idevicescreenshot: Remove unnecessary math functions to find a unique filename

Removes repeated malloc/free too, limits the maximum filenames to try to 65535
and fails if no unique filename could be found. I think this limit is VERY
generous. If there are really so many files to test against it will also cause
an unconveniently long delay, but I felt a lower limit could still be easily
reached.

1 files changed, 23 insertions, 15 deletions

diff --git a/tools/idevicescreenshot.c b/tools/idevicescreenshot.c
index f33e83e..62bb4a3 100644
--- a/tools/idevicescreenshot.c
+++ b/tools/idevicescreenshot.c
@@ -29,7 +29,6 @@
 #include <string.h>
 #include <stdlib.h>
 #include <errno.h>
-#include <math.h>
 #include <time.h>
 #include <unistd.h>
 #ifndef WIN32
@@ -121,17 +120,21 @@ int main(int argc, char **argv)
                         uint64_t imgsize = 0;
                         if (screenshotr_take_screenshot(shotr, &imgdata, &imgsize) == SCREENSHOTR_E_SUCCESS) {
                                 get_image_filename(imgdata, &filename);
-                                FILE *f = fopen(filename, "wb");
-                                if (f) {
-                                        if (fwrite(imgdata, 1, (size_t)imgsize, f) == (size_t)imgsize) {
-                                                printf("Screenshot saved to %s\n", filename);
-                                                result = 0;
+                                if (!filename) {
+                                        printf("FATAL: Could not find a unique filename!\n");
+                                } else {
+                                        FILE *f = fopen(filename, "wb");
+                                        if (f) {
+                                                if (fwrite(imgdata, 1, (size_t)imgsize, f) == (size_t)imgsize) {
+                                                        printf("Screenshot saved to %s\n", filename);
+                                                        result = 0;
+                                                } else {
+                                                        printf("Could not save screenshot to file %s!\n", filename);
+                                                }
+                                                fclose(f);
                                         } else {
-                                                printf("Could not save screenshot to file %s!\n", filename);
+                                                printf("Could not open %s for writing: %s\n", filename, strerror(errno));
                                         }
-                                        fclose(f);
-                                } else {
-                                        printf("Could not open %s for writing: %s\n", filename, strerror(errno));
                                 }
                         } else {
                                 printf("Could not get screenshot!\n");
@@ -179,6 +182,7 @@ void get_image_filename(char *imgdata, char **filename)
                 basename = (char*)malloc(strlen(*filename) + 1);
                 strcpy(basename, *filename);
                 free(*filename);
+                *filename = NULL;
         } else {
                 time_t now = time(NULL);
                 basename = (char*)malloc(32);
@@ -186,15 +190,19 @@ void get_image_filename(char *imgdata, char **filename)
         }
 
         // Ensure the filename is unique on disk.
-        char *unique_filename = (char*)malloc(strlen(basename) + strlen(fileext) + 1);
+        char *unique_filename = (char*)malloc(strlen(basename) + strlen(fileext) + 7);
         sprintf(unique_filename, "%s%s", basename, fileext);
         int i;
-        for (i = 2; access(unique_filename, F_OK) != -1; i++) {
-                free(unique_filename);
-                unique_filename = (char*)malloc(strlen(basename) + strlen(fileext) + floor(log10(i)) + 3);
+        for (i = 2; i < (1 << 16); i++) {
+                if (access(unique_filename, F_OK) == -1) {
+                        *filename = unique_filename;
+                        break;
+                }
                 sprintf(unique_filename, "%s-%d%s", basename, i, fileext);
         }
-        *filename = unique_filename;
+        if (!*filename) {
+                free(unique_filename);
+        }
         free(basename);
 }