Add support for compressed PDF streams, using Simon's new deflate library.

[sgt/halibut] / deflate.h

diff --git a/deflate.h b/deflate.h
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+/*
+ * Header file for my independent implementation of Deflate
+ * (RFC1951) compression.
+ */
+
+#ifndef DEFLATE_DEFLATE_H
+#define DEFLATE_DEFLATE_H
+
+enum {
+    DEFLATE_TYPE_BARE,
+    DEFLATE_TYPE_ZLIB
+};
+
+/* ----------------------------------------------------------------------
+ * Compression functions. Create a compression context with
+ * deflate_compress_new(); feed it data with repeated calls to
+ * deflate_compress_data(); destroy it with
+ * deflate_compress_free().
+ */
+
+typedef struct deflate_compress_ctx deflate_compress_ctx;
+
+/*
+ * Create a new compression context. `type' indicates whether it's
+ * bare Deflate (as used in, say, zip files) or Zlib (as used in,
+ * say, PDF).
+ */
+deflate_compress_ctx *deflate_compress_new(int type);
+
+/*
+ * Free a compression context previously allocated by
+ * deflate_compress_new().
+ */
+void deflate_compress_free(deflate_compress_ctx *ctx);
+
+/*
+ * Give the compression context some data to compress. The input
+ * data is passed in `inblock', and has length `inlen'. This
+ * function may or may not produce some output data; if so, it is
+ * written to a dynamically allocated chunk of memory, a pointer to
+ * that memory is stored in `outblock', and the length of output
+ * data is stored in `outlen'. It is common for no data to be
+ * output, if the input data has merely been stored in internal
+ * buffers.
+ * 
+ * `flushtype' indicates whether you want to force buffered data to
+ * be output. It can be one of the following values:
+ * 
+ *  - DEFLATE_NO_FLUSH: nothing is output if the compressor would
+ *    rather not. Use this when the best compression is desired
+ *    (i.e. most of the time).
+ *
+ *  - DEFLATE_SYNC_FLUSH: all the buffered data is output, but the
+ *    compressed data stream remains open and ready to continue
+ *    compressing data. Use this in interactive protocols when a
+ *    single compressed data stream is split across several network
+ *    packets.
+ * 
+ *  - DEFLATE_END_OF_DATA: all the buffered data is output and the
+ *    compressed data stream is cleaned up. Any checksums required
+ *    at the end of the stream are also output.
+ */
+int deflate_compress_data(deflate_compress_ctx *ctx,
+                         const void *inblock, int inlen, int flushtype,
+                         void **outblock, int *outlen);
+
+enum {
+    DEFLATE_NO_FLUSH,
+    DEFLATE_SYNC_FLUSH,
+    DEFLATE_END_OF_DATA
+};
+
+/* ----------------------------------------------------------------------
+ * Decompression functions. Create a decompression context with
+ * deflate_decompress_new(); feed it data with repeated calls to
+ * deflate_decompress_data(); destroy it with
+ * deflate_decompress_free().
+ */
+
+typedef struct deflate_decompress_ctx deflate_decompress_ctx;
+
+/*
+ * Create a new decompression context. `type' means the same as it
+ * does in deflate_compress_new().
+ */
+deflate_decompress_ctx *deflate_decompress_new(int type);
+
+/*
+ * Free a decompression context previously allocated by
+ * deflate_decompress_new().
+ */
+void deflate_decompress_free(deflate_decompress_ctx *ctx);
+
+/*
+ * Give the decompression context some data to decompress. The
+ * input data is passed in `inblock', and has length `inlen'. This
+ * function may or may not produce some output data; if so, it is
+ * written to a dynamically allocated chunk of memory, a pointer to
+ * that memory is stored in `outblock', and the length of output
+ * data is stored in `outlen'.
+ *
+ * FIXME: error reporting?
+ */
+int deflate_decompress_data(deflate_decompress_ctx *ctx,
+                           const void *inblock, int inlen,
+                           void **outblock, int *outlen);
+
+#endif /* DEFLATE_DEFLATE_H */