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136 lines
3.1 KiB
C
136 lines
3.1 KiB
C
#include "codeseg.h"
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#include "disasm.h"
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#include <string.h>
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#include <stdio.h>
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#include <stdlib.h>
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static unsigned char *find_ref_list (unsigned char *map, const char *type,
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int *num_resources);
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/* Returns a linked list of the code segments in the specified file, or
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* NULL if none were found.
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*/
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codeseg_t *
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read_code_segments (const char *filename)
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{
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FILE *rsrc_fp;
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unsigned char *rsrc, *orig_rsrc, *ref_list;
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unsigned long file_size;
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int i, num_code_resources;
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codeseg_t *prev;
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rsrc_fp = fopen (filename, "rb");
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if (rsrc_fp == NULL)
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{
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perror (filename);
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return NULL;
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}
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/* Compute the file's size. */
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fseek (rsrc_fp, 0, SEEK_END);
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file_size = ftell (rsrc_fp);
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fseek (rsrc_fp, 0, SEEK_SET);
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/* Read the entire resource file into core. */
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rsrc = orig_rsrc = (unsigned char *)malloc (file_size);
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if (fread (rsrc, 1, file_size, rsrc_fp) != file_size)
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{
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perror (filename);
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fclose (rsrc_fp);
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free (orig_rsrc);
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return NULL;
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}
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fclose (rsrc_fp);
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/* First, skip 512 bytes to skip over extra AppleDouble space. */
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rsrc += 512;
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if (read_long (rsrc) != 256)
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{
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fprintf (stderr, "%s: not a resource file (data offset != 256).\n",
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filename);
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free (orig_rsrc);
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return NULL;
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}
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ref_list = find_ref_list (rsrc + read_long (rsrc + 4), "CODE",
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&num_code_resources);
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if (ref_list == NULL || num_code_resources == 0)
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{
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fprintf (stderr, "%s: no code resources found.\n", filename);
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free (orig_rsrc);
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return NULL;
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}
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/* Read in all of the code resources. */
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for (i = 0, prev = NULL; i < num_code_resources; i++)
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{
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codeseg_t *c;
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unsigned char *data_start;
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c = (codeseg_t *)malloc (sizeof *c);
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memset (c, 0, sizeof *c);
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c->segment = read_short (ref_list);
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data_start = rsrc + 256 + (read_long (ref_list + 4) & 0xFFFFFF);
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c->num_code_bytes = read_long (data_start);
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c->code = (unsigned char *)malloc (c->num_code_bytes);
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if (c->code == NULL)
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{
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fprintf (stderr, "Tried to malloc 0x%lX bytes and failed.\n",
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(unsigned long)c->num_code_bytes);
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free (orig_rsrc);
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return NULL;
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}
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memcpy (c->code, data_start + 4, c->num_code_bytes);
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c->next = prev;
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prev = c;
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/* Move on to next ref_list entry. */
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ref_list += 12;
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}
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free (orig_rsrc);
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return prev;
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}
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static unsigned char *
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find_ref_list (unsigned char *map, const char *type, int *num_resources)
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{
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int i, num_types;
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unsigned char *type_list;
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*num_resources = 0; /* Default. */
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type_list = map + 28;
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num_types = read_short (type_list) + 1;
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for (i = 0, type_list += 2; i < num_types; i++)
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{
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if (!memcmp (type_list, type, 4))
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{
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*num_resources = read_short (type_list + 4) + 1;
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return map + 28 + read_short (type_list + 6);
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}
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/* Move on to next type list entry. */
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type_list += 8;
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}
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return NULL;
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}
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long
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read_long (const unsigned char *p)
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{
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return (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
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}
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short
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read_short (const unsigned char *p)
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{
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return (p[0] << 8) | p[1];
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}
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