mirror of
https://gitea.wildfiregames.com/0ad/0ad.git
synced 2026-07-10 09:55:16 +00:00
janwas
104 lines
2.9 KiB
C++
104 lines
2.9 KiB
C++
/**
|
|
* =========================================================================
|
|
* File : compression.h
|
|
* Project : 0 A.D.
|
|
* Description : interface for compressing/decompressing data streams.
|
|
* : currently implements "deflate" (RFC1951).
|
|
* =========================================================================
|
|
*/
|
|
|
|
// license: GPL; see lib/license.txt
|
|
|
|
#ifndef INCLUDED_COMPRESSION
|
|
#define INCLUDED_COMPRESSION
|
|
|
|
|
|
namespace ERR
|
|
{
|
|
const LibError COMPRESSION_UNKNOWN_METHOD = -110300;
|
|
}
|
|
|
|
enum ContextType
|
|
{
|
|
CT_COMPRESSION,
|
|
CT_DECOMPRESSION
|
|
};
|
|
|
|
enum CompressionMethod
|
|
{
|
|
CM_NONE,
|
|
|
|
// zlib "deflate" - see RFC 1750, 1751.
|
|
CM_DEFLATE,
|
|
|
|
CM_UNSUPPORTED
|
|
};
|
|
|
|
extern uintptr_t comp_alloc(ContextType type, CompressionMethod method);
|
|
|
|
/**
|
|
* @return an upper bound on the output size for the given amount of input.
|
|
* this is used when allocating a single buffer for the whole operation.
|
|
**/
|
|
extern size_t comp_max_output_size(uintptr_t ctx, size_t inSize);
|
|
|
|
/**
|
|
* set output buffer for subsequent comp_feed() calls.
|
|
*
|
|
* due to the comp_finish interface, output buffers must be contiguous or
|
|
* identical (otherwise IsAllowableOutputBuffer will complain).
|
|
**/
|
|
extern void comp_set_output(uintptr_t ctx, u8* out, size_t outSize);
|
|
|
|
/**
|
|
* allocate a new output buffer.
|
|
*
|
|
* @param size [bytes] to allocate.
|
|
*
|
|
* if a buffer had previously been allocated and is large enough, it is
|
|
* reused (this reduces the number of allocations). the buffer is
|
|
* automatically freed by comp_free.
|
|
**/
|
|
extern LibError comp_alloc_output(uintptr_t ctx, size_t inSize);
|
|
|
|
/**
|
|
* 'feed' the given buffer to the compressor/decompressor.
|
|
*
|
|
* @return number of output bytes produced or a negative LibError.
|
|
* note that 0 is a legitimate return value - this happens if the input
|
|
* buffer is small and the codec hasn't produced any output.
|
|
*
|
|
* note: after this call returns, the buffer may be overwritten or freed;
|
|
* we take care of copying and queuing any data that remains (e.g. due to
|
|
* lack of output buffer space).
|
|
**/
|
|
extern ssize_t comp_feed(uintptr_t ctx, const u8* in, size_t inSize);
|
|
|
|
/**
|
|
* conclude the compression/decompression operation.
|
|
*
|
|
* @param out, outSize receive the output buffer. this assumes identical or
|
|
* contiguous addresses were passed, which comp_set_output ensures.
|
|
* @param checksum
|
|
*
|
|
* note: this must always be called (even if the output buffer is already
|
|
* known) because it feeds any remaining queued input buffers.
|
|
**/
|
|
extern LibError comp_finish(uintptr_t ctx, u8** out, size_t* out_size, u32* checksum);
|
|
|
|
/**
|
|
* clear all previous state and prepare for reuse.
|
|
*
|
|
* this is as if the object were destroyed and re-created, but more
|
|
* efficient since it avoids reallocating a considerable amount of memory
|
|
* (about 200KB for LZ).
|
|
**/
|
|
extern void comp_reset(uintptr_t ctx);
|
|
|
|
/**
|
|
* free this context and all associated memory.
|
|
**/
|
|
extern void comp_free(uintptr_t ctx);
|
|
|
|
#endif // #ifndef INCLUDED_COMPRESSION
|