forked from ExternalVendorCode/Signal-Server
Initial Commit
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N9OZB
275
src/image.cc
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275
src/image.cc
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/*
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* Generic image output handling. This feature allows
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* for extensible image output formats and permits for
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* cleaner image rendering code in the model generation
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* routines by moving all of the file-format specific
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* logic to be handled here.
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*/
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#include <stdlib.h>
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#include <string.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <errno.h>
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#include <dlfcn.h>
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#include "image.hh"
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#include "image-ppm.hh"
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int get_dt(image_dispatch_table_t *dt, int format);
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int load_library(image_dispatch_table_t *dt);
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#define DISPATCH_TABLE(ctx) ((image_dispatch_table_t*)(ctx)->_dt)
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static int default_format = IMAGE_PPM;
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char *dynamic_backend = NULL;
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/*
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* image_set_format
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* Changes the default format for the next
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* uninitialized image canvas
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*/
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int image_set_format(int format){
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if(format <= IMAGE_DEFAULT || format >= IMAGE_FORMAT_MAX)
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return EINVAL;
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default_format = format;
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return 0;
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}
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/*
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* image_init
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* Initialize an image context. Must be called
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* before attempting to write any image data
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*/
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int image_init(image_ctx_t *ctx, \
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const size_t width, \
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const size_t height, \
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const int model, \
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const int format) {
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int success = 0;
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image_dispatch_table_t *dt;
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/* Perform some sanity checking on provided arguments */
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if(ctx == NULL)
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return EINVAL;
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if(width == 0 || height == 0)
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return EINVAL;
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if(model < 0 || model > IMAGE_MODEL_MAX)
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return EINVAL;
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if(format >= IMAGE_FORMAT_MAX || (format == IMAGE_LIBRARY && dynamic_backend == NULL))
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return EINVAL;
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memset(ctx,0x00,sizeof(image_ctx_t));
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/* Assign the initialize values to the processing context */
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ctx->width = width;
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ctx->height = height;
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ctx->model = model;
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if(format == IMAGE_DEFAULT)
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ctx->format = default_format;
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else
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ctx->format = format;
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/* Get the dispatch table for this image format */
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dt = (image_dispatch_table_t *) calloc(1,sizeof(image_dispatch_table_t));
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if(dt == NULL){
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fprintf(stderr,"Error allocating dispatch table\n");
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return ENOMEM;
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}
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success = get_dt(dt,ctx->format);
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if(success != 0){
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fprintf(stderr,"Error locating dispatch table\n");
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free(dt);
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return success;
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}
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ctx->_dt = (void*)dt;
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/* Call the format-specific initialization function */
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success = dt->init(ctx);
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if(success != 0){
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fprintf(stderr,"Error initializing image context\n");
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free(dt);
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return success;
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}
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ctx->initialized = 1;
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return success;
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}
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/*
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* image_add_pixel, image_set_pixel, image_get_pixel, image_write, image_free
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* Various setters ad getters for assigning pixel data. image_write
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* takes an open file handle and writes image data to it.
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* These functions simply wrap the underlying format-specific functions
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*/
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int image_add_pixel(image_ctx_t *ctx, const uint8_t r, const uint8_t g, const uint8_t b, const uint8_t a){
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if(ctx->initialized != 1) return EINVAL;
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return DISPATCH_TABLE(ctx)->add_pixel(ctx,r,g,b,a);
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}
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int image_set_pixel(image_ctx_t *ctx, const size_t x, const size_t y, const uint8_t r, const uint8_t g, const uint8_t b, const uint8_t a){
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size_t block_size;
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if(ctx->initialized != 1) return EINVAL;
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/* Image format handlers have the option to specify a _set_pixel handler */
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if(DISPATCH_TABLE(ctx)->set_pixel != NULL){
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return DISPATCH_TABLE(ctx)->set_pixel(ctx,x,y,r,g,b,a);
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}
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block_size = ctx->model == IMAGE_RGB ? RGB_SIZE : RGBA_SIZE;
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ctx->next_pixel = ctx->canvas + PIXEL_OFFSET(x,y,ctx->width,block_size);
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return DISPATCH_TABLE(ctx)->add_pixel(ctx,r,g,b,a);
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}
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int image_get_pixel(image_ctx_t *ctx, const size_t x, const size_t y, const uint8_t *r, const uint8_t *g, const uint8_t *b, const uint8_t *a){
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if(ctx->initialized != 1) return EINVAL;
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if(DISPATCH_TABLE(ctx)->get_pixel != NULL)
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return DISPATCH_TABLE(ctx)->get_pixel(ctx,x,y,r,g,b,a);
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return ENOSYS;
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}
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int image_write(image_ctx_t *ctx, FILE *fd){
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if(ctx->initialized != 1) return EINVAL;
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return DISPATCH_TABLE(ctx)->write(ctx,fd);
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}
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void image_free(image_ctx_t *ctx){
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if(ctx->initialized != 1) return;
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if(DISPATCH_TABLE(ctx)->free != NULL){
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DISPATCH_TABLE(ctx)->free(ctx);
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}
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if(ctx->canvas != NULL) free(ctx->canvas);
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}
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/*
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* image_get_filename
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* Creates an appropriate file name using data supplied
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* by the user. If the extension is already correct, return
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* that; if not append if there is space
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*/
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int image_get_filename(image_ctx_t *ctx, char *out, size_t len_out, char *in){
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size_t len_src;
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size_t len_ext;
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int success = 0;
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if(ctx->initialized != 1)
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return EINVAL;
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/* Get various lengths */
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len_src = strlen(in);
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len_ext = strlen(ctx->extension);
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if(len_src == 0){
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in = (char*)"output";
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len_src = 6;
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}
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if(len_src > len_ext && strcmp(in+len_src-len_ext,ctx->extension) == 0){
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/* Already has correct extension and fits in buffer */
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if(len_src < len_out)
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strncpy(in,out,len_out);
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else
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success = ENOMEM;
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}else if(len_src > len_ext){
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/* Doesn't have correct extension and fits */
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if(len_src + len_ext < len_out){
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strncpy(out,in,len_out);
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strncat(out,ctx->extension,len_out);
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}else
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success = ENOMEM;
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}else{
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/* The input buffer plus an extension cannot fit in the output buffer */
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fprintf(stderr,"Error building image output filename\n");
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success = ENOMEM;
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}
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return success;
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}
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/*
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* get_dt
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* Load the dispatch table for the specified image
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* format. Currently only pixmap supported.
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*/
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int get_dt(image_dispatch_table_t *dt, int format){
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int success = 0;
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memset((void*)dt,0x00,sizeof(image_dispatch_table_t));
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switch(format){
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case IMAGE_PPM:
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*dt = ppm_dt;
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break;
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case IMAGE_LIBRARY:
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success = load_library(dt);
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break;
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default:
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success = EINVAL;
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}
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return success;
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}
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/*
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* ==WARNING==: Here be dragons!
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* Experimantal features beyond this point.
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* Only use if you are sure you know what you
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* are doing!
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*/
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/*
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* image_set_library
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* Set the library to use for generating images
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*/
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int image_set_library(char *library){
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char *libname;
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size_t length;
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length = strlen(library) + 1;
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libname = (char*)calloc(length,sizeof(char));
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if(libname == NULL)
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return ENOMEM;
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strncpy(libname,library,length);
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dynamic_backend = libname;
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default_format = IMAGE_LIBRARY;
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return 0;
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}
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/*
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* image_get_library
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* Returns the current saved image rendering
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* library
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*/
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char* image_get_library(){
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return dynamic_backend;
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}
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/*
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* load_library
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* External image processing: experimental feature
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* Load an external library to perform image processing
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* It must be a custom compatible library
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*/
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int load_library(image_dispatch_table_t *dt){
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void *hndl;
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int success = 0;
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/* Validate object file */
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if(dynamic_backend == NULL || strlen(dynamic_backend) == 0){
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fprintf(stderr,"Custom image processor requested without specification\n");
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return EINVAL;
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}
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/* Load shared object and locate required exports */
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hndl = dlopen(dynamic_backend,RTLD_LAZY);
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if(hndl == NULL){
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fprintf(stderr,"Error loading shared object\n");
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return EINVAL;
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}
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/* Perform symbol lookup */
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if((dt->init = (_init*)dlsym(hndl,"lib_init")) == NULL ||
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(dt->add_pixel = (_add_pixel*)dlsym(hndl,"lib_add_pixel")) == NULL ||
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(dt->write = (_write*)dlsym(hndl,"lib_write")) == NULL){
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fprintf(stderr,"Invalid image processing module specified\n\t%s",dlerror());
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success = EINVAL;
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(void) dlclose(hndl);
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}
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/* Lookup optional symbols, these can return NULL */
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if(success == 0){
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dt->get_pixel = (_get_pixel*)dlsym(hndl,"lib_get_pixel");
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dt->set_pixel = (_set_pixel*)dlsym(hndl,"lib_set_pixel");
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dt->free = (_free*)dlsym(hndl,"lib_free");
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}
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return success;
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}
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