diff options
Diffstat (limited to 'src/enet/compress.c')
| -rw-r--r-- | src/enet/compress.c | 654 |
1 files changed, 0 insertions, 654 deletions
diff --git a/src/enet/compress.c b/src/enet/compress.c deleted file mode 100644 index 784489a78..000000000 --- a/src/enet/compress.c +++ /dev/null @@ -1,654 +0,0 @@ -/** - @file compress.c - @brief An adaptive order-2 PPM range coder -*/ -#define ENET_BUILDING_LIB 1 -#include <string.h> -#include "enet/enet.h" - -typedef struct _ENetSymbol -{ - /* binary indexed tree of symbols */ - enet_uint8 value; - enet_uint8 count; - enet_uint16 under; - enet_uint16 left, right; - - /* context defined by this symbol */ - enet_uint16 symbols; - enet_uint16 escapes; - enet_uint16 total; - enet_uint16 parent; -} ENetSymbol; - -/* adaptation constants tuned aggressively for small packet sizes rather than large file compression */ -enum -{ - ENET_RANGE_CODER_TOP = 1<<24, - ENET_RANGE_CODER_BOTTOM = 1<<16, - - ENET_CONTEXT_SYMBOL_DELTA = 3, - ENET_CONTEXT_SYMBOL_MINIMUM = 1, - ENET_CONTEXT_ESCAPE_MINIMUM = 1, - - ENET_SUBCONTEXT_ORDER = 2, - ENET_SUBCONTEXT_SYMBOL_DELTA = 2, - ENET_SUBCONTEXT_ESCAPE_DELTA = 5 -}; - -/* context exclusion roughly halves compression speed, so disable for now */ -#undef ENET_CONTEXT_EXCLUSION - -typedef struct _ENetRangeCoder -{ - /* only allocate enough symbols for reasonable MTUs, would need to be larger for large file compression */ - ENetSymbol symbols[4096]; -} ENetRangeCoder; - -void * -enet_range_coder_create (void) -{ - ENetRangeCoder * rangeCoder = (ENetRangeCoder *) enet_malloc (sizeof (ENetRangeCoder)); - if (rangeCoder == NULL) - return NULL; - - return rangeCoder; -} - -void -enet_range_coder_destroy (void * context) -{ - ENetRangeCoder * rangeCoder = (ENetRangeCoder *) context; - if (rangeCoder == NULL) - return; - - enet_free (rangeCoder); -} - -#define ENET_SYMBOL_CREATE(symbol, value_, count_) \ -{ \ - symbol = & rangeCoder -> symbols [nextSymbol ++]; \ - symbol -> value = value_; \ - symbol -> count = count_; \ - symbol -> under = count_; \ - symbol -> left = 0; \ - symbol -> right = 0; \ - symbol -> symbols = 0; \ - symbol -> escapes = 0; \ - symbol -> total = 0; \ - symbol -> parent = 0; \ -} - -#define ENET_CONTEXT_CREATE(context, escapes_, minimum) \ -{ \ - ENET_SYMBOL_CREATE (context, 0, 0); \ - (context) -> escapes = escapes_; \ - (context) -> total = escapes_ + 256*minimum; \ - (context) -> symbols = 0; \ -} - -static enet_uint16 -enet_symbol_rescale (ENetSymbol * symbol) -{ - enet_uint16 total = 0; - for (;;) - { - symbol -> count -= symbol->count >> 1; - symbol -> under = symbol -> count; - if (symbol -> left) - symbol -> under += enet_symbol_rescale (symbol + symbol -> left); - total += symbol -> under; - if (! symbol -> right) break; - symbol += symbol -> right; - } - return total; -} - -#define ENET_CONTEXT_RESCALE(context, minimum) \ -{ \ - (context) -> total = (context) -> symbols ? enet_symbol_rescale ((context) + (context) -> symbols) : 0; \ - (context) -> escapes -= (context) -> escapes >> 1; \ - (context) -> total += (context) -> escapes + 256*minimum; \ -} - -#define ENET_RANGE_CODER_OUTPUT(value) \ -{ \ - if (outData >= outEnd) \ - return 0; \ - * outData ++ = value; \ -} - -#define ENET_RANGE_CODER_ENCODE(under, count, total) \ -{ \ - encodeRange /= (total); \ - encodeLow += (under) * encodeRange; \ - encodeRange *= (count); \ - for (;;) \ - { \ - if((encodeLow ^ (encodeLow + encodeRange)) >= ENET_RANGE_CODER_TOP) \ - { \ - if(encodeRange >= ENET_RANGE_CODER_BOTTOM) break; \ - encodeRange = -encodeLow & (ENET_RANGE_CODER_BOTTOM - 1); \ - } \ - ENET_RANGE_CODER_OUTPUT (encodeLow >> 24); \ - encodeRange <<= 8; \ - encodeLow <<= 8; \ - } \ -} - -#define ENET_RANGE_CODER_FLUSH \ -{ \ - while (encodeLow) \ - { \ - ENET_RANGE_CODER_OUTPUT (encodeLow >> 24); \ - encodeLow <<= 8; \ - } \ -} - -#define ENET_RANGE_CODER_FREE_SYMBOLS \ -{ \ - if (nextSymbol >= sizeof (rangeCoder -> symbols) / sizeof (ENetSymbol) - ENET_SUBCONTEXT_ORDER ) \ - { \ - nextSymbol = 0; \ - ENET_CONTEXT_CREATE (root, ENET_CONTEXT_ESCAPE_MINIMUM, ENET_CONTEXT_SYMBOL_MINIMUM); \ - predicted = 0; \ - order = 0; \ - } \ -} - -#define ENET_CONTEXT_ENCODE(context, symbol_, value_, under_, count_, update, minimum) \ -{ \ - under_ = value*minimum; \ - count_ = minimum; \ - if (! (context) -> symbols) \ - { \ - ENET_SYMBOL_CREATE (symbol_, value_, update); \ - (context) -> symbols = symbol_ - (context); \ - } \ - else \ - { \ - ENetSymbol * node = (context) + (context) -> symbols; \ - for (;;) \ - { \ - if (value_ < node -> value) \ - { \ - node -> under += update; \ - if (node -> left) { node += node -> left; continue; } \ - ENET_SYMBOL_CREATE (symbol_, value_, update); \ - node -> left = symbol_ - node; \ - } \ - else \ - if (value_ > node -> value) \ - { \ - under_ += node -> under; \ - if (node -> right) { node += node -> right; continue; } \ - ENET_SYMBOL_CREATE (symbol_, value_, update); \ - node -> right = symbol_ - node; \ - } \ - else \ - { \ - count_ += node -> count; \ - under_ += node -> under - node -> count; \ - node -> under += update; \ - node -> count += update; \ - symbol_ = node; \ - } \ - break; \ - } \ - } \ -} - -#ifdef ENET_CONTEXT_EXCLUSION -static const ENetSymbol emptyContext = { 0, 0, 0, 0, 0, 0, 0, 0, 0 }; - -#define ENET_CONTEXT_WALK(context, body) \ -{ \ - const ENetSymbol * node = (context) + (context) -> symbols; \ - const ENetSymbol * stack [256]; \ - size_t stackSize = 0; \ - while (node -> left) \ - { \ - stack [stackSize ++] = node; \ - node += node -> left; \ - } \ - for (;;) \ - { \ - body; \ - if (node -> right) \ - { \ - node += node -> right; \ - while (node -> left) \ - { \ - stack [stackSize ++] = node; \ - node += node -> left; \ - } \ - } \ - else \ - if (stackSize <= 0) \ - break; \ - else \ - node = stack [-- stackSize]; \ - } \ -} - -#define ENET_CONTEXT_ENCODE_EXCLUDE(context, value_, under, total, minimum) \ -ENET_CONTEXT_WALK(context, { \ - if (node -> value != value_) \ - { \ - enet_uint16 parentCount = rangeCoder -> symbols [node -> parent].count + minimum; \ - if (node -> value < value_) \ - under -= parentCount; \ - total -= parentCount; \ - } \ -}) -#endif - -size_t -enet_range_coder_compress (void * context, const ENetBuffer * inBuffers, size_t inBufferCount, size_t inLimit, enet_uint8 * outData, size_t outLimit) -{ - ENetRangeCoder * rangeCoder = (ENetRangeCoder *) context; - enet_uint8 * outStart = outData, * outEnd = & outData [outLimit]; - const enet_uint8 * inData, * inEnd; - enet_uint32 encodeLow = 0, encodeRange = ~0; - ENetSymbol * root; - enet_uint16 predicted = 0; - size_t order = 0, nextSymbol = 0; - - if (rangeCoder == NULL || inBufferCount <= 0 || inLimit <= 0) - return 0; - - inData = (const enet_uint8 *) inBuffers -> data; - inEnd = & inData [inBuffers -> dataLength]; - inBuffers ++; - inBufferCount --; - - ENET_CONTEXT_CREATE (root, ENET_CONTEXT_ESCAPE_MINIMUM, ENET_CONTEXT_SYMBOL_MINIMUM); - - for (;;) - { - ENetSymbol * subcontext, * symbol; -#ifdef ENET_CONTEXT_EXCLUSION - const ENetSymbol * childContext = & emptyContext; -#endif - enet_uint8 value; - enet_uint16 count, under, * parent = & predicted, total; - if (inData >= inEnd) - { - if (inBufferCount <= 0) - break; - inData = (const enet_uint8 *) inBuffers -> data; - inEnd = & inData [inBuffers -> dataLength]; - inBuffers ++; - inBufferCount --; - } - value = * inData ++; - - for (subcontext = & rangeCoder -> symbols [predicted]; - subcontext != root; -#ifdef ENET_CONTEXT_EXCLUSION - childContext = subcontext, -#endif - subcontext = & rangeCoder -> symbols [subcontext -> parent]) - { - ENET_CONTEXT_ENCODE (subcontext, symbol, value, under, count, ENET_SUBCONTEXT_SYMBOL_DELTA, 0); - * parent = symbol - rangeCoder -> symbols; - parent = & symbol -> parent; - total = subcontext -> total; -#ifdef ENET_CONTEXT_EXCLUSION - if (childContext -> total > ENET_SUBCONTEXT_SYMBOL_DELTA + ENET_SUBCONTEXT_ESCAPE_DELTA) - ENET_CONTEXT_ENCODE_EXCLUDE (childContext, value, under, total, 0); -#endif - if (count > 0) - { - ENET_RANGE_CODER_ENCODE (subcontext -> escapes + under, count, total); - } - else - { - if (subcontext -> escapes > 0 && subcontext -> escapes < total) - ENET_RANGE_CODER_ENCODE (0, subcontext -> escapes, total); - subcontext -> escapes += ENET_SUBCONTEXT_ESCAPE_DELTA; - subcontext -> total += ENET_SUBCONTEXT_ESCAPE_DELTA; - } - subcontext -> total += ENET_SUBCONTEXT_SYMBOL_DELTA; - if (count > 0xFF - 2*ENET_SUBCONTEXT_SYMBOL_DELTA || subcontext -> total > ENET_RANGE_CODER_BOTTOM - 0x100) - ENET_CONTEXT_RESCALE (subcontext, 0); - if (count > 0) goto nextInput; - } - - ENET_CONTEXT_ENCODE (root, symbol, value, under, count, ENET_CONTEXT_SYMBOL_DELTA, ENET_CONTEXT_SYMBOL_MINIMUM); - * parent = symbol - rangeCoder -> symbols; - parent = & symbol -> parent; - total = root -> total; -#ifdef ENET_CONTEXT_EXCLUSION - if (childContext -> total > ENET_SUBCONTEXT_SYMBOL_DELTA + ENET_SUBCONTEXT_ESCAPE_DELTA) - ENET_CONTEXT_ENCODE_EXCLUDE (childContext, value, under, total, ENET_CONTEXT_SYMBOL_MINIMUM); -#endif - ENET_RANGE_CODER_ENCODE (root -> escapes + under, count, total); - root -> total += ENET_CONTEXT_SYMBOL_DELTA; - if (count > 0xFF - 2*ENET_CONTEXT_SYMBOL_DELTA + ENET_CONTEXT_SYMBOL_MINIMUM || root -> total > ENET_RANGE_CODER_BOTTOM - 0x100) - ENET_CONTEXT_RESCALE (root, ENET_CONTEXT_SYMBOL_MINIMUM); - - nextInput: - if (order >= ENET_SUBCONTEXT_ORDER) - predicted = rangeCoder -> symbols [predicted].parent; - else - order ++; - ENET_RANGE_CODER_FREE_SYMBOLS; - } - - ENET_RANGE_CODER_FLUSH; - - return (size_t) (outData - outStart); -} - -#define ENET_RANGE_CODER_SEED \ -{ \ - if (inData < inEnd) decodeCode |= * inData ++ << 24; \ - if (inData < inEnd) decodeCode |= * inData ++ << 16; \ - if (inData < inEnd) decodeCode |= * inData ++ << 8; \ - if (inData < inEnd) decodeCode |= * inData ++; \ -} - -#define ENET_RANGE_CODER_READ(total) ((decodeCode - decodeLow) / (decodeRange /= (total))) - -#define ENET_RANGE_CODER_DECODE(under, count, total) \ -{ \ - decodeLow += (under) * decodeRange; \ - decodeRange *= (count); \ - for (;;) \ - { \ - if((decodeLow ^ (decodeLow + decodeRange)) >= ENET_RANGE_CODER_TOP) \ - { \ - if(decodeRange >= ENET_RANGE_CODER_BOTTOM) break; \ - decodeRange = -decodeLow & (ENET_RANGE_CODER_BOTTOM - 1); \ - } \ - decodeCode <<= 8; \ - if (inData < inEnd) \ - decodeCode |= * inData ++; \ - decodeRange <<= 8; \ - decodeLow <<= 8; \ - } \ -} - -#define ENET_CONTEXT_DECODE(context, symbol_, code, value_, under_, count_, update, minimum, createRoot, visitNode, createRight, createLeft) \ -{ \ - under_ = 0; \ - count_ = minimum; \ - if (! (context) -> symbols) \ - { \ - createRoot; \ - } \ - else \ - { \ - ENetSymbol * node = (context) + (context) -> symbols; \ - for (;;) \ - { \ - enet_uint16 after = under_ + node -> under + (node -> value + 1)*minimum, before = node -> count + minimum; \ - visitNode; \ - if (code >= after) \ - { \ - under_ += node -> under; \ - if (node -> right) { node += node -> right; continue; } \ - createRight; \ - } \ - else \ - if (code < after - before) \ - { \ - node -> under += update; \ - if (node -> left) { node += node -> left; continue; } \ - createLeft; \ - } \ - else \ - { \ - value_ = node -> value; \ - count_ += node -> count; \ - under_ = after - before; \ - node -> under += update; \ - node -> count += update; \ - symbol_ = node; \ - } \ - break; \ - } \ - } \ -} - -#define ENET_CONTEXT_TRY_DECODE(context, symbol_, code, value_, under_, count_, update, minimum, exclude) \ -ENET_CONTEXT_DECODE (context, symbol_, code, value_, under_, count_, update, minimum, return 0, exclude (node -> value, after, before), return 0, return 0) - -#define ENET_CONTEXT_ROOT_DECODE(context, symbol_, code, value_, under_, count_, update, minimum, exclude) \ -ENET_CONTEXT_DECODE (context, symbol_, code, value_, under_, count_, update, minimum, \ - { \ - value_ = code / minimum; \ - under_ = code - code%minimum; \ - ENET_SYMBOL_CREATE (symbol_, value_, update); \ - (context) -> symbols = symbol_ - (context); \ - }, \ - exclude (node -> value, after, before), \ - { \ - value_ = node->value + 1 + (code - after)/minimum; \ - under_ = code - (code - after)%minimum; \ - ENET_SYMBOL_CREATE (symbol_, value_, update); \ - node -> right = symbol_ - node; \ - }, \ - { \ - value_ = node->value - 1 - (after - before - code - 1)/minimum; \ - under_ = code - (after - before - code - 1)%minimum; \ - ENET_SYMBOL_CREATE (symbol_, value_, update); \ - node -> left = symbol_ - node; \ - }) \ - -#ifdef ENET_CONTEXT_EXCLUSION -typedef struct _ENetExclude -{ - enet_uint8 value; - enet_uint16 under; -} ENetExclude; - -#define ENET_CONTEXT_DECODE_EXCLUDE(context, total, minimum) \ -{ \ - enet_uint16 under = 0; \ - nextExclude = excludes; \ - ENET_CONTEXT_WALK (context, { \ - under += rangeCoder -> symbols [node -> parent].count + minimum; \ - nextExclude -> value = node -> value; \ - nextExclude -> under = under; \ - nextExclude ++; \ - }); \ - total -= under; \ -} - -#define ENET_CONTEXT_EXCLUDED(value_, after, before) \ -{ \ - size_t low = 0, high = nextExclude - excludes; \ - for(;;) \ - { \ - size_t mid = (low + high) >> 1; \ - const ENetExclude * exclude = & excludes [mid]; \ - if (value_ < exclude -> value) \ - { \ - if (low + 1 < high) \ - { \ - high = mid; \ - continue; \ - } \ - if (exclude > excludes) \ - after -= exclude [-1].under; \ - } \ - else \ - { \ - if (value_ > exclude -> value) \ - { \ - if (low + 1 < high) \ - { \ - low = mid; \ - continue; \ - } \ - } \ - else \ - before = 0; \ - after -= exclude -> under; \ - } \ - break; \ - } \ -} -#endif - -#define ENET_CONTEXT_NOT_EXCLUDED(value_, after, before) - -size_t -enet_range_coder_decompress (void * context, const enet_uint8 * inData, size_t inLimit, enet_uint8 * outData, size_t outLimit) -{ - ENetRangeCoder * rangeCoder = (ENetRangeCoder *) context; - enet_uint8 * outStart = outData, * outEnd = & outData [outLimit]; - const enet_uint8 * inEnd = & inData [inLimit]; - enet_uint32 decodeLow = 0, decodeCode = 0, decodeRange = ~0; - ENetSymbol * root; - enet_uint16 predicted = 0; - size_t order = 0, nextSymbol = 0; -#ifdef ENET_CONTEXT_EXCLUSION - ENetExclude excludes [256]; - ENetExclude * nextExclude = excludes; -#endif - - if (rangeCoder == NULL || inLimit <= 0) - return 0; - - ENET_CONTEXT_CREATE (root, ENET_CONTEXT_ESCAPE_MINIMUM, ENET_CONTEXT_SYMBOL_MINIMUM); - - ENET_RANGE_CODER_SEED; - - for (;;) - { - ENetSymbol * subcontext, * symbol, * patch; -#ifdef ENET_CONTEXT_EXCLUSION - const ENetSymbol * childContext = & emptyContext; -#endif - enet_uint8 value = 0; - enet_uint16 code, under, count, bottom, * parent = & predicted, total; - - for (subcontext = & rangeCoder -> symbols [predicted]; - subcontext != root; -#ifdef ENET_CONTEXT_EXCLUSION - childContext = subcontext, -#endif - subcontext = & rangeCoder -> symbols [subcontext -> parent]) - { - if (subcontext -> escapes <= 0) - continue; - total = subcontext -> total; -#ifdef ENET_CONTEXT_EXCLUSION - if (childContext -> total > 0) - ENET_CONTEXT_DECODE_EXCLUDE (childContext, total, 0); -#endif - if (subcontext -> escapes >= total) - continue; - code = ENET_RANGE_CODER_READ (total); - if (code < subcontext -> escapes) - { - ENET_RANGE_CODER_DECODE (0, subcontext -> escapes, total); - continue; - } - code -= subcontext -> escapes; -#ifdef ENET_CONTEXT_EXCLUSION - if (childContext -> total > 0) - { - ENET_CONTEXT_TRY_DECODE (subcontext, symbol, code, value, under, count, ENET_SUBCONTEXT_SYMBOL_DELTA, 0, ENET_CONTEXT_EXCLUDED); - } - else -#endif - { - ENET_CONTEXT_TRY_DECODE (subcontext, symbol, code, value, under, count, ENET_SUBCONTEXT_SYMBOL_DELTA, 0, ENET_CONTEXT_NOT_EXCLUDED); - } - bottom = symbol - rangeCoder -> symbols; - ENET_RANGE_CODER_DECODE (subcontext -> escapes + under, count, total); - subcontext -> total += ENET_SUBCONTEXT_SYMBOL_DELTA; - if (count > 0xFF - 2*ENET_SUBCONTEXT_SYMBOL_DELTA || subcontext -> total > ENET_RANGE_CODER_BOTTOM - 0x100) - ENET_CONTEXT_RESCALE (subcontext, 0); - goto patchContexts; - } - - total = root -> total; -#ifdef ENET_CONTEXT_EXCLUSION - if (childContext -> total > 0) - ENET_CONTEXT_DECODE_EXCLUDE (childContext, total, ENET_CONTEXT_SYMBOL_MINIMUM); -#endif - code = ENET_RANGE_CODER_READ (total); - if (code < root -> escapes) - { - ENET_RANGE_CODER_DECODE (0, root -> escapes, total); - break; - } - code -= root -> escapes; -#ifdef ENET_CONTEXT_EXCLUSION - if (childContext -> total > 0) - { - ENET_CONTEXT_ROOT_DECODE (root, symbol, code, value, under, count, ENET_CONTEXT_SYMBOL_DELTA, ENET_CONTEXT_SYMBOL_MINIMUM, ENET_CONTEXT_EXCLUDED); - } - else -#endif - { - ENET_CONTEXT_ROOT_DECODE (root, symbol, code, value, under, count, ENET_CONTEXT_SYMBOL_DELTA, ENET_CONTEXT_SYMBOL_MINIMUM, ENET_CONTEXT_NOT_EXCLUDED); - } - bottom = symbol - rangeCoder -> symbols; - ENET_RANGE_CODER_DECODE (root -> escapes + under, count, total); - root -> total += ENET_CONTEXT_SYMBOL_DELTA; - if (count > 0xFF - 2*ENET_CONTEXT_SYMBOL_DELTA + ENET_CONTEXT_SYMBOL_MINIMUM || root -> total > ENET_RANGE_CODER_BOTTOM - 0x100) - ENET_CONTEXT_RESCALE (root, ENET_CONTEXT_SYMBOL_MINIMUM); - - patchContexts: - for (patch = & rangeCoder -> symbols [predicted]; - patch != subcontext; - patch = & rangeCoder -> symbols [patch -> parent]) - { - ENET_CONTEXT_ENCODE (patch, symbol, value, under, count, ENET_SUBCONTEXT_SYMBOL_DELTA, 0); - * parent = symbol - rangeCoder -> symbols; - parent = & symbol -> parent; - if (count <= 0) - { - patch -> escapes += ENET_SUBCONTEXT_ESCAPE_DELTA; - patch -> total += ENET_SUBCONTEXT_ESCAPE_DELTA; - } - patch -> total += ENET_SUBCONTEXT_SYMBOL_DELTA; - if (count > 0xFF - 2*ENET_SUBCONTEXT_SYMBOL_DELTA || patch -> total > ENET_RANGE_CODER_BOTTOM - 0x100) - ENET_CONTEXT_RESCALE (patch, 0); - } - * parent = bottom; - - ENET_RANGE_CODER_OUTPUT (value); - - if (order >= ENET_SUBCONTEXT_ORDER) - predicted = rangeCoder -> symbols [predicted].parent; - else - order ++; - ENET_RANGE_CODER_FREE_SYMBOLS; - } - - return (size_t) (outData - outStart); -} - -/** @defgroup host ENet host functions - @{ -*/ - -/** Sets the packet compressor the host should use to the default range coder. - @param host host to enable the range coder for - @returns 0 on success, < 0 on failure -*/ -int -enet_host_compress_with_range_coder (ENetHost * host) -{ - ENetCompressor compressor; - memset (& compressor, 0, sizeof (compressor)); - compressor.context = enet_range_coder_create(); - if (compressor.context == NULL) - return -1; - compressor.compress = enet_range_coder_compress; - compressor.decompress = enet_range_coder_decompress; - compressor.destroy = enet_range_coder_destroy; - enet_host_compress (host, & compressor); - return 0; -} - -/** @} */ - - |