238 lines
7.2 KiB
C
238 lines
7.2 KiB
C
/* *****************************************************************************
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* decode/std.c -- decode a "standard" CASIO file.
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* Copyright (C) 2017 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
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*
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* This file is part of libg1m.
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* libg1m is free software; you can redistribute it and/or modify it
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* under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation; either version 3.0 of the License,
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* or (at your option) any later version.
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*
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* libg1m is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with libg1m; if not, see <http://www.gnu.org/licenses/>.
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* ************************************************************************** */
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#include <libg1m/internals.h>
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#define FUNC(NAME) g1m_decode_std_##NAME
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/* ************************************************************************** */
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/* Getting the parsing function */
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/* ************************************************************************** */
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/* Correspondance type */
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typedef int (*decode_func)();
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struct corresp {
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unsigned int platform;
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unsigned int type;
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/* result */
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decode_func decode;
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};
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/* The correspondances */
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static struct corresp parsing_functions[] = {
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/* add-ins */
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{g1m_platform_fx, g1m_type_addin, FUNC(addin)},
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{g1m_platform_cp, g1m_type_addin, FUNC(cp_addin)},
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{g1m_platform_cg, g1m_type_addin, FUNC(cg_addin)},
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/* mcs */
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{g1m_platform_fx, g1m_type_mcs, FUNC(mcs)},
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{g1m_platform_cg, g1m_type_mcs, FUNC(mcs)},
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/* language files */
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{g1m_platform_fx, g1m_type_lang, FUNC(lang)},
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{g1m_platform_cg, g1m_type_lang, FUNC(cg_lang)},
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/* function keys file */
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{g1m_platform_fx, g1m_type_fkey, FUNC(fkey)},
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{g1m_platform_cg, g1m_type_fkey, FUNC(cg_fkey)},
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/* e-activities */
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{g1m_platform_fx, g1m_type_eact, FUNC(eact)},
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/* pictures */
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{g1m_platform_cg, g1m_type_pict, FUNC(g3p)},
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{g1m_platform_cp, g1m_type_pict, FUNC(c2p)},
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{0, 0, NULL}
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};
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/**
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* find_decode_function:
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* Find the parsing function.
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*
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* @arg platform the platform.
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* @arg type the type.
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* @arg rd pointer to the decode function.
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* @return the error code (0 if ok).
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*/
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static int find_decode_function(g1m_platform_t platform, g1m_type_t type,
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decode_func *rd)
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{
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/* get the function */
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struct corresp *c = parsing_functions - 1;
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while ((++c)->decode) {
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if (c->type != type)
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continue;
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if (c->platform != platform)
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continue;
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break;
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}
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if (!c->decode) {
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log_fatal("No parsing function was found for this type.");
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return (g1m_error_magic);
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}
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/* set the vars */
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*rd = c->decode;
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return (0);
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}
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/* ************************************************************************** */
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/* Main standard header decoding function */
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/* ************************************************************************** */
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/**
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* g1m_decode_std:
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* Decode a file with standard header.
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*
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* @arg handle the handle to create.
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* @arg path the path.
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* @arg buffer the buffer to read from.
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* @arg std the standard header.
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* @arg expected_types the expected types.
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* @return the error code (0 if ok).
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*/
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int g1m_decode_std(g1m_t **handle, const char *path, g1m_buffer_t *buffer,
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struct standard_header *std, g1m_type_t expected_types)
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{
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int err;
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/* reverse the standard header */
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uint8_t *u = (uint8_t*)std;
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uint32_t check = g1m_checksum32(std, sizeof(struct standard_header), 0);
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for (size_t i = 0; i < sizeof(struct standard_header); i++)
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u[i] = ~u[i];
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/* print header */
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log_info("Raw inverted standard header is:");
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logm_info(std, sizeof(struct standard_header));
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std->filesize = be32toh(std->filesize);
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std->number = be16toh(std->number);
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/* get the type */
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g1m_platform_t platform; g1m_type_t type;
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const char *type_string; unsigned int mflags;
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decode_func rd;
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if (g1m_maketype_std(path, std->main_id, std->subtype, &type_string,
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&mflags, &platform, &type))
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return (g1m_error_magic);
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log_info("Standard Header type is '%s'.", type_string);
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/* check control bytes */
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if (mflags & g1m_stdflag_check1
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&& std->control != ((std->filesize + 0x41) & 0xff)) {
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log_info("First control byte isn't right.");
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return (g1m_error_magic);
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} else if (mflags & g1m_stdflag_check2
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&& std->control2 != ((std->filesize + 0xb8) & 0xff)) {
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log_info("Second control byte isn't right.");
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return (g1m_error_magic);
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}
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/* check if there is a standard subheader */
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if (mflags & g1m_stdflag_sub) {
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log_info("Has a Standard Subheader!");
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DREAD(hd, standard_subheader)
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if (g1m_maketype_sub(hd.filetype, hd.platform,
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&mflags, &type, &platform))
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return (g1m_error_magic);
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/* TODO: controls */
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/* find the decode function */
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if (find_decode_function(platform, type, &rd))
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return (g1m_error_magic);
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if (expected_types && !(type & expected_types))
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return (g1m_error_wrong_type);
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/* read and decode for specific platforms */
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check = g1m_checksum32(&hd.filetype,
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sizeof(struct standard_subheader) - 4, check);
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if (platform == g1m_platform_cp) {
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DREAD(shd, _classpad_subheader)
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check = g1m_checksum32(&shd, sizeof(struct _classpad_subheader),
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check);
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/* decode the file content */
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err = (*rd)(handle, buffer, std, &hd, &shd, &check);
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if (err) return (err);
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} else if (platform == g1m_platform_cg) {
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DREAD(shd, _prizm_subheader)
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check = g1m_checksum32(&shd, sizeof(struct _prizm_subheader),
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check);
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/* decode the file content */
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err = (*rd)(handle, buffer, std, &hd, &shd, &check);
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if (err) return (err);
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/* read the footer */
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uint32_t endcheck; GREAD(&endcheck, sizeof(uint32_t))
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err = g1m_error_checksum;
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if (be32toh(endcheck) != be32toh(hd.checksum))
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goto fail;
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}
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/* check the sum */
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err = g1m_error_checksum;
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if (check != be32toh(hd.checksum))
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goto fail;
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/* no error */
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return (0);
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}
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/* check if there is a standard picture header */
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if (mflags & g1m_stdflag_pic) {
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log_info("Has a Standard Picture Header!");
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DREAD(hd, standard_picheader)
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/* correct the type; TODO: hardcode less */
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type = g1m_type_picture;
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if (!memcmp(hd.cp, "CC", 2))
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platform = g1m_platform_cp;
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else if (!memcmp(hd.cp, "CP", 2))
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platform = g1m_platform_cg;
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else {
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log_error("Unknown magic sequence: '%.2s'", hd.cp);
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return (g1m_error_magic);
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}
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/* find the decode function */
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if (find_decode_function(platform, type, &rd))
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return (g1m_error_magic);
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/* call it */
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err = (*rd)(handle, buffer, std, &hd);
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if (err) return (err);
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/* no error! */
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return (0);
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}
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/* find the decode function */
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if (find_decode_function(platform, type, &rd))
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return (g1m_error_magic);
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if (expected_types && !(type & expected_types))
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return (g1m_error_wrong_type);
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/* log some data */
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log_info("Standard Header filesize is %" PRIu32 "o.", std->filesize);
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log_info("Standard Header num is %" PRIu16 ".", std->number);
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/* subdecode. */
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return ((*rd)(handle, buffer, std));
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fail:
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g1m_free(*handle); *handle = NULL;
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return (err);
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}
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