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/* ______ ___ ___
* /\ _ \ /\_ \ /\_ \
* \ \ \L\ \\//\ \ \//\ \ __ __ _ __ ___
* \ \ __ \ \ \ \ \ \ \ /'__`\ /'_ `\/\`'__\/ __`\
* \ \ \/\ \ \_\ \_ \_\ \_/\ __//\ \L\ \ \ \//\ \L\ \
* \ \_\ \_\/\____\/\____\ \____\ \____ \ \_\\ \____/
* \/_/\/_/\/____/\/____/\/____/\/___L\ \/_/ \/___/
* /\____/
* \_/__/
*
* LBM reader.
*
* By Adrian Oboroc.
*
* See readme.txt for copyright information.
*/
#include <string.h>
#include "allegro.h"
#include "allegro/internal/aintern.h"
/* load_lbm:
* Loads IFF ILBM/PBM files with up to 8 bits per pixel, returning
* a bitmap structure and storing the palette data in the specified
* palette (this should be an array of at least 256 RGB structures).
*/
BITMAP *load_lbm(AL_CONST char *filename, RGB *pal)
{
#define IFF_FORM 0x4D524F46 /* 'FORM' - IFF FORM structure */
#define IFF_ILBM 0x4D424C49 /* 'ILBM' - interleaved bitmap */
#define IFF_PBM 0x204D4250 /* 'PBM ' - new DP2e format */
#define IFF_BMHD 0x44484D42 /* 'BMHD' - bitmap header */
#define IFF_CMAP 0x50414D43 /* 'CMAP' - color map (palette) */
#define IFF_BODY 0x59444F42 /* 'BODY' - bitmap data */
PACKFILE *f;
PALETTE tmppal;
BITMAP *b = NULL;
int w, h, i, x, y, bpl, ppl, pbm_mode;
char ch, cmp_type, bit_plane, color_depth;
unsigned char uc, check_flags, bit_mask, *line_buf;
long data_id, len, l;
int dest_depth = _color_load_depth(8, FALSE);
ASSERT(filename);
if (!pal)
pal = tmppal;
f = pack_fopen(filename, F_READ);
if (!f)
return NULL;
data_id = pack_igetl(f); /* read file header */
if (data_id != IFF_FORM) { /* check for 'FORM' id */
pack_fclose(f);
return NULL;
}
pack_igetl(f); /* skip FORM length */
data_id = pack_igetl(f); /* read id */
/* check image type ('ILBM' or 'PBM ') */
if ((data_id != IFF_ILBM) && (data_id != IFF_PBM)) {
pack_fclose(f);
return NULL;
}
pbm_mode = data_id == IFF_PBM;
data_id = pack_igetl(f); /* read id */
if (data_id != IFF_BMHD) { /* check for header */
pack_fclose(f);
return NULL;
}
len = pack_mgetl(f); /* read header length */
if (len != 20) { /* check, if it is right */
pack_fclose(f);
return NULL;
}
w = pack_mgetw(f); /* read screen width */
h = pack_mgetw(f); /* read screen height */
pack_igetw(f); /* skip initial x position */
pack_igetw(f); /* skip initial y position */
color_depth = pack_getc(f); /* get image depth */
if (color_depth > 8) {
pack_fclose(f);
return NULL;
}
pack_getc(f); /* skip masking type */
cmp_type = pack_getc(f); /* get compression type */
if ((cmp_type != 0) && (cmp_type != 1)) {
pack_fclose(f);
return NULL;
}
*allegro_errno = 0;
pack_getc(f); /* skip unused field */
pack_igetw(f); /* skip transparent color */
pack_getc(f); /* skip x aspect ratio */
pack_getc(f); /* skip y aspect ratio */
pack_igetw(f); /* skip default page width */
pack_igetw(f); /* skip default page height */
check_flags = 0;
do { /* We'll use cycle to skip possible junk */
/* chunks: ANNO, CAMG, GRAB, DEST, TEXT etc. */
data_id = pack_igetl(f);
switch(data_id) {
case IFF_CMAP:
memset(pal, 0, 256 * 3);
len = pack_mgetl(f) / 3;
for (i=0; i<len; i++) {
pal[i].r = pack_getc(f) >> 2;
pal[i].g = pack_getc(f) >> 2;
pal[i].b = pack_getc(f) >> 2;
}
check_flags |= 1; /* flag "palette read" */
break;
case IFF_BODY:
pack_igetl(f); /* skip BODY size */
b = create_bitmap_ex(8, w, h);
if (!b) {
pack_fclose(f);
return NULL;
}
memset(b->line[0], 0, w * h);
if (pbm_mode)
bpl = w;
else {
bpl = w >> 3; /* calc bytes per line */
if (w & 7) /* for finish bits */
bpl++;
}
if (bpl & 1) /* alignment */
bpl++;
line_buf = _AL_MALLOC_ATOMIC(bpl);
if (!line_buf) {
pack_fclose(f);
return NULL;
}
if (pbm_mode) {
for (y = 0; y < h; y++) {
if (cmp_type) {
i = 0;
while (i < bpl) {
uc = pack_getc(f);
if (uc < 128) {
uc++;
pack_fread(&line_buf[i], uc, f);
i += uc;
}
else if (uc > 128) {
uc = 257 - uc;
ch = pack_getc(f);
memset(&line_buf[i], ch, uc);
i += uc;
}
/* 128 (0x80) means NOP - no operation */
}
}
else /* pure theoretical situation */
pack_fread(line_buf, bpl, f);
memcpy(b->line[y], line_buf, bpl);
}
}
else {
for (y = 0; y < h; y++) {
for (bit_plane = 0; bit_plane < color_depth; bit_plane++) {
if (cmp_type) {
i = 0;
while (i < bpl) {
uc = pack_getc(f);
if (uc < 128) {
uc++;
pack_fread(&line_buf[i], uc, f);
i += uc;
}
else if (uc > 128) {
uc = 257 - uc;
ch = pack_getc(f);
memset(&line_buf[i], ch, uc);
i += uc;
}
/* 128 (0x80) means NOP - no operation */
}
}
else
pack_fread(line_buf, bpl, f);
bit_mask = 1 << bit_plane;
ppl = bpl; /* for all pixel blocks */
if (w & 7) /* may be, except the */
ppl--; /* the last */
for (x = 0; x < ppl; x++) {
if (line_buf[x] & 128)
b->line[y][x * 8] |= bit_mask;
if (line_buf[x] & 64)
b->line[y][x * 8 + 1] |= bit_mask;
if (line_buf[x] & 32)
b->line[y][x * 8 + 2] |= bit_mask;
if (line_buf[x] & 16)
b->line[y][x * 8 + 3] |= bit_mask;
if (line_buf[x] & 8)
b->line[y][x * 8 + 4] |= bit_mask;
if (line_buf[x] & 4)
b->line[y][x * 8 + 5] |= bit_mask;
if (line_buf[x] & 2)
b->line[y][x * 8 + 6] |= bit_mask;
if (line_buf[x] & 1)
b->line[y][x * 8 + 7] |= bit_mask;
}
/* last pixel block */
if (w & 7) {
x = bpl - 1;
/* no necessary to check if (w & 7) > 0 in */
/* first condition, because (w & 7) != 0 */
if (line_buf[x] & 128)
b->line[y][x * 8] |= bit_mask;
if ((line_buf[x] & 64) && ((w & 7) > 1))
b->line[y][x * 8 + 1] |= bit_mask;
if ((line_buf[x] & 32) && ((w & 7) > 2))
b->line[y][x * 8 + 2] |= bit_mask;
if ((line_buf[x] & 16) && ((w & 7) > 3))
b->line[y][x * 8 + 3] |= bit_mask;
if ((line_buf[x] & 8) && ((w & 7) > 4))
b->line[y][x * 8 + 4] |= bit_mask;
if ((line_buf[x] & 4) && ((w & 7) > 5))
b->line[y][x * 8 + 5] |= bit_mask;
if ((line_buf[x] & 2) && ((w & 7) > 6))
b->line[y][x * 8 + 6] |= bit_mask;
if ((line_buf[x] & 1) && ((w & 7) > 7))
b->line[y][x * 8 + 7] |= bit_mask;
}
}
}
}
_AL_FREE(line_buf);
check_flags |= 2; /* flag "bitmap read" */
break;
default: /* skip useless chunks */
len = pack_mgetl(f);
if (len & 1)
len++;
for (l=0; l < (len >> 1); l++)
pack_igetw(f);
}
/* Exit from loop if we are at the end of file, */
/* or if we loaded both bitmap and palette */
} while ((check_flags != 3) && (!pack_feof(f)));
pack_fclose(f);
if (check_flags != 3) {
if (check_flags & 2)
destroy_bitmap(b);
return FALSE;
}
if (*allegro_errno) {
destroy_bitmap(b);
return FALSE;
}
if (dest_depth != 8)
b = _fixup_loaded_bitmap(b, pal, dest_depth);
return b;
}
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