diff options
Diffstat (limited to 'indra/llcorehttp/bufferarray.cpp')
| -rw-r--r-- | indra/llcorehttp/bufferarray.cpp | 126 |
1 files changed, 88 insertions, 38 deletions
diff --git a/indra/llcorehttp/bufferarray.cpp b/indra/llcorehttp/bufferarray.cpp index 4c20350b13..c13b1a3540 100644 --- a/indra/llcorehttp/bufferarray.cpp +++ b/indra/llcorehttp/bufferarray.cpp @@ -27,6 +27,18 @@ #include "bufferarray.h" +// BufferArray is a list of chunks, each a BufferArray::Block, of contiguous +// data presented as a single array. Chunks are at least BufferArray::BLOCK_ALLOC_SIZE +// in length and can be larger. Any chunk may be partially filled or even +// empty. +// +// The BufferArray itself is sharable as a RefCounted entity. As shared +// reads don't work with the concept of a current position/seek value, +// none is kept with the object. Instead, the read and write operations +// all take position arguments. Single write/shared read isn't supported +// directly and any such attempts have to be serialized outside of this +// implementation. + namespace LLCore { @@ -58,7 +70,8 @@ public: static Block * alloc(size_t len); public: - size_t mLen; + size_t mUsed; + size_t mAlloced; // *NOTE: Must be last member of the object. We'll // overallocate as requested via operator new and index @@ -74,7 +87,6 @@ public: BufferArray::BufferArray() : LLCoreInt::RefCounted(true), - mPos(0), mLen(0) {} @@ -94,19 +106,45 @@ BufferArray::~BufferArray() size_t BufferArray::append(const char * src, size_t len) { - if (len) + const size_t ret(len); + + // First, try to copy into the last block + if (len && ! mBlocks.empty()) + { + Block & last(*mBlocks.back()); + if (last.mUsed < last.mAlloced) + { + // Some will fit... + const size_t copy_len((std::min)(len, (last.mAlloced - last.mUsed))); + + memcpy(&last.mData[last.mUsed], src, copy_len); + last.mUsed += copy_len; + llassert_always(last.mUsed <= last.mAlloced); + mLen += copy_len; + src += copy_len; + len -= copy_len; + } + } + + // Then get new blocks as needed + while (len) { + const size_t copy_len((std::min)(len, BLOCK_ALLOC_SIZE)); + if (mBlocks.size() >= mBlocks.capacity()) { mBlocks.reserve(mBlocks.size() + 5); } - Block * block = Block::alloc(len); - memcpy(block->mData, src, len); + Block * block = Block::alloc(BLOCK_ALLOC_SIZE); + memcpy(block->mData, src, copy_len); + block->mUsed = copy_len; + llassert_always(block->mUsed <= block->mAlloced); mBlocks.push_back(block); - mLen += len; - mPos = mLen; + mLen += copy_len; + src += copy_len; + len -= copy_len; } - return len; + return ret; } @@ -117,41 +155,33 @@ char * BufferArray::appendBufferAlloc(size_t len) { mBlocks.reserve(mBlocks.size() + 5); } - Block * block = Block::alloc(len); + Block * block = Block::alloc((std::max)(BLOCK_ALLOC_SIZE, len)); + block->mUsed = len; mBlocks.push_back(block); mLen += len; - mPos = mLen; return block->mData; } -size_t BufferArray::seek(size_t pos) +size_t BufferArray::read(size_t pos, char * dst, size_t len) { - if (pos > mLen) - pos = mLen; - mPos = pos; - return mPos; -} - - -size_t BufferArray::read(char * dst, size_t len) -{ - size_t result(0), offset(0); - size_t len_limit(mLen - mPos); + if (pos >= mLen) + return 0; + size_t len_limit(mLen - pos); len = std::min(len, len_limit); - - if (mPos >= mLen || 0 == len) + if (0 == len) return 0; + size_t result(0), offset(0); const int block_limit(mBlocks.size()); - int block_start(findBlock(mPos, &offset)); + int block_start(findBlock(pos, &offset)); if (block_start < 0) return 0; do { Block & block(*mBlocks[block_start]); - size_t block_limit(block.mLen - offset); + size_t block_limit(block.mUsed - offset); size_t block_len(std::min(block_limit, len)); memcpy(dst, &block.mData[offset], block_len); @@ -163,19 +193,18 @@ size_t BufferArray::read(char * dst, size_t len) } while (len && block_start < block_limit); - mPos += result; return result; } -size_t BufferArray::write(const char * src, size_t len) +size_t BufferArray::write(size_t pos, const char * src, size_t len) { - size_t result(0), offset(0); - if (mPos > mLen || 0 == len) + if (pos > mLen || 0 == len) return 0; + size_t result(0), offset(0); const int block_limit(mBlocks.size()); - int block_start(findBlock(mPos, &offset)); + int block_start(findBlock(pos, &offset)); if (block_start >= 0) { @@ -184,20 +213,39 @@ size_t BufferArray::write(const char * src, size_t len) do { Block & block(*mBlocks[block_start]); - size_t block_limit(block.mLen - offset); + size_t block_limit(block.mUsed - offset); size_t block_len(std::min(block_limit, len)); memcpy(&block.mData[offset], src, block_len); result += block_len; - len -= block_len; src += block_len; + len -= block_len; offset = 0; ++block_start; } while (len && block_start < block_limit); } - mPos += result; + // Something left, see if it will fit in the free + // space of the last block. + if (len && ! mBlocks.empty()) + { + Block & last(*mBlocks.back()); + if (last.mUsed < last.mAlloced) + { + // Some will fit... + const size_t copy_len((std::min)(len, (last.mAlloced - last.mUsed))); + + memcpy(&last.mData[last.mUsed], src, copy_len); + last.mUsed += copy_len; + result += copy_len; + llassert_always(last.mUsed <= last.mAlloced); + mLen += copy_len; + src += copy_len; + len -= copy_len; + } + } + if (len) { // Some or all of the remaining write data will @@ -218,12 +266,12 @@ int BufferArray::findBlock(size_t pos, size_t * ret_offset) const int block_limit(mBlocks.size()); for (int i(0); i < block_limit; ++i) { - if (pos < mBlocks[i]->mLen) + if (pos < mBlocks[i]->mUsed) { *ret_offset = pos; return i; } - pos -= mBlocks[i]->mLen; + pos -= mBlocks[i]->mUsed; } // Shouldn't get here but... @@ -237,7 +285,8 @@ int BufferArray::findBlock(size_t pos, size_t * ret_offset) BufferArray::Block::Block(size_t len) - : mLen(len) + : mUsed(0), + mAlloced(len) { memset(mData, 0, len); } @@ -245,7 +294,8 @@ BufferArray::Block::Block(size_t len) BufferArray::Block::~Block() { - mLen = 0; + mUsed = 0; + mAlloced = 0; } |