1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/buffer.c Mon Dec 27 16:51:10 2021 +0100
1.3 @@ -0,0 +1,328 @@
1.4 +/*
1.5 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
1.6 + *
1.7 + * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved.
1.8 + *
1.9 + * Redistribution and use in source and binary forms, with or without
1.10 + * modification, are permitted provided that the following conditions are met:
1.11 + *
1.12 + * 1. Redistributions of source code must retain the above copyright
1.13 + * notice, this list of conditions and the following disclaimer.
1.14 + *
1.15 + * 2. Redistributions in binary form must reproduce the above copyright
1.16 + * notice, this list of conditions and the following disclaimer in the
1.17 + * documentation and/or other materials provided with the distribution.
1.18 + *
1.19 + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
1.20 + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
1.21 + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
1.22 + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
1.23 + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
1.24 + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
1.25 + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
1.26 + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
1.27 + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
1.28 + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
1.29 + * POSSIBILITY OF SUCH DAMAGE.
1.30 + */
1.31 +
1.32 +#include "cx/buffer.h"
1.33 +#include "cx/utils.h"
1.34 +
1.35 +#include <stdlib.h>
1.36 +#include <string.h>
1.37 +
1.38 +CxBuffer cxBufferCreate(
1.39 + void *space,
1.40 + size_t capacity,
1.41 + int flags
1.42 +) {
1.43 + CxBuffer buffer = (CxBuffer) malloc(sizeof(cx_buffer_s));
1.44 + if (buffer) {
1.45 + buffer->flags = flags;
1.46 + if (!space) {
1.47 + buffer->bytes = malloc(capacity);
1.48 + if (!buffer->bytes) {
1.49 + free(buffer);
1.50 + return NULL;
1.51 + }
1.52 + memset(buffer->bytes, 0, capacity);
1.53 + buffer->flags |= CX_BUFFER_FREE_CONTENTS;
1.54 + } else {
1.55 + buffer->bytes = space;
1.56 + }
1.57 + buffer->capacity = capacity;
1.58 + buffer->size = 0;
1.59 +
1.60 + buffer->pos = 0;
1.61 + }
1.62 +
1.63 + return buffer;
1.64 +}
1.65 +
1.66 +void cxBufferDestroy(CxBuffer buffer) {
1.67 + if ((buffer->flags & CX_BUFFER_FREE_CONTENTS) == CX_BUFFER_FREE_CONTENTS) {
1.68 + free(buffer->bytes);
1.69 + }
1.70 + free(buffer);
1.71 +}
1.72 +
1.73 +CxBuffer cxBufferExtract(
1.74 + CxBuffer src,
1.75 + size_t start,
1.76 + size_t length,
1.77 + int flags
1.78 +) {
1.79 + if (src->size == 0 || length == 0 ||
1.80 + ((size_t) -1) - start < length || start + length > src->capacity) {
1.81 + return NULL;
1.82 + }
1.83 +
1.84 + CxBuffer dst = (CxBuffer) malloc(sizeof(cx_buffer_s));
1.85 + if (dst) {
1.86 + dst->bytes = malloc(length);
1.87 + if (!dst->bytes) {
1.88 + free(dst);
1.89 + return NULL;
1.90 + }
1.91 + dst->capacity = length;
1.92 + dst->size = length;
1.93 + dst->flags = flags | CX_BUFFER_FREE_CONTENTS;
1.94 + dst->pos = 0;
1.95 + memcpy(dst->bytes, src->bytes + start, length);
1.96 + }
1.97 + return dst;
1.98 +}
1.99 +
1.100 +int cxBufferSeek(
1.101 + CxBuffer buffer,
1.102 + off_t offset,
1.103 + int whence
1.104 +) {
1.105 + size_t npos;
1.106 + switch (whence) {
1.107 + case SEEK_CUR:
1.108 + npos = buffer->pos;
1.109 + break;
1.110 + case SEEK_END:
1.111 + npos = buffer->size;
1.112 + break;
1.113 + case SEEK_SET:
1.114 + npos = 0;
1.115 + break;
1.116 + default:
1.117 + return -1;
1.118 + }
1.119 +
1.120 + size_t opos = npos;
1.121 + npos += offset;
1.122 +
1.123 + if ((offset > 0 && npos < opos) || (offset < 0 && npos > opos)) {
1.124 + return -1;
1.125 + }
1.126 +
1.127 + if (npos >= buffer->size) {
1.128 + return -1;
1.129 + } else {
1.130 + buffer->pos = npos;
1.131 + return 0;
1.132 + }
1.133 +
1.134 +}
1.135 +
1.136 +int cxBufferEof(CxBuffer buffer) {
1.137 + return buffer->pos >= buffer->size;
1.138 +}
1.139 +
1.140 +int cxBufferMinimumCapacity(
1.141 + CxBuffer buffer,
1.142 + size_t additional_bytes
1.143 +) {
1.144 + size_t newcap = buffer->capacity + additional_bytes;
1.145 +
1.146 + // overflow protection
1.147 + if (newcap < buffer->capacity) {
1.148 + return -1;
1.149 + }
1.150 +
1.151 + unsigned char *newspace = realloc(buffer->bytes, newcap);
1.152 + if (newspace) {
1.153 + memset(newspace + buffer->size, 0, newcap - buffer->size);
1.154 + buffer->bytes = newspace;
1.155 + buffer->capacity = newcap;
1.156 + } else {
1.157 + return -1;
1.158 + }
1.159 +
1.160 + return 0;
1.161 +}
1.162 +
1.163 +size_t cxBufferWrite(
1.164 + const void *ptr,
1.165 + size_t size,
1.166 + size_t nitems,
1.167 + CxBuffer buffer
1.168 +) {
1.169 + size_t len;
1.170 + if (cx_szmul(size, nitems, &len)) {
1.171 + return 0;
1.172 + }
1.173 + size_t required = buffer->pos + len;
1.174 + if (buffer->pos > required) {
1.175 + return 0;
1.176 + }
1.177 +
1.178 + if (required > buffer->capacity) {
1.179 + if ((buffer->flags & CX_BUFFER_AUTO_EXTEND) == CX_BUFFER_AUTO_EXTEND) {
1.180 + if (cxBufferMinimumCapacity(buffer, required)) {
1.181 + return 0;
1.182 + }
1.183 + } else {
1.184 + len = buffer->capacity - buffer->pos;
1.185 + if (size > 1) {
1.186 + len -= len % size;
1.187 + }
1.188 + }
1.189 + }
1.190 +
1.191 + if (len == 0) {
1.192 + return len;
1.193 + }
1.194 +
1.195 + memcpy(buffer->bytes + buffer->pos, ptr, len);
1.196 + buffer->pos += len;
1.197 + if (buffer->pos > buffer->size) {
1.198 + buffer->size = buffer->pos;
1.199 + }
1.200 +
1.201 + return len / size;
1.202 +}
1.203 +
1.204 +size_t cxBufferRead(
1.205 + void *ptr,
1.206 + size_t size,
1.207 + size_t nitems,
1.208 + CxBuffer buffer
1.209 +) {
1.210 + size_t len;
1.211 + if (cx_szmul(size, nitems, &len)) {
1.212 + return 0;
1.213 + }
1.214 + if (buffer->pos + len > buffer->size) {
1.215 + len = buffer->size - buffer->pos;
1.216 + if (size > 1) len -= len % size;
1.217 + }
1.218 +
1.219 + if (len <= 0) {
1.220 + return len;
1.221 + }
1.222 +
1.223 + memcpy(ptr, buffer->bytes + buffer->pos, len);
1.224 + buffer->pos += len;
1.225 +
1.226 + return len / size;
1.227 +}
1.228 +
1.229 +int cxBufferPut(
1.230 + CxBuffer buffer,
1.231 + int c
1.232 +) {
1.233 + if (buffer->pos >= buffer->capacity) {
1.234 + if ((buffer->flags & CX_BUFFER_AUTO_EXTEND) == CX_BUFFER_AUTO_EXTEND) {
1.235 + if (cxBufferMinimumCapacity(buffer, buffer->capacity + 1)) {
1.236 + return EOF;
1.237 + }
1.238 + } else {
1.239 + return EOF;
1.240 + }
1.241 + }
1.242 +
1.243 + c &= 0xFF;
1.244 + buffer->bytes[buffer->pos] = (unsigned char) c;
1.245 + buffer->pos++;
1.246 + if (buffer->pos > buffer->size) {
1.247 + buffer->size = buffer->pos;
1.248 + }
1.249 + return c;
1.250 +}
1.251 +
1.252 +int cxBufferGet(CxBuffer buffer) {
1.253 + if (cxBufferEof(buffer)) {
1.254 + return EOF;
1.255 + } else {
1.256 + int c = buffer->bytes[buffer->pos];
1.257 + buffer->pos++;
1.258 + return c;
1.259 + }
1.260 +}
1.261 +
1.262 +size_t cxBufferPutString(
1.263 + CxBuffer buffer,
1.264 + const char *str
1.265 +) {
1.266 + return cxBufferWrite(str, 1, strlen(str), buffer);
1.267 +}
1.268 +
1.269 +int cxBufferShiftLeft(
1.270 + CxBuffer buffer,
1.271 + size_t shift
1.272 +) {
1.273 + if (shift >= buffer->size) {
1.274 + buffer->pos = buffer->size = 0;
1.275 + } else {
1.276 + memmove(buffer->bytes, buffer->bytes + shift, buffer->size - shift);
1.277 + buffer->size -= shift;
1.278 +
1.279 + if (buffer->pos >= shift) {
1.280 + buffer->pos -= shift;
1.281 + } else {
1.282 + buffer->pos = 0;
1.283 + }
1.284 + }
1.285 + return 0;
1.286 +}
1.287 +
1.288 +int cxBufferShiftRight(
1.289 + CxBuffer buffer,
1.290 + size_t shift
1.291 +) {
1.292 + size_t req_capacity = buffer->size + shift;
1.293 + size_t movebytes;
1.294 +
1.295 + // auto extend buffer, if required and enabled
1.296 + if (buffer->capacity < req_capacity) {
1.297 + if ((buffer->flags & CX_BUFFER_AUTO_EXTEND) == CX_BUFFER_AUTO_EXTEND) {
1.298 + if (cxBufferMinimumCapacity(buffer, req_capacity)) {
1.299 + return 1;
1.300 + }
1.301 + movebytes = buffer->size;
1.302 + } else {
1.303 + movebytes = buffer->capacity - shift;
1.304 + }
1.305 + } else {
1.306 + movebytes = buffer->size;
1.307 + }
1.308 +
1.309 + memmove(buffer->bytes + shift, buffer->bytes, movebytes);
1.310 + buffer->size = shift + movebytes;
1.311 +
1.312 + buffer->pos += shift;
1.313 + if (buffer->pos > buffer->size) {
1.314 + buffer->pos = buffer->size;
1.315 + }
1.316 +
1.317 + return 0;
1.318 +}
1.319 +
1.320 +int cxBufferShift(
1.321 + CxBuffer buffer,
1.322 + off_t shift
1.323 +) {
1.324 + if (shift < 0) {
1.325 + return cxBufferShiftLeft(buffer, (size_t) (-shift));
1.326 + } else if (shift > 0) {
1.327 + return cxBufferShiftRight(buffer, (size_t) shift);
1.328 + } else {
1.329 + return 0;
1.330 + }
1.331 +}
