GrowingBuffer.cpp

   1 /**
   2  * © 2008 by David ‘Bombe’ Roden <bombe@pterodactylus.net>
   3  */
   4
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <string.h>
   8 #include <stddef.h>
   9 #include "GrowingBuffer.h"
  10 #include "GlobalSettings.h"
  11
  12 GrowingBuffer::GrowingBuffer(size_t initialSize) {
  13         this->data = malloc(initialSize);
  14         this->size = initialSize;
  15         this->limit = 0;
  16         this->position = 0;
  17         GlobalSettings::isVerbose() && fprintf(stderr, "[%s:%d] created new GrowingBuffer with a size of %d.\n", __FILE__, __LINE__, initialSize);
  18 }
  19
  20 GrowingBuffer::~GrowingBuffer() {
  21         if (this->data) {
  22                 free(this->data);
  23         }
  24         GlobalSettings::isVerbose() && fprintf(stderr, "[%s:%d] destroyed GrowingBuffer.\n", __FILE__, __LINE__);
  25 }
  26
  27 size_t GrowingBuffer::getPosition() {
  28         return position;
  29 }
  30
  31 size_t GrowingBuffer::getLimit() {
  32         return limit;
  33 }
  34
  35 size_t GrowingBuffer::getSize() {
  36         return size;
  37 }
  38
  39 void GrowingBuffer::seek(size_t position) {
  40         this->position = (position > limit) ? limit : position;
  41         GlobalSettings::isVerbose() && fprintf(stderr, "[%s:%d] setting position to %d.\n", __FILE__, __LINE__, position);
  42 }
  43
  44 void* GrowingBuffer::read(void* buffer, size_t length) {
  45         size_t bytesToCopy = (length > (limit - position)) ? (limit - position) : length;
  46         GlobalSettings::isVerbose() && fprintf(stderr, "[%s:%d] copying %d bytes (%d requested) into buffer.\n", __FILE__, __LINE__, bytesToCopy, length);
  47         memcpy(buffer, (ptrdiff_t*) data + position, bytesToCopy);
  48         GlobalSettings::isVerbose() && fprintf(stderr, "[%s:%d] advancing position from %d to %d.\n", __FILE__, __LINE__, position, position + bytesToCopy);
  49         position += bytesToCopy;
  50         return buffer;
  51 }
  52
  53 void GrowingBuffer::write(const void* buffer, size_t length) {
  54         if (length > (size - limit)) {
  55                 int newSize = size;
  56                 do {
  57                         newSize *= 2;
  58                 } while (length > (newSize - limit));
  59                 GlobalSettings::isVerbose() && fprintf(stderr, "[%s:%d] resizing buffer from %d to %d bytes to fit in %d bytes.\n", __FILE__, __LINE__, size, newSize, length);
  60                 void* newData = malloc(newSize);
  61                 memcpy(newData, data, position);
  62                 free(data);
  63                 data = newData;
  64         }
  65         GlobalSettings::isVerbose() && fprintf(stderr, "[%s:%d] writing %d bytes to buffer at position %d.\n", __FILE__, __LINE__, length, limit);
  66         memcpy((ptrdiff_t*) data + limit, buffer, length);
  67         limit += length;
  68 }
  69
  70 void GrowingBuffer::cut() {
  71         GlobalSettings::isVerbose() && fprintf(stderr, "[%s:%d] discarding %d bytes.\n", __FILE__, __LINE__, position);
  72         memcpy(data, (ptrdiff_t*) data + position, position);
  73         limit = position;
  74         position = 0;
  75 }
  76
  77 void GrowingBuffer::truncate() {
  78         GlobalSettings::isVerbose() && fprintf(stderr, "[%s:%d] truncating %d bytes at position %d.\n", __FILE__, __LINE__, (limit - position), position);
  79         limit = position;
  80 }
  81
  82 void GrowingBuffer::clear() {
  83         GlobalSettings::isVerbose() && fprintf(stderr, "[%s:%d] clearing buffer, discarding %d bytes.\n", __FILE__, __LINE__, limit);
  84         position = 0;
  85         limit = 0;
  86 }
  87
  88 void GrowingBuffer::resize(double factor) {
  89         if (factor < 1.0) {
  90                 factor = 1.0;
  91         }
  92         if (size != (limit * factor)) {
  93                 GlobalSettings::isVerbose() && fprintf(stderr, "[%s:%d] resizing buffer from %d to %d bytes.\n", __FILE__, __LINE__, size, (size_t) (limit * factor));
  94                 void* newData = malloc((size_t) (limit * factor));
  95                 memcpy(newData, data, limit);
  96                 free(data);
  97                 data = newData;
  98         }
  99 }
 100