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COMMON: Add PackBitsReadStream to iff_container

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commit f01d4c5aa84d80bac1355f8b709f4e1244fec3dc 1 parent 0b72bd2
@tomaz82 tomaz82 authored
Showing with 80 additions and 8 deletions.
  1. +47 −0 common/iff_container.cpp
  2. +33 −8 common/iff_container.h
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47 common/iff_container.cpp
@@ -22,6 +22,7 @@
#include "common/iff_container.h"
#include "common/substream.h"
+#include "common/util.h"
namespace Common {
@@ -75,4 +76,50 @@ void IFFParser::parse(IFFCallback &callback) {
} while (!stop);
}
+
+PackBitsReadStream::PackBitsReadStream(Common::ReadStream &input) : _input(&input) {
+}
+
+PackBitsReadStream::~PackBitsReadStream() {
+}
+
+bool PackBitsReadStream::eos() const {
+ return _input->eos();
+}
+
+uint32 PackBitsReadStream::read(void *dataPtr, uint32 dataSize) {
+ byte *out = (byte *)dataPtr;
+ uint32 left = dataSize;
+
+ uint32 lenR = 0, lenW = 0;
+ while (left > 0 && !_input->eos()) {
+ lenR = _input->readByte();
+
+ if (lenR == 128) {
+ // no-op
+ lenW = 0;
+ } else if (lenR <= 127) {
+ // literal run
+ lenR++;
+ lenW = MIN(lenR, left);
+ for (uint32 j = 0; j < lenW; j++) {
+ *out++ = _input->readByte();
+ }
+ for (; lenR > lenW; lenR--) {
+ _input->readByte();
+ }
+ } else { // len > 128
+ // expand run
+ lenW = MIN((256 - lenR) + 1, left);
+ byte val = _input->readByte();
+ memset(out, val, lenW);
+ out += lenW;
+ }
+
+ left -= lenW;
+ }
+
+ return dataSize - left;
+}
+
} // End of namespace Common
View
41 common/iff_container.h
@@ -77,22 +77,22 @@ page 376) */
#define ID_copy MKTAG('(','c',')',' ')
/* EA IFF 85 Generic Copyright text chunk */
-/* ILBM chunks */
+/* IFF chunks */
#define ID_BMHD MKTAG('B','M','H','D')
-/* ILBM BitmapHeader */
+/* IFF BitmapHeader */
#define ID_CMAP MKTAG('C','M','A','P')
-/* ILBM 8bit RGB colormap */
+/* IFF 8bit RGB colormap */
#define ID_GRAB MKTAG('G','R','A','B')
-/* ILBM "hotspot" coordiantes */
+/* IFF "hotspot" coordiantes */
#define ID_DEST MKTAG('D','E','S','T')
-/* ILBM destination image info */
+/* IFF destination image info */
#define ID_SPRT MKTAG('S','P','R','T')
-/* ILBM sprite identifier */
+/* IFF sprite identifier */
#define ID_CAMG MKTAG('C','A','M','G')
/* Amiga viewportmodes */
#define ID_BODY MKTAG('B','O','D','Y')
-/* ILBM image data */
+/* IFF image data */
#define ID_CRNG MKTAG('C','R','N','G')
/* color cycling */
#define ID_CCRT MKTAG('C','C','R','T')
@@ -114,7 +114,7 @@ page 376) */
#define ID_PCHG MKTAG('P','C','H','G')
/* Line by line palette control information (Sebastiano Vigna) */
#define ID_PRVW MKTAG('P','R','V','W')
-/* A mini duplicate ILBM used for preview (Gary Bonham) */
+/* A mini duplicate IFF used for preview (Gary Bonham) */
#define ID_XBMI MKTAG('X','B','M','I')
/* eXtended BitMap Information (Soft-Logik) */
#define ID_CTBL MKTAG('C','T','B','L')
@@ -239,6 +239,31 @@ class IFFParser {
};
+/**
+ * Decode a given PackBits encoded stream.
+ *
+ * PackBits is an RLE compression algorithm introduced by Apple. It is also
+ * used to encode ILBM and PBM subtypes of IFF files, and some flavors of
+ * TIFF.
+ *
+ * As there is no compression across row boundaries in the above formats,
+ * read() will extract a *new* line on each call, discarding any alignment
+ * or padding.
+ */
+class PackBitsReadStream : public Common::ReadStream {
+
+protected:
+ Common::ReadStream *_input;
+
+public:
+ PackBitsReadStream(Common::ReadStream &input);
+ ~PackBitsReadStream();
+
+ virtual bool eos() const;
+
+ uint32 read(void *dataPtr, uint32 dataSize);
+};
+
} // namespace Common
#endif
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