124 lines
3.9 KiB
C
124 lines
3.9 KiB
C
/**
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* A thredsafe buffer
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*/
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#include <stdlib.h>
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#include "libp2p/utils/threadsafe_buffer.h"
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#include "libp2p/utils/logger.h"
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/***
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* Allocate a new context
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* @returns a newly allocated context, or NULL on error (out of memory?)
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*/
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struct ThreadsafeBufferContext* threadsafe_buffer_context_new() {
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struct ThreadsafeBufferContext* context = (struct ThreadsafeBufferContext*) malloc(sizeof(struct ThreadsafeBufferContext));
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if (context != NULL) {
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context->buffer_size = 0;
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context->buffer = NULL;
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pthread_mutex_init(&context->lock, NULL);
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}
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return context;
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}
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/***
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* Free resources of a buffer context
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* @param context the context
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*/
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void threadsafe_buffer_context_free(struct ThreadsafeBufferContext* context) {
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if (context != NULL) {
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if (context->buffer != NULL)
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free(context->buffer);
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free(context);
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}
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}
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/***
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* Read from the buffer without destroying its contents or moving its read pointer
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* @param context the context
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* @param results where to put the results
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* @param results_size the size of the results
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* @returns number of bytes read
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*/
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size_t threadsafe_buffer_peek(struct ThreadsafeBufferContext* context, uint8_t* results, size_t results_size) {
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size_t bytes_read = 0;
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if (context == NULL)
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return 0;
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pthread_mutex_lock(&context->lock);
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// do the read
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if (context->buffer != NULL && context->buffer_size > 0) {
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bytes_read = results_size < context->buffer_size ? results_size : context->buffer_size;
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memcpy(results, context->buffer, bytes_read);
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}
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pthread_mutex_unlock(&context->lock);
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return bytes_read;
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}
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/***
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* Read from the buffer.
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* NOTE: If results_size is more than what is left in the buffer, this will read everything.
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* @param context the context
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* @param results where to put the results
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* @param results_size the size of the buffer
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* @returns number of bytes read
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*/
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size_t threadsafe_buffer_read(struct ThreadsafeBufferContext* context, uint8_t* results, size_t results_size) {
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size_t bytes_read = 0;
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if (context == NULL)
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return 0;
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pthread_mutex_lock(&context->lock);
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// do the read
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if (context->buffer != NULL && context->buffer_size > 0) {
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bytes_read = results_size < context->buffer_size ? results_size : context->buffer_size;
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libp2p_logger_debug("threadsafe_buffer", "read: We want to read %d bytes, and have %d in the buffer. Therefore, we will read %d.\n", results_size, context->buffer_size, bytes_read);
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memcpy(results, context->buffer, bytes_read);
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}
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// adjust the size
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if (bytes_read > 0) {
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if (context->buffer_size - bytes_read > 0) {
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// more remains
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size_t new_buffer_size = context->buffer_size - bytes_read;
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uint8_t* new_buffer = (uint8_t*) malloc(new_buffer_size);
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memcpy(new_buffer, &context->buffer[bytes_read], new_buffer_size);
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free(context->buffer);
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context->buffer = new_buffer;
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context->buffer_size = new_buffer_size;
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} else {
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// everything has been read
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free(context->buffer);
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context->buffer = NULL;
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context->buffer_size = 0;
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}
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}
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pthread_mutex_unlock(&context->lock);
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return bytes_read;
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}
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/****
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* Add bytes to the end of the buffer
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* @param context the context
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* @param bytes the bytes to add
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* @param bytes_size the size of bytes
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* @returns the size added to the buffer (0 on error)
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*/
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size_t threadsafe_buffer_write(struct ThreadsafeBufferContext* context, const uint8_t* bytes, size_t bytes_size) {
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if (context == NULL)
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return 0;
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if (bytes_size == 0)
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return 0;
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size_t bytes_copied = 0;
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pthread_mutex_lock(&context->lock);
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// allocate memory
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uint8_t* new_buffer = (uint8_t*) realloc(context->buffer, context->buffer_size + bytes_size);
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if (new_buffer != NULL) {
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// copy data
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memcpy(&new_buffer[context->buffer_size], bytes, bytes_size);
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context->buffer_size += bytes_size;
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context->buffer = new_buffer;
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bytes_copied = bytes_size;
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libp2p_logger_debug("threadsafe_buffer", "write: Added %d bytes. Buffer now contains %d bytes.\n", bytes_size, context->buffer_size);
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}
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pthread_mutex_unlock(&context->lock);
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return bytes_copied;
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}
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