blorblib.c

/* blorblib.c: Blorb file reader library, version 1.0.2.
    Designed by Andrew Plotkin <erkyrath@eblong.com>
    http://www.eblong.com/zarf/blorb/index.html
    
    This is portable code to read a Blorb file. Add it to your
    interpreter, #include "blorb.h", and you're ready to go.
*/

#include <stdio.h>
#include <stdlib.h>
#include "blorb.h"
#include "blorblow.h"

#ifdef BLORB_BIG_ENDIAN
static char contentsticker[] = "\nBlorb Library 1.0 (big-endian)\n";
#define bb_native2(v) (v)
#define bb_native4(v) (v)
#endif

#ifdef BLORB_LITTLE_ENDIAN
static char contentsticker[] = "\nBlorb Library 1.0 (little-endian)\n";
#define bb_native2(v)   \
    ( (((uint16)(v) >> 8) & 0x00ff)    \
    | (((uint16)(v) << 8) & 0xff00))
#define bb_native4(v)   \
    ( (((uint32)(v) >> 24) & 0x000000ff)    \
    | (((uint32)(v) >>  8) & 0x0000ff00)    \
    | (((uint32)(v) <<  8) & 0x00ff0000)   \
    | (((uint32)(v) << 24) & 0xff000000))
#endif

#ifndef bb_native4
"You must define either BLORB_BIG_ENDIAN or BLORB_LITTLE_ENDIAN in blorb.h \
    in order to compile this library.";
#endif

static int lib_inited = FALSE;

static bb_err_t bb_initialize_map(bb_map_t *map);
static bb_err_t bb_initialize(void);
static int sortsplot(bb_resdesc_t **p1, bb_resdesc_t **p2);

/* Do some one-time startup tests. */
static bb_err_t bb_initialize()
{
    union {
        uint32 val;
        char ch[4];
    } test;
    uint32 val;
    
    if (sizeof(uint32) != 4 || sizeof(uint16) != 2)
        return bb_err_CompileTime; /* Basic types are the wrong size. */
    
    test.ch[0] = 0x13;
    test.ch[1] = 0x57;
    test.ch[2] = 0x9a;
    test.ch[3] = 0xce;
    val = test.val;    
    if (bb_native4(val) != 0x13579ace)
        return bb_err_CompileTime; /* Wrong endianness. */
    
    return bb_err_None;
}

bb_err_t bb_create_map(FILE *file, bb_map_t **newmap)
{
    bb_err_t err;
    bb_map_t *map;
    size_t readlen;
    uint32 nextpos, totallength;
    bb_chunkdesc_t *chunks;
    int chunks_size, numchunks;
    uint32 buffer[4];
    
    *newmap = NULL;
    
    if (!lib_inited) {
        err = bb_initialize();
        if (err)
            return err;
        lib_inited = TRUE;
    }

    /* First, chew through the file and index the chunks. */
    
    err = fseek(file, 0, 0);
    if (err) 
        return bb_err_Read;
    
    readlen = fread(buffer, sizeof(uint32), 3, file);
    if (readlen != 3)
        return bb_err_Read;
    
    if (bb_native4(buffer[0]) != bb_ID_FORM)
        return bb_err_Format;
    if (bb_native4(buffer[2]) != bb_ID_IFRS)
        return bb_err_Format;
    
    totallength = bb_native4(buffer[1]) + 8;
    nextpos = 12;

    chunks_size = 8;
    numchunks = 0;
    chunks = (bb_chunkdesc_t *)malloc(sizeof(bb_chunkdesc_t) * chunks_size);

    while (nextpos < totallength) {
        uint32 type, len;
        int chunum;
        bb_chunkdesc_t *chu;
        
        err = fseek(file, nextpos, 0);
        if (err) 
            return bb_err_Read;
        
        readlen = fread(buffer, sizeof(uint32), 2, file);
        if (readlen != 2)
            return bb_err_Read;
        
        type = bb_native4(buffer[0]);
        len = bb_native4(buffer[1]);
        
        if (numchunks >= chunks_size) {
            chunks_size *= 2;
            chunks = (bb_chunkdesc_t *)realloc(chunks, 
                sizeof(bb_chunkdesc_t) * chunks_size);
        }
        
        chunum = numchunks;
        chu = &(chunks[chunum]);
        numchunks++;
        
        chu->type = type;
        chu->startpos = nextpos;
        if (type == bb_ID_FORM) {
            chu->datpos = nextpos;
            chu->len = len+8;
        }
        else {
            chu->datpos = nextpos+8;
            chu->len = len;
        }
        chu->ptr = NULL;
        chu->auxdatnum = -1;
        
        nextpos = nextpos + len + 8;
        if (nextpos & 1)
            nextpos++;
            
        if (nextpos > totallength)
            return bb_err_Format;
    }
    
    /* The basic IFF structure seems to be ok, and we have a list of
        chunks. Now we allocate the map structure itself. */
    
    map = (bb_map_t *)malloc(sizeof(bb_map_t));
    if (!map) {
        free(chunks);
        return bb_err_Alloc;
    }
        
    map->inited = bb_Inited_Magic;
    map->file = file;
    map->chunks = chunks;
    map->numchunks = numchunks;
    map->resources = NULL;
    map->ressorted = NULL;
    map->numresources = 0;
    map->releasenum = 0;
    map->zheader = NULL;
    map->resolution = NULL;
    map->palettechunk = -1;
    map->palette = NULL;
    map->auxsound = NULL;
    map->auxpict = NULL;
    
    /* Now we do everything else involved in loading the Blorb file,
        such as building resource lists. */
    
    err = bb_initialize_map(map);
    if (err) {
        bb_destroy_map(map);
        return err;
    }
    
    *newmap = map;
    return bb_err_None;
}

static bb_err_t bb_initialize_map(bb_map_t *map)
{
    /* It is important that the map structure be kept valid during this
        function. If this returns an error, bb_destroy_map() will be called. */
        
    int ix, jx;
    bb_result_t chunkres;
    bb_err_t err;
    uint32 *ptr;
    uint32 len;
    uint32 val;
    int numres;
    int gotindex = FALSE; 

    for (ix=0; ix<map->numchunks; ix++) {
        bb_chunkdesc_t *chu = &map->chunks[ix];
        
        switch (chu->type) {
        
            case bb_ID_RIdx:
                /* Resource index chunk: build the resource list and sort it. */
                
                if (gotindex) 
                    return bb_err_Format; /* duplicate index chunk */
                err = bb_load_chunk_by_number(map, bb_method_Memory, 
                    &chunkres, ix);
                if (err) 
                    return err;
                
                ptr = chunkres.data.ptr;
                len = chunkres.length;
                val = ptr[0];
                numres = bb_native4(val);

                if (numres) {
                    int ix2;
                    bb_resdesc_t *resources;
                    bb_resdesc_t **ressorted;
                    
                    if (len != numres*12+4)
                        return bb_err_Format; /* bad length field */
                    
                    resources = (bb_resdesc_t *)malloc(numres * sizeof(bb_resdesc_t));
                    ressorted = (bb_resdesc_t **)malloc(numres * sizeof(bb_resdesc_t *));
                    if (!ressorted || !resources)
                        return bb_err_Alloc;
                    
                    ix2 = 0;
                    for (jx=0; jx<numres; jx++) {
                        bb_resdesc_t *res = &(resources[jx]);
                        uint32 respos;
                        
                        val = ptr[1+jx*3];
                        res->usage = bb_native4(val);
                        val = ptr[2+jx*3];
                        res->resnum = bb_native4(val);
                        val = ptr[3+jx*3];
                        respos = bb_native4(val);
                        
                        while (ix2 < map->numchunks && map->chunks[ix2].startpos < respos)
                            ix2++;
                        
                        if (ix2 >= map->numchunks || map->chunks[ix2].startpos != respos)
                            return bb_err_Format; /* start pos does not match a real chunk */
                        
                        res->chunknum = ix2;
                        
                        ressorted[jx] = res;
                    }
                    
                    /* Sort a resource list (actually a list of pointers to structures
                        in map->resources.) This makes it easy to find resources by
                        usage and resource number. */
                    qsort(ressorted, numres, sizeof(bb_resdesc_t *), 
                        (int (*)())&sortsplot);
                    
                    map->numresources = numres;
                    map->resources = resources;
                    map->ressorted = ressorted;
                }
                
                bb_unload_chunk(map, ix);
                gotindex = TRUE;
                break;
            
            case bb_ID_RelN:
                /* Release number chunk: Get the release number. */
                
                err = bb_load_chunk_by_number(map, bb_method_Memory, 
                    &chunkres, ix);
                if (err) 
                    return err;
                
                if (chunkres.length != 2)
                    return bb_err_Format;
                
                {
                    uint16 val = *((uint16 *)chunkres.data.ptr);
                    map->releasenum = bb_native2(val);
                }

                bb_unload_chunk(map, ix);
                break;
            
            case bb_ID_IFhd:
                /* Z-header chunk: Get the header info. */
                
                err = bb_load_chunk_by_number(map, bb_method_Memory, 
                    &chunkres, ix);
                if (err) 
                    return err;
                
                if (chunkres.length < 13)
                    return bb_err_Format;
                
                {
                    uint16 val;
                    bb_zheader_t *head = (bb_zheader_t *)malloc(sizeof(bb_zheader_t));
                    if (!head)
                        return bb_err_Alloc;
                    
                    val = ((uint16 *)(chunkres.data.ptr))[0];
                    head->releasenum = bb_native2(val);
                    
                    val = ((uint16 *)(chunkres.data.ptr))[4];
                    head->checksum = bb_native2(val);
                    
                    for (jx=0; jx<6; jx++) {
                        head->serialnum[jx] = ((char *)(chunkres.data.ptr))[2+jx];
                    }
                    
                    map->zheader = head;
                }
                
                bb_unload_chunk(map, ix);
                break;
                
            case bb_ID_Reso:
                /* Resolution chunk: Get the window size data, and resolution
                    ratios for images. */
                    
                err = bb_load_chunk_by_number(map, bb_method_Memory, 
                    &chunkres, ix);
                if (err) 
                    return err;
                
                if (chunkres.length < 24)
                    return bb_err_Format;
                
                ptr = chunkres.data.ptr;
                len = chunkres.length;
                
                {
                    bb_resolution_t *reso = (bb_resolution_t *)malloc(sizeof(bb_resolution_t));
                    if (!reso)
                        return bb_err_Alloc;
                    
                    reso->px = bb_native4(ptr[0]);
                    reso->py = bb_native4(ptr[1]);
                    reso->minx = bb_native4(ptr[2]);
                    reso->miny = bb_native4(ptr[3]);
                    reso->maxx = bb_native4(ptr[4]);
                    reso->maxy = bb_native4(ptr[5]);
                    
                    map->resolution = reso;
                }

                ptr += 6;
                len -= 6*4;
                
                len = len / 28;
                
                if (len) {
                    bb_aux_pict_t *aux = (bb_aux_pict_t *)malloc(len * sizeof(bb_aux_pict_t)); 
                
                    for (jx=0; jx<len; jx++, ptr += 7) {
                        bb_result_t res;
                        
                        err = bb_load_resource(map, bb_method_DontLoad, &res, 
                            bb_ID_Pict, bb_native4(ptr[0]));
                        if (!err) {
                            bb_chunkdesc_t *chu = &(map->chunks[res.chunknum]);
                            if (chu->auxdatnum != -1)
                                return bb_err_Format; /* two image entries for this resource */
                            chu->auxdatnum = jx;
                            aux[jx].ratnum = bb_native4(ptr[1]);
                            aux[jx].ratden = bb_native4(ptr[2]);
                            aux[jx].minnum = bb_native4(ptr[3]);
                            aux[jx].minden = bb_native4(ptr[4]);
                            aux[jx].maxnum = bb_native4(ptr[5]);
                            aux[jx].maxden = bb_native4(ptr[6]);
                        }
                    }
                    
                    map->auxpict = aux;
                }
                
                bb_unload_chunk(map, ix);
                break;
            
            case bb_ID_Loop:
                /* Looping chunk: Get looping data for sounds. */
                    
                err = bb_load_chunk_by_number(map, bb_method_Memory, 
                    &chunkres, ix);
                if (err) 
                    return err;
                
                ptr = chunkres.data.ptr;
                len = chunkres.length;
                
                len = len / 8;
                
                if (len) {
                    bb_aux_sound_t *aux = (bb_aux_sound_t *)malloc(len * sizeof(bb_aux_sound_t)); 
                
                    for (jx=0; jx<len; jx++, ptr += 2) {
                        bb_result_t res;
                        
                        err = bb_load_resource(map, bb_method_DontLoad, &res, 
                            bb_ID_Snd, bb_native4(ptr[0]));
                        if (!err) {
                            bb_chunkdesc_t *chu = &(map->chunks[res.chunknum]);
                            if (chu->auxdatnum != -1)
                                return bb_err_Format; /* two looping entries for this resource */
                            chu->auxdatnum = jx;
                            aux[jx].repeats = bb_native4(ptr[1]);
                        }
                    }
                    
                    map->auxsound = aux;
                }
                
                bb_unload_chunk(map, ix);
                break;
            
            case bb_ID_Plte:
                /* Palette chunk: Don't get the palette info now, since it may
                    be large and the interpreter may not care. But remember
                    the chunk number in case the interpreter asks later. */
                    
                map->palettechunk = ix;
                break;
        }
    }
    
    return bb_err_None;
}

bb_err_t bb_destroy_map(bb_map_t *map)
{
    int ix;
    
    if (!map || !map->chunks || map->inited != bb_Inited_Magic)
        return bb_err_NotAMap;
    
    for (ix=0; ix<map->numchunks; ix++) {
        bb_chunkdesc_t *chu = &(map->chunks[ix]);
        if (chu->ptr) {
            free(chu->ptr);
            chu->ptr = NULL;
        }
    }
    
    if (map->chunks) {
        free(map->chunks);
        map->chunks = NULL;
    }
    
    map->numchunks = 0;
    
    if (map->resources) {
        free(map->resources);
        map->resources = NULL;
    }
    
    if (map->ressorted) {
        free(map->ressorted);
        map->ressorted = NULL;
    }
    
    map->numresources = 0;
    
    if (map->zheader) {
        free(map->zheader);
        map->zheader = NULL;
    }

    if (map->resolution) {
        free(map->resolution);
        map->resolution = NULL;
    }

    if (map->palette) {
        if (!map->palette->isdirect && map->palette->data.table.colors) {
            free(map->palette->data.table.colors);
            map->palette->data.table.colors = NULL;
        }
        free(map->palette);
        map->palette = NULL;
    }

    if (map->auxsound) {
        free(map->auxsound);
        map->auxsound = NULL;
    }

    if (map->auxpict) {
        free(map->auxpict);
        map->auxpict = NULL;
    }

    map->file = NULL;
    map->inited = 0;
    
    free(map);

    return bb_err_None;
}

/* Turn a four-byte constant into a string. This returns a static buffer,
    so if you call it twice, the old value gets overwritten. */
char *bb_id_to_string(uint32 id)
{
    static char buf[5];
    buf[0] = (id >> 24) & 0xff;
    buf[1] = (id >> 16) & 0xff;
    buf[2] = (id >> 8) & 0xff;
    buf[3] = (id) & 0xff;
    buf[4] = '\0';
    return buf;
}

/* Turn an error code into a string describing the error. */
char *bb_err_to_string(bb_err_t err)
{
    switch (err) {
        case bb_err_None:
            return "ok";
        case bb_err_CompileTime:
            return "library compiled wrong";
        case bb_err_Alloc:
            return "cannot allocate memory";
        case bb_err_Read:
            return "cannot read from file";
        case bb_err_NotAMap:
            return "map structure is bad";
        case bb_err_Format:
            return "bad format in Blorb file";
        case bb_err_NotFound:
            return "data not found";
        default:
            return "unknown error";
    }
}

/* This is used for binary searching and quicksorting the resource pointer list. */
static int sortsplot(bb_resdesc_t **p1, bb_resdesc_t **p2)
{
    bb_resdesc_t *v1 = *p1;
    bb_resdesc_t *v2 = *p2;
    if (v1->usage < v2->usage)
        return -1;
    if (v1->usage > v2->usage)
        return 1;
    return v1->resnum - v2->resnum;
}

bb_err_t bb_load_chunk_by_type(bb_map_t *map, int method, bb_result_t *res, 
    uint32 type, int count)
{
    int ix;
    
    for (ix=0; ix < map->numchunks; ix++) {
        if (map->chunks[ix].type == type) {
            if (count == 0)
                break;
            count--;
        }
    }
    
    if (ix >= map->numchunks) {
        return bb_err_NotFound;
    }
    
    return bb_load_chunk_by_number(map, method, res, ix);
}

bb_err_t bb_load_chunk_by_number(bb_map_t *map, int method, bb_result_t *res, 
    int chunknum)
{
    bb_chunkdesc_t *chu;
    
    if (chunknum < 0 || chunknum >= map->numchunks)
        return bb_err_NotFound;

    chu = &(map->chunks[chunknum]);
    
    switch (method) {
    
        case bb_method_DontLoad:
            /* do nothing */
            break;
            
        case bb_method_FilePos:
            res->data.startpos = chu->datpos;
            break;
            
        case bb_method_Memory:
            if (!chu->ptr) {
                bb_err_t err;
                size_t readlen;
                void *dat = malloc(chu->len);
                
                if (!dat)
                    return bb_err_Alloc;
                
                err = fseek(map->file, chu->datpos, 0);
                if (err) 
                    return bb_err_Read;
                
                readlen = fread(dat, 1, chu->len, map->file);
                if (readlen != chu->len)
                    return bb_err_Read;
                
                chu->ptr = dat;
            }
            res->data.ptr = chu->ptr;
            break;
    }
    
    res->chunknum = chunknum;
    res->length = chu->len;
    
    return bb_err_None;
}

bb_err_t bb_load_resource(bb_map_t *map, int method, bb_result_t *res, 
    uint32 usage, int resnum)
{
    bb_resdesc_t sample;
    bb_resdesc_t *ptr;
    bb_resdesc_t **found;
    
    sample.usage = usage;
    sample.resnum = resnum;
    ptr = &sample;
    
    found = bsearch(&ptr, map->ressorted, map->numresources, sizeof(bb_resdesc_t *), 
        (int (*)())&sortsplot);
    
    if (!found)
        return bb_err_NotFound;
    
    return bb_load_chunk_by_number(map, method, res, (*found)->chunknum);
}

bb_err_t bb_unload_chunk(bb_map_t *map, int chunknum)
{
    bb_chunkdesc_t *chu;
    
    if (chunknum < 0 || chunknum >= map->numchunks)
        return bb_err_NotFound;

    chu = &(map->chunks[chunknum]);
    
    if (chu->ptr) {
        free(chu->ptr);
        chu->ptr = NULL;
    }
    
    return bb_err_None;
}

bb_err_t bb_count_resources(bb_map_t *map, uint32 usage,
    int *num, int *min, int *max)
{
    int ix;
    int count, minval, maxval, val;
    
    count = 0;
    minval = 0;
    maxval = 0;
    
    for (ix=0; ix<map->numresources; ix++) {
        if (map->resources[ix].usage == usage) {
            val = map->resources[ix].resnum;
            if (count == 0) {
                count++;
                minval = val;
                maxval = val;
            }
            else {
                count++;
                if (val < minval)
                    minval = val;
                if (val > maxval)
                    maxval = val;
            }
        }
    }
    
    if (num)
        *num = count;
    if (min)
        *min = minval;
    if (max)
        *max = maxval;
    
    return bb_err_None;
}

uint16 bb_get_release_num(bb_map_t *map)
{
    return map->releasenum;
}

bb_zheader_t *bb_get_zheader(bb_map_t *map)
{
    return map->zheader;
}

bb_resolution_t *bb_get_resolution(bb_map_t *map)
{
    return map->resolution;
}

bb_err_t bb_get_palette(bb_map_t *map, bb_palette_t **res)
{
    int ix;
    bb_err_t err;

    if (res)
        *res = NULL;

    if (map->palettechunk < 0) {
        return bb_err_None;
    }
    
    if (!map->palette) {
        bb_result_t chunkres;
        bb_palette_t *pal;
        unsigned char *ptr;
        
        pal = (bb_palette_t *)malloc(sizeof(bb_palette_t));
        if (!pal)
            return bb_err_Alloc;
            
        err = bb_load_chunk_by_number(map, bb_method_Memory, &chunkres, 
            map->palettechunk);
        if (err)
            return err;
        
        ptr = chunkres.data.ptr;
        
        if (chunkres.length == 1) {
            int val = ptr[0];
            if (val != 16 && val != 32)
                return bb_err_Format;
            pal->isdirect = TRUE;
            pal->data.depth = val;
        }
        else {
            int size = chunkres.length / 3;
            bb_color_t *colors = (bb_color_t *)malloc(size * sizeof(bb_color_t));
            if (!colors)
                return bb_err_Alloc;
            if (size < 1 || size > 256)
                return bb_err_Format;
            for (ix=0; ix<size; ix++) {
                colors[ix].red   = ptr[ix*3+0];
                colors[ix].green = ptr[ix*3+1];
                colors[ix].blue  = ptr[ix*3+2];
            }
            pal->isdirect = FALSE;
            pal->data.table.numcolors = size;
            pal->data.table.colors = colors;
        }
        
        bb_unload_chunk(map, map->palettechunk);
        map->palette = pal;
    }
    
    if (res)
        *res = map->palette;
    return bb_err_None;
}

bb_err_t bb_load_resource_pict(bb_map_t *map, int method, bb_result_t *res, 
    int resnum, bb_aux_pict_t **auxdata)
{
    bb_err_t err;
    
    if (auxdata)
        *auxdata = NULL;
    
    err = bb_load_resource(map, method, res, bb_ID_Pict, resnum);
    if (err)
        return err;
    
    if (auxdata) {
        bb_chunkdesc_t *chu = &(map->chunks[res->chunknum]);
        if (chu->auxdatnum >= 0 && map->auxpict) {
            *auxdata = &(map->auxpict[chu->auxdatnum]);
        }
    }

    return bb_err_None;
}

bb_err_t bb_load_resource_snd(bb_map_t *map, int method, bb_result_t *res, 
    int resnum, bb_aux_sound_t **auxdata)
{
    bb_err_t err;
    
    if (auxdata)
        *auxdata = NULL;
    
    err = bb_load_resource(map, method, res, bb_ID_Pict, resnum);
    if (err)
        return err;
    
    if (auxdata) {
        bb_chunkdesc_t *chu = &(map->chunks[res->chunknum]);
        if (chu->auxdatnum >= 0 && map->auxsound) {
            *auxdata = &(map->auxsound[chu->auxdatnum]);
        }
    }

    return bb_err_None;
}