check if the frame dimensions are valid for a given format
// returns non-zero for valid width and height
static inline int areValidDimensions(const VSFormat *fi, int width, int height) {
    return !(width % (1 << fi->subSamplingW) || height % (1 << fi->subSamplingH));
}

#endif