diff options
Diffstat (limited to 'channels/rdpsnd/client/ios/TPCircularBuffer.c')
| -rw-r--r-- | channels/rdpsnd/client/ios/TPCircularBuffer.c | 153 |
1 files changed, 153 insertions, 0 deletions
diff --git a/channels/rdpsnd/client/ios/TPCircularBuffer.c b/channels/rdpsnd/client/ios/TPCircularBuffer.c new file mode 100644 index 0000000..b29f611 --- /dev/null +++ b/channels/rdpsnd/client/ios/TPCircularBuffer.c @@ -0,0 +1,153 @@ +// +// TPCircularBuffer.c +// Circular/Ring buffer implementation +// +// https://github.com/michaeltyson/TPCircularBuffer +// +// Created by Michael Tyson on 10/12/2011. +// +// Copyright (C) 2012-2013 A Tasty Pixel +// +// This software is provided 'as-is', without any express or implied +// warranty. In no event will the authors be held liable for any damages +// arising from the use of this software. +// +// Permission is granted to anyone to use this software for any purpose, +// including commercial applications, and to alter it and redistribute it +// freely, subject to the following restrictions: +// +// 1. The origin of this software must not be misrepresented; you must not +// claim that you wrote the original software. If you use this software +// in a product, an acknowledgment in the product documentation would be +// appreciated but is not required. +// +// 2. Altered source versions must be plainly marked as such, and must not be +// misrepresented as being the original software. +// +// 3. This notice may not be removed or altered from any source distribution. +// + +#include <winpr/wlog.h> + +#include "TPCircularBuffer.h" +#include "rdpsnd_main.h" + +#include <mach/mach.h> +#include <stdio.h> + +#define reportResult(result, operation) (_reportResult((result), (operation), __FILE__, __LINE__)) +static inline bool _reportResult(kern_return_t result, const char* operation, const char* file, + int line) +{ + if (result != ERR_SUCCESS) + { + WLog_DBG(TAG, "%s:%d: %s: %s\n", file, line, operation, mach_error_string(result)); + return false; + } + return true; +} + +bool TPCircularBufferInit(TPCircularBuffer* buffer, int length) +{ + + // Keep trying until we get our buffer, needed to handle race conditions + int retries = 3; + while (true) + { + + buffer->length = round_page(length); // We need whole page sizes + + // Temporarily allocate twice the length, so we have the contiguous address space to + // support a second instance of the buffer directly after + vm_address_t bufferAddress; + kern_return_t result = vm_allocate(mach_task_self(), &bufferAddress, buffer->length * 2, + VM_FLAGS_ANYWHERE); // allocate anywhere it'll fit + if (result != ERR_SUCCESS) + { + if (retries-- == 0) + { + reportResult(result, "Buffer allocation"); + return false; + } + // Try again if we fail + continue; + } + + // Now replace the second half of the allocation with a virtual copy of the first half. + // Deallocate the second half... + result = vm_deallocate(mach_task_self(), bufferAddress + buffer->length, buffer->length); + if (result != ERR_SUCCESS) + { + if (retries-- == 0) + { + reportResult(result, "Buffer deallocation"); + return false; + } + // If this fails somehow, deallocate the whole region and try again + vm_deallocate(mach_task_self(), bufferAddress, buffer->length); + continue; + } + + // Re-map the buffer to the address space immediately after the buffer + vm_address_t virtualAddress = bufferAddress + buffer->length; + vm_prot_t cur_prot, max_prot; + result = vm_remap(mach_task_self(), + &virtualAddress, // mirror target + buffer->length, // size of mirror + 0, // auto alignment + 0, // force remapping to virtualAddress + mach_task_self(), // same task + bufferAddress, // mirror source + 0, // MAP READ-WRITE, NOT COPY + &cur_prot, // unused protection struct + &max_prot, // unused protection struct + VM_INHERIT_DEFAULT); + if (result != ERR_SUCCESS) + { + if (retries-- == 0) + { + reportResult(result, "Remap buffer memory"); + return false; + } + // If this remap failed, we hit a race condition, so deallocate and try again + vm_deallocate(mach_task_self(), bufferAddress, buffer->length); + continue; + } + + if (virtualAddress != bufferAddress + buffer->length) + { + // If the memory is not contiguous, clean up both allocated buffers and try again + if (retries-- == 0) + { + WLog_DBG(TAG, "Couldn't map buffer memory to end of buffer"); + return false; + } + + vm_deallocate(mach_task_self(), virtualAddress, buffer->length); + vm_deallocate(mach_task_self(), bufferAddress, buffer->length); + continue; + } + + buffer->buffer = (void*)bufferAddress; + buffer->fillCount = 0; + buffer->head = buffer->tail = 0; + + return true; + } + return false; +} + +void TPCircularBufferCleanup(TPCircularBuffer* buffer) +{ + vm_deallocate(mach_task_self(), (vm_address_t)buffer->buffer, buffer->length * 2); + memset(buffer, 0, sizeof(TPCircularBuffer)); +} + +void TPCircularBufferClear(TPCircularBuffer* buffer) +{ + int32_t fillCount; + if (TPCircularBufferTail(buffer, &fillCount)) + { + TPCircularBufferConsume(buffer, fillCount); + } +} |