ref: 0ec9859ec8cf39ce1223516161fb39ea44ed5c33
dir: /src/memio.c/
// Emacs style mode select -*- C++ -*- //----------------------------------------------------------------------------- // // Copyright(C) 1993-1996 Id Software, Inc. // Copyright(C) 2005 Simon Howard // // This program is free software; you can redistribute it and/or // modify it under the terms of the GNU General Public License // as published by the Free Software Foundation; either version 2 // of the License, or (at your option) any later version. // // This program is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // // You should have received a copy of the GNU General Public License // along with this program; if not, write to the Free Software // Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA // 02111-1307, USA. // // Emulates the IO functions in C stdio.h reading and writing to // memory. // #include <stdio.h> #include <stdlib.h> #include <string.h> #include "memio.h" #include "z_zone.h" typedef enum { MODE_READ, MODE_WRITE, } memfile_mode_t; struct _MEMFILE { unsigned char *buf; size_t buflen; size_t alloced; unsigned int position; memfile_mode_t mode; }; // Open a memory area for reading MEMFILE *mem_fopen_read(void *buf, size_t buflen) { MEMFILE *file; file = Z_Malloc(sizeof(MEMFILE), PU_STATIC, 0); file->buf = (unsigned char *) buf; file->buflen = buflen; file->position = 0; file->mode = MODE_READ; return file; } // Read bytes size_t mem_fread(void *buf, size_t size, size_t nmemb, MEMFILE *stream) { size_t items; if (stream->mode != MODE_READ) { printf("not a read stream\n"); return -1; } // Trying to read more bytes than we have left? items = nmemb; if (items * size > stream->buflen - stream->position) { items = (stream->buflen - stream->position) / size; } // Copy bytes to buffer memcpy(buf, stream->buf + stream->position, items * size); // Update position stream->position += items * size; return items; } // Open a memory area for writing MEMFILE *mem_fopen_write(void) { MEMFILE *file; file = Z_Malloc(sizeof(MEMFILE), PU_STATIC, 0); file->alloced = 1024; file->buf = Z_Malloc(file->alloced, PU_STATIC, 0); file->buflen = 0; file->position = 0; file->mode = MODE_WRITE; return file; } // Write bytes to stream size_t mem_fwrite(const void *ptr, size_t size, size_t nmemb, MEMFILE *stream) { size_t bytes; if (stream->mode != MODE_WRITE) { return -1; } // More bytes than can fit in the buffer? // If so, reallocate bigger. bytes = size * nmemb; while (bytes > stream->alloced - stream->position) { unsigned char *newbuf; newbuf = Z_Malloc(stream->alloced * 2, PU_STATIC, 0); memcpy(newbuf, stream->buf, stream->alloced); Z_Free(stream->buf); stream->buf = newbuf; stream->alloced *= 2; } // Copy into buffer memcpy(stream->buf + stream->position, ptr, bytes); stream->position += bytes; if (stream->position > stream->buflen) stream->buflen = stream->position; return nmemb; } void mem_get_buf(MEMFILE *stream, void **buf, size_t *buflen) { *buf = stream->buf; *buflen = stream->buflen; } void mem_fclose(MEMFILE *stream) { if (stream->mode == MODE_WRITE) { Z_Free(stream->buf); } Z_Free(stream); } long mem_ftell(MEMFILE *stream) { return stream->position; } int mem_fseek(MEMFILE *stream, signed long position, mem_rel_t whence) { unsigned int newpos; switch (whence) { case MEM_SEEK_SET: newpos = (int) position; break; case MEM_SEEK_CUR: newpos = (int) (stream->position + position); break; case MEM_SEEK_END: newpos = (int) (stream->buflen + position); break; default: return -1; } if (newpos < stream->buflen) { stream->position = newpos; return 0; } else { printf("Error seeking to %i\n", newpos); return -1; } }