diff options
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/exe2ico.c | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/tools/exe2ico.c b/tools/exe2ico.c new file mode 100644 index 0000000..5d92994 --- /dev/null +++ b/tools/exe2ico.c @@ -0,0 +1,165 @@ +/* Copyright (C) 2022 June McEnroe <june@causal.agency> + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU Affero General Public License as published by + * the Free Software Foundation, either version 3 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 Affero General Public License for more details. + * + * You should have received a copy of the GNU Affero General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <SDL_rwops.h> +#include <stdarg.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +static void errx(int eval, const char *fmt, ...) { + va_list ap; + va_start(ap, fmt); + vfprintf(stderr, fmt, ap); + va_end(ap); + putc('\n', stderr); + exit(eval); +} +static void err(int eval, const char *fmt, ...) { + va_list ap; + va_start(ap, fmt); + vfprintf(stderr, fmt, ap); + va_end(ap); + fprintf(stderr, ": %s\n", SDL_GetError()); + exit(eval); +} + +int main(int argc, char *argv[]) { + if (argc < 2) return 1; + const char *exePath = argv[1]; + const char *name = strrchr(exePath, '/'); + name = (name ? &name[1] : exePath); + char icoPath[256]; + snprintf( + icoPath, sizeof(icoPath), "%.*s.ICO", (int)strcspn(name, "."), name + ); + + SDL_RWops *exe = SDL_RWFromFile(exePath, "rb"); + if (!exe) err(1, "%s", exePath); + SDL_RWops *ico = SDL_RWFromFile(icoPath, "wb"); + if (!ico) err(1, "%s", icoPath); + + // Read the EXE header + if (SDL_ReadU8(exe) != 'M' || SDL_ReadU8(exe) != 'Z') { + errx(1, "%s: invalid MZ signature", exePath); + } + SDL_RWseek(exe, 0x3C, RW_SEEK_SET); + Uint16 neOffset = SDL_ReadLE16(exe); + SDL_RWseek(exe, neOffset, RW_SEEK_SET); + Uint8 sig[2] = { SDL_ReadU8(exe), SDL_ReadU8(exe) }; + if (sig[0] == 'P' && sig[1] == 'E') { + errx(1, "%s: not implemented for PE", exePath); + } + if (sig[0] != 'N' || sig[1] != 'E') { + errx(1, "%s: invalid NE/PE signature", exePath); + } + + // Read the NE header + SDL_RWseek(exe, neOffset + 0x24, RW_SEEK_SET); + Uint16 resourceTableOffset = neOffset + SDL_ReadLE16(exe); + + // Find the RT_GROUP_ICON resource + SDL_RWseek(exe, resourceTableOffset, RW_SEEK_SET); + Uint16 alignmentShift = SDL_ReadLE16(exe); + for (;;) { + Uint16 typeID = SDL_ReadLE16(exe); + Uint16 count = SDL_ReadLE16(exe); + SDL_ReadLE32(exe); // reserved + if (!typeID) { + errx(1, "%s: no group icon resource", exePath); + } + if (typeID == 0x800E) break; + SDL_RWseek(exe, 0x0C * count, RW_SEEK_CUR); + } + + // Copy the ICONHEADER + // https://devblogs.microsoft.com/oldnewthing/20101018-00/?p=12513 + SDL_RWseek(exe, (Uint32)SDL_ReadLE16(exe) << alignmentShift, RW_SEEK_SET); + SDL_WriteLE16(ico, SDL_ReadLE16(exe)); // reserved + SDL_WriteLE16(ico, SDL_ReadLE16(exe)); // type + Uint16 iconDirCount = SDL_ReadLE16(exe); + SDL_WriteLE16(ico, iconDirCount); + + // Copy ICONDIRENTRY's. The entries in the RT_GROUP_ICON resource differ + // from those in ICO in their last field. In ICO, it is a 32-bit offset + // of the icon data in the ICO file. In the resource, it is a 16-bit + // resource ID of an RT_ICON resource. Here we assume the resources are + // in the same order as the entries referencing them. We translate the + // resource IDs into data offsets by simply tallying up the data lengths + // so far. The data offsets need to be aligned to alignmentShift to match + // up with the lengths of the icon resources. + Uint32 iconDirLength = 0x06 + 0x10 * iconDirCount; + Uint32 dataOffset = iconDirLength; + dataOffset += -dataOffset & ((1 << alignmentShift) - 1); + for (Uint16 i = 0; i < iconDirCount; ++i) { + SDL_WriteU8(ico, SDL_ReadU8(exe)); // width + SDL_WriteU8(ico, SDL_ReadU8(exe)); // height + SDL_WriteU8(ico, SDL_ReadU8(exe)); // colors + SDL_WriteU8(ico, SDL_ReadU8(exe)); // reserved + SDL_WriteLE16(ico, SDL_ReadLE16(exe)); // color planes + SDL_WriteLE16(ico, SDL_ReadLE16(exe)); // bits per pixel + Uint32 dataLength = SDL_ReadLE32(exe); + SDL_ReadLE16(exe); // resource ID, assumed sequential + SDL_WriteLE32(ico, dataLength); + SDL_WriteLE32(ico, dataOffset); + dataOffset += dataLength; + dataOffset += -dataOffset & ((1 << alignmentShift) - 1); + } + // Padding before the first aligned data offset + for (Uint8 i = 0; i < (-iconDirLength & ((1 << alignmentShift) - 1)); ++i) { + SDL_WriteU8(ico, 0); + } + + // Find the RT_ICON resources + SDL_RWseek(exe, resourceTableOffset + 0x02, RW_SEEK_SET); + Uint16 resourceCount; + for (;;) { + Uint16 typeID = SDL_ReadLE16(exe); + resourceCount = SDL_ReadLE16(exe); + SDL_ReadLE32(exe); // reserved + if (!typeID) { + errx(1, "%s: no icon resources", exePath); + } + if (typeID == 0x8003) break; + SDL_RWseek(exe, 0x0C * resourceCount, RW_SEEK_CUR); + } + + // Copy all icon data sequentially + Uint8 *data = NULL; + for (Uint16 i = 0; i < resourceCount; ++i) { + Uint32 dataOffset = (Uint32)SDL_ReadLE16(exe) << alignmentShift; + Uint32 dataLength = (Uint32)SDL_ReadLE16(exe) << alignmentShift; + SDL_ReadLE16(exe); // flags + SDL_ReadLE16(exe); // resource ID + SDL_ReadLE32(exe); // reserved + Sint64 nextResource = SDL_RWtell(exe); + if (nextResource < 0) err(1, "%s", exePath); + + SDL_RWseek(exe, dataOffset, RW_SEEK_SET); + data = realloc(data, dataLength); + if (!data) errx(1, "malloc failed"); + size_t num = SDL_RWread(exe, data, dataLength, 1); + if (!num) err(1, "%s", exePath); + num = SDL_RWwrite(ico, data, dataLength, 1); + if (!num) err(1, "%s", icoPath); + + SDL_RWseek(exe, nextResource, RW_SEEK_SET); + } + free(data); + + SDL_RWclose(ico); + SDL_RWclose(exe); +} |