diff options
Diffstat (limited to 'memview.c')
| -rw-r--r-- | memview.c | 161 |
1 files changed, 0 insertions, 161 deletions
diff --git a/memview.c b/memview.c deleted file mode 100644 index 95a3c6c..0000000 --- a/memview.c +++ /dev/null @@ -1,161 +0,0 @@ -#include <stdlib.h> -#include <stdint.h> -#include <stdbool.h> -#include <assert.h> -#include <limits.h> -#include <string.h> -#include <SDL.h> - -#include "memview.h" -#include "procfs.h" - -struct viewer { - int fd; - SDL_Renderer *renderer; - SDL_Texture *page_texture; - uint8_t page_buffer[PAGE_SIZE]; -}; - -#define BIT_OF(X, I) (((X) >> (I)) & 1ULL) - -static uintptr_t zorder(unsigned int x, unsigned int y) { - uintptr_t z = 0; - // interleaving bits results in a point on the z-order curve - for (int i = 0; i < sizeof(x) * CHAR_BIT; i++) - z |= (BIT_OF(x, i) << i*2) | (BIT_OF(y, i) << (i*2 + 1)); - return z; -} - -static void unzorder(uintptr_t z, unsigned int *x, unsigned int *y) { - *x = 0; *y = 0; - for (int i = 0; i < sizeof(z) * CHAR_BIT / 2; i++) { - *x |= BIT_OF(z, i*2) << i; - *y |= BIT_OF(z, i*2 + 1) << i; - } -} - -uintptr_t to_addr(int x, int y) { - unsigned int ux, uy; - memcpy(&ux, &x, sizeof(unsigned int)); - memcpy(&uy, &y, sizeof(unsigned int)); - uintptr_t page = zorder(ux / PAGE_WIDTH, uy / PAGE_HEIGHT); - int offset = - x % PAGE_WIDTH / CHAR_BIT + y % PAGE_HEIGHT * PAGE_WIDTH / CHAR_BIT; - return page * PAGE_SIZE + offset; -} - -void to_pos(uintptr_t addr, int *x, int *y) { - unsigned int px, py; - unzorder(addr / PAGE_SIZE, &px, &py); - int offset = addr % PAGE_SIZE; - unsigned int ux = px * PAGE_WIDTH + offset % PAGE_WIDTH; - unsigned int uy = py * PAGE_HEIGHT + offset / PAGE_WIDTH; - memcpy(x, &ux, sizeof(int)); - memcpy(y, &uy, sizeof(int)); -} - -struct viewer *create_viewer(int fd, SDL_Renderer *renderer) { - struct viewer *v = calloc(1, sizeof(struct viewer)); - if (!v) return NULL; - v->fd = fd; v->renderer = renderer; - v->page_texture = SDL_CreateTexture(v->renderer, - SDL_PIXELFORMAT_RGBA32, - SDL_TEXTUREACCESS_STREAMING, - PAGE_WIDTH, PAGE_HEIGHT); - if (!v->page_texture) {free(v); return NULL;} - return v; -} - -void destroy_viewer(struct viewer *v) { - SDL_DestroyTexture(v->page_texture); - free(v); -} - -static void render_page(SDL_Texture *tex, uint8_t *data) { - uint32_t *pixels; int pitch; - assert(SDL_LockTexture(tex, NULL, (void **) &pixels, &pitch) != -1); - if (data) { - for (int i = 0; i < PAGE_SIZE; i++) { - for (int j = 0; j < CHAR_BIT; j++) { - uint8_t bit = (data[i] >> j) & 1; - pixels[i * CHAR_BIT + j] = bit ? 0xFFFFFFFF : 0xFF000000; - } - } - } else { - for (int i = 0; i < PAGE_WIDTH * PAGE_HEIGHT; i++) - pixels[i] = - ((i / 16) + i / PAGE_WIDTH / 16) % 2 ? 0xFF111111 : 0xFF333333; - } - SDL_UnlockTexture(tex); -} - -static uint64_t fnv(uint8_t *data, size_t size) { - uint64_t hash = 0xcbf29ce484222325; - for (size_t i = 0; i < size; i++) { - hash ^= data[i]; - hash *= 0x100000001b3; - } - return hash; -} - -static uint64_t hashes[1024] = {0}; - -bool render_pages(struct viewer *v, - int x, int y, int width, int height, double scale, bool refresh) { - int page_x = x / PAGE_WIDTH; - int page_y = y / PAGE_HEIGHT; - - int offs_x = x % PAGE_WIDTH * scale; - int offs_y = y % PAGE_HEIGHT * scale; - - int page_width = PAGE_WIDTH * scale; - int page_height = PAGE_HEIGHT * scale; - - int view_width = width / page_width; - int view_height = height / page_height; - - bool present = false; - for (int draw_y = -1; draw_y <= view_height + 1; draw_y++) { - for (int draw_x = -1; draw_x <= view_width + 1; draw_x++) { - SDL_Rect src = {0, 0, PAGE_WIDTH, PAGE_HEIGHT}; - SDL_Rect dest = { - draw_x * page_width - offs_x, draw_y * page_height - offs_y, - page_width, page_height - }; - uintptr_t page = zorder(page_x + draw_x, page_y + draw_y); - bool success = read_page(v->fd, page, v->page_buffer) != -1; - - uint64_t hash = fnv(v->page_buffer, success ? PAGE_SIZE : 0); - if (refresh || hashes[page % 1024] != hash) { - render_page(v->page_texture, success ? v->page_buffer : NULL); - SDL_RenderCopy(v->renderer, v->page_texture, &src, &dest); - present = true; - } - hashes[page % 1024] = hash; - } - } - return present; -} - -static void write_bit(int fd, int x, int y, bool bit) { - uintptr_t addr = to_addr(x, y); - int bit_offs = x % CHAR_BIT; - uint8_t byte; - if (read_mem(fd, addr, &byte, 1) == -1) return; - byte = (byte & ~(1 << bit_offs)) | (bit << bit_offs); - write_mem(fd, addr, &byte, 1); -} - -void pencil(struct viewer *v, - double x1, double y1, double x2, double y2, bool bit) { - double dx = (x2 - x1); - double dy = (y2 - y1); - int step = abs(dx) >= abs(dy) ? abs(dx) : abs(dy); - dx = dx / step; dy = dy / step; - double x = x1; double y = y1; - for (int i = 0; i <= step; i++) { - write_bit(v->fd, x, y, bit); - x = x + dx; - y = y + dy; - } -} |