Pillow/libImaging/Storage.c

/*
 * The Python Imaging Library
 * $Id$
 *
 * imaging storage object
 *
 * This baseline implementation is designed to efficiently handle
 * large images, provided they fit into the available memory.
 *
 * history:
 * 1995-06-15 fl   Created
 * 1995-09-12 fl   Updated API, compiles silently under ANSI C++
 * 1995-11-26 fl   Compiles silently under Borland 4.5 as well
 * 1996-05-05 fl   Correctly test status from Prologue
 * 1997-05-12 fl   Increased THRESHOLD (to speed up Tk interface)
 * 1997-05-30 fl   Added support for floating point images
 * 1997-11-17 fl   Added support for "RGBX" images
 * 1998-01-11 fl   Added support for integer images
 * 1998-03-05 fl   Exported Prologue/Epilogue functions
 * 1998-07-01 fl   Added basic "YCrCb" support
 * 1998-07-03 fl   Attach palette in prologue for "P" images
 * 1998-07-09 hk   Don't report MemoryError on zero-size images
 * 1998-07-12 fl   Change "YCrCb" to "YCbCr" (!)
 * 1998-10-26 fl   Added "I;16" and "I;16B" storage modes (experimental)
 * 1998-12-29 fl   Fixed allocation bug caused by previous fix
 * 1999-02-03 fl   Added "RGBa" and "BGR" modes (experimental)
 * 2001-04-22 fl   Fixed potential memory leak in ImagingCopyPalette
 * 2003-09-26 fl   Added "LA" and "PA" modes (experimental)
 * 2005-10-02 fl   Added image counter
 *
 * Copyright (c) 1998-2005 by Secret Labs AB
 * Copyright (c) 1995-2005 by Fredrik Lundh
 *
 * See the README file for information on usage and redistribution.
 */


#include "Imaging.h"
#include <string.h>


int ImagingNewCount = 0;

/* --------------------------------------------------------------------
 * Standard image object.
 */

Imaging
ImagingNewPrologueSubtype(const char *mode, int xsize, int ysize, int size)
{
    Imaging im;

    /* linesize overflow check, roughly the current largest space req'd */
    if (xsize > (INT_MAX / 4) - 1) {
        return (Imaging) ImagingError_MemoryError();
    }

    im = (Imaging) calloc(1, size);
    if (!im) {
        return (Imaging) ImagingError_MemoryError();
    }

    /* Setup image descriptor */
    im->xsize = xsize;
    im->ysize = ysize;

    im->type = IMAGING_TYPE_UINT8;

    if (strcmp(mode, "1") == 0) {
        /* 1-bit images */
        im->bands = im->pixelsize = 1;
        im->linesize = xsize;

    } else if (strcmp(mode, "P") == 0) {
        /* 8-bit palette mapped images */
        im->bands = im->pixelsize = 1;
        im->linesize = xsize;
        im->palette = ImagingPaletteNew("RGB");

    } else if (strcmp(mode, "PA") == 0) {
        /* 8-bit palette with alpha */
        im->bands = 2;
        im->pixelsize = 4; /* store in image32 memory */
        im->linesize = xsize * 4;
        im->palette = ImagingPaletteNew("RGB");

    } else if (strcmp(mode, "L") == 0) {
        /* 8-bit greyscale (luminance) images */
        im->bands = im->pixelsize = 1;
        im->linesize = xsize;

    } else if (strcmp(mode, "LA") == 0) {
        /* 8-bit greyscale (luminance) with alpha */
        im->bands = 2;
        im->pixelsize = 4; /* store in image32 memory */
        im->linesize = xsize * 4;

    } else if (strcmp(mode, "La") == 0) {
        /* 8-bit greyscale (luminance) with premultiplied alpha */
        im->bands = 2;
        im->pixelsize = 4; /* store in image32 memory */
        im->linesize = xsize * 4;

    } else if (strcmp(mode, "F") == 0) {
        /* 32-bit floating point images */
        im->bands = 1;
        im->pixelsize = 4;
        im->linesize = xsize * 4;
        im->type = IMAGING_TYPE_FLOAT32;

    } else if (strcmp(mode, "I") == 0) {
        /* 32-bit integer images */
        im->bands = 1;
        im->pixelsize = 4;
        im->linesize = xsize * 4;
        im->type = IMAGING_TYPE_INT32;

    } else if (strcmp(mode, "I;16") == 0 || strcmp(mode, "I;16L") == 0 \
                           || strcmp(mode, "I;16B") == 0 || strcmp(mode, "I;16N") == 0)  {
        /* EXPERIMENTAL */
        /* 16-bit raw integer images */
        im->bands = 1;
        im->pixelsize = 2;
        im->linesize = xsize * 2;
        im->type = IMAGING_TYPE_SPECIAL;

    } else if (strcmp(mode, "RGB") == 0) {
        /* 24-bit true colour images */
        im->bands = 3;
        im->pixelsize = 4;
        im->linesize = xsize * 4;

    } else if (strcmp(mode, "BGR;15") == 0) {
        /* EXPERIMENTAL */
        /* 15-bit true colour */
        im->bands = 1;
        im->pixelsize = 2;
        im->linesize = (xsize*2 + 3) & -4;
        im->type = IMAGING_TYPE_SPECIAL;

    } else if (strcmp(mode, "BGR;16") == 0) {
        /* EXPERIMENTAL */
        /* 16-bit reversed true colour */
        im->bands = 1;
        im->pixelsize = 2;
        im->linesize = (xsize*2 + 3) & -4;
        im->type = IMAGING_TYPE_SPECIAL;

    } else if (strcmp(mode, "BGR;24") == 0) {
        /* EXPERIMENTAL */
        /* 24-bit reversed true colour */
        im->bands = 1;
        im->pixelsize = 3;
        im->linesize = (xsize*3 + 3) & -4;
        im->type = IMAGING_TYPE_SPECIAL;

    } else if (strcmp(mode, "BGR;32") == 0) {
        /* EXPERIMENTAL */
        /* 32-bit reversed true colour */
        im->bands = 1;
        im->pixelsize = 4;
        im->linesize = (xsize*4 + 3) & -4;
        im->type = IMAGING_TYPE_SPECIAL;

    } else if (strcmp(mode, "RGBX") == 0) {
        /* 32-bit true colour images with padding */
        im->bands = im->pixelsize = 4;
        im->linesize = xsize * 4;

    } else if (strcmp(mode, "RGBA") == 0) {
        /* 32-bit true colour images with alpha */
        im->bands = im->pixelsize = 4;
        im->linesize = xsize * 4;

    } else if (strcmp(mode, "RGBa") == 0) {
        /* EXPERIMENTAL */
        /* 32-bit true colour images with premultiplied alpha */
        im->bands = im->pixelsize = 4;
        im->linesize = xsize * 4;

    } else if (strcmp(mode, "CMYK") == 0) {
        /* 32-bit colour separation */
        im->bands = im->pixelsize = 4;
        im->linesize = xsize * 4;

    } else if (strcmp(mode, "YCbCr") == 0) {
        /* 24-bit video format */
        im->bands = 3;
        im->pixelsize = 4;
        im->linesize = xsize * 4;

    } else if (strcmp(mode, "LAB") == 0) {
        /* 24-bit color, luminance, + 2 color channels */
        /* L is uint8, a,b are int8 */
        im->bands = 3;
        im->pixelsize = 4;
        im->linesize = xsize * 4;

    } else if (strcmp(mode, "HSV") == 0) {
        /* 24-bit color, luminance, + 2 color channels */
        /* L is uint8, a,b are int8 */
        im->bands = 3;
        im->pixelsize = 4;
        im->linesize = xsize * 4;

    } else {
        free(im);
        return (Imaging) ImagingError_ValueError("unrecognized image mode");
    }

    /* Setup image descriptor */
    strcpy(im->mode, mode);

    /* Pointer array (allocate at least one line, to avoid MemoryError
       exceptions on platforms where calloc(0, x) returns NULL) */
    im->image = (char **) calloc((ysize > 0) ? ysize : 1, sizeof(void *));

    if ( ! im->image) {
        free(im);
        return (Imaging) ImagingError_MemoryError();
    }

    /* Initialize alias pointers to pixel data. */
    switch (im->pixelsize) {
    case 1: case 2: case 3:
        im->image8 = (UINT8 **) im->image;
        break;
    case 4:
        im->image32 = (INT32 **) im->image;
        break;
    }

    ImagingNewCount++;

    return im;
}

Imaging
ImagingNewPrologue(const char *mode, int xsize, int ysize)
{
    return ImagingNewPrologueSubtype(
        mode, xsize, ysize, sizeof(struct ImagingMemoryInstance));
}

void
ImagingDelete(Imaging im)
{
    if (!im)
        return;

    if (im->palette)
        ImagingPaletteDelete(im->palette);

    if (im->destroy)
        im->destroy(im);

    if (im->image)
        free(im->image);

    free(im);
}


/* Array Storage Type */
/* ------------------ */
/* Allocate image as an array of line buffers. */

static void
ImagingDestroyArray(Imaging im)
{
    int y;

    if (im->image)
        for (y = 0; y < im->ysize; y++)
            if (im->image[y])
                free(im->image[y]);
}

Imaging
ImagingAllocateArray(Imaging im, int dirty)
{
    ImagingSectionCookie cookie;

    int y;
    char* p;

    ImagingSectionEnter(&cookie);

    /* Allocate image as an array of lines */
    for (y = 0; y < im->ysize; y++) {
        /* malloc check linesize checked in prologue */
        if (dirty) {
            p = (char *) malloc(im->linesize);
        } else {
            p = (char *) calloc(1, im->linesize);
        }
        if (!p) {
            ImagingDestroyArray(im);
            break;
        }
        im->image[y] = p;
    }

    ImagingSectionLeave(&cookie);

    if (y != im->ysize) {
        return (Imaging) ImagingError_MemoryError();
    }

    im->destroy = ImagingDestroyArray;

    return im;
}


/* Block Storage Type */
/* ------------------ */
/* Allocate image as a single block. */

static void
ImagingDestroyBlock(Imaging im)
{
    if (im->block)
        free(im->block);
}

Imaging
ImagingAllocateBlock(Imaging im, int dirty)
{
    Py_ssize_t y, i;

    /* We shouldn't overflow, since the threshold defined
       below says that we're only going to allocate max 4M
       here before going to the array allocator. Check anyway.
    */
    if (im->linesize &&
        im->ysize > INT_MAX / im->linesize) {
        /* punt if we're going to overflow */
        return (Imaging) ImagingError_MemoryError();
    }

    if (im->ysize * im->linesize <= 0) {
        /* some platforms return NULL for malloc(0); this fix
           prevents MemoryError on zero-sized images on such
           platforms */
        im->block = (char *) malloc(1);
    } else {
        if (dirty) {
            /* malloc check ok, overflow check above */
            im->block = (char *) malloc(im->ysize * im->linesize);
        } else {
            /* malloc check ok, overflow check above */
            im->block = (char *) calloc(im->ysize, im->linesize);
        }
    }

    if ( ! im->block) {
        return (Imaging) ImagingError_MemoryError();
    }

    for (y = i = 0; y < im->ysize; y++) {
        im->image[y] = im->block + i;
        i += im->linesize;
    }
    
    im->destroy = ImagingDestroyBlock;

    return im;
}

/* --------------------------------------------------------------------
 * Create a new, internally allocated, image.
 */
#if defined(IMAGING_SMALL_MODEL)
#define THRESHOLD       16384L
#else
#define THRESHOLD       (2048*2048*4L)
#endif

Imaging
ImagingNewInternal(const char* mode, int xsize, int ysize, int dirty)
{
    Imaging im;

    if (xsize < 0 || ysize < 0) {
        return (Imaging) ImagingError_ValueError("bad image size");
    }

    im = ImagingNewPrologue(mode, xsize, ysize);
    if ( ! im)
        return NULL;

    if (im->ysize && im->linesize <= THRESHOLD / im->ysize) {
        if (ImagingAllocateBlock(im, dirty)) {
            return im;
        }
        /* assume memory error; try allocating in array mode instead */
        ImagingError_Clear();
    }

    if (ImagingAllocateArray(im, dirty)) {
        return im;
    }

    ImagingDelete(im);
    return NULL;
}

Imaging
ImagingNew(const char* mode, int xsize, int ysize)
{
    return ImagingNewInternal(mode, xsize, ysize, 0);
}

Imaging
ImagingNewDirty(const char* mode, int xsize, int ysize)
{
    return ImagingNewInternal(mode, xsize, ysize, 1);
}

Imaging
ImagingNewBlock(const char* mode, int xsize, int ysize)
{
    Imaging im;

    im = ImagingNewPrologue(mode, xsize, ysize);
    if ( ! im)
        return NULL;

    if (ImagingAllocateBlock(im, 0)) {
        return im;
    }

    ImagingDelete(im);
    return NULL;
}

Imaging
ImagingNew2Dirty(const char* mode, Imaging imOut, Imaging imIn)
{
    /* allocate or validate output image */

    if (imOut) {
        /* make sure images match */
        if (strcmp(imOut->mode, mode) != 0
            || imOut->xsize != imIn->xsize
            || imOut->ysize != imIn->ysize) {
            return ImagingError_Mismatch();
        }
    } else {
        /* create new image */
        imOut = ImagingNewDirty(mode, imIn->xsize, imIn->ysize);
        if (!imOut)
            return NULL;
    }

    return imOut;
}

void
ImagingCopyPalette(Imaging destination, Imaging source)
{
    if (source->palette) {
        if (destination->palette)
            ImagingPaletteDelete(destination->palette);
        destination->palette = ImagingPaletteDuplicate(source->palette);
    }
}