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Make the PNG reader code re-useable

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Kovid Goyal
2018-07-07 07:46:15 +05:30
parent aeed20087e
commit 2b035739f8
6 changed files with 160 additions and 80 deletions
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81
kitty/graphics.c
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@@ -15,8 +15,8 @@
#include <stdlib.h>
#include <zlib.h>
#include <png.h>
#include <structmember.h>
#include "png-reader.h"
PyTypeObject GraphicsManager_Type;
#define STORAGE_LIMIT (320 * (1024 * 1024))
@@ -227,87 +227,14 @@ err:
return ok;
}
struct fake_file { uint8_t *buf; size_t sz, cur; };
static void
read_png_from_buffer(png_structp png, png_bytep out, png_size_t length) {
struct fake_file *f = png_get_io_ptr(png);
if (f) {
size_t amt = MIN(length, f->sz - f->cur);
memcpy(out, f->buf + f->cur, amt);
f->cur += amt;
}
}
static void
read_png_error_handler(png_structp png_ptr, png_const_charp msg) {
jmp_buf *jb;
set_add_response("EBADPNG", msg);
jb = png_get_error_ptr(png_ptr);
if (jb == NULL) fatal("read_png_error_handler: could not retrieve jmp_buf");
longjmp(*jb, 1);
}
static void
read_png_warn_handler(png_structp UNUSED png_ptr, png_const_charp UNUSED msg) {
// ignore warnings
}
struct png_jmp_data { uint8_t *decompressed; bool ok; png_bytep *row_pointers; int width, height; size_t sz; };
static void
inflate_png_inner(struct png_jmp_data *d, uint8_t *buf, size_t bufsz) {
struct fake_file f = {.buf = buf, .sz = bufsz};
png_structp png = NULL;
png_infop info = NULL;
jmp_buf jb;
png = png_create_read_struct(PNG_LIBPNG_VER_STRING, &jb, read_png_error_handler, read_png_warn_handler);
if (!png) ABRT(ENOMEM, "Failed to create PNG read structure");
info = png_create_info_struct(png);
if (!info) ABRT(ENOMEM, "Failed to create PNG info structure");
if (setjmp(jb)) goto err;
png_set_read_fn(png, &f, read_png_from_buffer);
png_read_info(png, info);
png_byte color_type, bit_depth;
d->width = png_get_image_width(png, info);
d->height = png_get_image_height(png, info);
color_type = png_get_color_type(png, info);
bit_depth = png_get_bit_depth(png, info);
// Ensure we get RGBA data out of libpng
if (bit_depth == 16) png_set_strip_16(png);
if (color_type == PNG_COLOR_TYPE_PALETTE) png_set_palette_to_rgb(png);
// PNG_COLOR_TYPE_GRAY_ALPHA is always 8 or 16bit depth.
if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) png_set_expand_gray_1_2_4_to_8(png);
if (png_get_valid(png, info, PNG_INFO_tRNS)) png_set_tRNS_to_alpha(png);
// These color_type don't have an alpha channel then fill it with 0xff.
if (color_type == PNG_COLOR_TYPE_RGB || color_type == PNG_COLOR_TYPE_GRAY || color_type == PNG_COLOR_TYPE_PALETTE) png_set_filler(png, 0xFF, PNG_FILLER_AFTER);
if (color_type == PNG_COLOR_TYPE_GRAY || color_type == PNG_COLOR_TYPE_GRAY_ALPHA) png_set_gray_to_rgb(png);
png_read_update_info(png, info);
int rowbytes = png_get_rowbytes(png, info);
d->sz = rowbytes * d->height * sizeof(png_byte);
d->decompressed = malloc(d->sz + 16);
if (d->decompressed == NULL) ABRT(ENOMEM, "Out of memory allocating decompression buffer for PNG");
d->row_pointers = malloc(d->height * sizeof(png_bytep));
if (d->row_pointers == NULL) ABRT(ENOMEM, "Out of memory allocating row_pointers buffer for PNG");
for (int i = 0; i < d->height; i++) d->row_pointers[i] = d->decompressed + i * rowbytes;
png_read_image(png, d->row_pointers);
d->ok = true;
err:
if (png) png_destroy_read_struct(&png, info ? &info : NULL, NULL);
return;
png_error_handler(const char *code, const char *msg) {
set_add_response(code, "%s", msg);
}
static inline bool
inflate_png(GraphicsManager UNUSED *self, Image *img, uint8_t *buf, size_t bufsz) {
struct png_jmp_data d = {0};
png_read_data d = {.err_handler=png_error_handler};
inflate_png_inner(&d, buf, bufsz);
if (d.ok) {
free_load_data(&img->load_data);