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@483: #include <string.h>
universe@483: 
universe@483: CxBuffer cxBufferCreate(
universe@483:         void *space,
universe@483:         size_t capacity,
universe@483:         int flags
universe@483: ) {
universe@483:     CxBuffer buffer = (CxBuffer) malloc(sizeof(cx_buffer_s));
universe@483:     if (buffer) {
universe@483:         buffer->flags = flags;
universe@483:         if (!space) {
universe@483:             buffer->bytes = malloc(capacity);
universe@483:             if (!buffer->bytes) {
universe@483:                 free(buffer);
universe@483:                 return NULL;
universe@483:             }
universe@483:             memset(buffer->bytes, 0, capacity);
universe@483:             buffer->flags |= CX_BUFFER_FREE_CONTENTS;
universe@483:         } else {
universe@483:             buffer->bytes = space;
universe@483:         }
universe@483:         buffer->capacity = capacity;
universe@483:         buffer->size = 0;
universe@483: 
universe@483:         buffer->pos = 0;
universe@483:     }
universe@483: 
universe@483:     return buffer;
universe@483: }
universe@483: 
universe@483: void cxBufferDestroy(CxBuffer buffer) {
universe@483:     if ((buffer->flags & CX_BUFFER_FREE_CONTENTS) == CX_BUFFER_FREE_CONTENTS) {
universe@483:         free(buffer->bytes);
universe@483:     }
universe@483:     free(buffer);
universe@483: }
universe@483: 
universe@483: CxBuffer cxBufferExtract(
universe@483:         CxBuffer src,
universe@483:         size_t start,
universe@483:         size_t length,
universe@483:         int flags
universe@483: ) {
universe@483:     if (src->size == 0 || length == 0 ||
universe@483:         ((size_t) -1) - start < length || start + length > src->capacity) {
universe@483:         return NULL;
universe@483:     }
universe@483: 
universe@483:     CxBuffer dst = (CxBuffer) malloc(sizeof(cx_buffer_s));
universe@483:     if (dst) {
universe@483:         dst->bytes = malloc(length);
universe@483:         if (!dst->bytes) {
universe@483:             free(dst);
universe@483:             return NULL;
universe@483:         }
universe@483:         dst->capacity = length;
universe@483:         dst->size = length;
universe@483:         dst->flags = flags | CX_BUFFER_FREE_CONTENTS;
universe@483:         dst->pos = 0;
universe@483:         memcpy(dst->bytes, src->bytes + start, length);
universe@483:     }
universe@483:     return dst;
universe@483: }
universe@483: 
universe@483: int cxBufferSeek(
universe@483:         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@483: int cxBufferEof(CxBuffer buffer) {
universe@483:     return buffer->pos >= buffer->size;
universe@483: }
universe@483: 
universe@483: int cxBufferMinimumCapacity(
universe@483:         CxBuffer buffer,
universe@483:         size_t additional_bytes
universe@483: ) {
universe@483:     size_t newcap = buffer->capacity + additional_bytes;
universe@483: 
universe@483:     // overflow protection
universe@483:     if (newcap < buffer->capacity) {
universe@483:         return -1;
universe@483:     }
universe@483: 
universe@483:     unsigned char *newspace = realloc(buffer->bytes, newcap);
universe@483:     if (newspace) {
universe@483:         memset(newspace + buffer->size, 0, newcap - buffer->size);
universe@483:         buffer->bytes = newspace;
universe@483:         buffer->capacity = newcap;
universe@483:     } else {
universe@483:         return -1;
universe@483:     }
universe@483: 
universe@483:     return 0;
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@483:         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:     size_t required = buffer->pos + len;
universe@483:     if (buffer->pos > required) {
universe@483:         return 0;
universe@483:     }
universe@483: 
universe@483:     if (required > buffer->capacity) {
universe@483:         if ((buffer->flags & CX_BUFFER_AUTO_EXTEND) == CX_BUFFER_AUTO_EXTEND) {
universe@483:             if (cxBufferMinimumCapacity(buffer, required)) {
universe@483:                 return 0;
universe@483:             }
universe@483:         } else {
universe@483:             len = buffer->capacity - buffer->pos;
universe@483:             if (size > 1) {
universe@483:                 len -= len % size;
universe@483:             }
universe@483:         }
universe@483:     }
universe@483: 
universe@483:     if (len == 0) {
universe@483:         return len;
universe@483:     }
universe@483: 
universe@483:     memcpy(buffer->bytes + buffer->pos, ptr, len);
universe@483:     buffer->pos += len;
universe@483:     if (buffer->pos > buffer->size) {
universe@483:         buffer->size = buffer->pos;
universe@483:     }
universe@483: 
universe@483:     return len / size;
universe@483: }
universe@483: 
universe@483: size_t cxBufferRead(
universe@483:         void *ptr,
universe@483:         size_t size,
universe@483:         size_t nitems,
universe@483:         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@483: int cxBufferPut(
universe@483:         CxBuffer buffer,
universe@483:         int c
universe@483: ) {
universe@483:     if (buffer->pos >= buffer->capacity) {
universe@483:         if ((buffer->flags & CX_BUFFER_AUTO_EXTEND) == CX_BUFFER_AUTO_EXTEND) {
universe@483:             if (cxBufferMinimumCapacity(buffer, buffer->capacity + 1)) {
universe@483:                 return EOF;
universe@483:             }
universe@483:         } else {
universe@483:             return EOF;
universe@483:         }
universe@483:     }
universe@483: 
universe@483:     c &= 0xFF;
universe@483:     buffer->bytes[buffer->pos] = (unsigned char) c;
universe@483:     buffer->pos++;
universe@483:     if (buffer->pos > buffer->size) {
universe@483:         buffer->size = buffer->pos;
universe@483:     }
universe@483:     return c;
universe@483: }
universe@483: 
universe@483: 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: size_t cxBufferPutString(
universe@483:         CxBuffer buffer,
universe@483:         const char *str
universe@483: ) {
universe@483:     return cxBufferWrite(str, 1, strlen(str), buffer);
universe@483: }
universe@483: 
universe@483: int cxBufferShiftLeft(
universe@483:         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@483:         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@483:         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: }