universe@483: /*
universe@483:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
universe@483:  *
universe@483:  * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved.
universe@483:  *
universe@483:  * Redistribution and use in source and binary forms, with or without
universe@483:  * modification, are permitted provided that the following conditions are met:
universe@483:  *
universe@483:  *   1. Redistributions of source code must retain the above copyright
universe@483:  *      notice, this list of conditions and the following disclaimer.
universe@483:  *
universe@483:  *   2. Redistributions in binary form must reproduce the above copyright
universe@483:  *      notice, this list of conditions and the following disclaimer in the
universe@483:  *      documentation and/or other materials provided with the distribution.
universe@483:  *
universe@483:  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
universe@483:  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
universe@483:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
universe@483:  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
universe@483:  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
universe@483:  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
universe@483:  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
universe@483:  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
universe@483:  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
universe@483:  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
universe@483:  * POSSIBILITY OF SUCH DAMAGE.
universe@483:  */
universe@483: 
universe@483: #include "cx/buffer.h"
universe@483: #include "cx/utils.h"
universe@483: 
universe@483: #include <stdlib.h>
universe@530: #include <stdio.h>
universe@483: #include <string.h>
universe@539: #include <stdint.h>
universe@483: 
universe@501: int cxBufferInit(
universe@501:         CxBuffer *buffer,
universe@483:         void *space,
universe@483:         size_t capacity,
universe@529:         CxAllocator const *allocator,
universe@483:         int flags
universe@483: ) {
universe@501:     buffer->allocator = allocator;
universe@501:     buffer->flags = flags;
universe@501:     if (!space) {
universe@501:         buffer->bytes = cxMalloc(allocator, capacity);
universe@501:         if (buffer->bytes == NULL) {
universe@501:             return 1;
universe@483:         }
universe@501:         buffer->flags |= CX_BUFFER_FREE_CONTENTS;
universe@501:     } else {
universe@501:         buffer->bytes = space;
universe@501:     }
universe@501:     buffer->capacity = capacity;
universe@501:     buffer->size = 0;
universe@539:     buffer->pos = 0;
universe@483: 
universe@539:     buffer->flush_func = NULL;
universe@541:     buffer->flush_target = NULL;
universe@539:     buffer->flush_blkmax = 0;
universe@539:     buffer->flush_blksize = 4096;
universe@539:     buffer->flush_threshold = SIZE_MAX;
universe@483: 
universe@501:     return 0;
universe@483: }
universe@483: 
universe@500: void cxBufferDestroy(CxBuffer *buffer) {
universe@483:     if ((buffer->flags & CX_BUFFER_FREE_CONTENTS) == CX_BUFFER_FREE_CONTENTS) {
universe@501:         cxFree(buffer->allocator, buffer->bytes);
universe@483:     }
universe@483: }
universe@483: 
universe@483: int cxBufferSeek(
universe@500:         CxBuffer *buffer,
universe@483:         off_t offset,
universe@483:         int whence
universe@483: ) {
universe@483:     size_t npos;
universe@483:     switch (whence) {
universe@483:         case SEEK_CUR:
universe@483:             npos = buffer->pos;
universe@483:             break;
universe@483:         case SEEK_END:
universe@483:             npos = buffer->size;
universe@483:             break;
universe@483:         case SEEK_SET:
universe@483:             npos = 0;
universe@483:             break;
universe@483:         default:
universe@483:             return -1;
universe@483:     }
universe@483: 
universe@483:     size_t opos = npos;
universe@483:     npos += offset;
universe@483: 
universe@483:     if ((offset > 0 && npos < opos) || (offset < 0 && npos > opos)) {
universe@483:         return -1;
universe@483:     }
universe@483: 
universe@483:     if (npos >= buffer->size) {
universe@483:         return -1;
universe@483:     } else {
universe@483:         buffer->pos = npos;
universe@483:         return 0;
universe@483:     }
universe@483: 
universe@483: }
universe@483: 
universe@529: void cxBufferClear(CxBuffer *buffer) {
universe@529:     memset(buffer->bytes, 0, buffer->size);
universe@529:     buffer->size = 0;
universe@529:     buffer->pos = 0;
universe@529: }
universe@529: 
universe@529: int cxBufferEof(CxBuffer const *buffer) {
universe@483:     return buffer->pos >= buffer->size;
universe@483: }
universe@483: 
universe@483: int cxBufferMinimumCapacity(
universe@500:         CxBuffer *buffer,
universe@532:         size_t newcap
universe@483: ) {
universe@532:     if (newcap <= buffer->capacity) {
universe@532:         return 0;
universe@483:     }
universe@483: 
universe@536:     if (cxReallocate(buffer->allocator,
universe@536:                      (void **) &buffer->bytes, newcap) == 0) {
universe@483:         buffer->capacity = newcap;
universe@533:         return 0;
universe@483:     } else {
universe@483:         return -1;
universe@483:     }
universe@483: }
universe@483: 
universe@483: size_t cxBufferWrite(
universe@489:         void const *ptr,
universe@483:         size_t size,
universe@483:         size_t nitems,
universe@500:         CxBuffer *buffer
universe@483: ) {
universe@539:     // TODO: optimize for special case size == nitems == 1
universe@483:     size_t len;
universe@483:     if (cx_szmul(size, nitems, &len)) {
universe@483:         return 0;
universe@483:     }
universe@483:     size_t required = buffer->pos + len;
universe@483:     if (buffer->pos > required) {
universe@483:         return 0;
universe@483:     }
universe@483: 
universe@539:     bool perform_flush = false;
universe@483:     if (required > buffer->capacity) {
universe@539:         if ((buffer->flags & CX_BUFFER_AUTO_EXTEND) == CX_BUFFER_AUTO_EXTEND && required) {
universe@539:             if (buffer->flush_blkmax > 0 && required > buffer->flush_threshold) {
universe@539:                 perform_flush = true;
universe@539:             } else {
universe@539:                 if (cxBufferMinimumCapacity(buffer, required)) {
universe@539:                     return 0;
universe@539:                 }
universe@483:             }
universe@483:         } else {
universe@539:             if (buffer->flush_blkmax > 0) {
universe@539:                 perform_flush = true;
universe@539:             } else {
universe@539:                 // truncate data to be written, if we can neither extend nor flush
universe@539:                 len = buffer->capacity - buffer->pos;
universe@539:                 if (size > 1) {
universe@539:                     // TODO: this is bugged - it would only discard one element and not as many as required
universe@539:                     len -= len % size;
universe@539:                 }
universe@540:                 nitems = len / size;
universe@483:             }
universe@483:         }
universe@483:     }
universe@483: 
universe@483:     if (len == 0) {
universe@483:         return len;
universe@483:     }
universe@483: 
universe@539:     if (perform_flush) {
universe@539:         // TODO: implement flushing
universe@539:         // (1) determine how many bytes to flush (use flushmax = blkmax * blksize)
universe@539:         // (2) if len is larger than the number computed in (1) we need more flush cycles, compute how many
universe@539:         // (3) determine how many bytes from the buffer shall be flushed
universe@539:         // (4) if something remains in the buffer, shift the buffer to the left
universe@539:         // (4a) if buffer was shifted, append the new data to the buffer
universe@539:         // (4b) if the buffer was flushed entirely AND the new data also fits into flushmax,
universe@539:         //      directly write the new data to the flush sink
universe@539:         return 0; // remove this after implementation
universe@539:     } else {
universe@539:         memcpy(buffer->bytes + buffer->pos, ptr, len);
universe@539:         buffer->pos += len;
universe@539:         if (buffer->pos > buffer->size) {
universe@539:             buffer->size = buffer->pos;
universe@539:         }
universe@483:     }
universe@483: 
universe@539:     return nitems;
universe@483: }
universe@483: 
universe@538: int cxBufferPut(
universe@538:         CxBuffer *buffer,
universe@538:         int c
universe@538: ) {
universe@538:     c &= 0xFF;
universe@538:     unsigned char const ch = c;
universe@538:     if (cxBufferWrite(&ch, 1, 1, buffer) == 1) {
universe@538:         return c;
universe@538:     } else {
universe@538:         return EOF;
universe@538:     }
universe@538: }
universe@538: 
universe@538: size_t cxBufferPutString(
universe@538:         CxBuffer *buffer,
universe@538:         const char *str
universe@538: ) {
universe@538:     return cxBufferWrite(str, 1, strlen(str), buffer);
universe@538: }
universe@538: 
universe@483: size_t cxBufferRead(
universe@483:         void *ptr,
universe@483:         size_t size,
universe@483:         size_t nitems,
universe@500:         CxBuffer *buffer
universe@483: ) {
universe@483:     size_t len;
universe@483:     if (cx_szmul(size, nitems, &len)) {
universe@483:         return 0;
universe@483:     }
universe@483:     if (buffer->pos + len > buffer->size) {
universe@483:         len = buffer->size - buffer->pos;
universe@483:         if (size > 1) len -= len % size;
universe@483:     }
universe@483: 
universe@483:     if (len <= 0) {
universe@483:         return len;
universe@483:     }
universe@483: 
universe@483:     memcpy(ptr, buffer->bytes + buffer->pos, len);
universe@483:     buffer->pos += len;
universe@483: 
universe@483:     return len / size;
universe@483: }
universe@483: 
universe@500: int cxBufferGet(CxBuffer *buffer) {
universe@483:     if (cxBufferEof(buffer)) {
universe@483:         return EOF;
universe@483:     } else {
universe@483:         int c = buffer->bytes[buffer->pos];
universe@483:         buffer->pos++;
universe@483:         return c;
universe@483:     }
universe@483: }
universe@483: 
universe@483: int cxBufferShiftLeft(
universe@500:         CxBuffer *buffer,
universe@483:         size_t shift
universe@483: ) {
universe@483:     if (shift >= buffer->size) {
universe@483:         buffer->pos = buffer->size = 0;
universe@483:     } else {
universe@483:         memmove(buffer->bytes, buffer->bytes + shift, buffer->size - shift);
universe@483:         buffer->size -= shift;
universe@483: 
universe@483:         if (buffer->pos >= shift) {
universe@483:             buffer->pos -= shift;
universe@483:         } else {
universe@483:             buffer->pos = 0;
universe@483:         }
universe@483:     }
universe@483:     return 0;
universe@483: }
universe@483: 
universe@483: int cxBufferShiftRight(
universe@500:         CxBuffer *buffer,
universe@483:         size_t shift
universe@483: ) {
universe@483:     size_t req_capacity = buffer->size + shift;
universe@483:     size_t movebytes;
universe@483: 
universe@483:     // auto extend buffer, if required and enabled
universe@483:     if (buffer->capacity < req_capacity) {
universe@483:         if ((buffer->flags & CX_BUFFER_AUTO_EXTEND) == CX_BUFFER_AUTO_EXTEND) {
universe@483:             if (cxBufferMinimumCapacity(buffer, req_capacity)) {
universe@483:                 return 1;
universe@483:             }
universe@483:             movebytes = buffer->size;
universe@483:         } else {
universe@483:             movebytes = buffer->capacity - shift;
universe@483:         }
universe@483:     } else {
universe@483:         movebytes = buffer->size;
universe@483:     }
universe@483: 
universe@483:     memmove(buffer->bytes + shift, buffer->bytes, movebytes);
universe@483:     buffer->size = shift + movebytes;
universe@483: 
universe@483:     buffer->pos += shift;
universe@483:     if (buffer->pos > buffer->size) {
universe@483:         buffer->pos = buffer->size;
universe@483:     }
universe@483: 
universe@483:     return 0;
universe@483: }
universe@483: 
universe@483: int cxBufferShift(
universe@500:         CxBuffer *buffer,
universe@483:         off_t shift
universe@483: ) {
universe@483:     if (shift < 0) {
universe@483:         return cxBufferShiftLeft(buffer, (size_t) (-shift));
universe@483:     } else if (shift > 0) {
universe@483:         return cxBufferShiftRight(buffer, (size_t) shift);
universe@483:     } else {
universe@483:         return 0;
universe@483:     }
universe@483: }