From 3c0422b998b73227f4eed3f5d6f4390bd2c827bc Mon Sep 17 00:00:00 2001
From: Jef Roosens <roosensjef@gmail.com>
Date: Sun, 20 Nov 2022 18:00:13 +0100
Subject: [PATCH] feat(package): first version of parse function in C

---
 src/package/c/package_info.c | 106 ++++++++++++++++++++++++++++++++++-
 src/package/c/package_info.h |   2 +-
 2 files changed, 106 insertions(+), 2 deletions(-)

diff --git a/src/package/c/package_info.c b/src/package/c/package_info.c
index a8959ff..79d8720 100644
--- a/src/package/c/package_info.c
+++ b/src/package/c/package_info.c
@@ -1,3 +1,5 @@
+#include <stdbool.h>
+
 #include "package_info.h"
 
 PkgInfo *package_info_init() {
@@ -41,6 +43,108 @@ void package_info_free(PkgInfo **ptp) {
 	*ptp = NULL;
 }
 
-void package_info_parse(PkgInfo *pkg_info, const char *pkg_info_str) {
+/**
+ * Advance the pointer until all spaces are skipped.
+ */
+static inline char *trim_spaces_front(char *ptr) {
+	while (ptr[0] == ' ') {
+		ptr++;
+	}
 
+	return ptr;
+}
+
+/**
+ * Given a string pointer in the middle of a string, move over all spaces in the
+ * given direction. The final space is replaced with a NULL-byte.
+ */
+static inline void trim_spaces_back(char *ptr) {
+	if (ptr[0] != ' ') {
+		return;
+	}
+
+	while (ptr[-1] == ' ') {
+		ptr--;
+	}
+
+	ptr[0] = '\0';
+}
+
+#define PKG_INFO_STRING(key, field) if (strcmp(key_ptr, key) == 0) { pkg_info->field = strdup(value_ptr); goto advance; }
+#define PKG_INFO_INT(key, field) if (strcmp(key_ptr, key) == 0) { pkg_info->field = atoi(value_ptr); goto advance; }
+#define PKG_INFO_ARRAY(key, field) if (strcmp(key_ptr, key) == 0) { dynarray_add(pkg_info->field, value_ptr); goto advance; }
+
+int package_info_parse(PkgInfo *pkg_info, char *pkg_info_str) {
+	char *offset_ptr, *equals_ptr, *key_ptr, *value_ptr;
+
+	bool end = false;
+
+	// Iterate over all lines in file
+	while (!end) {
+		// This pointer will always point to the final character of the
+		// current line, be it the position of a newline or the NULL byte at
+		// the end of the entire string
+		offset_ptr = strchr(pkg_info_str, '\n');
+
+		// We replace the newline with a NULL byte. Now we know the line runs
+		// until the next NULL byte.
+		if (offset_ptr != NULL) {
+			offset_ptr[0] = '\0';
+		} else {
+			// Advance pointer to the NULL byte of the string
+			offset_ptr = pkg_info_str + 1;
+
+			while (*offset_ptr != '\0') {
+				offset_ptr++;
+			}
+
+			end = true;
+		}
+
+		// Skip comment lines
+		if (pkg_info_str[0] == '#') {
+			goto advance;
+		}
+
+		equals_ptr = strchr(pkg_info_str, '=');
+
+		// If a line doesn't contain an equals sign, the file is invalid
+		if (equals_ptr == NULL) {
+			return 1;
+		}
+
+		// Trim whitespace from key
+		key_ptr = trim_spaces_front(pkg_info_str);
+		trim_spaces_back(equals_ptr - 1);
+
+		// Trim spaces from value
+		value_ptr = trim_spaces_front(equals_ptr + 1);
+		trim_spaces_back(offset_ptr - 1);
+
+		// Match key
+		PKG_INFO_STRING("pkgname", name);
+		PKG_INFO_STRING("pkgbase", base);
+		PKG_INFO_STRING("pkgver", version);
+		PKG_INFO_STRING("pkgdesc", description);
+		PKG_INFO_INT("size", size);
+		PKG_INFO_STRING("url", url);
+		PKG_INFO_STRING("arch", arch);
+		PKG_INFO_INT("builddate", build_date);
+		PKG_INFO_STRING("packager", packager);
+		PKG_INFO_STRING("pgpsig", pgpsig);
+		PKG_INFO_INT("pgpsigsize", pgpsigsize);
+		PKG_INFO_ARRAY("group", groups);
+		PKG_INFO_ARRAY("license", licenses);
+		PKG_INFO_ARRAY("replaces", replaces);
+		PKG_INFO_ARRAY("depend", depends);
+		PKG_INFO_ARRAY("optdepend", optdepends);
+		PKG_INFO_ARRAY("makedepend", makedepends);
+		PKG_INFO_ARRAY("checkdepend", checkdepends);
+
+advance:
+		pkg_info_str = offset_ptr + 1;
+		continue;
+	}
+
+	return 0;
 }
diff --git a/src/package/c/package_info.h b/src/package/c/package_info.h
index 7e16f4b..c3df790 100644
--- a/src/package/c/package_info.h
+++ b/src/package/c/package_info.h
@@ -33,7 +33,7 @@ typedef struct pkg_info {
 } PkgInfo;
 
 PkgInfo *package_info_init();
-void package_info_parse(PkgInfo *pkg_info, const char *pkg_info_str);
+int package_info_parse(PkgInfo *pkg_info, char *pkg_info_str);
 void package_info_free(PkgInfo **ptp);
 
 #endif