157 lines
4.4 KiB
C
157 lines
4.4 KiB
C
/* ************************************************************************** */
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/* _____ _ */
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/* parse/picture.c |_ _|__ _ _| |__ ___ _ _ */
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/* | Project: libg1m | |/ _ \| | | | '_ \ / _ \ | | | */
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/* | | (_) | |_| | | | | __/ |_| | */
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/* By: thomas <thomas@touhey.fr> |_|\___/ \__,_|_| |_|\___|\__, |.fr */
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/* Last updated: 2016/12/01 13:33:45 |___/ */
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/* */
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/* ************************************************************************** */
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#include <libg1m/internals.h>
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#include <zlib.h>
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/**
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* g3p_deobfuscate:
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* De-obfuscate the image data.
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*
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* @arg buf the buffer.
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* @arg n the buffer size.
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*/
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static void g3p_deobfuscate(uint8_t *buf, size_t n)
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{
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while (n--) {
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int byte = *buf;
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*buf++ = (byte >> 3) | ((byte & 0x7) << 5);
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}
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}
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/**
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* g1m_parse_g3p:
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* Parse a G3P file.
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*
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* @arg handle the handle.
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* @arg stream the stream to parse from.
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* @arg std the standard header.
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* @return the error code (0 if ok).
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*/
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int g1m_parse_g3p(g1m_t *handle, FILE *stream,
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struct standard_header *std)
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{
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/* get the G3P global header */
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DREAD(hd, g3p_subheader)
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hd.g3p_size = be32toh(hd.g3p_size);
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/* check magic */
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if (memcmp(hd.magic, "CP", 2)) {
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log_fatal("could not read 'CP'.");
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return (g1m_error_magic);
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}
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/* read the image header */
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DREAD(ihd, g3p_imageheader)
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/* correct endianness */
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ihd.df_size = be32toh(ihd.df_size);
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ihd.width = be16toh(ihd.width);
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ihd.height = be16toh(ihd.height);
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ihd.color_depth = be16toh(ihd.color_depth);
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ihd.data_size = be32toh(ihd.data_size);
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/* check some little things */
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int is_obfuscated =
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((std->obfuscated + 8) & 0xff) != ((std->filesize & 0xff00) >> 8);
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int has_footer = 1; /* might change? */
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size_t deflated_image_size = ihd.data_size - has_footer * 0x4;
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/* log info */
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log_info("Width: %" PRIu16 "px, height: %" PRIu16 "px",
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ihd.width, ihd.height);
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log_info("Pixel depth: %s",
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(ihd.color_depth == g3p_color_4bit) ? "4-bit" : "16-bit");
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log_info("Deflated image length: %" PRIuSIZE "o", deflated_image_size);
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log_info("Is obfuscated: %s", is_obfuscated ? "yes" : "no");
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/* read image */
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uint8_t deflated_image[deflated_image_size];
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READ(deflated_image, deflated_image_size)
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/* read footer and check sum */
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if (has_footer) {
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DREAD(ft, g3p_imagefooter);
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ft.checksum = be32toh(ft.checksum);
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uLong adl = adler32(0, deflated_image, deflated_image_size);
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if (adl != ft.checksum) {
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log_fatal("Incorrect Adler32 checksum!");
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log_fatal("Expected %" PRIu32 ", got %lu",
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ft.checksum, adl);
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return (g1m_error_magic);
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}
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}
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/* unobfuscate if required */
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if (is_obfuscated)
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g3p_deobfuscate(deflated_image, deflated_image_size);
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/* find out length of inflated data */
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uLongf inflated_size = 0L; int z_err;
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if ((z_err = uncompress(Z_NULL, &inflated_size, deflated_image,
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deflated_image_size)) != Z_MEM_ERROR) {
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log_fatal("Zlib error: error #%d", z_err);
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return (g1m_error_magic);
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}
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log_info("Inflated image size is %lu", inflated_size);
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/* allocate space for it, and uncompress */
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uint8_t inflated_image[inflated_size];
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if ((z_err = uncompress(inflated_image, &inflated_size, deflated_image,
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deflated_image_size))) {
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log_fatal("Zlib error: error #%d", z_err);
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return (g1m_error_magic);
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}
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/* allocate picture in handle */
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int w = ihd.width, h = ihd.height;
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handle->width = w;
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handle->height = h;
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handle->pixels = alloc_pixels(w, h);
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if (!handle->pixels) return (g1m_error_alloc);
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prepare_pixels(handle->pixels, w, h)
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/* then store it */
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switch (ihd.color_depth) {
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case g3p_color_4bit:
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g1m_pixels_from_packed4bits(handle->pixels, inflated_image, w, h);
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default: /* case g3p_color_16bit: */
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g1m_pixels_from_16bits(handle->pixels, inflated_image, w, h);
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}
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/* no error */
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return (0);
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}
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/**
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* g1m_parse_c2p:
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* Parse Classpad images.
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*
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* @arg handle the handle.
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* @arg stream the stream to parse from.
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* @return the error code (0 if ok).
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*/
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int g1m_parse_c2p(g1m_t *handle, FILE *stream,
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struct standard_header *std)
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{
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(void)std;
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(void)handle;
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(void)stream;
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/* TODO */
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log_info("C2P files are not managed yet.");
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log_info("Size is %" PRIuSIZE " o", sizeof(struct c2p_subheader));
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/* no error */
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return (0);
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}
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