refactor: Hashing function now streams data into hasher instead of doing it in one go.

include/vieter_package.h

@@ -1,21 +1,23 @@
 #ifndef VIETER_PACKAGE
 #define VIETER_PACKAGE
 
-#include <stdint.h>
-#include <stdbool.h>
-#include <string.h>
-#include <stdlib.h>
-
-#include <archive.h>
-#include <archive_entry.h>
-
 typedef struct vieter_package vieter_package;
 
+typedef enum vieter_package_error {
+	vieter_package_ok = 0,
+	vieter_package_unarchive_error = 1,
+	vieter_package_stat_error = 2
+} vieter_package_error;
+
+/*
+ * Allocate an empty package
+ */
+vieter_package *vieter_package_init();
+
 /*
  * Parse package file into something usable by libvieter.
- * The pointer returned by this function will need to freed at a later point.
  */
-vieter_package *vieter_package_read_archive(const char *pkg_path);
+vieter_package_error vieter_package_read_archive(vieter_package *pkg, const char *pkg_path);
 
 /*
  * Deallocate a package.

src/package/vieter_package.c

@@ -1,30 +1,29 @@
+#include <stdlib.h>
+#include <stdbool.h>
+#include <archive.h>
+#include <archive_entry.h>
+
 #include "vieter_package_internal.h"
 #include "sha256.h"
 
-#define SMALL_BUFF_SIZE 128
-
 #define ADD_STRING(section, field) if (pkg_info->field != 0) { \
-	snprintf(aux, SMALL_BUFF_SIZE, section, pkg_info->field); \
-	if (buff_size < strlen(description) + SMALL_BUFF_SIZE + 1) { \
+	size_to_be_written = snprintf(aux, small_buff_size, section, pkg_info->field); \
+	if (size_to_be_written > small_buff_size) { \
+		aux = realloc(aux, size_to_be_written + 1); \
+		small_buff_size = size_to_be_written + 1; \
+		snprintf(aux, small_buff_size, section, pkg_info->field); \
+	} \
+	if (buff_size < strlen(description) + small_buff_size + 1) { \
 		description = realloc(description, buff_size * 2); \
 		buff_size *= 2; \
 	} \
 	strcat(description, aux); \
 }
+
 #define ADD_ARRAY(section, field) i = 0; if (pkg_info->field != NULL) { \
-	snprintf(aux, SMALL_BUFF_SIZE, section, pkg_info->field->array[i]); i++; \
-	if (buff_size < strlen(description) + SMALL_BUFF_SIZE + 1) { \
-		description = realloc(description, buff_size * 2); \
-		buff_size *= 2; \
-	} \
-	strcat(description, aux); \
+	ADD_STRING(section, field->array[i]); i++; \
 	while (pkg_info->field->array[i] != NULL) { \
-	snprintf(aux, SMALL_BUFF_SIZE, "\n%s", pkg_info->field->array[i]); i++; \
-		if (buff_size < strlen(description) + SMALL_BUFF_SIZE + 1) { \
-			description = realloc(description, buff_size * 2); \
-			buff_size *= 2; \
-		} \
-		strcat(description, aux); \
+		ADD_STRING("\n%s", field->array[i]); i++; \
 	} \
 }
 
@@ -41,7 +40,7 @@ vieter_package *vieter_package_init() {
 	return calloc(sizeof(vieter_package_info), 1);
 }
 
-vieter_package *vieter_package_read_archive(const char *pkg_path) {
+vieter_package_error vieter_package_read_archive(vieter_package *pkg, const char *pkg_path) {
 	struct archive *a = archive_read_new();
 	struct archive_entry *entry = archive_entry_new();
 
@@ -58,7 +57,7 @@ vieter_package *vieter_package_read_archive(const char *pkg_path) {
 
 	// Exit early if we weren't able to successfully open the archive for reading
 	if (r != ARCHIVE_OK) {
-		return NULL;
+		return vieter_package_unarchive_error;
 	}
 
 	int compression_code = archive_filter_code(a, 0);
@@ -104,7 +103,9 @@ vieter_package *vieter_package_read_archive(const char *pkg_path) {
 	struct stat stats;
 
 	if (stat(pkg_path, &stats) != 0) {
-		return NULL;
+		// errno is set if stat() fails; the calling function should check
+		// the value of errno in case vieter_package_stat_error is returned
+		return vieter_package_stat_error;
 	}
 
 	pkg_info->csize = stats.st_size;
@@ -112,31 +113,31 @@ vieter_package *vieter_package_read_archive(const char *pkg_path) {
 	archive_read_free(a);
 
 	// Create final return value
-	vieter_package *pkg = vieter_package_init();
 	pkg->path = strdup(pkg_path);
 	pkg->info = pkg_info;
 	pkg->files = files;
 	pkg->compression = compression_code;
 
-	return pkg;
+	return vieter_package_ok;
 }
 
 void vieter_package_sha256sum(vieter_package *pkg, char *res) {
 	FILE *f = fopen(pkg->path, "r");
-	fseek(f, 0, SEEK_END);
-	size_t size = ftell(f);
-	rewind(f);
-	unsigned char *in = malloc(size);
-	fread(in, 1, size, f);
-	fclose(f);
+	// Try to read 100KiB at a time
+	unsigned char *in = malloc(102400);
+	// Actual number of bytes read
+	size_t read_size;
 
-	unsigned char hash[32];
 	SHA256_CTX *ctx = malloc(sizeof(SHA256_CTX));
-
 	sha256_init(ctx);
-	sha256_update(ctx, in, size);
+	while ((read_size = fread(in, 1, 102400, f)) != 0) {
+		sha256_update(ctx, in, read_size);
+	}
+	unsigned char hash[SHA256_BLOCK_SIZE];
+
 	sha256_final(ctx, hash);
 
+	fclose(f);
 	free(in);
 	free(ctx);
 
@@ -147,8 +148,8 @@ void vieter_package_sha256sum(vieter_package *pkg, char *res) {
 	unsigned int half_byte = 0;
 	int j = 0;
 
-	// We advance in the string 2 bytes for every one byte of the hash
-	for (int i = 0; i < 32; i++) {
+	// We advance 2 bytes in the string for every one byte of the hash
+	for (int i = 0; i < SHA256_BLOCK_SIZE; i++) {
 		// We transform the first half byte into the second character to keep
 		// each byte from becoming reversed in the final string
 		half_byte = hash[i] & 0b1111;
@@ -170,19 +171,32 @@ void vieter_package_sha256sum(vieter_package *pkg, char *res) {
 	res[j] = '\0';
 }
 
+
+
 char *vieter_package_to_description(vieter_package *pkg) {
 	vieter_package_info *pkg_info = pkg->info;
 
 	size_t buff_size = 1024;
-	char aux[SMALL_BUFF_SIZE];
+	int small_buff_size = 128;
+	int size_to_be_written;
+	char *aux = malloc(sizeof(char) * small_buff_size);
 	char *description = malloc(sizeof(char) * buff_size);
 	// Helper variable for ADD_ARRAY macro
 	int i;
 
 	// special case for FILENAME
 	// assuming .pkg.tar.zst; other formats are valid, this should account for that
-	snprintf(aux, SMALL_BUFF_SIZE, "%%FILENAME%%\n%s-%s-%s.pkg.tar.zst", pkg_info->name,
+	size_to_be_written = snprintf(aux, small_buff_size, "%%FILENAME%%\n%s-%s-%s.pkg.tar.zst", pkg_info->name,
 			pkg_info->version, pkg_info->arch);
+
+	// We neither want to let an arbritrarily long input to overflow the buffer
+	// nor to truncate perfectly valid inputs
+	if (size_to_be_written > small_buff_size) {
+		aux = realloc(aux, size_to_be_written + 1);
+		small_buff_size = size_to_be_written + 1;
+		snprintf(aux, small_buff_size, "%%FILENAME%%\n%s-%s-%s.pkg.tar.zst", pkg_info->name,
+				pkg_info->version, pkg_info->arch);
+	}
 	strcpy(description, aux);
 
 	ADD_STRING("\n\n%%NAME%%\n%s", name);
@@ -193,11 +207,11 @@ char *vieter_package_to_description(vieter_package *pkg) {
 	ADD_STRING("\n\n%%CSIZE%%\n%ld", csize);
 	ADD_STRING("\n\n%%ISIZE%%\n%ld", size);
 
-	char checksum[65];
+	char checksum[SHA256_BLOCK_SIZE * 2 + 1];
 	vieter_package_sha256sum(pkg, checksum);
 
-	snprintf(aux, SMALL_BUFF_SIZE, "\n\n%%SHA256SUM%%\n%s", checksum);
-	if (buff_size < strlen(description) + SMALL_BUFF_SIZE + 1) {
+	snprintf(aux, small_buff_size, "\n\n%%SHA256SUM%%\n%s", checksum);
+	if (buff_size < strlen(description) + small_buff_size + 1) {
 		description = realloc(description, buff_size * 2);
 		buff_size *= 2;
 	}
@@ -216,8 +230,7 @@ char *vieter_package_to_description(vieter_package *pkg) {
 	ADD_ARRAY("\n\n%%MAKEDEPENDS%%\n%s", makedepends);
 	ADD_ARRAY("\n\n%%CHECKDEPENDS%%\n%s", checkdepends);
 
-	snprintf(aux, SMALL_BUFF_SIZE, "\n\n");
-	strcat(description, aux);
+	strcat(description, "\n\n");
 
 	return description;
 }

src/package/vieter_package_dynarray.c

@@ -12,12 +12,18 @@ void vieter_package_dynarray_add(vieter_package_dynarray *da, const char *s) {
 	// An empty vieter_package_dynarray does not have an allocated internal array yet
 	if (da->size == 0) {
 		da->array = malloc(sizeof(char*) * da->capacity);
+
+		// Initialise all char*'s to 0 so array[i] == NULL can be used to see if field is empty
+		memset(da->array, 0, sizeof(char*) * da->capacity);
 	}
 	// Double array size if it's full
 	else if (da->size == da->capacity) {
 		// if the realloc fails, access to memory in da->array is lost
 		da->array = realloc(da->array, sizeof(char*) * da->capacity * 2);
 		da->capacity *= 2;
+
+		// Same as the previous memset, but only for newly allocated pointers
+		memset(da->array + da->size, 0, sizeof(char*) * da->capacity / 2);
 	}
 	
 	da->array[da->size] = strdup(s);

test/package/test_package.c

@@ -39,8 +39,9 @@ void test_info_parse() {
 }
 
 void test_pkg_read_archive_files() {
-	vieter_package *pkg = vieter_package_read_archive("./test/package/xcursor-dmz-0.4.5-2-any.pkg.tar.zst");
-	TEST_ASSERT_(pkg != NULL, "failure parsing pkg archive");
+	vieter_package *pkg = vieter_package_init();
+	vieter_package_error e = vieter_package_read_archive(pkg, "./test/package/xcursor-dmz-0.4.5-2-any.pkg.tar.zst");
+	TEST_ASSERT_(e == vieter_package_ok, "failure parsing pkg archive");
 
 	FILE *f = fopen("./test/package/files", "r");
 	TEST_ASSERT_(f != NULL, "could not find test files file in ./test/package");
@@ -58,12 +59,12 @@ void test_pkg_read_archive_files() {
 	TEST_CHECK(pkg->compression = 14);
 
 	vieter_package_free(&pkg);
-
 }
 
 void test_pkg_read_archive_desc() {
-	vieter_package *pkg = vieter_package_read_archive("./test/package/xcursor-dmz-0.4.5-2-any.pkg.tar.zst");
-	TEST_ASSERT_(pkg != NULL, "failure parsing pkg archive");
+	vieter_package *pkg = vieter_package_init();
+	vieter_package_error e = vieter_package_read_archive(pkg, "./test/package/xcursor-dmz-0.4.5-2-any.pkg.tar.zst");
+	TEST_ASSERT_(e == vieter_package_ok, "failure parsing pkg archive");
 
 	char *description = vieter_package_to_description(pkg);