/* 
 * SGI rgb file reader borrowed from gltk library
 */

#include "togl.h"               /* added by GG to include windows.h */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "image.h"

#ifndef SEEK_SET
#  define SEEK_SET 0
#endif


static void
tkQuit(void)
{
    exit(0);
}


/******************************************************************************/

typedef struct _rawImageRec
{
    unsigned short imagic;
    unsigned short type;
    unsigned short dim;
    unsigned short sizeX, sizeY, sizeZ;
    unsigned long min, max;
    unsigned long wasteBytes;
    char    name[80];
    unsigned long colorMap;
    FILE   *file;
    unsigned char *tmp, *tmpR, *tmpG, *tmpB, *tmpA;
    unsigned long rleEnd;
    GLuint *rowStart;
    GLint  *rowSize;
} rawImageRec;


/******************************************************************************/

static void
ConvertShort(unsigned short *array, long length)
{
    unsigned long b1, b2;
    unsigned char *ptr;

    ptr = (unsigned char *) array;
    while (length--) {
        b1 = *ptr++;
        b2 = *ptr++;
        *array++ = (unsigned short) ((b1 << 8) | b2);
    }
}

static void
ConvertLong(GLuint *array, long length)
{
    unsigned long b1, b2, b3, b4;
    unsigned char *ptr;

    ptr = (unsigned char *) array;
    while (length--) {
        b1 = *ptr++;
        b2 = *ptr++;
        b3 = *ptr++;
        b4 = *ptr++;
        *array++ = (b1 << 24) | (b2 << 16) | (b3 << 8) | (b4);
    }
}

static rawImageRec *
RawImageOpen(const char *fileName)
{
    union
    {
        int     testWord;
        char    testByte[4];
    } endianTest;
    rawImageRec *raw;
    GLenum  swapFlag;
    int     x;

    endianTest.testWord = 1;
    if (endianTest.testByte[0] == 1) {
        swapFlag = GL_TRUE;
    } else {
        swapFlag = GL_FALSE;
    }

    raw = (rawImageRec *) malloc(sizeof (rawImageRec));
    if (raw == NULL) {
        fprintf(stderr, "Out of memory!\n");
        tkQuit();
    }
    if ((raw->file = fopen(fileName, "rb")) == NULL) {
        perror(fileName);
        tkQuit();
    }

    fread(raw, 1, 12, raw->file);

    if (swapFlag) {
        ConvertShort(&raw->imagic, 6);
    }

    raw->tmp = (unsigned char *) malloc(raw->sizeX * 256);
    raw->tmpR = (unsigned char *) malloc(raw->sizeX * 256);
    raw->tmpG = (unsigned char *) malloc(raw->sizeX * 256);
    raw->tmpB = (unsigned char *) malloc(raw->sizeX * 256);
    raw->tmpA = (unsigned char *) malloc(raw->sizeX * 256);
    if (raw->tmp == NULL || raw->tmpR == NULL || raw->tmpG == NULL ||
            raw->tmpB == NULL || raw->tmpA == NULL) {
        fprintf(stderr, "Out of memory!\n");
        tkQuit();
    }

    if ((raw->type & 0xFF00) == 0x0100) {
        x = raw->sizeY * raw->sizeZ * sizeof (GLuint);
        raw->rowStart = (GLuint *) malloc(x);
        raw->rowSize = (GLint *) malloc(x);
        if (raw->rowStart == NULL || raw->rowSize == NULL) {
            fprintf(stderr, "Out of memory!\n");
            tkQuit();
        }
        raw->rleEnd = 512 + (2 * x);
        fseek(raw->file, 512, SEEK_SET);
        fread(raw->rowStart, 1, x, raw->file);
        fread(raw->rowSize, 1, x, raw->file);
        if (swapFlag) {
            ConvertLong(raw->rowStart, x / sizeof (GLuint));
            ConvertLong((GLuint *) raw->rowSize, x / sizeof (GLint));
        }
    }
    return raw;
}

static void
RawImageClose(rawImageRec * raw)
{

    fclose(raw->file);
    free(raw->tmp);
    free(raw->tmpR);
    free(raw->tmpG);
    free(raw->tmpB);
    free(raw->tmpA);
    free(raw);
}

static void
RawImageGetRow(rawImageRec * raw, unsigned char *buf, int y, int z)
{
    unsigned char *iPtr, *oPtr, pixel;
    int     count;

    if ((raw->type & 0xFF00) == 0x0100) {
        fseek(raw->file, raw->rowStart[y + z * raw->sizeY], SEEK_SET);
        fread(raw->tmp, 1, (unsigned int) raw->rowSize[y + z * raw->sizeY],
                raw->file);

        iPtr = raw->tmp;
        oPtr = buf;
        while (1) {
            pixel = *iPtr++;
            count = (int) (pixel & 0x7F);
            if (!count) {
                return;
            }
            if (pixel & 0x80) {
                while (count--) {
                    *oPtr++ = *iPtr++;
                }
            } else {
                pixel = *iPtr++;
                while (count--) {
                    *oPtr++ = pixel;
                }
            }
        }
    } else {
        fseek(raw->file, 512 + (y * raw->sizeX) + (z * raw->sizeX * raw->sizeY),
                SEEK_SET);
        fread(buf, 1, raw->sizeX, raw->file);
    }
}

static void
RawImageGetData(rawImageRec * raw, TK_RGBImageRec * final)
{
    unsigned char *ptr;
    int     i, j;

    final->data =
            (unsigned char *) malloc((raw->sizeX + 1) * (raw->sizeY + 1) * 4);
    if (final->data == NULL) {
        fprintf(stderr, "Out of memory!\n");
        tkQuit();
    }

    ptr = final->data;
    for (i = 0; i < (int) (raw->sizeY); i++) {
        RawImageGetRow(raw, raw->tmpR, i, 0);
        RawImageGetRow(raw, raw->tmpG, i, 1);
        RawImageGetRow(raw, raw->tmpB, i, 2);
        if (raw->sizeZ == 4) {
            /* 4 components */
            RawImageGetRow(raw, raw->tmpA, i, 3);
            for (j = 0; j < (int) (raw->sizeX); j++) {
                *ptr++ = *(raw->tmpR + j);
                *ptr++ = *(raw->tmpG + j);
                *ptr++ = *(raw->tmpB + j);
                *ptr++ = *(raw->tmpA + j);
            }
        } else {
            /* 3 components */
            for (j = 0; j < (int) (raw->sizeX); j++) {
                *ptr++ = *(raw->tmpR + j);
                *ptr++ = *(raw->tmpG + j);
                *ptr++ = *(raw->tmpB + j);
            }
        }
    }
}

TK_RGBImageRec *
tkRGBImageLoad(const char *fileName)
{
    rawImageRec *raw;
    TK_RGBImageRec *final;

    raw = RawImageOpen(fileName);
    final = (TK_RGBImageRec *) malloc(sizeof (TK_RGBImageRec));
    if (final == NULL) {
        fprintf(stderr, "Out of memory!\n");
        tkQuit();
    }
    final->sizeX = raw->sizeX;
    final->sizeY = raw->sizeY;
    final->sizeZ = raw->sizeZ;
    RawImageGetData(raw, final);
    RawImageClose(raw);
    return final;
}

/******************************************************************************/
