--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/ucx/buffer.c Mon May 22 16:17:26 2023 +0200
@@ -0,0 +1,415 @@
+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ *
+ * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "cx/buffer.h"
+#include "cx/utils.h"
+
+#include <stdio.h>
+#include <string.h>
+
+int cxBufferInit(
+ CxBuffer *buffer,
+ void *space,
+ size_t capacity,
+ CxAllocator const *allocator,
+ int flags
+) {
+ if (allocator == NULL) allocator = cxDefaultAllocator;
+ buffer->allocator = allocator;
+ buffer->flags = flags;
+ if (!space) {
+ buffer->bytes = cxMalloc(allocator, capacity);
+ if (buffer->bytes == NULL) {
+ return 1;
+ }
+ buffer->flags |= CX_BUFFER_FREE_CONTENTS;
+ } else {
+ buffer->bytes = space;
+ }
+ buffer->capacity = capacity;
+ buffer->size = 0;
+ buffer->pos = 0;
+
+ buffer->flush_func = NULL;
+ buffer->flush_target = NULL;
+ buffer->flush_blkmax = 0;
+ buffer->flush_blksize = 4096;
+ buffer->flush_threshold = SIZE_MAX;
+
+ return 0;
+}
+
+void cxBufferDestroy(CxBuffer *buffer) {
+ if ((buffer->flags & CX_BUFFER_FREE_CONTENTS) == CX_BUFFER_FREE_CONTENTS) {
+ cxFree(buffer->allocator, buffer->bytes);
+ }
+}
+
+CxBuffer *cxBufferCreate(
+ void *space,
+ size_t capacity,
+ CxAllocator const *allocator,
+ int flags
+) {
+ CxBuffer *buf = cxMalloc(allocator, sizeof(CxBuffer));
+ if (buf == NULL) return NULL;
+ if (0 == cxBufferInit(buf, space, capacity, allocator, flags)) {
+ return buf;
+ } else {
+ cxFree(allocator, buf);
+ return NULL;
+ }
+}
+
+void cxBufferFree(CxBuffer *buffer) {
+ if ((buffer->flags & CX_BUFFER_FREE_CONTENTS) == CX_BUFFER_FREE_CONTENTS) {
+ cxFree(buffer->allocator, buffer->bytes);
+ }
+ cxFree(buffer->allocator, buffer);
+}
+
+int cxBufferSeek(
+ CxBuffer *buffer,
+ off_t offset,
+ int whence
+) {
+ size_t npos;
+ switch (whence) {
+ case SEEK_CUR:
+ npos = buffer->pos;
+ break;
+ case SEEK_END:
+ npos = buffer->size;
+ break;
+ case SEEK_SET:
+ npos = 0;
+ break;
+ default:
+ return -1;
+ }
+
+ size_t opos = npos;
+ npos += offset;
+
+ if ((offset > 0 && npos < opos) || (offset < 0 && npos > opos)) {
+ return -1;
+ }
+
+ if (npos >= buffer->size) {
+ return -1;
+ } else {
+ buffer->pos = npos;
+ return 0;
+ }
+
+}
+
+void cxBufferClear(CxBuffer *buffer) {
+ memset(buffer->bytes, 0, buffer->size);
+ buffer->size = 0;
+ buffer->pos = 0;
+}
+
+int cxBufferEof(CxBuffer const *buffer) {
+ return buffer->pos >= buffer->size;
+}
+
+int cxBufferMinimumCapacity(
+ CxBuffer *buffer,
+ size_t newcap
+) {
+ if (newcap <= buffer->capacity) {
+ return 0;
+ }
+
+ if (cxReallocate(buffer->allocator,
+ (void **) &buffer->bytes, newcap) == 0) {
+ buffer->capacity = newcap;
+ return 0;
+ } else {
+ return -1;
+ }
+}
+
+/**
+ * Helps flushing data to the flush target of a buffer.
+ *
+ * @param buffer the buffer containing the config
+ * @param space the data to flush
+ * @param size the element size
+ * @param nitems the number of items
+ * @return the number of items flushed
+ */
+static size_t cx_buffer_write_flush_helper(
+ CxBuffer *buffer,
+ unsigned char const *space,
+ size_t size,
+ size_t nitems
+) {
+ size_t pos = 0;
+ size_t remaining = nitems;
+ size_t max_items = buffer->flush_blksize / size;
+ while (remaining > 0) {
+ size_t items = remaining > max_items ? max_items : remaining;
+ size_t flushed = buffer->flush_func(
+ space + pos,
+ size, items,
+ buffer->flush_target);
+ if (flushed > 0) {
+ pos += (flushed * size);
+ remaining -= flushed;
+ } else {
+ // if no bytes can be flushed out anymore, we give up
+ break;
+ }
+ }
+ return nitems - remaining;
+}
+
+size_t cxBufferWrite(
+ void const *ptr,
+ size_t size,
+ size_t nitems,
+ CxBuffer *buffer
+) {
+ // optimize for easy case
+ if (size == 1 && (buffer->capacity - buffer->pos) >= nitems) {
+ memcpy(buffer->bytes + buffer->pos, ptr, nitems);
+ buffer->pos += nitems;
+ if (buffer->pos > buffer->size) {
+ buffer->size = buffer->pos;
+ }
+ return nitems;
+ }
+
+ size_t len;
+ size_t nitems_out = nitems;
+ if (cx_szmul(size, nitems, &len)) {
+ return 0;
+ }
+ size_t required = buffer->pos + len;
+ if (buffer->pos > required) {
+ return 0;
+ }
+
+ bool perform_flush = false;
+ if (required > buffer->capacity) {
+ if ((buffer->flags & CX_BUFFER_AUTO_EXTEND) == CX_BUFFER_AUTO_EXTEND && required) {
+ if (buffer->flush_blkmax > 0 && required > buffer->flush_threshold) {
+ perform_flush = true;
+ } else {
+ if (cxBufferMinimumCapacity(buffer, required)) {
+ return 0;
+ }
+ }
+ } else {
+ if (buffer->flush_blkmax > 0) {
+ perform_flush = true;
+ } else {
+ // truncate data to be written, if we can neither extend nor flush
+ len = buffer->capacity - buffer->pos;
+ if (size > 1) {
+ len -= len % size;
+ }
+ nitems_out = len / size;
+ }
+ }
+ }
+
+ if (len == 0) {
+ return len;
+ }
+
+ if (perform_flush) {
+ size_t flush_max;
+ if (cx_szmul(buffer->flush_blkmax, buffer->flush_blksize, &flush_max)) {
+ return 0;
+ }
+ size_t flush_pos = buffer->flush_func == NULL || buffer->flush_target == NULL
+ ? buffer->pos
+ : cx_buffer_write_flush_helper(buffer, buffer->bytes, 1, buffer->pos);
+ if (flush_pos == buffer->pos) {
+ // entire buffer has been flushed, we can reset
+ buffer->size = buffer->pos = 0;
+
+ size_t items_flush; // how many items can also be directly flushed
+ size_t items_keep; // how many items have to be written to the buffer
+
+ items_flush = flush_max >= required ? nitems : (flush_max - flush_pos) / size;
+ if (items_flush > 0) {
+ items_flush = cx_buffer_write_flush_helper(buffer, ptr, size, items_flush / size);
+ // in case we could not flush everything, keep the rest
+ }
+ items_keep = nitems - items_flush;
+ if (items_keep > 0) {
+ // try again with the remaining stuff
+ unsigned char const *new_ptr = ptr;
+ new_ptr += items_flush * size;
+ // report the directly flushed items as written plus the remaining stuff
+ return items_flush + cxBufferWrite(new_ptr, size, items_keep, buffer);
+ } else {
+ // all items have been flushed - report them as written
+ return nitems;
+ }
+ } else if (flush_pos == 0) {
+ // nothing could be flushed at all, we immediately give up without writing any data
+ return 0;
+ } else {
+ // we were partially successful, we shift left and try again
+ cxBufferShiftLeft(buffer, flush_pos);
+ return cxBufferWrite(ptr, size, nitems, buffer);
+ }
+ } else {
+ memcpy(buffer->bytes + buffer->pos, ptr, len);
+ buffer->pos += len;
+ if (buffer->pos > buffer->size) {
+ buffer->size = buffer->pos;
+ }
+ return nitems_out;
+ }
+
+}
+
+int cxBufferPut(
+ CxBuffer *buffer,
+ int c
+) {
+ c &= 0xFF;
+ unsigned char const ch = c;
+ if (cxBufferWrite(&ch, 1, 1, buffer) == 1) {
+ return c;
+ } else {
+ return EOF;
+ }
+}
+
+size_t cxBufferPutString(
+ CxBuffer *buffer,
+ const char *str
+) {
+ return cxBufferWrite(str, 1, strlen(str), buffer);
+}
+
+size_t cxBufferRead(
+ void *ptr,
+ size_t size,
+ size_t nitems,
+ CxBuffer *buffer
+) {
+ size_t len;
+ if (cx_szmul(size, nitems, &len)) {
+ return 0;
+ }
+ if (buffer->pos + len > buffer->size) {
+ len = buffer->size - buffer->pos;
+ if (size > 1) len -= len % size;
+ }
+
+ if (len <= 0) {
+ return len;
+ }
+
+ memcpy(ptr, buffer->bytes + buffer->pos, len);
+ buffer->pos += len;
+
+ return len / size;
+}
+
+int cxBufferGet(CxBuffer *buffer) {
+ if (cxBufferEof(buffer)) {
+ return EOF;
+ } else {
+ int c = buffer->bytes[buffer->pos];
+ buffer->pos++;
+ return c;
+ }
+}
+
+int cxBufferShiftLeft(
+ CxBuffer *buffer,
+ size_t shift
+) {
+ if (shift >= buffer->size) {
+ buffer->pos = buffer->size = 0;
+ } else {
+ memmove(buffer->bytes, buffer->bytes + shift, buffer->size - shift);
+ buffer->size -= shift;
+
+ if (buffer->pos >= shift) {
+ buffer->pos -= shift;
+ } else {
+ buffer->pos = 0;
+ }
+ }
+ return 0;
+}
+
+int cxBufferShiftRight(
+ CxBuffer *buffer,
+ size_t shift
+) {
+ size_t req_capacity = buffer->size + shift;
+ size_t movebytes;
+
+ // auto extend buffer, if required and enabled
+ if (buffer->capacity < req_capacity) {
+ if ((buffer->flags & CX_BUFFER_AUTO_EXTEND) == CX_BUFFER_AUTO_EXTEND) {
+ if (cxBufferMinimumCapacity(buffer, req_capacity)) {
+ return 1;
+ }
+ movebytes = buffer->size;
+ } else {
+ movebytes = buffer->capacity - shift;
+ }
+ } else {
+ movebytes = buffer->size;
+ }
+
+ memmove(buffer->bytes + shift, buffer->bytes, movebytes);
+ buffer->size = shift + movebytes;
+
+ buffer->pos += shift;
+ if (buffer->pos > buffer->size) {
+ buffer->pos = buffer->size;
+ }
+
+ return 0;
+}
+
+int cxBufferShift(
+ CxBuffer *buffer,
+ off_t shift
+) {
+ if (shift < 0) {
+ return cxBufferShiftLeft(buffer, (size_t) (-shift));
+ } else if (shift > 0) {
+ return cxBufferShiftRight(buffer, (size_t) shift);
+ } else {
+ return 0;
+ }
+}