113 lines
2.6 KiB
C
113 lines
2.6 KiB
C
//
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// Copyright 2011-2014 NimbusKit
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// Originally ported from https://github.com/ingenuitas/python-tesseract/blob/master/fmemopen.c
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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#ifdef __APPLE__
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/mman.h>
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FILE *fmemopen(void *buf, size_t size, const char *mode);
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struct fmem {
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size_t pos;
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size_t size;
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char *buffer;
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};
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typedef struct fmem fmem_t;
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static int readfn(void *handler, char *buf, int size) {
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fmem_t *mem = handler;
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size_t available = mem->size - mem->pos;
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if (size > available) {
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size = available;
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}
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memcpy(buf, mem->buffer + mem->pos, sizeof(char) * size);
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mem->pos += size;
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return size;
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}
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static int writefn(void *handler, const char *buf, int size) {
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fmem_t *mem = handler;
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size_t available = mem->size - mem->pos;
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if (size > available) {
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size = available;
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}
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memcpy(mem->buffer + mem->pos, buf, sizeof(char) * size);
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mem->pos += size;
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return size;
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}
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static fpos_t seekfn(void *handler, fpos_t offset, int whence) {
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size_t pos;
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fmem_t *mem = handler;
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switch (whence) {
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case SEEK_SET: {
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if (offset >= 0) {
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pos = (size_t)offset;
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} else {
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pos = 0;
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}
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break;
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}
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case SEEK_CUR: {
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if (offset >= 0 || (size_t)(-offset) <= mem->pos) {
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pos = mem->pos + (size_t)offset;
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} else {
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pos = 0;
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}
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break;
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}
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case SEEK_END: pos = mem->size + (size_t)offset; break;
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default: return -1;
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}
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if (pos > mem->size) {
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return -1;
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}
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mem->pos = pos;
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return (fpos_t)pos;
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}
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static int closefn(void *handler) {
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free(handler);
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return 0;
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}
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FILE *fmemopen(void *buf, size_t size, const char *mode) {
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// This data is released on fclose.
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fmem_t* mem = (fmem_t *) malloc(sizeof(fmem_t));
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// Zero-out the structure.
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memset(mem, 0, sizeof(fmem_t));
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mem->size = size;
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mem->buffer = buf;
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// funopen's man page: https://developer.apple.com/library/mac/#documentation/Darwin/Reference/ManPages/man3/funopen.3.html
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return funopen(mem, readfn, writefn, seekfn, closefn);
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}
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#endif
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