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authorDaniel Jones <admin@danieljon.es>2019-12-26 16:54:07 +1030
committerDaniel Jones <admin@danieljon.es>2019-12-26 16:54:07 +1030
commitd5d0883ec84653c13c01d35824c95fa3dd682348 (patch)
tree2f7669d1ccbdcbbc3642f7ea6e28a1fe01316ca9
parent7d224879505009b62849b7c90a085f5b17375c27 (diff)
downloadwebsitegenerator-d5d0883ec84653c13c01d35824c95fa3dd682348.tar.gz
websitegenerator-d5d0883ec84653c13c01d35824c95fa3dd682348.zip
added ability to write to an offset in a file
-rw-r--r--pages.c87
-rw-r--r--pages.h1
2 files changed, 88 insertions, 0 deletions
diff --git a/pages.c b/pages.c
index 49f95c4..c4172ea 100644
--- a/pages.c
+++ b/pages.c
@@ -201,6 +201,92 @@ deletebytes(const char *file, long offset, size_t bytes)
}
int
+writefileatbyte(const char *dest, const char *source, long offset)
+{
+ /*
+ * write file 'source' into 'output_dir'/'file' starting at offset 'offset'
+ * return 1 on success. 0 on failure
+ */
+
+ char filename[512] = {0};
+ size_t length = 512;
+ strncat(filename, output_dir, length-1);
+ length = length - strlen(output_dir);
+ strncat(filename, dest, length-1);
+
+ FILE *in = fopen(filename, "r");
+ if (!in)
+ {
+ fprintf(stderr, "unable to open file '%s', unrecoverable failure\n", filename);
+ return 0;
+ }
+
+ FILE *tmp = fopen("tmp.tmp", "w");
+ if (!tmp)
+ {
+ fprintf(stderr, "unable to open temp file, unrecoverable failure\n");
+ fclose(in);
+ return 0;
+ }
+
+ FILE *src = fopen(source, "r");
+ if (!src)
+ {
+ fprintf(stderr, "unable to open file '%s', unrecoverable failure\n", source);
+ fclose(in);
+ fclose(tmp);
+ return 0;
+ }
+
+ /*
+ * read file 'in' until byte 'offset', writing into file 'tmp'
+ * write file 'src' into 'tmp'
+ * finish writing file 'in' into 'tmp'
+ * delete file 'filename'
+ * rename file 'tmp' 'filename'
+ */
+
+ char c, t, a;
+ long curpos = 1;
+ while ((c = fgetc(in)) != EOF)
+ {
+ if (curpos == offset)
+ {
+ while ((t = fgetc(src)) != EOF)
+ {
+ /* prevent writing end of line '\n' if the next char is EOF */
+ a = fgetc(src);
+ ungetc(a, src);
+ if (a == EOF && t == '\n')
+ continue;
+ fputc(t, tmp);
+ }
+ }
+ fputc(c, tmp);
+ curpos++;
+ }
+
+ fclose(tmp);
+ fclose(in);
+ fclose(src);
+
+ if (remove(filename) == -1)
+ {
+ fprintf(stderr, "unable to delete file '%s', unrecoverable failure\n", filename);
+ return 0;
+ }
+
+ if (rename("tmp.tmp", filename) == -1)
+ {
+
+ fprintf(stderr, "unable to rename tmp file to '%s', unrecoverable failure\n", filename);
+ return 0;
+ }
+
+ return 1;
+}
+
+int
frontpage(int flags)
{
if (!createfile(frontpage_index_output))
@@ -227,5 +313,6 @@ frontpage(int flags)
fprintf(stderr, "unable to generate frontpage\n");
return 0;
}
+ writefileatbyte(frontpage_index_output, "source.txt", substrpos);
return 1;
}
diff --git a/pages.h b/pages.h
index 907d66e..658f17a 100644
--- a/pages.h
+++ b/pages.h
@@ -25,6 +25,7 @@
int createfile(const char *file);
long findstring(const char *file, const char *str);
int deletebytes(const char *file, long offset, size_t bytes);
+int writefileatbyte(const char *dest, const char *source, long offset);
/* generators (to be put into the pages array) */
int frontpage(int flags);