94 lines
2.8 KiB
C
94 lines
2.8 KiB
C
/* _______ ____ __ ___ ___
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* \ _ \ \ / \ / \ \ / / ' ' '
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* | | \ \ | | || | \/ | . .
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* | | | | | | || ||\ /| |
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* | | | | | | || || \/ | | ' ' '
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* | | | | | | || || | | . .
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* | |_/ / \ \__// || | |
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* /_______/ynamic \____/niversal /__\ /____\usic /| . . ibliotheque
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* / \
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* / . \
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* memfile.c - Module for reading data from / / \ \
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* memory using a DUMBFILE. | < / \_
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* | \/ /\ /
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* By entheh. \_ / > /
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* | \ / /
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* | ' /
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* \__/
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*/
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#include <stdlib.h>
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#include <string.h>
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#include "dumb.h"
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typedef struct MEMFILE MEMFILE;
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struct MEMFILE {
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const char *ptr, *ptr_begin;
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size_t left, size;
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};
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static int dumb_memfile_skip(void *f, dumb_off_t n) {
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MEMFILE *m = f;
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if (n > (dumb_off_t)m->left)
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return -1;
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m->ptr += n;
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m->left -= n;
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return 0;
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}
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static int dumb_memfile_getc(void *f) {
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MEMFILE *m = f;
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if (m->left <= 0)
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return -1;
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m->left--;
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return *(const unsigned char *)m->ptr++;
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}
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static dumb_ssize_t dumb_memfile_getnc(char *ptr, size_t n, void *f) {
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MEMFILE *m = f;
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if (n > m->left)
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n = m->left;
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memcpy(ptr, m->ptr, n);
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m->ptr += n;
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m->left -= n;
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return n;
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}
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static void dumb_memfile_close(void *f) { free(f); }
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static int dumb_memfile_seek(void *f, dumb_off_t n) {
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MEMFILE *m = f;
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m->ptr = m->ptr_begin + n;
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m->left = m->size - n;
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return 0;
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}
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static dumb_off_t dumb_memfile_get_size(void *f) {
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MEMFILE *m = f;
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return m->size;
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}
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static const DUMBFILE_SYSTEM memfile_dfs = {NULL,
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&dumb_memfile_skip,
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&dumb_memfile_getc,
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&dumb_memfile_getnc,
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&dumb_memfile_close,
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&dumb_memfile_seek,
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&dumb_memfile_get_size};
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DUMBFILE *dumbfile_open_memory(const char *data, size_t size) {
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MEMFILE *m = malloc(sizeof(*m));
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if (!m)
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return NULL;
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m->ptr_begin = data;
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m->ptr = data;
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m->left = size;
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m->size = size;
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return dumbfile_open_ex(m, &memfile_dfs);
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}
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